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HiltonSteve
21-05-2010, 02:33 AM
I have started work on something which I believe will be a big help to the many people out there who want to get into building their own CNC mill / router.

I am putting together a 3D CAD design for a router which will be able to be manufactured out of MDF and cheap materials to give people a starting point into this hobby or should I say obsession which some of us have!

Why am I doing this? Let me explain...

I am a time served BREL (British Rail) machinist with plenty of manual and CNC machining experience and always wanted a milling machine at home (like quite a few of us) so that I could 'make things!'. When I initially thought about building something I started hunting around the internet and it all seemed quite daunting and very complicated but the more I read and the more questions that I asked (especially on this forum!) the more I started to realize that it should not be too difficult to put something together. I began designing my machine which took about 2 weeks based around the help and advice that I had been given then 3 months later I had a finished working router.

But, i had a slight advantage which made life a lot easier....

I could do the drawings, I am a machinist by trade, I had a friend that had a manual bridgeport milling machine which i used to make a lot of my parts and I bought myself a lathe to make the rest. Oh and JohnS helped me out a bit.....!

So I now want to come up with a complete design and full set of drawings so that it will be possible for more or less anyone to put together a basic cnc router with as little difficulty as possible. I will be making the first machines myself to prove the designs and will tweak them along the way to fine tune them before any drawings or designs are released. I want to be happy with them first!

Also I will be prepared to either manufacture myself or get components made that people are struggling to make, not all the components but just the parts which will be difficult to make at home. How much will these cost? Not as much as you think! I am not here to earn a living from this just give people a chance to get started.

The design so far consists of a 18mm and 25mm MDF frame construction, M12 leadscrews all round with M12 plastic leadscrew nuts, homemade linear guide system. Steppers to be decided but probably 23's. I have a bit more to do on the design and still yet to build a working model so if anyone has any 'sensible' suggestions then my ears are open, just remember though that the key to this is to keep the price down, we are not looking for accuracy just a starting point for people to get going in CNC machining.

John S
21-05-2010, 09:05 AM
sOUNDS GOOD STEVE,
WHAT ABOUT THE ELECTRONICS ? You need something better than the CaPs LoCk button on this freeking keyboard.
Drivers seem to be the stumbling block to cost.

The all in 1 Chinese boards are not for beginners, in fact I don't know who they are aimed at unless it's belling electric fires ?
Roy's System 4 is a nice system but can't be called cheap for a start up MDF unit

HiltonSteve
21-05-2010, 09:25 AM
I hear what you are saying about the electronics and I do not know of a really cheap way of putting together a stepper controller system either. But if you do go with do go with one of Roy's system 4 boards then you would be looking at about 260 with a power supply which is not over expensive and this could be used with a bigger/better machine later on if needed.

Add on to this the cost of 3 steppers at 25-35 depending on where you get them from and what spec you want and you are up and running with the electronics for around 350.

Would a newbie CNC builder think 350 is expensive for a stepper motor and controller solution? I don't know! Are there any newbie's out there to answer this one for us??

Wobblybootie
21-05-2010, 10:36 AM
Nice thread, From my own point of view, yes 350 is a huge amount of money. Maybe my own personal situation is clouding things. There must be other folks out there who are finding finances tight but they may think differently about finding a few hundred pounds.

If I was to be totally honest with myself, I should walk away from CNC and take up stamp collecting. However I have never given up on a challenge yet and I do not intend to start now!! I have something like 50 a month to finance my build so its going to take a while!!

I will say I was close to wrapping my hand in and calling it a day but there are a couple of guys here who have helped me make a start and unless they request anonymity I shall name them later.

As to the electrics ... somewhere on this forum was a post by a guy who has a 3 axis machine running on a board he has built himself and sells it ready made or in kit form for around 60 ( http://www.planet-cnc.com ) I do not know enough about controllers etc to pass judgement here. So I do not know if it would be of use.

There are plenty of plans on the web many of them using MDF and skate bearings etc but then they end up using threaded rod which seems to lead to more anguish than pleasure.

If you can come up with something that is ' cheap ', can produce acceptable results and can enable guys to 'learn' then go for it.

I for one will be watching developments.

John S
21-05-2010, 12:24 PM
That Planet board is just the controller at 148 euros for the board and software, you still need drivers after that so basically the Planet board is virtually the same price as mach3.

Wobblybootie
21-05-2010, 12:32 PM
Sorry John, I must have misunderstood the website, but he does state.

"CNC motion controller is a link between personal computer and drivers for stepper motors. It uses USB port which is available on all modern computers and laptops. This is a complete (software/hardware) solution and it does NOT require any additional software (Mach3 is NOT needed)".

I assumed it was a complete package.

I will shut up in areas I have no experience.

John S
21-05-2010, 01:23 PM
Don't apologise or you will never learn anything,
it is confusing for a beginner to get all the building blocks of what is required into position.
I'll post later tonight , busy at the moment the kettle is playing up and that Bastard Smoking Monkey has forgot all about the hobnobs.

.

HiltonSteve
21-05-2010, 07:27 PM
Sorry John, been a bit busy this week and not had chance to call in. I did pick up a packet of Hobnobs but ate them on the way to Anglesey yesterday. Don't worry though, Tesco's have plenty more...

Had a good chat with John today on the phone about this project and as usual he has come up with quite few interesting idea's, mainly to help keep the cost down and still produce a reasonable quality machine. I will be looking into these a bit more over the next week before I go any further with the design as sourcing the right components at the right price can sometimes be a pain in the arse, but I am on it...

Wobbly, I hear what you are saying regarding the cost of the drivers and we may be able to come up with another option to reduce the price. They may not have all features or be of the same quality as the ones which you can get from Zapp or DIYCNC but they may work well as a starting point. Not promising anything at this stage but watch this space...

Just off down to B & Q to do a bit of component sourcing.

