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Heliox
30-12-2017, 01:13 AM
Hi Guys

My first post.
I have limited budget but like most people would like to get best bang for my buck (actually pounds).

I want to cut glassfibre and carbon fibre sheet up to 5-8 mm.

Various timber up to 25mm (ply, mdf, some hardwoods)

I would also like to cut Aluminium upto 30mm (nothing too fancy just brackets for 22-25mm tubes).

I have relatively good experience at various engineering and workshop skills so am not put off self building.

However I do not know much about CNC builds other than some basics from trawling the web. (which brought me here)
My Budget is around £500-700

I quite like the look of this machine https://www.youtube.com/watch?v=6g0k9oSLejQ
But there is limited info on it.

I am looking at these two items to buy:
http://www.ebay.co.uk/itm/Revolutionary-CNC-Kit-4-Axis-3-5A-M335-Stepper-Drivers-4x-Nema23-1-26Nm-Motors/391789465219?hash=item5b3878ce83:g:ieQAAOSwP4ZZwxp L

or

http://www.ebay.co.uk/itm/Cnc-Kit-3-Axis-Tb6560-Stepper-Motor-Driver-Mill-Router-Nema-23-Motor-24V10A-Psu/401363174854?epid=8005008379&hash=item5d731c05c6:g:LVoAAOSwhYdZ2y6u

The spindle:
https://www.ebay.co.uk/itm/EU-STOCK-2-2KW-Square-Air-Cooled-Spindle-Motor-ER20-220V-for-CNC-Router-Milling/262986503302?hash=item3d3b379486:g:dS8AAOSwuMZZGX~ J

or

http://www.ebay.co.uk/itm/EU-Quality-2-2KW-Air-cooled-spindle-motor-ER20-24000rpm-80mm-for-CNC-Router/253335154227?hash=item3afbf3ae33:g:BKUAAOSwuk1Zu4L 3

Would this spindle be good powerful enough to do what I want? and those driver packages and stepper motors how suitable are they or are there better options, I see some are using arduinos but that package including motors seem reasonable?

Any recommendations on design,,,,,(I'd like to build as big as possible)
I was looking at the Ox on youtube and elsewhere but unsure what design would be best and where to start from here?

Sam0117
31-12-2017, 07:27 PM
Hey Heliox

Welcome to the forum

I’m not very experienced in building a cnc router and currently under the design stage an when I’m done will put it up to be judged lol from what I’ve ne reading an researching, I think your budget might need to stretch abit more if your looking to do aluminium aswell, there’s plenty of people who can refer you to contacts to get parts cheaper an deals, also don’t order your electronics until your design in in place as things will change and you don’t want to be stuck with parts you’ve brought that aren’t no good,

The design your looking at if you go onto the guys channel he has got a build log to give you a better understanding of his design, and I believe them Nema motors your looking at are too small nM wise, I think they would suit a 3D printer more, the standard seems to be 3nM or more from what I’ve read.

With regards to the spindle water cooled is the best option, for the amount of noise a air cooled produces and at low speeds might not cool the spindle efficient enough, again people can give you contacts to sort that for you with a vfd to go with it, best thing is start with your design and there’s plenty of sticky threads to help with your design an then go from there.

Again I’m not a expert but there are a lot on here so just thought I’d give you a few things from what I’ve been looking at and reading, looking forward to seeing what you design

All the best

Neale
31-12-2017, 07:52 PM
Those kits look attractive, but are underpowered (low-torque steppers, low voltage PSU, inadequate drivers) and the TB6560-based version also has the problem that all the electronics is integrated on to one board so when one of the drivers goes pop (these versions do...) you have to scrap the lot.

The electronics is not the right place to start. Although you have talked about the materials you would like to cut, you haven't mentioned cutting area which is a major design driver. And although everyone would like to cut aluminium, that's a big step in rigidity and accuracy over and above what's needed for wood.

