Pader

I have already published this instructable but wish to add it to the CNC competition but do not have link to do so.

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Obviously, threaded rod is a hardware store item and you cannot get complete accuracy from them, but the cost of that length of lead screw is prohibitive. You pays your money and takes your choice.However, losses can be mitigated by using the step function of the motors and over 1800mm average out the losses which are pretty small especially if you take care of backlash.

My only suggestion is that you buy one of the many versions of mini-lathe that can be found on ebay. My one was purchased from Amadeal Ltd and has served me well. The one caveat is that you will need to go right through the lathe and tighten the whole thing up and adjust the slides and lead screw cap as not too much attention has been paid during manufacture. I would also recommend, to increase accuracy, that the built in tray is fixed securely to a heavy steel base.I would also recommend that you replace the nylon main drive gears with metal items which though slightly noisier will not cause a catastrophic drive failure as occurred on my machine.As to accuracy, the only way that I know of is to fit a 2 axis DRO of which there are plenty on ebay with 5um (or 1um to special order) resol…

My only suggestion is that you buy one of the many versions of mini-lathe that can be found on ebay. My one was purchased from Amadeal Ltd and has served me well. The one caveat is that you will need to go right through the lathe and tighten the whole thing up and adjust the slides and lead screw cap as not too much attention has been paid during manufacture. I would also recommend, to increase accuracy, that the built in tray is fixed securely to a heavy steel base.I would also recommend that you replace the nylon main drive gears with metal items which though slightly noisier will not cause a catastrophic drive failure as occurred on my machine.As to accuracy, the only way that I know of is to fit a 2 axis DRO of which there are plenty on ebay with 5um (or 1um to special order) resolution, I bought a similar 3 axis unit for my CNC machine with a 1700mm, 460mm and 320mm sensor for less than £300 delivered.Other than that, I cannot make any other suggestion unless you have your own base cast at a foundry and machined to flatness by precision engineers but then you are talking thousands.

The support extrusions may not be all that easy to locate, but as i suggested, a couple of cheap, surface ground spirit levels at 1800 long will do the trick.I have the machine stripped down for a rewire and fitting of coolant plumbing for the work piece and the spindle at the moment

I have made a number of instrument fascias using acrylic sheet using automotive, matt black spray that my laser etcher burns through easily. It has the advantage of drying quickly if laid on in one or two light coats (hold it up to a light source to check coverage between coats). In the case of the fascias, I gave a light spray with a white compatible spray over the etched areas to achieve professional quality fascias.I have no doubt that the same technique can be used for PCB etching but obviously, omitting the white spray part.

I have been theorising on building a numerical position display on my CNC machine using an up/down counter. Could you enlighten me as to whether the DIR+ and DIR- signals to the stepper drivers are at the same potential or is one signal the absence of a 'high' level?

This is a useful link for chemical compatibility too: https://www.coleparmer.com/Chemical-Resistance

Hello,I have HSMXpress loaded and registered into Solidworks but I can find no trace of it in the menu system. There certainly is no 'CAM' tag.Can anyone set me in the right direction?