Quick question - what size bed / work area do you think would be acceptable, I was thinking that a bed of 400 x 300 would be ok but I am open to suggestions. We don't want to go too big though as that could create more problems and start pushing the price up.

Wobblybootie
21-05-2010, 09:09 PM
Wobbly, I hear what you are saying regarding the cost of the drivers and we may be able to come up with another option to reduce the price. They may not have all features or be of the same quality as the ones which you can get from Zapp or DIYCNC but they may work well as a starting point. Not promising anything at this stage but watch this space...

I do not want to sound ungrateful because I am not, :redface: I have the plans for a 1200 X 800 Gantry style machine and a 4' X 2' surface table to use as a base. I am not aiming to follow the plans to the letter and I may have to revise my own strategy. So I am open to all ideas, I know I have to walk (hobble) before I can run.

I appear to have interest in a product I could put together and I cannot afford to ignore the chance of income. :wink:

You can be sure of one thing ... I shall be following this thread closely and will make use of any and all the developments I can.

irving2008
21-05-2010, 11:23 PM
How about making it modular in structure so it can be expanded say over the range, say, 400/600/800/1000 x 300/450/600/750. If it is rigid enough as a 1000x750 design it can be scaled as needed.

John S
21-05-2010, 11:44 PM
Hang on , am I missing something here ?
Steve was on about doing a MDF starter machine so we are talking about simple slides and build and now people are throwing 1200 x 800 into the plot.

so MDF, drawer slides, simple 24 volt drivers at 1/2 stepping onto M12 screwed rod running 1200 x 800 or similar size for three pounds seventeen and sixpence.

Oh nearly forgot, it must be capable of 6 metres per minute cutting.

.

Wobblybootie
22-05-2010, 09:24 AM
John, Just because I said I was looking at a 1200 X 800 machine does not mean I am dismissing Steve's efforts. MDF I have, Threaded rod I have, so I can see no reason why I cannot follow his plan and learn from those who know what they are talking about!! In the meantime I can gather together the items for the larger machine.

I am looking at this (CNC) as a means to an end and not just a hobby. For years I have been unable to contribute anything but my War Pension to the household but with the help of an organisation called Combat Stress I have started to become somebody again. I cannot and will not ignore the possibility of making my family some extra income however small

With that said, Steve, crack on!! Whatever knowledge and experience I can gain from your hard work will be put to good use.

I shall now retire to my Sanger and put on my Flak Jacket and tin lid!!

HiltonSteve
22-05-2010, 10:44 AM
Making the design scalable may or may not be an option, depends what happens with the linear slides and what they end up being constructed from but I will know more next week.

As for the stepper controller, would there be any interest in a handheld controller that took away the need for a PC?

This is the initial description - The handheld controller will read from a USB memory stick and execute NC files with no need for a PC at all (however currently a PC is required to edit the pin config / steps per unit etc file which is then uploaded to the device using a memory stick) only a problem if you don't have a PC!!!!. It will also allow manual data entry via an inductive keypad and jogging of the machine. It uses a 3.5" colour TFT screen and is designed to plug into a 25 pin break out board. It uses a 100Mhz processor for stepper timing which should be more than enough.

I have already seen a prototype which works very well.

Estimated price - 200-250

It will look something like the attached image.

irving2008
22-05-2010, 11:03 AM
Its a nice idea Steve, but if this is CNC for beginners then my 2p is that this complicates things - the device you show is still only a controller, you still need the stepper drivers, and I would argue most who are interested in building a CNC machine have access to a PC.

I think concentrating the electronics side on either sourcing a cheap driver set or, complementing the intent of the design, a cheap, easy to build, set of drivers would be better value. There is a wealth of knowledge about EMC and MACH3 and, esp in the case of EMC, there are a lot of cheap PC available to run the free software. Indeed, for real low cost, EMC2 (free) on a PC sourced from eBay has got to be a better option - there's a good selection of P3 and P4 systems which would run EMC available for <100 and some as low as 30.

John S
22-05-2010, 11:15 AM
[FONT=Verdana][SIZE=2]which is then uploaded to the device using a memory stick) only a problem if you don't have a PC!!!!.


How the fook are you reading this then ?

Wobblybootie
22-05-2010, 11:52 AM
Steve, I know it would involve more work by yourself and those who could assist you but why not offer both the Pendant and the EMC2 options. Let the folks choose.

I for one like the idea of the Pendant (I am thinking of the dust problem which would not be so much of a worry for those who will be machining metals etc.) It may not be something I can implement straight off but to have the option would be great.

John S
22-05-2010, 12:16 PM
there's a good selection of P3 and P4 systems which would run EMC available for <100 and some as low as 30.

Agreed you only need to look around.

I just bought a stack of these for an average price of 38 and these were complete systems with TFT monitors and a licensed copy of XP

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170476010886

That's cheaper than a copy of XP. Nice thing was they were only 15 miles away so well worth the trip to collect and save shipping.

irving2008
22-05-2010, 12:27 PM
Agreed you only need to look around.

I just bought a stack of these for an average price of 38 and these were complete systems with TFT monitors and a licensed copy of XP

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170476010886

That's cheaper than a copy of XP. Nice thing was they were only 15 miles away so well worth the trip to collect and save shipping.And with XP SP2 going out of support now and Windows7 SP1 due soon, there will be a lot of ex-corporate desktops coming available in the next year, perfect for EMC2/Linux or MACH3/XP...

8iggles
24-05-2010, 08:09 PM
I hear what you are saying about the electronics and I do not know of a really cheap way of putting together a stepper controller system either. But if you do go with do go with one of Roy's system 4 boards then you would be looking at about 260 with a power supply which is not over expensive and this could be used with a bigger/better machine later on if needed.

Would a newbie CNC builder think 350 is expensive for a stepper motor and controller solution? I don't know! Are there any newbie's out there to answer this one for us??

