The garage might be a better place to post this. I'm not sure.

This is the part in question:
http://www.mcmaster.com/#catalog/115/1157/=uvbih

The 1/4 to 3/4" spider coupler that I was going to use to attach my stepper motors to the threaded rod for my homebrew CNC.

Now the 3/4" end comes keyed and works fine, but the 1/4" does not.

My question is, should I just look to find couplers that ARE keyed, or would it be possible to hunt down some tool to key these pieces myself. I have absolutely no practical experience in this field.

Thanks.

3/4/2009 1:06:39 PM

keyway dims (http://www.mcmaster.com/#catalog/115/1154/=uzu2d)

find the correct key (http://www.mcmaster.com/#woodruff-keys/=uzv39)

find the correct key seat cutter (http://www.mcmaster.com/#woodruff-keyseat-cutters/=uzvjg)

EDIT: Ok after re-reading what you wrote, I think you are trying to cut the keyway into the coupling hub, no? If so you need a broach. http://www.mcmaster.com/#about-keyway-broaches/=v09og

[Edited on March 4, 2009 at 6:08 PM. Reason : ]

3/4/2009 5:39:36 PM

mcmaster is overpriced

try grainger or msc

3/4/2009 8:37:12 PM

Its funny that this got posted today, I just finished my homebrew CNC over the weekend.

Pics and video at:

http://picasaweb.google.com/john.marsh/CNCMachine#

3/4/2009 9:35:39 PM

how accurate is it?

3/4/2009 9:37:21 PM

Before the CNC conversion, I had it around 0.001" (not great for making engines, but great for my needs). This micro mill has shit for rigidity and the backlash is really bad. I spent hours upon hours getting it down to 0.001".

Since i've done the conversion, i haven't readjusted the mill yet. I'm aiming for 0.0005", but we will see.

3/4/2009 9:49:48 PM

178 bucks!? oh no... no no no no fuck that.


^where did you get those couplers?

[Edited on March 4, 2009 at 11:18 PM. Reason : ^]

3/4/2009 11:13:06 PM

^^ haha yeah this one is not going to be nearly as accurate, but should still get the job done. This frankenstein is made of MDF. lulz.

3/4/2009 11:15:05 PM

McMaster.

I ground a flat on each stepper shaft for the set screw to lock into.

There really isnt that much torque.

3/5/2009 12:11:35 AM

any updates wolfmarsh?

3/15/2009 11:10:58 AM

Nah, havent had a chance to tram it after the upgrade yet. Having newborn twins will do that.

If i had to guess, ill be doing it this weekend.

3/15/2009 7:11:30 PM

congrats on the twins.

When you get it fired up and rolling be sure to update us. It's inspired a few I'm sure!

3/16/2009 8:04:19 AM