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dpgoldberg
09-14-2010, 01:31 AM
I'm planning to use 1/2"-10 Acme precision threaded rod on my CNC Router. McMaster Carr sells this rod in made from both 1018 Carbon Steel and Heat-Treated 4140 Alloy Steel. The catalog says the Alloy Steel is "harder than the carbon steel for greater strength and durability". The alloy steel is also almost double the cost of the carbon steel. Considering that I'm going to use Delrin anti-backlash nuts, and that these rods will be turning at relatively low rpms, is it really necessary to use the alloy steel? I would think a CNC router is fairly low wear compared with most of the industrial applications these rods are sold for.

There's also stainless steel but that's way too expensive!

arizonavideo
09-14-2010, 02:02 AM
I have both and the plain 1040 rods are just fine.

CarveOne
09-14-2010, 06:58 AM
I'm planning to use 1/2"-10 Acme precision threaded rod on my CNC Router. McMaster Carr sells this rod in made from both 1018 Carbon Steel and Heat-Treated 4140 Alloy Steel. The catalog says the Alloy Steel is "harder than the carbon steel for greater strength and durability". The alloy steel is also almost double the cost of the carbon steel. Considering that I'm going to use Delrin anti-backlash nuts, and that these rods will be turning at relatively low rpms, is it really necessary to use the alloy steel? I would think a CNC router is fairly low wear compared with most of the industrial applications these rods are sold for.

There's also stainless steel but that's way too expensive!

It comes in roll threaded (probably carbon steel) and ground thread (probably alloy steel). The very low priced rods from Enco that I have needed honing with a knife sharpening stone and polishing with 600 grit sandpaper to get the wire edges off of the threads. Not hard to do, but is some work. If not cleaned off, these general purpose rods will quickly destroy delrin nuts.

My Enco 1 start ACME threaded rods have a little spiral to them when you roll them across a flat surface. This will limit your maximum rpms before whipping sets in. I ended up replacing them with McMaster 1/2-10 5 start ACME rods. Much better quality at about seven times the cost. ($7 versus $51 each) No honing and sanding required and has a polished steel look.

CarveOne

dpgoldberg
09-15-2010, 01:07 AM
While we're on the subject of Acme threaded rod - what are the preferences as far as 2 start vs. 5 start?

arizonavideo
09-15-2010, 03:40 AM
For almost any router the slowest screw you would want is a 4 TPI screw.

I would go with the 4 start 2 TPI screw if you plan on doing wood and are using any of the lower voltage stepper drivers of less than 50V.

Roton is the place to buy you screws.

http://www.roton.com/

This screw.

http://www.roton.com/Mating_Components.aspx?family=7060986

Dumpster CNC has the nuts.

http://www.dumpstercnc.com/

For screws measuring 1/2" diameter with 8 TPI and a 4 start acme thread form.


The cut easy just give them some time to break in.

dpgoldberg
09-15-2010, 12:40 PM
For almost any router the slowest screw you would want is a 4 TPI screw.

I would go with the 4 start 2 TPI screw if you plan on doing wood and are using any of the lower voltage stepper drivers of less than 50V.

Roton is the place to buy you screws.

http://www.roton.com/

This screw.

http://www.roton.com/Mating_Components.aspx?family=7060986

Dumpster CNC has the nuts.

http://www.dumpstercnc.com/

.

The screws you referenced are Roton's "Hi-Lead" which look different than Acme threads. Do the DumpsterCNC nuts work on these rods? Roton also sells anti-backlash nuts like Dumpster but they are nearly twice the price.

Thanks for your help.