[johnnyt74]

Hi all,

Last year my mate bought me an arduino for Christmas and I decided to have a go at building my own 3 axis CNC machine with it.

So far so good... I've got a machine that now drives on all axis but I'm stuck as to where I go from here?

What do people use as the 'base' part of the machine? i.e. what do people use to clamp the wood to as the machine works on it?

Can you buy aluminium plates with pre-drilled/tapped holes in and some form of clamping bracket that you screw into it?

Or do people just normally use a wooden base and then screw the piece of wood they are working on to the wooden base?

These are probably stupid questions but I'm completely new to the CNC world and so any pointers / advice would be much appreciated.

Thanks

John :-)

PS. I've attached a piccy of the machine so far....

[awerby]

A piece of plywood would be better than nothing, and would give you something to screw into and hold your projects down to. You could use a piece of aluminum, but I haven't seen the pre-drilled and tapped ones you mention. You might have to do all that yourself. Once you've done that, you can put a piece of MDF or something on top of it, and surface that with your router so you know it's flat.

[johnnyt74]

A piece of plywood would be better than nothing, and would give you something to screw into and hold your projects down to. You could use a piece of aluminum, but I haven't seen the pre-drilled and tapped ones you mention. You might have to do all that yourself. Once you've done that, you can put a piece of MDF or something on top of it, and surface that with your router so you know it's flat.

Hi Andrew,
Thank you for taking the time to get back to me. Much appreciated.

What is the "norm" with these things? Do most people just use plywood and screw through their job and into the plywood? Or are there special 'clamps' that you can by that you screw into plywood but around the edge of your job to clamp it? Or something else?

Thanks again for your help.

John :-)

[john-100]

on many machines you see Aluminum T-slot Extruded Profile 2080 used for the base

Attachment 406244

if I remember correctly the "T" slots are 40mm apart

for your initial tests I think Andrew Werby has the answer

a sheet of plywood is not too expensive when you plunge the cutter into the base while your learning

I can not remember which forum it was on
but I have only read of a tapped plate fixture being use once

like this
Attachment 406246

I expect its going to be an expensive solution

John

[johnnyt74]

Hi John

Thanks for the info. I used some ally extruded stuff for the frame. I'll have a look for that 2080 stuff. I've not heard of that before.

You and Andrew are correct about the wood for testing but I just wanted something correct for the finished article.

Also, what do people use as clamps? Do you know of anything suitable?

Thanks for all your help

John

[awerby]

With home-built machines, there's no "norm" - people do all sorts of things. The best choice really depends on what you're intending to use this thing for. If you've got a particular part you need to do over and over, you can build a fixture onto the bed of the router that it snaps into and always is in the same place when the job starts. If you're doing a lot of thin, flat cut-out pieces, you might want to rig up a vacuum pod, which will suck them down until you release the vacuum. If you're doing 3D parts that need to flip over to cut the other side, you can set up some stops and pins that align the workpiece so it's registered correctly when flipped. For wooden parts, you can set up stops on the edges and use wedges to hold the work in place without piercing it. And sure; there are tons of clamps and clamp systems you can buy (or make). Most are based on T-slots (which you can probably find a machine shop to do for you, in an aluminum plate), but others don't require them. I'm not sure what's available in Australia, but here's a US company that makes a line of various low-rise clamping devices: https://www.miteebite.com/

[johnnyt74]

With home-built machines, there's no "norm" - people do all sorts of things. The best choice really depends on what you're intending to use this thing for. If you've got a particular part you need to do over and over, you can build a fixture onto the bed of the router that it snaps into and always is in the same place when the job starts. If you're doing a lot of thin, flat cut-out pieces, you might want to rig up a vacuum pod, which will suck them down until you release the vacuum. If you're doing 3D parts that need to flip over to cut the other side, you can set up some stops and pins that align the workpiece so it's registered correctly when flipped. For wooden parts, you can set up stops on the edges and use wedges to hold the work in place without piercing it. And sure; there are tons of clamps and clamp systems you can buy (or make). Most are based on T-slots (which you can probably find a machine shop to do for you, in an aluminum plate), but others don't require them. I'm not sure what's available in Australia, but here's a US company that makes a line of various low-rise clamping devices: https://www.miteebite.com/

That's great thanks. You are perfectly correct of course. I wasn't thinking of all the different applications. I'll start with some ply and look at different clamping methods and go from there.

Thanks again for all the help. I appreciate it.

