This is the thread to discuss beta kits
Some feedback I'm getting through email:
Regarding the sliding element; It is not very easy to put screws on the inside of a tube. It might also be better to use two pieces of plastic cut so that they meet at
opposing corners. The plastic pads are non-uniform and some of them stick out and work there way off when the sliding element tubes are set down on end.
Swapping them between tubes or trimming them might fix that issue. The inside side of the pad that is cut also tends to bend inward.
Two of the captive leadnuts need the thread re-tapping for a couple of the screwholes, as the thread doesn't go all the way through. Also the screwhole spacing on four of the [shaft mounts] are too far apart to hold the skate bearings in place, so i need larger headed screws or another way to hold the bearings in place.
Just starting to assemble the cnc contraptor. I have found that the screws for the bearings allows one thead or less to hold on the outside nut. I have replace them with 10-24X5/8". This gives about one thread outside of the outside nut.
I'm having some diffaculty(sp) gitting the bearings and the rails adjusted. For me, one of the screw heads on one side or the other rubs. I've put a digital caliper on the rails, and have them adjusted to withing a couple of thousends(sp). Where can I locate the correct way to adjust the rails and bearings?
Thank for your help.
Kits arrived yesterday and I have been like a kid at Christmas! Everything is better than I expected. Thanks for the great kits!
Do I owe Vitaly Mankevich any for extra postage?
It's great to get feedback, please keep it coming.
The rails are self-adjusting, but the linear bearings need to be adjusted. The right position for the ball bearing axis is 5/16" from the tube base. The best (known) way to adjust it is to put something 1/8" thick (like UHMWPE angle) under the nut and tighten the screw in this position. It's not perfect but it seems to work.
You also mention that one of the screw heads rubs (I'm assuming against the drill rod on the rail) - does this mean that the screws are inserted from the inside of the linear bearing, like on the left? The correct way is shown on the right.
As far as the extra postage, it was only a few dollars so don't worry about it.
Thanks for your help with the linear rails!
I now have the miniCNC up and running and responding to G-codes!
I do find that typing in a line at a time to be slow and tiresum.
I found your Python script and have tied to use it but get an error of cannot find "Serial".
Would you post or respond with a link to the location of the "Serial" module, please?
I have looked through the Arduino 0018 manuals and online help and cannot seam to locate the information.
Thanks in advance for your help
ps - in order to run stepper motors faster, a higher voltage source is required. The back EMF from the motor inductance limits how quickly you can step. With a higher voltage, the current builds quicker in the inductance, and the result is a quicker step.
That enabled me to have a real CNC Machine, thow a small one.
Now, all I have to do is learn how to machine!
Thank you for having such a clean design, and for all your help.
I will get back with you when I have learned a bit more.
I will try to get a avi of this machine when I can get it a little better.
Happy to hear that! Pictures/videos of your machine would be great. We've been meaning to create a starter page for subtractive fabrication (probably using CamBam app), with basic tutorials such as cutting something out of plywood/plastics and milling a pcb (you can see steps in this direction in the following thread: http://www.contraptor.org/forum/t-192541/mini-cnc-case-study)