Great thread, for me this is just what is needed, because a lot of people are enjoying this as their Hobby and are unlikely to have funds from a "bottomless pit" and wont be making "loads a money"

I finally took the plunge and went for a system 4 and also got the spindle board (but thats for later). I justified the cost to myself with the good reports I read on here, and the help thats available from Roy. Also this will be ok when I move on to bigger and better things much later

I've got mine up and running and cutting basic shapes out and drawing - But this is very time consuming because I'm still fascinated every time I see it running :)

I'm running with 10t timing pulleys and direct driving these through a short piece of rubber hose, just temp to get the feel of things and start to get to grips with cad- cam- code process

So my answer is yes its more expensive than the fleabay route, but the reputation for support and service that I will need when I reach the "brick wall" is by far is the best route for me :)

Cheers Shaun

Ross77
24-05-2010, 11:19 PM
I finally took the plunge and went for a system 4 and also got the spindle board (but thats for later). I justified the cost to myself with the good reports I read on here, and the help thats available from Roy. Also this will be OK when I move on to bigger and better things much later


I would agree that getting good drivers to start with is a good plan, and defiantly don't get bogged down with building some for a first machine (been there tried that). There is too much to do and just having smoother steeper drives really transformed my x-y table.
I got the 4.2amp with micro stepping from Gary(115 for 3 i think) There also optically isolated so I didn't bother with a BOB. cut one plug of a printer lead and hard wired it :whistling:

Like Shaun I justified the cost as A; they can be used on the next machine or B; used on more than one if the same motors and settings are used.

HiltonSteve
24-05-2010, 11:34 PM
Quick update.....

Been hunting around for a cheap off the shelf option for linear slides and to be honest I am struggling, everything I have found comes at a cost which I think for what we are trying to achieve is too expensive. But I have another plan, ordered today some engineering plastic from a company I deal with and I am going to try and make a very simple but hopefully very cheap alternative. Will let you know how I get on when I have tried it, I know it will work but not sure how well yet...

Some of you may find my next bit of news interesting...

A stepper controller at the right price...! I have decided to go with 17 size steppers for this project now because it reduces the costs all round and takes a big chunk out of the total build cost, using 17 size steppers also means we do not need powerful drivers and I think that I have come up with just the thing. See details below...

Oh, and they are made in the UK!

Motor Outputs


3 x Allegro A4983 Microstepping Stepper motor controller (fixed at 1.5 amps 8th stepping)

Some features of the driver IC's

• Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)
• Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection

Outputs


1 x 12vdc output for laser / external relay or contractor rated at max 500ma.
2 x 6a relays rated for 230vac.


Connections


It requires a PSU minimum 4 amp 2.5mm laptop type connector. (an old laptop power supply will be suitable)
1 x male DB25 connector (for connection to parallel port, cable not supplied)
1 x female DB9 connector (to breakout unused parallel port connections, for limits etc)
1 x 6 way Phoenix screw clamp connector (for E-Stop input, and outputs)
3 x 4 way Phoenix screw less connector ( for X, Y & Z axis motor connections)


Enclosure

The system is enclosed within an all Aluminium enclosure for maximum heat dissipation and RF shielding. In the top of the enclosure is a 12vdc fan to provide active cooling of the driver IC's
Dimensions Height, Width, Depth = 55mm x 100mm x 120mm

Cost will be around 120-130 so hopefully this will be of more interest to the people on a tight budget.

irving2008
24-05-2010, 11:51 PM
Thats going to limit you to motors with around 1Nm of torque, which motors did you have in mind? there are some NEMA23 motors that will fit the bill at 1.4A capability.

I dont know what you plan with the slides, but you need to focus on keeping the friction low if you are using small motors..

HiltonSteve
25-05-2010, 12:17 AM
Thats going to limit you to motors with around 1Nm of torque, which motors did you have in mind? there are some NEMA23 motors that will fit the bill at 1.4A capability.

I dont know what you plan with the slides, but you need to focus on keeping the friction low if you are using small motors..

I hear what you are saying about the linear slides which is why I want to try a few different idea's using the engineering plastic for the linear bearings and silver steel as guide rails, lets just see how I get on!

The reason for using the controller together with 17Nm motors is because I have seen it working on a small machine with very good results, have a look at the image below.

If anyone is interested then I know where you can buy these machines fully assembled and ready to go, cost price 450. All you will need is a stepper controller as per the one I have listed above and you will be away. They are also made in the UK.

Before you ask I do not have any technical info on the machines but if anyone is interested then PM me and I will pass your details on.

irving2008
25-05-2010, 12:18 AM
Is that one of the Marchant Dice ones?

HiltonSteve
25-05-2010, 12:22 AM
Is that one of the Marchant Dice ones?

No!

Designed and made in Derby, and not by me or John before you ask!

Zephyr
25-05-2010, 01:17 PM
I'd like to say that I think this idea is brilliant and just what I needed.

I was just about to start a new thread about a newbie being in a difficult position - especially one with practically no machining experience, no previous knowledge of G-code or CNC, no machine-filled workshop and very little money to spend etc.. I include the contents here so you can see where I'm coming from.

-----------

"I've designed a machine and think it should do what I want (machining hard-wood). It's a moving gantry type and will have a working area of X=610mm Y=900mm Z=200mm.

I don't have a workshop so I either have to pay people to make the parts for me or buy a ready-made machine or a kit.

The prices of new ready-mades are high (money is another problem of course) and none that I've seen have the Z-axis travel that I need. In short, I need a machine to make my machine.

I'd welcome any suggestions about this as I'm sure others have this problem. Would anyone want to make parts for me, does anyone have a machine for sale or know where I can get one (or a kit) at a reasonable cost?"

-----------

I've reached pensionable age without a half-decent pension so I'm doing this because I need to earn money. I plan to make wood items and (hopefully) sell them at craft fairs around the Berwick upon Tweed area where I now live. (I'm from Nottingham so I know many of the places mentioned in posts).