Cheers

John :-)

[dharmic]

I went from the 2080 supplied with my machine to a machined 1/2" threaded & dowelled tool plate similar to John's photos.

The tool plate cost about $300 for the stock and about 2 days of machinist time being shuffled between a CNC and manual pedestal mill, fitting in between jobs where I was working. I don't know what it would have cost to just throw in a big CNC and be done but guessing it'd be at least another $500. So it wasn't cheap. But it's considerably reduced the bowing I got in the 2080 under load cutting aluminium (Z would distort maybe 0.5mm) and made clamping down a lot easier. Worth it for me, you might not find it so.

Yours looks like a fairly lightweight spindle, so maybe not such a big issue. I'd be inclined to start with 19mm plywood nested into the frame. That'll help keep the machine square in X and Y. Bolt another layer of 12 or 19mm plywood to the top of it. It'll help stiffen the machine in Z and give you a sacrificial piece that's easy to replace when you inevitably run your tool a bit too low. It also gives you something you can just screw your workpieces into with wood screws. Easy, fast.

After that it gets complicated with all sorts of commercial and home made hold-down systems. But I've seen plenty of guys just screw their workpiece into the top and let rip - with great results.

[robwiacek]

Get some cheap MDF mate.
Keep it simple stupids
I even use particle board on top of my extruded aluminum base.
Then you can just screw on some clamps.
I use plexiglass 1”x 3” with 1 hole in it for the sheetrock screw.
It’s then a low profile and a great grip!


Sent from my iPhone using Tapatalk

[cyclestart]

I use 2 sheets of MDF, the top sheet is a spoil board that can be resurfaced as needed.
The spoil board has a pattern of flanged E-Z LOKS installed from the bottom side. The downside to this set-up is the limited number
of times the spoil board can be resurfaced. Alternately the e-z locks could be installed in the bottom sheet of MDF.
Link --> https://www.ezlok.com/e-z-hex-thread...-for-soft-wood

For clamps I use these most often
Link --> https://www.thingiverse.com/thing:776
The fastening is done with assorted 1/4-20 bolts instead of that knob thing. Spit dowel to fit the top notches provides sure clamping.

My work is mostly sheet goods.

[milo30]

I rarely ever use clamps. I have MDF spoilboard and use screws. You must be comfortable that your screws arn't anywhere that they can be hit by the bit. Depending on what you are cutting, 2 sided tape can work good. There are some DIY pucks that people have made using a tube and compressor to make a small vacuum on the table. The slotted aluminum can use t-bolt clamps pretty well just make sure that there is clearance everywhere you have the clamp from the gantry and router. There are a lot of DIY clamps that people have made with wood and a t-bolt which work well also.

I would just use MDF for the table and see what you think. you can always change it later with more expensive aluminum.

[wizard]

Hi John

Thanks for the info. I used some ally extruded stuff for the frame. I'll have a look for that 2080 stuff. I've not heard of that before.

That is one good.choice but you can actually find extrusions meant to be machine tables. However you don’t have to go the extrusion route.

You and Andrew are correct about the wood for testing but I just wanted something correct for the finished article.

Here is your problem - there is no correct solution. Beyond that if you are working in wood it is extremely common to have a spoil board on top of whatever the actual table is made of.

Also, what do people use as clamps? Do you know of anything suitable?

There are literally thousands of possibilities here. In many cases the volume of manufacture is important because it can justify making fixtures. Perhaps the simplest approach for wood, where you can afford abit of waste, is deck screws into the spoil board. There are many other ways to hold the material in position, even a machinist vice can be justified in some cases. In the end best depends upon what you are doing.

Thanks for all your help

John

Well I hoped that helped.

There are a couple of things to keep in mind when it comes to work piece hold downs. The first and most important is the method safe and secure for the machining operations to be performed. You don’t want the work piece being flung out too bounce off your head.
The second issue is that the work piece holding method can not interfere with tool paths. This may seem obvious but even seasoned operators have broken cutters by running into a clamp.

As for the threaded tooling plate as a machine table I actually like that concept for its versatility. They are not cheap though especially if you get something stiff enough for long spans. However if you plan to machine metals in the future the investment might be worthwhile. Such stable invites the proper usage of toe clamps, edge lamps and vise hold downs. If you never expect to do anything other than wood such a table is likely a waste.

Lastly and a bit of repitition is the idea of securely holding the workpiece. There is nothing worse than having a item ruined because it slipped under a cutter.