I have to change the threaded rod as both ends have burrs on them which would damage the threads of the leadnut. To speed up the process I will stick with the 1/4-20 thread for now but in stainless steel, hopefully the whip should reduce. I cannot find acme rod in my neck of the woods but in time I will aquire some.
I used 5/16-18 but modified my anti-backlash nuts to use actual nuts within them, and just keep it lubed, they work really well and have several hours on them and have not had to adjust or replace them yet.
Looks really great.....did you buy the vcarve software...i cant believe how fast it cuts stuff out.....my small signs take more time to lock down that to carve.....i finally got some paint mask and am going to try it tomorrow......will post painted stuff over the weekend ont the other thread.
Thanks for the link Mike.
I have not bought the Vcarve software yet Bob. I should have all the funds together soon.
Took a break from the repairs. Presently I am trying to eliminate a little binding in the threaded rod nut. The 5/16-18 seems to working much better in terms of whip reduction. I turned the rod by chucking a drilling machine on and it seemed to work fine.
I drool for that kind of price here in Barbados. The store I went into had a 6' length of 3/8-16 stainless for BDS $80.00 (US $40.00), they had no 5/16-18 stainless in stock so I settled for regular 5/16-18 at BDS $9.00 (US $4.50 ). The duties raise the prices of everything in Barbados.
After numerous interruptions I finally got the machine to the stage of speed testing. I still have to bolt up the leadnut to the gantry but the clamps will do for now. I got up to 70"/min using 5/16-18 rod with no whip , thats the fastest I will run for now as I cannot go much faster with Mach3 set to 35,000 pulses per second. Then again just for fun I will Mach 3 on 45,000 pulses temporarily just to see what speed I can achieve without whipping (a little grease a must for me on the leadscrew at these high speeds).
Advice to new builders of the JGRO: Go with the 5/16-18 threaded rod at least on long axis instead of 1/4-20. Use the skate bearings all over the machine not just for the runners.
Well I am back to cutting materials, however I may have to fashion another nut as the integrity of the replacement nut was compromised by a clump of super glue that got onto the lead screw and was pulled through the lead nut threads. It is working for now anyway bit I may consider a metal nut soon.
Good thing about a smaller number of threads per inch is that it allows me more speed from Mach3. I am jogging at 70"/min on the Y-Axis(long) with no whip.
Here is a pic of the first part cut after repairs. It is a motor plate. The reason it has 8 holes is that 4 holes in a square pattern will secure the motor and the other 4 which will be outside of the square of the motor base will secure the plate to the machine.
The bearing hole is slightly too large and I will adjust this in NC-plot if possible. I have lots of these skate bearings with flanges which were obtained from numerous raids on copier machines. The copiers also carry some of these bearings without the flanges.
I was running at 1016 mm/min or 40"/min using a 1/8" straight bit and the router flat out (~25,000 RPM). This material is medium density but it cuts well without burning. An upcut spiral bit is best however as it ejects the chips quickly and they do not have a chance to clog.
I will try posting a video of the next cut.