[stef_d]

[QUOTE=hemsworthlad;764419]Hi Stef,



Can i just make a suggestion that you add a small flat landing plate where the cross brace bolts so that it keeps the cross braces level and flush with the side beams.
This will help when you come to set the bed on the frame and also take a bit of the strain off the bolts, will also make assembly a lot easier.
QUOTE]

on the underside ?
got you.
Stef

[hemsworthlad]

[quote=stef_d;764445]

Hi Stef,


on the underside ?
got you.
Stef

Yep simple small plate on underside of long rail it will help lots.

[LazyMan]

What would you recommend filling the feet with?
would concrete be a good idea ?
I am thinking of drilling the feet for the cross section and all the beams, inserting some M8 treads, living about 2cm sticking out either side. Then filling with concrete. I can then bolt the cross sections and beams to the thread, right accross the feet, as opposed to just on one wall, which i dont like anymore ! The concrete should allow me to tighten the bolts without having to make bosses for each piece of thread. Hopefully, the concrete will not go to powder when tighten.
Problem i have with concrete, is that I cant "undo"! If it turns out that it wasnt a good idea, well, i am stuck with it.

For sound dampening you could fill your steel beams with sand. Engineers have filled the steel construction of park roller coasters for sound dampening with claims of noise being cut down by up to 50%. It would be the least permanent solution.

[stef_d]

For sound dampening you could fill your steel beams with sand. Engineers have filled the steel construction of park roller coasters for sound dampening with claims of noise being cut down by up to 50%. It would be the least permanent solution.

Yes, sand is an option, however, using concrete will double as "crush" stop for all the threads crossing the rectangular section.
I mounted the 2 screws and rail support beams for the 1900 x axis.
fairly happy with it so far.

[hemsworthlad]

Yes, sand is an option, however, using concrete will double as "crush" stop for all the threads crossing the rectangular section.
I mounted the 2 screws and rail support beams for the 1900 x axis.
fairly happy with it so far.

Hi Stef,

That's looking very familiar.!!

A word of caution if your planning on using a hollow gantry.

My gantry is hollow and while very strong with no flex or twisting etc it does resonate a little making it noisey when cutting hard materials like aluminium or steel.
It doesn't affect the quality of the finish but i do have to keep this in mind when cutting ali or steel and keep the depth of cut low and turn up the feeds.
If i try to cut too deep 4mm+ in ali/steel the noise level goes up and so does the resonance which i'm sure if i didnt keep the cuts shallow would show in a poor finish.

This is about the only thing i would change about my machine if starting it again and i do plan on changing it when i get chance for a piece of 120x80 aluminium profile.
The machine does everything i want and the resonance doesn't limit my speeds and to be honest i wouldn't cut ali or steel any differant even if it didnt resonate because i like the shallow cuts @ high feed rates way of machineing and i only plan on changeing it for the sake of ironing out week spots and this is about the only one and it's purely for noise reasons.

Hope this helps.

[hemsworthlad]

One other thing or tip, Think about ways to cover the screws and also i would cover the sides of the bed to stop chips flying thru to the screws.

I'm just about to put a Aluminium bed to replace the temp MDF one on mine and when i do then i'm going to make a under tray to allow me to use coolant and put heavy duty plastic up the sides fastened to the top rails which will still allow for the bed to be raised up and down.

The chips that come from ali fly every where and stick to every thing that is slightly oily or greasy and the screws are in direct firing line, at the very least i would make some wipers to place either side of the nut and again this is another little upgrade i will do when i get chance.!! . . . . . So it'll proberbly never get done.?

[itel933]

Hi Im new to the site and even newer to CNC. Im an inventor and would like to start using a CNC to make things.....the only problem is that I am completely and totally lost. I keep reading on multiple sites to make one yourself and on other sites that have "diy starter kits" Can anyone help this newbee in starting his first CNC.

[hemsworthlad]

Hi Im new to the site and even newer to CNC. Im an inventor and would like to start using a CNC to make things.....the only problem is that I am completely and totally lost. I keep reading on multiple sites to make one yourself and on other sites that have "diy starter kits" Can anyone help this newbee in starting his first CNC.

Yes i'm sure we can there's meny helpful and very knowledgable people on this site, But it would be better if you started a thread of your own so that Stef's thread doesn't get hi-jacked.
Give as much information as you can to what you want from the machine and some idea of size you want to cut.
Also the amount of money you intend investing will play a large part in how you go about designing and planning the style of machine.

Just let me warn you thou before you get to involved, it's very very very very addictive.!!

If you dont want to start a thread just PM me and i'll be pleased to help.

[itel933]

Yes i'm sure we can there's meny helpful and very knowledgable people on this site, But it would be better if you started a thread of your own so that Stef's thread doesn't get hi-jacked.
Give as much information as you can to what you want from the machine and some idea of size you want to cut.
Also the amount of money you intend investing will play a large part in how you go about designing and planning the style of machine.

Just let me warn you thou before you get to involved, it's very very very very addictive.!!