The machine I want to build will eventually have to make long parts and this is why I want a large size although I could start with one smaller and then, maybe, scale it up.

My thoughts are that 1 Nm motors will be too small (for my sized machine) but I accept that using larger size 3Nm will increase the cost.

I was also thinking of using Roys drivers and BOB because they seem to be reliable and the last thing I want as a newbie is an unreliable driver problem to sort out. There are too many problems for a novice like me and I need to reduce the potential for problems. Personally I would want a driver system that would control the larger 3Nm motors.

In answer to HiltonSteve's question, I think 350 is a reasonable price to pay for something (electronics) that will probably work and not give problems but I know other people might find that price too high.

Like Wobblybootie I want something I can afford and that works.

I'm not sure about using threaded-rod for leadscrews though as I think this would produce too many accuracy problems.

I hope me throwing my 3pennorth in helps. If you want to ask anything please do. I'm filling up with enthusiasm and hope again - after getting despondent about all the complexities of this project.

I use Ubuntu GNU-Linux and also EMC2 (both free of cost) and it seems to work very well in simulation mode. I use QCAD and recommend this as a cheap yet execellent 2D package (the book that came with it was essential for a novice like me). I don't use MSWindows so any expensive Windows-only software is out.

It's good when someone with experience offers his knowledge and help to people like me with very little experience but a definite need and a lot of enthusiasm - and I appreciate this.


Sorry if this is a bit rambling. I'm normally a bit more logical than this but it is a long, exciting thread - and I think it's got wings.

Regards,


Keith.

Robin Hewitt
25-05-2010, 03:18 PM
Been hunting around for a cheap off the shelf option for linear slides and to be honest I am struggling

Have you looked at the DryLin slides from RS? Only vaguely grot, low profile, easy to mount and cheap as chips.

HiltonSteve
25-05-2010, 10:08 PM
Have you looked at the DryLin slides from RS? Only vaguely grot, low profile, easy to mount and cheap as chips.

Yes Robin, I have been looking at these and I have a few samples from the IGUS man who called in a few weeks back. What I can't work out is which will be most suitable though as when I start guessing at the loads that they will be needing to take then it push's me towards the heavier ones which start to get expensive. Go to the IGUS website and there is a product selector there, have a play and see what results you get.

irving2008
26-05-2010, 12:10 AM
Loads wont be that high. more critical is friction. By way of example, using four 10mm W-series (2 x WS-10,500, 2 x WJ200UM-01-10, 2 x WJ200UM-01-10 LL) spaced 100mm apart on 500mm long rails 250mm apart for a gantry where the drive is central and the cutting force approx 50mm above the bearings. A 15Kg gantry accelerating at 10m/s^2 will need 200N of force to overcome friction- thats about a third of what you'll get from a 1Nm motor on a 12x3mm screw, and will be ok on wear for 15years continuous running (at a max speed of 900mm/min)!

Thats 80 approx for rails and carriages (RS prices)

Wobblybootie
26-05-2010, 08:20 AM
I think the IGUS 'N' series may come out a little cheaper but I am not sure how mounting the gantry to them would work. The holes / clearance do not appear that big (well, I know what I mean)

Robin Hewitt
26-05-2010, 10:36 AM
Okay, hows about put the gantry on rollers? A pair of widely spaced ball bearings at either end riunning on a steel bar glued to the base, plus one sprung roller between each pair to hold it down.

To hold it square, a similar arrangement, turned through 90 degrees and close to the screw.

Wouldn't work so good for the Y but it fixes the big axis and gets your overall cost down.

You'd need some powerful springs which would want to bend the MDF, but an iron inclusion would fix that. Goodbye friction :smile:

mel_earp
26-05-2010, 03:23 PM
OK - this is from the perspective of someone who hasn't built anything, but I have read loads. When I had some time to look at my potential router, I looked up and down the cost scale of every option I could find for the slides. The cheapest of all was drawer slides, but clearly not good enough.

It seems to me that you are on the path to re-invent the skate bearing on angle solution. You can see them all over the place. Here is just one example, albeit a crude one with the skate carriages riding on round rails - er pipes actually. Most examples ride on inverted angle.

With a set of 8 bearings at a fiver or less, this is pretty cheap and low friction.

8iggles
27-05-2010, 07:35 AM
Skate bearings have to be the best all round DIY solution for me, low cost, the effectiveness of them, 8mm shaft.....the tubing is a little harder to find (for free) I'm up to 38 skate bearings now with 4 more shortly on the drive reduction

Another thing that has worked well for me is the 12mm threaded rod across the table as this way only needs sides making - crude but easy to adjust and mount things from etc

Cheers Shaun

HiltonSteve
27-05-2010, 09:37 PM
Right, I have been listening to what everyone is saying and after looking at the IGUS slides again I have decided to go with the Drylin N 27mm version, this is mainly for ease of assembly and they should be more than up to the job. At RS prices it will cost around the 80 mark for everything which is 12 carriages and 2m of rail, these are at RS prices so I should be able to get it cheaper after I speak to my IGUS man in the morning. This may seem expensive to some but you have to bear in mind the lack of skill and tools that will be required to get your linear rails sorted which are a very important component.

I know the skate bearing idea will work out cheaper but for a first time builder I am not so sure that it is the way to go, using the igus drylin N will make assembly so much easier and I have got a cunning plan as to how it will fit in with the design and a simple way to mount it...

Also been thinking about the leadscrews and may go for M12 trapezoidal (depending on the cost) with some simple anti-backlash plastic nuts. May cost a little more than standard M12 threaded bar but I think that the benefits will outweigh the cost.

17 size steppers should come in at around 10-12 each so total build cost is not looking too bad.

MDF will either be 18mm or 25mm, not sure yet until I get something drawn up and see what fits best but hoping that 18mm will be good enough.

Table size looks like it will end up at 500mm x 300mm with 2 rails on the X and Y axis as this way all the linear rail will be used without any waste, the remaining 400mm can be cut in half and used for the Z.