Give a bit more detail on your machine needs, and look through the build logs on this site. It's a bit of a trawl through a lot of threads, but there's a good chance that someone has built a machine similar to the one you would like, and that will give you a realistic idea of the art of the possible. Lightweight commercially- or kit-built machines might work for you, but they also have limitations and you need to go down that route with your eyes open. I'm not saying don't, just be aware of the compromises you are making and decide realistically if that's for you.

Ask questions and listen to the answers - there's a lot of experience on this site from people happy to help.

Just as a stake in the ground, thinking about budget - my roughly 1500x750 cutting area machine that will probably tackle aluminium although only used for wood so far cost around £2500 in materials, ballscrews, guide rails, electronics, etc. It all depends on where and how you source materials and your own machining and assembly skills and facilities.

But good luck - it's great fun building a machine like this! Just be realistic :smile:

Desertboy
31-12-2017, 08:48 PM
You're not going to do it on your budget sorry to tell you this, it's depressing I know and I thought I could build one on a budget and I got a lot of stuff for almost nothing including the frame and it still cost £1500

You need a vfd for the spindles they won't work without it.

I'd say neale's right £2500 is the zone I had to work real hard and had a lot of luck to get mine to £1500 some things are not worth wasting money on like those motors and drivers you linked to other things you can scrimp on get a $5 BOB for now, make your PSU, beg a cheap table to put it on. But don't cheap ass the drivers, the frame, the slides, the motors or the ballscrews as these can;t be upgraded easily without the first ones having little resale value. Also 10mm pitch ballscrews, don't make my mistake Heliox 01-01-2018, 11:33 AM Hey Heliox Welcome to the forum I think your budget might need to stretch abit more if your looking to do aluminium aswell, there’s plenty of people who can refer you to contacts to get parts cheaper an deals, also don’t order your electronics until your design in in place as things will change and you don’t want to be stuck with parts you’ve brought that aren’t no good, go onto the guys channel he has got a build log to give you a better understanding of his design, and I believe them Nema motors your looking at are too small nM wise, I think they would suit a 3D printer more, the standard seems to be 3nM or more from what I’ve read. With regards to the spindle water cooled is the best option, again people can give you contacts to sort that for you with a vfd to go with it Sam, Thanks alot for that input, I'm a good listener, and what you said makes sense. Those kits look attractive, but are underpowered .............The electronics is not the right place to start. Although you have talked about the materials you would like to cut, you haven't mentioned cutting area which is a major design driver. And although everyone would like to cut aluminium, that's a big step in rigidity and accuracy over and above what's needed for wood. You need to go down that route with your eyes open. I'm not saying don't, just be aware of the compromises you are making and decide realistically if that's for you. Ask questions and listen to the answers - there's a lot of experience on this site from people happy to help. Just as a stake in the ground, thinking about budget - my roughly 1500x750 cutting area machine so far cost around £2500 But good luck - it's great fun building a machine like this! Just be realistic :smile: You're not going to do it on your budget sorry to tell you this, it still cost £1500 You need a vfd for the spindles they won't work without it. I'd say neale's right £2500 is the zone I had to work real hard and had a lot of luck to get mine to £1500 some things are not worth wasting money on like those motors and drivers you linked to other things you can scrimp on get a$5 BOB for now, make your PSU, beg a cheap table to put it on. But don't cheap ass the drivers, the frame, the slides, the motors or the ballscrews as these can;t be upgraded easily without the first ones having little resale value.

Also 10mm pitch ballscrews, don't make my mistake

Guys already Iv'e made some some design decisions, I am only going to cut card, I won't bother with any electronics, card will be 2mm thick, work size 300mm x 300mm.............aye, Iv'e already got the kit for that, a good stanley knife and my right hand :yahoo: I'll spend the other 499 quid on Ibuprofen and beers to aid the repetitive strain syndrome I'll have lol.

o.k Jokes aside, I get it, and I don't believe in reinventing the wheel after receiving good advice so thanks all.

o.k here goes.

my main desire/requirement right now is to cut carbon or GRP plates, and likely never to be above 3mm thick. (though I assume if it were 30mm thick I would just need more tool passes, not a stronger machine) So realistically from what you guys say, if I get sidetracked from that objective to wanting to cut Aluminium and wood etc then I am looking at bigger costs.