If you dont want to start a thread just PM me and i'll be pleased to help.

I dont know how to do either....how do i start a thread....not sure If I started one or not...as helpful as this site is, it's certainly not user friendly.

[hemsworthlad]

I dont know how to do either....how do i start a thread....not sure If I started one or not...as helpful as this site is, it's certainly not user friendly.

Ok it's not so bad when you get used to it.

Starting a thread is easy, just click on the button that says New Thread.

Go to the main woodworking forum screen and you will find it between sub-forums and Threads in forums sections or in the Diy-cnc router table machine forum page it's just above the main section and too the left.

[stef_d]

One other thing or tip, Think about ways to cover the screws and also i would cover the sides of the bed to stop chips flying thru to the screws.

I'm just about to put a Aluminium bed to replace the temp MDF one on mine and when i do then i'm going to make a under tray to allow me to use coolant and put heavy duty plastic up the sides fastened to the top rails which will still allow for the bed to be raised up and down.

The chips that come from ali fly every where and stick to every thing that is slightly oily or greasy and the screws are in direct firing line, at the very least i would make some wipers to place either side of the nut and again this is another little upgrade i will do when i get chance.!! . . . . . So it'll proberbly never get done.?

Thanks for the tips Dean !
I considered placing shielding plates on the side of the bed, so that's something i will most likely do.
The blocks went on fine on the screws.. i did as you suggested, plus a little oil before lightly tapping them in.
I havent finished the design of the gantry yet, so your input is most welcome..
so what do you suggest, a completely solid aluminium gantry ? or still a hollow profile ?
At the moment, all i have is 2 pieces of 50x80mm aluminim, 4mm thick in 1200mm. i was planning to join them together on their broad side (like in the picture). maybe also have a plate covering them both. Then a 20mm thick aluminium plate on either side of the gantry, to join to the nuts.

[hemsworthlad]

No i would try to stay away from hollow gantry if pos or at least fill it with something dense.

If your design needs 2 pieces then personaly i would use 2x 80x80 solid aluminium extrusion profiles or better still 1x 80x160 piece if butting upto each other.

I can get 80x80 for £40+vat per mtr or the lite version for £30+Vat so this will give you some idea of cost's, i,m sure there will be a supplier in france giving similar prices.
If not and you need some drop me a line.

[hemsworthlad]

The other plus to extrusion is the ease of mounting rails and ballscrews makes life so much easier and you havent got to drill and tapp a couple of hundred holes.! and it's very quick to assemble.
Also makes mounting things like limit switchs etc very easy.!

[archer3d]

as for using concrete to fill the tubes, it seems like a great idea, but having worked with cement it does shrink and my concern would be that if it shrinks inside the tube when it drys then the cement will rattle, I am no expert by a long shot and have never tried it, this was just a thought

archer3d

[slavkok]

Iron/Steell has near same shrinkage coeficient and works. But Alu is out of range. For dampening resonence just fill tube with dry sand.

[archer3d]

Iron/Steell has near same shrinkage coeficient and works. But Alu is out of range. For dampening resonence just fill tube with dry sand.

slavkok I was referring to the concrete shrinking as it dries inside the tube, not with temperature change.

archer3d

[slavkok]

Ahh... I just read too fast.

But still. To dampen resonance just put dry sand inside. It's work well and if you decide to get rid of it just shake sand out.

:idea:

[stef_d]

Ahh... I just read too fast.

But still. To dampen resonance just put dry sand inside. It's work well and if you decide to get rid of it just shake sand out.

:idea:

yes, thanks for the comment re shrinkage.. didnt think about that. ok, i need to find a way to get around that problem. maybe filling the post with concrete, let it set/shrink for a few days in the sun, and then just poor resin in the gap. that stuff is liquid enough to get in there.

sand is good for sound, but useless as a crush stopper. i need something solid, as i have a few threads through those tubes.

re the gantry.. i'll think about it in the next few days !

[stef_d]

I refenforced and painted the machine. looking good an up to the job, so far.
I also started to roughly align the x axis rails.
These will have to be dead symetrical on the supporting beam (at least at the extreme ends.) since the lead screw is mounted on the beams two, and both sides are mirrored. Therefore, if i have the exact same distance between the edge of the support beam and the rail at both ends, the lead screw has to be properly aligned too. Same on the oposite side.
This means that any adjustement in the spacing between the two rails will have to be done by ajusting the distance between the support beams (either skim of shim).
a quick check showed about 0.5mm out. i should be able to adjust that.
now if both ends of the rails are properly spaced, they is no reason that the middle shouldnt be. If is itsnt (say the beams curve in) then i can adjust the rail position, on the beam, on the middle section.

[stef_d]

the gantry is up.
not qutie finished, as i still need to install a few reenforcing plates and brackets, but it feels pretty solid already. i cannot feel any racking. I tried pushing on one side only, as far out as i could, but no sign of racking. it was still sqaure when i reach the end of the table.

I also prepared the motor mount on the long axis