I think at this stage I need to get the design done and get something made to see how it performs, enough talking about it, lets get something put together and see what happens. Yes there will be issues but we have to make a machine to find them, some of the issues will have to be acceptable for a low cost machine but I want to get it as good and as simple as possible for a reasonable build cost.

Drawing tonight/tomorrow so will get the designs up on here when I have something to show you all.

irving2008
27-05-2010, 10:37 PM
Are you proposing fixed gantry/moving table or a moving gantry? If the expected workpiece is relatively lightweight (small amount of MDF, balsa wood, PCBs, etc.) I'd suggest a moving table design gives more bang for the buck so to speak. A moving gantry is going to be quite a lot heavier, harder to make rigid and will limit the performance with a small motor.

I concur on the 12x3 trapezoidal. Its not so expensive and even without an antibacklash nut will give a better result than M12 rod.

What about the spindle? Dremmel or something meatier?

Oh and on the stepper drivers, came across these (http://www.virtualvillage.co.uk/stepper-motor-controller-driver-006408-001.html)... no idea how good or what chip, was thinking about getting one to find out but at 8.99/channel.... They also do a cheap (30) 27v/13A PSU (http://www.virtualvillage.co.uk/27v-dc-13a-110-220v-switching-power-supply-008030-014.html)

HiltonSteve
27-05-2010, 11:24 PM
I was thinking of going for a moving table as like you say it will give more bang for buck and the design should end up simpler which is what we are aiming for.

Spindle - will probably go with a dremel to start with as I happen to have a couple kicking around and they should suit what we will be cutting, there are plenty of dremel's on ebay and also copies for not a lot of money so it makes sense to go down that road. I will design it with the option to put something meatier on there but I really don't think it will be suitable for an entry level type machine but then again you never know!

Just checked out those stepper drivers and they don't look too bad, especially for 8.99. Has anyone ever had a go with one of these before?

John S
27-05-2010, 11:48 PM
Had a quick look, can't see how to adjust motor amperage, resistors ? and they are probably unipolar for that money.
Worth sending for a couple of handfuls though just to play with.

HiltonSteve
27-05-2010, 11:56 PM
Thinking about the trapezoidal again, just changed my mind and now going for M10 x 2mm. A little bit cheaper and no micro-stepping drivers needed.

1 stepper motor rev = 200 steps @ 2mm pitch means 1 step = 0.01mm - I know you can state whatever steps per unit you want to in mach3 but this way it will keep it simpler for the beginners...

Starting to talk in numbers and equations like Irving now!

HiltonSteve
28-05-2010, 12:14 AM
Had a quick look, can't see how to adjust motor amperage, resistors ? and they are probably unipolar for that money.
Worth sending for a couple of handfuls though just to play with.

Bi-polar John, just found some on ebay - http://cgi.ebay.co.uk/Stepper-Motor-Controller-Driver-Board-Bipolar-Dual-Mode-/270584173748?cmd=ViewItem&pt=LH_DefaultDomain_3&hash=item3f0012d4b4

John S
28-05-2010, 12:27 AM
Virtual village UK - rho
From Hong Kong

He's me thinking it was the village down the road ?
.

HiltonSteve
28-05-2010, 12:35 AM
Virtual village UK - rho
From Hong Kong

He's me thinking it was the village down the road ?
.

Not on your own.....

HiltonSteve
29-05-2010, 11:37 PM
Been playing with a few idea's and I have attached a quick render and also a 3D PDF file to help you understand what I am thinking.

To open the PDF you may need the latest Adobe reader V9 (free to download), you will be able to spin it round, zoom in and out and take it apart. Easier than doing loads of drawings from various angles.

I have used the IGUS N profile 27mm for all the slides, not 100% sure that this is the way to go though.

This is just a concept drawing, 18mm MDF all round and I have tried to make everything as close to actual size as possible so that I can get an idea of how it will fit together.

Anyway take a look and let me know your thoughts, I have a few things that I am not happy with but it would be interesting to get some more opinions.

Lee Roberts
30-05-2010, 04:14 AM
Hi Steve,

It’s looking good, I’ve not replied but I’m following :).

I think one thing that sticks out as a possible concern to me is that, when I built my rockcliff machine the 13x13” Y Table (the bit you put your work on):

2218

Started to bend and go banana shaped in a very short amount of time. I did have an unnecessary pocket along the length and I think this helped it on its journey to becoming banana like. My concern is that yours may do the same, an option to stiffen it all up maybe to add some ribs under the table the same shape as the Y Axis ball screw floating end plate in your model.

I would prefer if the machine was a flying gantry type as well, if you think about it the design at the moment needs a bigger foot print then if it was done as a flying gantry type.

So I’m thinking, take off the support footer for each of the gantry side plates, mount them at each end of the Y Table (possibly even double them up), use two lengths of MDF that run underneath/in-between the rails and Y Axis plate, this would then hopefully give you the clearance for the ribs.

Just my observations mate, what do I know :confused:

O nice Z Axis design as well, i like it :cool:

Zephyr
31-05-2010, 11:25 AM
I have a suggestion about sealing MDF.

As most of us know from experience (there are a lot of MDF 'bananas' around), MDF is hygroscopic and will absorb moisture from the air. If it absorbs water from the air unevenly and/or the MDF sheet is not a uniform thickness it will warp. Sealing it all over against moisture absorption could be the answer to preventing it warping.

One sealant could be plain old boiled linseed oil which, if put on correctly will polymerize like plastic and it’s also a little flexible as well. It's also cheap.

Clean the dust of the MDF. Round off any sharp corners if possible.

The first coat can be boiled linseed oil diluted 50:50 with turpentine or white spirit put on fairly quickly (to prevent warping). Wipe it on with a cloth and leave to dry (supported on blocks) in moving air away from heat or direct sun.