(I do want to keep cost down as this is a startup venture with one specific material to cut to my designs).

1. work size will be approx 1000 x 600mm, I am open to change on this for cost effectiveness, the components will not be wider than 250mm square so having a 1000 x 600mm CNC I reckon I can produce 4-6 at a time. but if it were more cost effective to build 2 machines that cut 2 at a time I would do that, not that I intend to, but for example If I only could cut one at a time, then I only need a machine that will cut 250mm square 3mm plunge into carbon fibre plate, so I am open to changing the size depending on cost, if I have to run the machine twice to produce 3 parts, 4 parts,,5,6,7 etc so be it.

So because I would like to batch produce these components, if I could do 20 in a day I'd be happy. and that will determine machine size.
But it seems a waste to limit my machine to just 250mm square 3mm carbon fibre plates if with a little extra grunt and money I could build something capable of more.

2. forget cutting aluminium (I'll have to build or buy another machine in the future.....shame that:whistle:

3. water cooled spindle,,,,,,,,,,whats a VFD?........variable frequency drive ? i.e speed controller?

4. decent nema motors (even if I oversize them to able to use on another machine).......how do you calculate the nM required, what is the relationship between the force and table size? I guess the longer and wider the ball screw and hardness of materials being cut to travel speed determines the motor force needed? but how do you decide or calculate it,,,,yes I could copy another design for that but is there some rule of thumb?

5. What's a $5 BOB? 6. I already got a Table, it is an old school classroom table, 1" steel legs/frame and a formica type top bolted to it, I can attach my machine to that. This forum needs a glossary for us noobs ;-) Thanks for the input guys. Desertboy 01-01-2018, 12:15 PM Sam, Thanks alot for that input, I'm a good listener, and what you said makes sense. 3. water cooled spindle,,,,,,,,,,whats a VFD?........variable frequency drive ? i.e speed controller? 4. decent nema motors (even if I oversize them to able to use on another machine).......how do you calculate the nM required, what is the relationship between the force and table size? I guess the longer and wider the ball screw and hardness of materials being cut to travel speed determines the motor force needed? but how do you decide or calculate it,,,,yes I could copy another design for that but is there some rule of thumb? 5. What's a$5 BOB?

6. I already got a Table, it is an old school classroom table, 1" steel legs/frame and a formica type top bolted to it, I can attach my machine to that.

This forum needs a glossary for us noobs ;-)

Thanks for the input guys.

Can you weld? Or do you know someone who can and will for free. This will save you a lot of money.

You will need slides
https://www.ebay.co.uk/itm/15-1500mm-2x-Linear-Guideway-Rail-4x-Square-Type-Bearing-Block-GOOD-PRESTIGE/192385680153?epid=894797018&hash=item2ccb148319:g:7ioAAOSwyi9aJP-x
This is the cheapest I've found them and I have this exact set very happy with them, you will not find them cheaper than this new.

You will need a drive as well, ballscrew is your best choice here Ebay is your friend but expect £250 and maybe some import tax.

3. Variable frequency drive it's a inverter that drives the spindle. Spindles are not running 240v single phase they are 3 phase and need the VFD to drive them you cannot connect a spindle directly to either single phase of 3 phase otherwise you get the magic smoke. Water cooled spindle are much quieter if you need a water pump pay postage I'll send you one for free I have a box of them. £200 for spindle with VFD.

4. Everyone seems to go for 3nm Nema 23's ~£30 a motor, I have 2nm on my machine £20 a motor. You definitely don't want less than 2nm.

