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Grit monkey
02-10-2013, 11:17 PM
Hi all,

I'm a joiner by trade and have always been interested in working with wood/Alu but sadly don't have a workshop at the moment.
Knowing that the router is the most versatile tool in any woodworkers (power)tool arsenal, but most things have to be jigged(lack of space for jigs), I decided I'd like to try my hand with a bench mounted CNC router. I have a "box room" upstairs which, at the moment is used for a bit of storage, which can be used for a bench mounted machine.

Now, I don't think I'd have any trouble with designing a self build, the hardest part (before I actually turn on a machine) would be learning how to use the drawing programs (I'm currently "trying" to teach myself draftsight).

I would like an aluminium machine to cut down on the weight, given that it would be located upstairs. I've read quite a few threads and notice that the vast majority try stay away from aluminium, preferring steel due to its superior rigidity. I also realise that lots of members say that cost is also an issue (what is saved on steel over alloy more to spend on better components), but I'm quite lucky that I have a good friend who works for a local stockholder, so procurement of materials should be ok.

My idea initially for a strong rigid alloy base (yes, I can already hear you chuckling to yourselves lol) is to build a torsion box and have another friend who is coded, weld it all together, then to make sure it is perfectly flat, it's then back to friend 1 and his contacts to have the box surface ground on both top and bottom (just like sending a piece of wood through a planer thicknesser really).

I also have the blessing of SWMBO for this project, she has even told me she was going to buy one of the Chinese 3020 outfits from a well known auction site!

Anyway, I feel I've waffled on enough for now, I just hope that you are all as welcoming when I'm bending your ears with stuff that I feel I may be out of my depth with(hopefully in the very near future).

Martin.

mekanik
03-10-2013, 11:02 AM
Hi Martin welcome to the forum.
If you give the guys an idea of the table size/working area you are looking for they will be able to set you on the right path, also go to the build logs and have a read, i am a noob to so can't offer much in the way of assistance but if Jazz pops in he might have a better idea if your ally frame is going to move following welding, you are very fortunate have the facilities you mentioned and i can't see a problem but others know better, are you living in a detached property ? could get a bit noisy.
Good luck
Mike

Grit monkey
03-10-2013, 07:10 PM
Hi Mike,

Thanks for the welcome.
I meant to say the maximum footprint last night, why I didn't I don't really know! The absolute maximum footprint for the machine would be 1200mmx700mm. It would be great if the table were sat on a cabinet with some kind of extraction unit in there(I did have something similar when I rented a unit, this was a router table build though).

You're right about noise, I have used the router in there and it is extremely loud, even with ear defenders! Fortunately we live in a semi-detached house, and the box room is the furthest room from the neighbours(they couldn't hear the router).

I am planning on making something very simple at first, like a few name plates to get used to how things work, the I'd like to move on to wooden hand holds and fingerboards as per the photo, that climbers use to train on.
The ones in the linked photo's were made by hand after making a jig. One of the reasons I want to build a CNC machine is that it's a heck of a lot easier to play with the design and physically make a prototype.

Unfortunately the links are facebook links.
https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash2/285372_10151412461888077_551772865_n.jpg
https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-frc1/379369_10151412462673077_99415652_n.jpg
https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-prn1/64886_10151412460093077_1186717358_n.jpg

Martin.

Grit monkey
03-10-2013, 07:36 PM
Hi Mike,

Thanks for the welcome.
I meant to say the maximum footprint last night, why I didn't I don't really know! The absolute maximum footprint for the machine would be 1200mmx700mm. It would be great if the table were sat on a cabinet with some kind of extraction unit in there(I did have something similar when I rented a unit, this was a router table build though).

You're right about noise, I have used the router in there and it is extremely loud, even with ear defenders! Fortunately we live in a semi-detached house, and the box room is the furthest room from the neighbours(they couldn't hear the router).

I am planning on making something very simple at first, like a few name plates to get used to how things work, the I'd like to move on to wooden hand holds and fingerboards as per the photo, that climbers use to train on.
The ones in the linked photo's were made by hand after making a jig. One of the reasons I want to build a CNC machine is that it's a heck of a lot easier to play with the design and physically make a prototype.

Unfortunately the links are facebook links.
https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash2/285372_10151412461888077_551772865_n.jpg
https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-frc1/379369_10151412462673077_99415652_n.jpg
https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-prn1/64886_10151412460093077_1186717358_n.jpg

Martin.

JAZZCNC
03-10-2013, 09:03 PM
Hi Martin,

With those friends then your sorted and just need a decent design that's tailored to your requirements. It's not difficult really and a lot easier if you can narrow the use to a specific area like Woods, plastics etc. If your wanting a machine that cuts everything IE: Soft and Semi hard materials like Aluminium then it gets more critical regards design.
To build an all-round-machine then really it will most likely be "Jack of all trades master of none" and it's very very difficult to build a machine that excels at everything.
I find from experience that you get a much better machine with an easier build if you identify your Main need and build to suit that need.