2nd coat can be 75% boiled linseed oil 25% turps. wiped on quickly with a cloth. Don’t leave pools or surplus on the surface - they won’t dry properly and won’t polymerize.

These 2 diluted oil coats will go into the MDF and provide a better key for the next coats.

Next use neat linseed oil wiped on with a cloth and again taking care to remove any surplus. The MDF should then be fairly well sealed but the more coats you put on the more effective and long lasting the seal will be. 3 or 4 more coats at least of neat linseed oil wouldn’t go amiss.

I know it’s time-consuming but people without much money to spare would rather spend their time and it’s low tech.

Don't seal moisture inside damp MDF. Make sure it's as dry as possible and the ambient air isn't humid either.

A very light sanding with fine glass paper between coats will help to key the coats but vacuum-clean the dust off.

Remember safety. Wear rubber gloves, don’t breathe in the fumes or dust, dispose of oily cloths safely - either in a bucket of water or wash them out thoroughly and dry them outside. Oil-soaked cloths are a potential fire hazard.

I'm not suggesting you try this on an important or complex part. Try it on a test piece first.

I hope this helps and that I'm not 'teaching people how to suck eggs'. Let me know if I am and I'll shut up. If anyone tries it I'd be interested in how well it worked for them.

Regards.

John S
31-05-2010, 11:41 AM
What about the waterproof versions of MDF for critical components. ?

Robin Hewitt
31-05-2010, 12:38 PM
What about the waterproof versions of MDF for critical components. ?

Steve, up on our industrial estate, makes custom furniture to fit your house using MDF and wood mouldings. He always uses a green coloured variety of MDF because he can't afford to have it warping.

Wobblybootie
31-05-2010, 12:46 PM
That sounds interesting ... Fancy a stroll along there if the weather is nice Robin? ... :whistling:

Only joking ... I shall google and ask a chippie type contact for further info.

pjl83
02-06-2010, 10:30 PM
With a set of 8 bearings at a fiver or less, this is pretty cheap and low friction.

Can I ask where you found this price? I was looking at the "piece of angle skate" option but couldn't find a price like this??

Thanks
Paul

irving2008
02-06-2010, 10:56 PM
Can I ask where you found this price? I was looking at the "piece of angle skate" option but couldn't find a price like this??

Thanks
PaulTry here (http://www.vapourised.com/product.asp?pid=23430&1=1&node=38&sizeFilter=)... how good they are I dont know... or good old fleabay (http://cgi.ebay.co.uk/608-ZZ-METAL-SHIELDED-BEARING-SKATE-BEARING-PACK-8-/320316813754)

HiltonSteve
03-06-2010, 10:43 AM
Has anyone ever built any of these skate bearing linear guides and had decent results?

Just don't like the look of them but not had any experience with them either.

mel_earp
03-06-2010, 12:32 PM
The cheapest I have ever seen is 2.99 (http://cgi.ebay.co.uk/10-x-608-2RS-QUALITY-SKATEBOARD-BEARINGS-8x22x7mm-/310144192157?cmd=ViewItem&pt=UK_Sporting_Goods_Skateboarding_Skating_ET&hash=item483608ce9d) and that is for 10. Obviously you are not going to get top quality for that price, but I bought a set for a fiver for something other than CNC and they work just fine (light duty) - smooth as silk and no play.

I haven't tried skate carriages, but I go on what people write and look for majority views and counter views. On the US CNCZone (http://www.cnczone.com/forums/index.php) there are dozens of builds using this method and many look really good for a cheap build. I am quite surprised no-one here has chirped up to say they have done it. Also, the original buildyourowncnc (http://buildyourcnc.com/latest.aspx) uses this method, but they have changed to V-Groove bearings. Those videos might be of help to you. Some bits look a bit crude, but there is also some good stuff.

pjl83
03-06-2010, 03:35 PM
Thanks,

I've found some in Nottingham on fleabay. I contacted the guy and I can go and fetch them :) That way I can see what they're like before I bye and also save on shipping!

Ross77
03-06-2010, 11:32 PM
Has anyone ever built any of these skate bearing linear guides and had decent results?

Just don't like the look of them but not had any experience with them either.

Hi Steve, interesting project. You must have plenty of spare time :smile:

I've not used the skate bear guides but share your concern. To me the results would seem to be heavily depend on the workmanship and there could potentially be a lot of alignment issues:eek: (the poor results might put off some beginners)

What I do know is that the twin 25mm unsupported rails that I was going to use for my mill used a solid bronze bush on 1 side and 2 opposing skate bearings on the other and it always seems notchy when they are adjusted up tight. The solid bushing was silky smooth tho.

I know that unsupported rail are always shot down because they flex but considering the aim of this project and the small spans I'm sure it would be the best option to balance ease of use, cost and performance. There is the option for solid bushing or ball bearings that would provide the flexibility required.

With regard to using mdf, when I used to work for a car audio shop we built lots of custom Sub boxes and it was always apparent how much stronger the structure was when the joints were routed, glued and screwed so I would defiantly recommend this form of construction. if you dont mind me interfering I can help with options for stiffening the bed to keep Lee happy :heehee: (easy. dont remove a big chunk of material at max bending:rofl:)

Better shut up now, later

Wobblybootie
04-06-2010, 07:44 AM
Another method that appears to be popular when joining MDF at 90deg is to use the 'Brass' rods and screws, as used in beds (the kind you sleep in) ...

Robin Hewitt
04-06-2010, 12:51 PM
Just a thought :naughty:

If you are going to use skate bearings why not use good old hexagon bar stock to beef up your bearing faces?

mel_earp
04-06-2010, 06:40 PM
Good idea. With the more usual angle configuration you end up having to mount the carriage on a 45 deg chamfer of some description. With this, you get the bearings at 60 deg and a flat on top/bottom. to mount the carriage.

With the bearings being at 60 deg, they would be best run on round or hex rail rather than 90 deg angle.