5. Breakout board to connect to parallel port on a PC, this means you need a desktop PC to drive the machine but it's the cheapest possible way (Yes even cheaper than arduino)

Think about how your going to control the machine you can buy Mach 3 £200 or use linuxcnc free I chose linuxcnc ;) You need to generate Gcode for the machine most of us are using fusion 360 for this but there's many ways of doing it depending on the job.

I understand the need to cheap ass it I really do I would never have built my machine if I knew what it would cost lol but I'm so glad I did. The best thing you can do first is learn! Read people diaries ask questions. If the job you have for it is profitable you can probably find someone on here to make them for you and still make money giving you a cnc fund ;)

Don't get put off by the cost because in the end the cost will seem nothing to amount of work you have to put in lol, there's a reason we all take 3-9 months to build our machines the first time it's a lot of work when you include what you have to learn.

But once you've done it you're in a special club for sadists that only members can ever understand lol.

It's also highly addictive ;) Most of us on this site would rather get 2 3m lengths of 25mm Hiwin's with carriages for Xmas than a new Iphone, which is the way it should be to ;

Now I built one I can say you build must start in cad! I thought I could build one without cad I was so wrong lol I was being idle. I could have worked it out on paper but damn it would have be sadistic and expensive with mistakes.

Neale
01-01-2018, 02:20 PM
1.That's a good size. Big enough to be useful, but not so big that you start to give significant construction issues. It's not really worth going much smaller unless you have to because of lack of space. The finished machine will end up around 300mm bigger than the cutting area in each dimension (give or take a bit).

2. By keeping the size down, you can get reasonable strength again without going to anything too ambitious by way of construction. You might end up with something that can cut aluminium with care.

3. As said, water cooling means that the spindle is quieter, and can run for hours without problem. So can air-cooling, but you need to be a bit more careful about dust management so that it doesn't clog. You are right about VFD. Generally these can be controlled manually via the front panel or connected to your control box for software control of start/stop/speed.

4. There are some spreadsheets on this site which will allow you to calculate the exact motor spec required. However, to be pragmatic about it, the answer for this general class of machine is NEMA23, 3Nm or 4Nm. Might as well go for the more powerful as there is barely any cost difference. Don't go for cheap eBay motors as these are generally high-inductance and for various reasons this is a bad thing!

5. BOB is break-out board, and functionally it is a kind of junction box that takes the connections from your PC parallel port and makes it easy to connect the stepper motor drivers and things like emergency stop buttons and limit switches (for end-of-travel detection). It does a little more than that (like provide isolation between PC and drivers for protection of one from t'other) and might also provide the signals you need to control the VFD but if you think of it as a junction box, you won't be far wrong. There are really cheap BOBs that will do the job. However, they assume that you are using a parallel port on your PC and a lot of modern PCs don't have these although you can add them via an add-on interface card. That brings up questions of Mach3/Windows, or LinuxCNC. That's another whole story but not really one that needs too much thought at this stage. There are other alternatives which complicate the story as well - we'll leave that one for now!

6. You will be astonished at how fast and how violently a decent machine can shake itself around. Even if you are not doing fancy 3D carving (and you will be able to) even things like boring holes involve frequent and rapid direction changes. That table will hold the machine while static but it's going to need quite a bit of bracing to handle dynamic loads.

Keep asking. Don't get upset if you get your leg pulled from time to time. Goes with the turf! But you'll get plenty of useful info as well.

Clive S
01-01-2018, 04:43 PM
What Neale has said.
Plus:-

You could go with supported rails but if you do you will wish you had gone of proper profile rails, although 15mm rails will do and are plenty strong enough the 20mm are much easier to mount and are not much different in price.

For a machine that size I would go with ally profile 90x45 The holes in the ends of them can be tapped M12 use two pieces for the gantry arranged in an L config and three for the main frame with ally end plates 20mm thick. Check out Joe Harris on here and see his vids all built with simple hand tools.

