DIY CNC Milling Machine From Scratch

[dazza]

its an impressive build so far totts,wheres the adjustable gas strut from and whats it rated at?thanks

[totts]

http://www.strutsdirect.co.uk/produc...-sd03-400-p-76

Their postage is a little high but not to badly priced.

They come in many lengths n sizes, mines adjustable set at 1200N but will release the pressure when everything is assembled.

[dazza]

not bad at all,thanks a lot,
keen to see this mill in action.,i did toy with making my own for a while then bottled it and bought an sx3.

[totts]

Yeah i came very close to getting an sx3, axminster had a 10% off all machines, and when i went on the website they had been reduced due to discontinuing them, and could have picked a new one up for £800!

Only thing that stopped me is the need for a slightly bigger travel and higher spindle speeds.

Have you a video of your sx3 in action?

[dazza]

Have you a video of your sx3 in action?

no not yet I bought it new from arc a while back and immediately ripped it aprt and fitted ball screws and steppers.(wishing I put profile rail on it after seeing what you and jonathan are upto..upgrade for the future maybe)at the minute im on the wiring so a week or two away yet.

[totts]

Will be very interested to see it running! Yeah profile rail is bloody exspensive tho :(

[totts]

Got some steel strips made up now ready to be bolted onto the bed, just waiting for some stainless steel countersunk screws to turn up!

[charlieuk]

I would be very carfull filling anything like that with that much epoxy and when it cures it can produce a huge amount of heat and contained in a metal tube you could have a small disaster on your hands. If you do want to do this make sure it is extremely slow curing and if anything put some bags of ice around it to keep the heat down and only do a little at a time.

He’s talking in terms of adding strength to the machine and he’s right but I was really referring to eliminating resonance more than anything, I can’t see that adding ribs/reinforcing plates wouldn’t add extra strength to the column, I think they would help towards stopping any twist in the column at the very least.

I think the problem with concrete is that it’s relatively brittle (though I note your suggestion of using rebar), cracks could form in the concrete and over time it may break down inside the column, I don’t know enough but I’m guessing that it doesn’t really have the same dampening properties as other materials, epoxy resin is a favourite but so is kiln dried sand and the sand is cheaper in comparison.

I think what I will do with mine is to, reinforce the column on the inside, use a mix of aggregate (different sizes, type 2, pea shingle and so on) to then fill the column, then backfill the lot with epoxy resin (filling up the leftover voids) all the way to the top, hopefully creating one solid mass. The idea being the aggregate is just away to use less resin (cost vs. cost) but also brings back the properties of using sand.

.Me

[Lee Roberts]

I would be very carfull filling anything like that with that much epoxy and when it cures it can produce a huge amount of heat and contained in a metal tube you could have a small disaster on your hands. If you do want to do this make sure it is extremely slow curing and if anything put some bags of ice around it to keep the heat down and only do a little at a time.

Thanks for the heads up Charlie, is it really that bad?

.Me

[charlieuk]

Thanks for the heads up Charlie, is it really that bad?

.Me

depends exactly on the epoxy but yes especially in warm temps, if you left a cup of epoxy to cure on its own you would be surprised how much smoke it can make! its a exothermic reaction so when if heat starts to build its a chain reaction and just gets hotter and hotter and will quickly turn into a smoking and bubbling mess. Ive never had flames but have heard of it. It all so doesn't make any different if you have some sort of filler mixed in with the epoxy so less actual resin to fill the space it will still have the same effect. As i said small quantities a bit at a time in a cold temp is your safest bet.