Also, does this mean that you are going to have to drill and tap the bar stock to fit the bearings? No big deal for you guys, but might not suite a beginner.

irving2008
04-06-2010, 08:48 PM
Good idea. With the more usual angle configuration you end up having to mount the carriage on a 45 deg chamfer of some description. With this, you get the bearings at 60 deg and a flat on top/bottom. to mount the carriage.

With the bearings being at 60 deg, they would be best run on round or hex rail rather than 90 deg angle.

Also, does this mean that you are going to have to drill and tap the bar stock to fit the bearings? No big deal for you guys, but might not suite a beginner.I'll refer you back to the first post "Also I will be prepared to either manufacture myself or get components made that people are struggling to make, not all the components but just the parts which will be difficult to make at home. How much will these cost? Not as much as you think! I am not here to earn a living from this just give people a chance to get started." This would be a good example of where others could help out. However even a beginner would benefit from investing a few quid in a cheap drill press adaptor (http://cgi.ebay.co.uk/VERTICAL-DRILL-PRESS-ADAPTOR-BOLTS-ONTO-WORKBENCH-/290440785297) to get a bit of accuracy! Drilling and tapping hex bar stock wouldn't be that difficult.

mel_earp
04-06-2010, 09:27 PM
I understand the points you make Irving. If the target audience is the beginner then surely it is worth taking the views of the beginner - and I am totally a beginner who has made nothing CNC, just read a lot. From my perspective wood is good and metal is difficult (can't think of a suitable rhyme). For others it will be different and they will prefer metal to wood.

The common skate carriage is easily made because in the basic form you saw a bit off, drill four holes and bolt the bits together. As you go more complex then more chance of error or frustration.

And I do have a drill press.

Wobblybootie
04-06-2010, 10:00 PM
However even a beginner would benefit from investing a few quid in a cheap drill press adaptor (http://cgi.ebay.co.uk/VERTICAL-DRILL-PRESS-ADAPTOR-BOLTS-ONTO-WORKBENCH-/290440785297) to get a bit of accuracy! Drilling and tapping hex bar stock wouldn't be that difficult.

Careful ... SWMBO bought me one of those from B&Q... the 43mm euro collar would not grip a 43mm drill with a piece of 240 grit paper wrapped around it and also the casting was 3deg. off centre. It may have been a Friday afternoon special, but Wolf or Draper offer better quality (for a price)

pjl83
04-06-2010, 10:15 PM
I've been thinking about my own build plans and how I'm going to run the bed. I'm considering the skate method as it's simple and cheap. I then thought about using v-groove bearings and running them directly on top of a piece of angle. My sketch-up skills aren't great but hopefully you get the idea. It would be a moving bed with the top bearings attached to the gantry. It's only an idea I had today so they may be obviously floors that I'd not considered yet but it may be worth experimenting with?

http://i175.photobucket.com/albums/w131/pjl83/vgrooveguide.jpg

HiltonSteve
07-06-2010, 11:45 PM
Sorry not replied for a while but I am up to my nuts in other jobs that needs to be done before I get time to play, one of them being fitting a new bathroom... seemed like a good idea at the time..!

Anyway, I should get a few hours at it again later this week so fingers crossed and keep the idea's coming because there are a few good one's in there.

Can anyone put tiles up??? only a couple of hundred.... will keep you fed with tea and hobnobs... Give me some time to do something that I enjoy doing instead.

irving2008
08-06-2010, 12:00 AM
Off topic - Ah, I take it you've not done one of those before :) there's always a first time... never (in my book at least) a second one... this time i got a couple of nice Polish guys, nicknamed Radish and Leek (thats my nearest pronounciation of their names) who did a blinding job in a week that would have taken me months (plumbing, tiling, electrical - I can do it, just not as quickly) and that included keeping building control happy...

John S
08-06-2010, 12:52 AM
and that included keeping building control happy...

Never managed that............................

Lee Roberts
08-06-2010, 01:59 AM
Heheh i'm in the middle of doing my bath room Steve, need another 3 box's and im done!

Robin Hewitt
08-06-2010, 10:50 AM
seemed like a good idea at the time..

A good idea to you or to her? There is a way out.

I am a disaster at home improvements, paint flies everywhere, she'd never ask me to do tiling.

She used to make me do car repairs in the cold and rain, eventually I put the car together without the head gasket, gritted my teeth and turned the key. Cost me 600 for new valves but she never asked me to do car repairs again. Money well spent.

irving2008
08-06-2010, 11:00 AM
...I put the car together without the head gasket, gritted my teeth and turned the key. Cost me 600 for new valves but she never asked me to do car repairs again. Money well spent.Sorry, I couldnt ever do that to a car... thats sacrilege! Although working on cars in the rain is something I do try to avoid, I do recall changing the gearbox on my 1965 Triumph TR4 in 6" of snow... mad or what?

Robin Hewitt
08-06-2010, 11:16 AM
Sorry, I couldnt ever do that to a car... thats sacrilege!

But I don't drive bird magnets like you do, this was utilitarian.

I hate driving, bores me to tears :rolleyes:

John S
08-06-2010, 12:58 PM
Wots a bird magnet ?

How many can you get in a 3 tonne truck ?

Unless you can get a full size set of gas bottles into a vehicle without struggling, it's a waste of road tax.

Wobblybootie
14-06-2010, 11:20 AM
I was sent this link to look at as a method of using telescopic drawer slides for linear guides ... I must admit I had not thought of using them like this ... http://imagebin.ca/img/tt45r26C.jpg It may be worth considering, but I will leave it up to those with superior knowledge to pass judgement ...

michael
22-06-2010, 09:52 PM
Is that one of the Marchant Dice ones?

Cheeky b*stard. No it is not!!!!!!!!!!!!!!!!

michael
22-06-2010, 09:55 PM
No!

Designed and made in Derby, and not by me or John before you ask!