Start a build log to keep all the questions in one place

Heliox
01-01-2018, 09:32 PM
Can you weld? Or do you know someone who can and will for free. This will save you a lot of money.

You will need slides
https://www.ebay.co.uk/itm/15-1500mm-2x-Linear-Guideway-Rail-4x-Square-Type-Bearing-Block-GOOD-PRESTIGE/192385680153?epid=894797018&hash=item2ccb148319:g:7ioAAOSwyi9aJP-x
This is the cheapest I've found them and I have this exact set very happy with them, you will not find them cheaper than this new.

You will need a drive as well, ballscrew is your best choice here Ebay is your friend but expect £250 and maybe some import tax.

3. Variable frequency drive it's a inverter that drives the spindle. Spindles are not running 240v single phase they are 3 phase and need the VFD to drive them you cannot connect a spindle directly to either single phase of 3 phase otherwise you get the magic smoke. Water cooled spindle are much quieter if you need a water pump pay postage I'll send you one for free I have a box of them. £200 for spindle with VFD.

4. Everyone seems to go for 3nm Nema 23's ~£30 a motor, I have 2nm on my machine £20 a motor. You definitely don't want less than 2nm.

5. Breakout board to connect to parallel port on a PC, this means you need a desktop PC to drive the machine but it's the cheapest possible way (Yes even cheaper than arduino)

Think about how your going to control the machine you can buy Mach 3 £200 or use linuxcnc free I chose linuxcnc ;) You need to generate Gcode for the machine most of us are using fusion 360 for this but there's many ways of doing it depending on the job.

The best thing you can do first is learn! Read people diaries ask questions. If the job you have for it is profitable you can probably find someone on here to make them for you and still make money giving you a cnc fund ;)

But once you've done it you're in a special club for sadists that only members can ever understand lol.

It's also highly addictive ;) Most of us on this site would rather get 2 3m lengths of 25mm Hiwin's with carriages for Xmas than a new Iphone, which is the way it should be to ;

Now I built one I can say you build must start in cad! I thought I could build one without cad I was so wrong lol I was being idle. I could have worked it out on paper but damn it would have be sadistic and expensive with mistakes.

1.That's a good size. Big enough to be useful, but not so big that you start to give significant construction issues.

3. As said, water cooling means that the spindle is quieter, and can run for hours without problem. So can air-cooling, but you need to be a bit more careful about dust management so that it doesn't clog.

4. to be pragmatic about it, NEMA23, 3Nm or 4Nm. Might as well go for the more powerful.

6. You will be astonished at how fast and how violently a decent machine can shake itself around. That table will hold the machine while static but it's going to need quite a bit of bracing to handle dynamic loads.

Keep asking. Don't get upset if you get your leg pulled from time to time. Goes with the turf! But you'll get plenty of useful info as well.

What Neale has said.
Plus:-

You could go with supported rails but if you do you will wish you had gone of proper profile rails, although 15mm rails will do and are plenty strong enough the 20mm are much easier to mount and are not much different in price.

For a machine that size I would go with ally profile 90x45 The holes in the ends of them can be tapped M12 use two pieces for the gantry arranged in an L config and three for the main frame with ally end plates 20mm thick. Check out Joe Harris on here and see his vids all built with simple hand tools.

Start a build log to keep all the questions in one place

Guys what can I say, thanks I'm off to a flying start already with all those suggestions, many thanks.

re: preferring Hiwins to a new Iphone,,,lol,,,I totally get that angle ;-)

You've thrown me with the "can you weld" question? I can as it happens (I used to be a coded welding inspector offshore, among other things) but can't think what you'd be welding on a CNC machine, unless your talking about welding some of the Ali (or Steel) sheets/brackets/side plates? And to be honest I'd probably get someone else to do it as I haven't in a long time, other than a bit of mig and stick on various bit's in the workshop. (oh and I don't have roof on my workshop at the moment).

