1/2" 5-start for Z-axis?

[Biff]

Going to be ordering some parts soon and I'm using 1/2" 5start for X and Y. The acme rod I'm getting locally come in 6ft. lengths so there will be enough left over to use for the Z axis. Is there any issues with this or should I be using a finer thread?

BTW My machine will probably be a mish-mash of the JGRO, Joes2006, etc. machines and I will be mounting a bosch colt router. Also a G540 drive and 381oz steppers.

Thanks.

[CarveOne]

Originally Posted by Biff Going to be ordering some parts soon and I'm using 1/2" 5start for X and Y. The acme rod I'm getting locally come in 6ft. lengths so there will be enough left over to use for the Z axis. Is there any issues with this or should I be using a finer thread? BTW My machine will probably be a mish-mash of the JGRO, Joes2006, etc. machines and I will be mounting a bosch colt router. Also a G540 drive and 381oz steppers. Thanks.

There are no problems with 5 start on my two Z axis assemblies. It's a little quick if you only have 4.5" Z travel and you have 250 ipm manual jog speed though. You can slow it down in Mach3 or EMC2.

I like having X,Y, and Z the same on one machine. I use R&P X and Y with 5 start screw Z on my other machine.

CarveOne

[Biff]

Thanks,

I did some digging and found a thread from a couple years ago that pretty much says the same thing. It was mentioned that there was the possibility of back-drive when the machine was shut off so I'll just have to be aware of that... or use a spring.

[CarveOne]

Originally Posted by Biff Thanks, I did some digging and found a thread from a couple years ago that pretty much says the same thing. It was mentioned that there was the possibility of back-drive when the machine was shut off so I'll just have to be aware of that... or use a spring.

I'm not having any problems with that at all. The weight of my router and the moving part of the Z axis is about 10 pounds. If you are using a very heavy spindle and your Z axis moving parts are mostly steel you might have some reason to worry.

CarveOne

[louieatienza]

I have 1/2"-8, 8 start (1 TPI or 1" lead) on my machine (otherwise similar to CarveOne's small Solsylva machine) and have not had problems with backdriving. I don't have the heaviest router mounted, but with the stepper and AB nut attached, there seems to be enough "hold" when the machine is off. Once the machine is on, I'd probably flex my machine before the screw backdrives....

I also set the jog speed on the Z a lot slower, 120IPM on the Z and 350 on the X/Y....