Have I been gone that long everyone thinks i'm dead??? John, Steve, Lee????

irving2008
22-06-2010, 10:13 PM
Have I been gone that long everyone thinks i'm dead??? John, Steve, Lee????

I hear knocking... Is there someone there???:eek:

welcome back... it seems a while... lol

John S
22-06-2010, 11:03 PM
Yup.............

.

cartman1973
01-07-2010, 09:18 PM
As a bewildered newbie I would just like to voice my support for this project - and from my perspective the original proposed target cost of approx 350 seems reasonable, particularly if we can spread it out as we build the router over time. Thanks for your work on this and I wait with excited impatience to see how it turns out, and the chance to be a guinea pig builder for you...

gorbo
17-08-2010, 11:37 PM
I am also a newbie and I expect that when I build my machine it will cost me 1000+ because I want it as good as I can get it, when you consider this is done over a year its not to bad, some hobbies cost money, a lot of money that's the way it is but having said that, if someone can build a good machine below 1000 please give me your tips!!

Robin Hewitt
18-08-2010, 12:04 AM
if someone can build a good machine below 1000 please give me your tips!!

A "good machine", as in 'commercial', would have a cast iron gantry.

If you don't have chums at the foundry, a cheap alternative would be box section iron filled with concrete and don't be mean with the cement when you mix it.

Heavy kills vibration, concrete resists bending when you load it.

1 pound force will accelerate a mass of 32.16 lbs at 1 ft/s/s.
1 Newton will accelerate a mass of 1kg at 1 m/s/s
A 1Nm motor on to a 5mm pitch screw will give you 125N thrust.

John51
30-10-2010, 01:39 AM
Hi all, this is my 3rd revival of interest in cnc, story so far: That's cool but it's expensive, interest wanes. That's cool and doesn't have to be expensive but it's complex, interest wanes. Maybe I could make a few bob from this, interest rises. lol

Someone that knows someone close to you looks at something produced on YOUR cnc machine and says... I want one...how much? When this happens, all of our expense is justified. iow, it's not the making of a few bob that is the priority, it's the being able to use the motive of making a few bob in order to do what you wanted to do anyway that is important. Cue Douglas Adams and the software that gives you reasons for getting whatever it is that you want. (I've forgotten what that software is called.) :)

So what does this machine make that other people want? I think this has to be decided first.

Whatever newbie machine is being designed, it has to make stuff that other people want or there is not much point to doing it, might as well build a toy robot that only does somersaults or buy a Lego Mindstorms.

So what can this cheapo newbie machine make?

[btw, I hope that I'm not being seen as negative, I think that it's a great idea.]

John51
30-10-2010, 01:48 AM
Not yet familiar with the site, the pic is of a 95 milling work table that looks like it could do with a couple of stepper motors, there's your X-Y axis. Choose a corner of the workshop with 2 load bearing walls, build a strong shelf for the work table and add a cross section for the Z axis up above. Just a thought.

CraigRK
06-05-2012, 09:14 AM
Sorry not replied for a while but I am up to my nuts in other jobs that needs to be done before I get time to play, one of them being fitting a new bathroom... seemed like a good idea at the time..!

Anyway, I should get a few hours at it again later this week so fingers crossed and keep the idea's coming because there are a few good one's in there.

Can anyone put tiles up??? only a couple of hundred.... will keep you fed with tea and hobnobs... Give me some time to do something that I enjoy doing instead.

So, is that bathroom done yet? has this made any progress?

HiltonSteve
10-06-2012, 11:02 AM
So, is that bathroom done yet? has this made any progress?

Bathroom done...

And new single storey extension on the back of the house together with a new kitchen. The next time the wife comes up with one of these ideas then I must either talk her out of it or pack a case for her.

Thrown everything out the workshop so it no longer looks like a builders merchants and swept the floor, you can now walk round without breaking your ankle...

May look at getting something moving again on this one, but the one thing that stopped me before apart from the DIY was people saying that it was too expensive. Building any cnc machine is time consuming and will mean you having to put your hand in your pocket a few times but look at it as in investment, I made a few small plaques out of a bit of oak last week which took me a couple of hours, sold them for 120...😊

Not just about making money but also learning something along the way.

What sort of price for building a small MDF machine do you think is reasonable?

Tenson
10-06-2012, 02:42 PM
What exactly is wrong with the all in one boards for a beginner machine? It works great on my CNC3040, although I realize it is slow.

Oops, I didn't realize this thread was 9 pages long I only read the first one!

Jonathan
10-06-2012, 03:33 PM
What exactly is wrong with the all in one boards for a beginner machine?

http://www.mycncuk.com/forums/showthread.php/1373-eBay-TB6560-Stepper-Motor-Driver-Boards

For a 'beginner machine' clearly they serve a useful introductory purpose, however having used both performance wise there's just no comparison. I guess the risk is people may be put off CNC all-together by the poorer performance and faults if they occur.

Briefly, most of the all-in-one boards I've seen (TB6560 is a good example) use either one or two single ICs which contain the 8 MOSFETs required to drive a stepper motor in bi-polar configuration. The good single drivers use 8 individual MOSFETs, which has numerous advantages. The main one is all these H-bridge ICs tend to have much lower voltage ratings which very severely limits performance, so people often try to push them outside the ratings resulting in premature failure. Often they are sold with cheap stepper motors that have a high inductance, so actually require an even greater voltage. In addition to this the current ratings are generally lower - I don't think there are any available which will deliver the 4.2A required for a 3Nm stepper motor, so again the torque can be limited unless the machine/motors are small.
For single MOSFETs there's a much greater choice available, so you can get ones with better ratings which helps to lower the heat dissipation and other useful characteristics. A significant advantage is the controller has full control over the switching of the 8-MOSFETs - this makes it possible to add features such as resonance damping and vector current control which improve high-speed torque, so you get more torque from the same motor.

Clearly there's no definitive answer, each machine is different...but in general I wouldn't advise getting them.