Software: I have been using Sketchup for a number of years, so no issues with a bit of CAD, I was about to download Fusion 360 a few days ago, haven't got round to it yet, but I did see you can use it free as a small business or hobbyist/student so that's good.
I also downloaded a few weeks ago a plugin for sketchup that produces G code 'SketchuCam'
I got that here http://phlatforum.com/xenforo/

Re: The controller/PC,,,,,,it just so happens I scrounged a windows XP (or vista) desktop tower off my father in law about 3 yrs ago, and funny enough I wanted it for the parallel port as I have an old laptop with a parallel port that I use to send files to a large A0 A1 printer plotter I bought off eBay a few years ago, the laptop screen is dodgy sometimes so I got the tower for that as backup,,,it's sat in the box just in case but I took it out a few days ago and powered it all up,,with the intention of possibly using it as a dedicated CNC computer, but I also bought a 3d Printer last week that I thought I might use it dedicated for that too. (Tronxy x5s, not arrived yet).

BOB's,,,,,,,,,,familiar with the concept of them, and why opto isolation etc.

Re: the table and how violent the machines can be, I get that Neale and agree with you, many moons ago I worked installing multitool CNC machines in Cosworth in Northampton and I also worked for Sony in Bridgend and Festo pnuematics, so I totally get where your coming from re: the forces, In fact anyone who has had a run-off with a decent hand held plunge router knows when you bolt something like that down and start cutting things there's alot to go wrong and fly about and all round alot of harnessed energy. (I'd thought about bolting the table down, adding a decent slab of something on top to give it a bit more mass and some form of diagonal bracing and beefing up the legs).

Dust management,,,,,mmmm yes that has been in the back of my mind as an issue, not for clogging a spindle but just the sheer pain in the rear factor of capturing it all, I have an axminster dust extractor for a Jet table saw, but extracting carbon fibre dust is going to be a different ball game, I'm contemplating a glass fibre wet tray into the design so the parts are submerged in water during the cutting, something similar to a wet tile cutting machine, has anyone seen anything like that on a CNC on this forum?

I see you all recommend the linear profile rails opposed to the round supported rails, why is this? are the profile rails less susceptible to play? or wear? less vibration? what's the negative issue with the round supported rails?

Sam0117
01-01-2018, 10:31 PM
if you can weld then making a cnc out of steel would be an advantage as welds are stronger than fixing with bolts an nuts, if you do use ally then people tend to bolt them, I think it personal preference, I know you said you have a table to use as a base so you could weld extra supports to brace an sniffen it.

As to regards to designing your cnc in a cad program before you get to building, I’m currently doing it and I’m getting all my demensions off the net, ie rail sizes and block diemensions, so the information is out there just obvious you have to draw each part in your cad program, I’m not sure if you can find them as a open source design and just put them into your design, I’m using solidworks so don’t know if I could attach what I have to help you out design wise. As soon as I’m finished with mine I’ll let you have a look lol

The linear rails are better as they take more load and has massive advantage over the supported rails, there are videos that compare the two if you want to see why, the main thing that made me choose linear rails is there more accurate and have a lot less play the the blocks, again I’m still learning but the price difference it’ll be silly to go cheap on a key parts like rails, ball screws an spindle as there not easy to upgrade in the future.

I hope this helps and looking forward to seeing what you come up with, I’m still along way from getting my build log off the ground

Heliox
01-01-2018, 11:28 PM
Sounds good to me.
I'll go watch the videos on the rail comparisons.

re:welding, my only concern is steel is very difficult to weld and maintain high tolerances, for instance creating a right angle between two pieces of steel, after you have prepped and clamped into position, then welded and cooled down, you might end up with 88 degrees instead of 90, most things that doesnt matter, but if you then wanted a true 90 deg out of it you'd have to machine faces.

I think that is why Ali extrusions are desirable as they are made to high tolerance and obviously adjustable to square up.

Maybe there are welded CNC machines on here, I'll take a look out of interest. But unless there are huge advantages I'd be prefer to bolt together, and maybe weld the odd bracket if needed.

