[hoss2006]

Chuckie, I am just starting my X2 conversion and I am planning to keep the stock screws. I am interested your split nut modification. I think the photo you showed earlier in this thread was the X axis nut. Do you have a photo of the Y axis nut? As you know, these mount to the bed differently. My question is, do you use a shim in the spit to keep it from pinching completely closed when mounted in the machine? It seems that the way the mounting system works (1 setscrew on Y and 2 on X) - pressing the nut against the back of the slot - would close the slot and potentially bind the screw.

Cheers,
Michael

Check out how LMS splits theirs in this kit.
CNC X and Y-Axis Motor Mounts and Screws for Mini Mill
Hoss

[mhackney]

Thanks guys, that is exactly what I was thinking.

Cheers,
Michael

[chukkie]

If you look at the picture real good you can see I drilled and tap an extra hole for the x-axis and drilled, tap and recessed 2 holes for the y-axis. I did all this so I could adjust it without taking things apart. Also the split nuts have 2 pass holes in them on the split side so the mounting bolts will pass thru the first part of the split nuts and the center bolts are the adjusters.

[alex781]

Great conversion and impressive output! Hope it's still working well for you.

Sorry to revive the thread with a newbie question, I am using this as the basis for my X2 build. Rather than drilling new holes for adjusting backlash on the X and Y axes, would it be a bad idea to use the original mounting screws to 'pinch' the split nuts? Obviously they could not be turned as tightly, I am not sure if that is a problem.

[hoss2006]

Great conversion and impressive output! Hope it's still working well for you.

Sorry to revive the thread with a newbie question, I am using this as the basis for my X2 build. Rather than drilling new holes for adjusting backlash on the X and Y axes, would it be a bad idea to use the original mounting screws to 'pinch' the split nuts? Obviously they could not be turned as tightly, I am not sure if that is a problem.

That wouldn't hold them securely enough. They would shift side to side and cause binding.
Eventually they would work themselves loose and there goes your anti-backlash.
Hoss

[alex781]

That wouldn't hold them securely enough. They would shift side to side and cause binding.
Eventually they would work themselves loose and there goes your anti-backlash.
Hoss

Thanks, I was thinking to use some epoxy to hold the nut but I'm beginning to realize its hard to further simplify this conversion.

(Just one of those guys who hates putting holes in their mill -not something that's held you back!)

[chukkie]

Great conversion and impressive output! Hope it's still working well for you.

It's still going strong.

[alex781]

I have nearly finished my cnc conversion using the split nut backlash solution outlined here. The carriage (if that's the correct term for the part between the X and Y axis) has turned out great, but the split nuts less so as I made the cut with a hacksaw that refused to follow a straight line.

I can see that the thin (adjustable) side of the split nut has holes to let the mounting screws through. Any idea if it would work just as well if I sawed the corners off rather than drilling? Something like this, to save me the headache of aligning holes:



Thanks for any comments/suggestions, I would be over the moon if I could produce the kind of parts shown here!

[chukkie]

Looks like it would work to me.

[alex781]

Looks like it would work to me.

Well now i've temporarily attached a mini 4"x4" compound table to the bare base of the X2 with F-clamps, so I can cut the mounting holes in the nut with a slot drill. (Was going to drill with a regular twist drill bit but I assume it's better for adjustability for the surface in contact with the mounting screws to be flat). Anyway thanks for the ideas

[alex781]

My mill is up and running, just a quick question for any X2 users -is it the case that the fine feed wheel on the Z does not have the same TPI as the X and Y axis? (if you can say a rack and pinion has a TPI)

The fine feed wheel is marked from 0 to 60 and the others are 0 to 62.5.
I am trying to calculate my steps per inch, it should be 12800 for the x and y using half steps and 2:1 timing pulleys.

Thanks

[hoss2006]

are you using the fine feed for cnc?
it has tons of backlash which is why most go with direct drive instead.
it's turning a worm gear which is driving the pinion on the rack so it's not the same "TPI"
as the x and y.
use your steps for the x if its the same belt ratio to get you in the ballpark
and use the Mach axis calibration to get it just right.
[nomedia="http://www.youtube.com/watch?v=XkO5tc-jSxw"]YouTube- Improved Mach 3 Axis Calibration[/nomedia]
Hoss

[alex781]

are you using the fine feed for cnc?
it has tons of backlash which is why most go with direct drive instead.
it's turning a worm gear which is driving the pinion on the rack so it's not the same "TPI"
as the x and y.
use your steps for the x if its the same belt ratio to get you in the ballpark
and use the Mach axis calibration to get it just right.
YouTube- Improved Mach 3 Axis Calibration
Hoss

I am using the fine feed for CNC just to keep the costs down, less than $800 spent in hardware at this point. I'm sure it won't be quick or easy to duplicate but Chuck's level of backlash on the Z using the stock controls would be ideal.
Thanks for the vid link, the whole series is a great resource and I'm learning a lot. it didn't occur to me that the X & Y leadscrew thread could be slightly more or less than 16tpi! I hope it's at least consistent across the length.

[TroyO]

Alex, that way of making splitting the nuts will work just fine. That's how mine ended up.

It wasn't my intention... LOL, I just mis-measured (Or at least mis-installed) mine and the set screws that hold the nut in place cracked a corner off. Anyway... I went ahead and cut the rest off just about exactly as you have pictured and it works just dandy. (By the way... thanks Chukkie! That mod seems to work great... even if I futzed it a little, LOL.)

PS... I think the part between the table and base is called the "Saddle".

[alex781]

Alex, that way of making splitting the nuts will work just fine. That's how mine ended up.

It wasn't my intention... LOL, I just mis-measured (Or at least mis-installed) mine and the set screws that hold the nut in place cracked a corner off. Anyway... I went ahead and cut the rest off just about exactly as you have pictured and it works just dandy. (By the way... thanks Chukkie! That mod seems to work great... even if I futzed it a little, LOL.)

PS... I think the part between the table and base is called the "Saddle".

LOL I knew the hole placement would be a hassle and 'cutting corners' is what I normally do. It's split now and seems to do the job. I take it you converted an X2 as well, is there a write up for your build? Thx for the vocab check

[TroyO]

Nope, no conversion... just making it the best hand-cranker I can.

[alex781]

I am finding the split nuts on my build make the axes very stiff at sub 0.003", wondered if this was normal, or a problem with how I split them.

I imagine those thrust bearings on your Y axis were to reduce stiffness? I should probably test again with a better dial indicator.