Now from what your saying wood use will be your main Use and that makes building decent DIY machine much easier has the tolerances and strength required for wood are much less than say cutting Aluminium or cutting to Very fine engraving tolerances.
Now I'm not saying you can just throw it together and still needs certain amount of care to design and attention to build quality but the it's much less forgiving.

If you have experienced Welders and Grinding services available then it will certainly help big time regards build accuracy you then just need a design that suits your requirement best and correct choice of components.

Post your ideas and lets have look.!!

Good luck.

Grit monkey
03-10-2013, 09:44 PM
Hi Jazz,

Thanks for your advice. I've seen quite a lot of threads you've posted on and you sure do help a lot of people, for which I'm sure everyone is very grateful!(how on earth do you find time to get into the workshop? haha.

I will try get a rough drawing knocked up in sketchup and post here on this thread. How soon I do this is entirely dependent on my nearly 2 year old daughter giving daddy time(or not turning off the computer!). I have seen links on threads on here where I can get some plugins for the parts needed which can then be added to the drawing.

I think I would, at some point like to make an entry into machining alloys (think tax disc holder for the bike, just pretty basic stuff really) so I take your point about not being able to throw stuff together and expect excellent tolerances, but I do tend to over engineer anyway. I've done lots of concrete shuttering, so this is where the over engineering comes from.

Anyway, thanks again Jazz, I'm sure I'll be calling on your knowledge at some point in the (hopefully) not too distant future :)

Due to my low paid job, the build will take quite some time, but it would be well worth the wait.

JAZZCNC
03-10-2013, 10:29 PM
I've seen quite a lot of threads you've posted on and you sure do help a lot of people, for which I'm sure everyone is very grateful!(how on earth do you find time to get into the workshop? haha.

Ah well that's the beauty of CNC.? . . .Setup. . click cycle start and walk away. Thou it does take a while to get the trust in machine to do that and walk into house.!! . . . . Often thou on an evening I'm sat in my swivel chair in workshop watching it cut while typing these replies.! . . Like Now. . Lol

Crack on and get in-touch when your ready

Dean.

Grit monkey
03-10-2013, 11:27 PM
Ok, I've managed to grab a few minutes on sketchup and here is pic of the torsion box.

The method I've used makes for an extremely rigid construction. The top and bottom would be 15mm alu, and the inside of the box would be 10mm alu with the perimeter double skinned to allow plenty for any fastenings.
10320

Ps, the overall size of the box is 1100mm x 700mm x 130mm

~andy
03-10-2013, 11:54 PM
What's your calculated weight for this monster base? :whistle:

JAZZCNC
04-10-2013, 01:22 AM
Ok, I've managed to grab a few minutes on sketchup and here is pic of the torsion box.

The method I've used makes for an extremely rigid construction. The top and bottom would be 15mm alu, and the inside of the box would be 10mm alu with the perimeter double skinned to allow plenty for any fastenings.
10320

Ps, the overall size of the box is 1100mm x 700mm x 130mm

Massive OTT really and you could easily get away with half the amount of material and still be plenty strong enough. Your mate won't thank you either having to Weld that lot. . .Lol

Also You say your short of funds do you know how much Aluminium plate costs.? . . . . Even at mate rates that much plate will cost plenty.!

Grit monkey
04-10-2013, 10:45 PM
Thank you for the chat Jazz, very informative and certainly lots of food for thought and I think I'll be taking your advice and going with a wood machine.

Anyway, time to get sketching! :smile:

Grit monkey
08-10-2013, 09:52 PM
1039010391I have taken on board the advice given and have drawn another base.
The top is 1100mm x 700mm x 15mm, the sides are 100mm x 10mm as are the braces on the inside. The channel I have left because I'm undecided whether or not to use two steppers for the x-axis or just the one, in all likelihood it will one in the centre
with an upgrade to two when funds allow.
So far the base alone will weigh somewhere iro 50.6 Kg. I haven't yet sourced a stockholder but will ask for recommendations when I'm ready to start buying.

With the base, I will need to think about where to fasten the linear rails, will they be better on the side of the base giving more work area? will they be better on the top for rigidity? Does where I want them to fit have a bearing on the type of linear rail used?

Comments welcome.

EddyCurrent
08-10-2013, 11:12 PM
Instead of that I'd be tempted to think about a plywood fire door cut in two.

JAZZCNC
09-10-2013, 02:20 AM
Instead of that I'd be tempted to think about a plywood fire door cut in two.

What.!!! . . .Plywood Fire door cut in two is only any good has Fire wood.! . . . . No wood based machine could compare to same or similar designed machine built from aluminium just like an Aluminium based machine of same design couldn't compare to Cast iron machine of same design so that's just silly suggestion to me. :thumbdown:

njhussey
09-10-2013, 09:50 AM
Your aluminium base at 50.6 kg isn't that much of a saving in terms of weight over a steel base frame. My base is 1300 x 700 and I'm making it out of 4mm thick steel. The calculated weight of mine (from the steel stockholder's data book) is 74.4kg and the cost of the steel (I've got 1m of 50x50 box, 2.5m of 50x25box and 4.9m of 100x50 box left over for other projects from the 7.5m lengths I purchased.) is 95. If your mates can weld then steel is much easier to weld than Aluminium and much cheaper which I'd have thought is a driving factor?

How are you thinking of connecting the ballscrew (if you're thinking of one central one) to the gantry sides? You'll need to raise the box up on legs (additional weight and cost) to do it with that layout?
Can you not use a steel base out of 3mm thick steel (to save weight) like the below?
1039210393

JAZZCNC
09-10-2013, 11:30 AM
1039010391I have taken on board the advice given and have drawn another base.

Hi Martin,

Being honest now considering your going to use Aluminium or steel construction materials I think your over complicating this machine with the Torsion box (TB) design.
If using wood then I'd say fine has the Torsion box will compensate for what material lacks in strength but with Ali or steel then you don't have this problem for the level of accuracy required. Only reason I would maybe consider going to to the trouble and expense of TB is if I needed to hold very fine tolerances, and by that I mean really high like 0.0001.

Don't know if your aware of a guy on the forum called Micheal Marino.? But trying to cut very long story short I built Michael a machine from my scrap and scrounged parts from various mates etc. Micheal wanted to contribute but couldn't for distance and other issues reasons won't get into so the only way he could was with design so I mostly left design to him with just bit of guidance from me and between us came up with something that fitted his needs.

Now Sure Michael won't like me saying this but it's true he's Considered one of the best in world for building Custom harmonicas for world class players so the detail and accuracy of his very complex 3D combs his very high. . . . . So to give an idea of what can be archived this machine on a daily basis works to 0.01mm or better in Acrylic and some very very expensive exotic hard woods using Tiny cutters!!

Now the reason Michaels machine can hold these levels of detail is because of design style targeted to his needs just has much has the Strength of materials used along with attention to detail and build quality.

Now having seen (via email) the higher gantry sided design you have in mind then I can tell you the TB won't give you any more accuracy than if building in a conventional manner. The gantry sides will dictate the level not the base.

Now that said for the past 5yrs I have built and refined very similar machine(without TB) for cutting Wood,plastics and Light Ali work made from Profile and Ali plate and can tell you 100% it will do the job no problem with excellent accuracy with good DOC for it's targeted usage SOFTER materials and light ALU work.

BUT If needed to cut Hard materials IE Alu,Brass,copper,mild steel etc to higher accuracy and usable DOC etc then it requires a different design and your TB won't change or add anything of any note other than expense and time to a machine with high gantry sides.!

So if your usage is to cut Soft/hardwood materials to acceptable level of accuracy and DOC etc then go with conventional design and save the money and hassle of building TB. . . . Anything more then forget this design it will under perform.!!

Like Neil says I'd also use Steel to cut down on expense. Can tell you 110% that machine built from steel with Ali bed will do everything you want if designed to your needs and won't cost the earth.

EddyCurrent
09-10-2013, 02:45 PM
What.!!! . . .Plywood Fire door cut in two is only any good has Fire wood.! . . . . No wood based machine could compare to same or similar designed machine built from aluminium just like an Aluminium based machine of same design couldn't compare to Cast iron machine of same design so that's just silly suggestion to me. :thumbdown:

You are correct, I just went to the other extreme, I can't help thinking it's a bit over the top for a base on this size of machine.

Grit monkey
09-10-2013, 08:26 PM
Thank you for taking the time to reply guys.

On reflection, I think with the Aluminium design I was thinking more form over function. So from here on in it's definitely only function!

Neil, I like your design, in particular the short legs, which would be helpful getting the machine base into the room where it's going to be used.
While It would be a rarity to be cutting any non ferrous would I need so many supports along the x axis?

Jazz,

When you say Ali bed, do you mean plate or the extrusion?

Cheers.

JAZZCNC
09-10-2013, 09:17 PM
When you say Ali bed, do you mean plate or the extrusion?

Was meaning Ali plate but either would work ok.

Martin If you want to see the machine I talk about in last post then get in touch. It's nearly finished but not moving just yet has i'm still doing electrics but will be going to it's new owner in a few weeks time so let me know and will try to arrange before it goes.

This machine will do every thing you want easily and when you see how strong you'll have a better under standing of where to go.

Grit monkey
09-10-2013, 11:09 PM
Thank you for your offer Jazz, I've sent you an Email.