Desertboy
02-01-2018, 03:45 AM
Cad models aren't so bad, you can download dxf's from KJN aluminium if using aluminium profile, Hiwin cad models are available from their website make sure you get the right model (It's the carriages you have to watch mostly) I never cad the ballscrews out I just did the maths using the datasheets but you could cad them if needed the thread is irrelevant. I certainly never picked up a pair of verneirs during my build lol

The information you need on the ballscrews are on the datasheets for BK12/BF12 and dsg16 if using 16mm ballscrews.

Further to what clive said about 15mm being harder to mount you need spacers see below.

23525

also greasing 15mm rails is also a PITA.

If you have trouble finding cad models grabcad is good but I always grab the models directly from manufacturer or reseller if I can as accuracy is important.

Lots of people makes their frames from welded steel box section and then use epoxy resin to level the box section where you fit the linear slides. Steel is a lot cheaper than aluminium extrusion, it's also popular to mix steel everything with an aluminium extrusion gantry which is my plan for my next build.

There's £600+ in aluminium and fittings in my router if I'd paid retail for it and I have 120cm * 70cm travel. You could certainly do something in steel a lot cheaper than that and of course it's stronger.

Accuracy with a steel a frame is nowhere as important as you think depending on how you fit the hiwin's the most important thing is they are level and parallel to each other. I'm going to weld mine together myself but have the steel cut by someone else (Who will be super accurate and square) to make things easier then you need a level working space and so decent magnetic clamps should be fine.

This is a quick mockup I did in fusion 360 for my next router, see how I'm planning to mix steel with extrusion. The cost of those 2 pieces of 9090 extrusion is £240 alone! My design is a nightmare because I want the Hiwin's sideways on so the frame does have to be very accurate and epoxy levelling for the Hiwin's will be difficult as I'll have to turn the router 90° to level each side. Mount the Hiwin's on top and you can don't need the frame to nearly as accurate.

23526

That's not a ballscrew it's a cylinder I extruded with BK fitting's I downloaded the important bit is the DSG ballnut housing as this is your mounting point.

Prices add up quickly I've spent over £80 just on T nuts to fit the Hiwin's to the extrusion and M4, M5, M6, M8 & M12 bolts. If you use corners it becomes even more expensive.

Heliox
02-01-2018, 09:49 AM
Ah ha,,,,,welding now it makes sense.

I see now, yes for sure if your including a frame there would be alot of welding, and I see that shimming out the rails with epoxy etc will give you the alignment accuracy where needed.

Lot of interesting points in your post, I'll digest that some more later.

Out of interest why are you choosing to mount the rails on the side rather than on top? is there an advantage or is it to do with working width?

Also to reduce materials; at a cursory glance if you wanted side mount rails I wonder if you would gain strength and reduce flexing movements by putting those rails on the inside of the frame?
(Though no doubt you'd probably lose some working width).

Clive S
02-01-2018, 10:48 AM
Also to reduce materials; at a cursory glance if you wanted side mount rails I wonder if you would gain strength and reduce flexing movements by putting those rails on the inside of the frame?
(Though no doubt you'd probably lose some working width).

If you go the steel route mount the rails on the top as it is much easier, the way the epoxy works is that you make a moat on the two rails with a bridge between them this way the epoxy will flow around and give you the flat plane you require.

You use the very slow curing epoxy made by Wests 205 - 109 fluid for about 8 hours.

Search of the forum for epoxy levelling 23527

Heliox
02-01-2018, 12:46 PM
Thanks Clive

I would have thought there are other benefits to mounting the rails on top too, like the slider bearing are being worn either side rather than all the weight and action being applied to topside...................Although it is probably negligible over time anyway.

I like the Frame, neat job, is it 75mm box section your using or is that 100mm? ( I was trying to guess from the clamps and mdf).

Epoxy, I haven't specifically looked yet but I did see some where making Epoxy square pads, but what you have done there is much better, less chance of the epoxy shattering with long strips like that too as opposed to isolated squares.

I got a load of Epoxy here...and I guess besides a slow cure pre warming will make it like water to get the level, in fact you can get laminating epoxy which is quite thin and you buy the slow activator...(I repair boats occasionally). I buy from East Coast Fibreglass supplies, and CFS fibreglass suppliers.

How are you sealing the MDF mould to stop the Epoxy running out underneath? have you stuck it down with a grab adhesive or some sealant?

I make grp moulds occasionally and I use modelling clay (the GRP suppliers sell it) to make fillets around edge. you never see square edges with GRP parts, always rounded,,and it is done with modelling clay and a wooden spatula,,,or finger to make smooth radius. (Though in the case of what you have done there it wouldn't be applicable because the radius would create a lip in the epoxy down the edge). Anyhow just thought I'd pass that on as the clay is handy for various temporary shaping and sealing once you have used it for that kind of thing.

Some polyurethane glue like gorilla glue, or even an expanding foam gun would make a good seal too,and be easy to peel off afterwards.

Clive S
02-01-2018, 01:10 PM
My frame is made out of 60x60x5 box, what is not shown is the table bed as that is adjustable in that it can be moved to different positions but in reality I have never moved it.23528

I sealed it with decorators caulk the epoxy is 5mm thick it came from East Coast Fibreglass. You have to be very careful with the sealing. It was left for about 8 days before removing the mdf

Heliox
02-01-2018, 02:24 PM
Looks Grand!

I did notice in the last photo, the bolt holes for adjusting the bed height.

Those side plates look Beefy, I can just make out you have them rebated into the bottom plate, is there a fillet weld along sides too I think I can make one out in the photo, or is just bolted?

Desertboy
02-01-2018, 03:09 PM
My frame is made out of 60x60x5 box, what is not shown is the table bed as that is adjustable in that it can be moved to different positions but in reality I have never moved it.23528

I sealed it with decorators caulk the epoxy is 5mm thick it came from East Coast Fibreglass. You have to be very careful with the sealing. It was left for about 8 days before removing the mdf

That's a damned nice machine there

Clive S
02-01-2018, 04:17 PM
Looks Grand!

I did notice in the last photo, the bolt holes for adjusting the bed height.

Those side plates look Beefy, I can just make out you have them rebated into the bottom plate, is there a fillet weld along sides too I think I can make one out in the photo, or is just bolted?

The bed sits on angle that is bolt through the holes if you bolt the bed directly to the frame you would pull the sides in.
But as I said its never been moved.

Heliox
02-01-2018, 07:12 PM
The bed sits on angle that is bolt through the holes if you bolt the bed directly to the frame you would pull the sides in.
But as I said its never been moved.

Sorry Clive, my question was about the polished Aluminium side plates on the Gantry being rebated into their bottom plates, is it bolted and welded or just bolted?

(I just carried on from talking about the adjustable bed and should have worded it better).

Clive S
02-01-2018, 10:57 PM
Sorry Clive, my question was about the polished Aluminium side plates on the Gantry being rebated into their bottom plates, is it bolted and welded or just bolted?

Ok some pics: 2352923530\pi

The two cross beams are 60x60x5 with 12mm plate welded on the ends then they were machined both front faces & top and bottom also the ends were machined parallel with each other at a local engineers.

The front plate is ecocast 20mm screwed to the two beams.

The gantry sides are 20mm rebated into the bottom plate. There are 4x M12 bolts to fix each box section to the side

mekanik
03-01-2018, 09:30 AM
That's a cracking build Clive

Clive S
03-01-2018, 09:45 AM
That's a cracking build Clive

Thanks, I could never have done it without drawing in CAD first and with the help of this forum:yahoo:

Heliox
05-01-2018, 08:48 PM
Thanks Clive.

That for sure looks solid. I think I'll be here a few weeks reading through all the posts :dog: