CRP109-00 ACME 5 start nut availability

[WJHildreth]

Michael,

I sent this question to you and should have posted it here. I am only repeating for the benefit of others.

The ACME nut you specify in the KRMx01 book from CNC Router Parts, part number CRP109-00 no longer seems to be available on their website and in its place offers part number CRP161-00-02, an aluminum enclosed nut.

I wanted to know if this nut was a replacement for the original and if it required two of them per carriage like the original.

Your advice was to use the original nuts as they are still available. In order to use the new ones, modifications had to be made to the machine.

I think it is the dumster nut thread below perhaps.

If the original nuts are still available, where do I get them? From CNC Router Parts? Do you have an alternate source for them?

Thanks for your time,

Joe Hildreth

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[msimpson99]

The original nut is this section:
ACME Drive Parts | CNCRouterParts

The actual nut is located here:
Single Piece ACME Nut - CRP108-00 | CNCRouterParts

[WJHildreth]

Thanks Michael.

I was confused because the original nut was not available through them. After talking to the folks at CNC Router parts and looking at the drawings for the original and new nut, I see that the center height from the base to the leadscrew and the hole distance from center are the same.

I am out of town at the moment but will order them when I get back home. I have to admit eight of these at $35 each was a bit of sticker shock. Sometimes I just forget the costs of things. The nuts do look sturdy and of good quality.

Hope to get some time to get back to building soon.

Thanks again for all your help Michael, I really do appreciate it.

Joe

[WJHildreth]

Michael,

A quick question. I am ready to drill the supports for the Y-Axis carriages and am looking at the new nuts. These come with 5/16-18 socket head cap screws. The plans have these holes at 5/6 and you specified 1/4-20 bolts. These holes were made for a little adjustment, correct? So it should be no problem if I drill them 3/8? I guess I am being over cautious here! Just wanted to touch base anyway. You know it is bad to have everything to build the whole dang machine and I have been so busy that I am only on the Y-Axios carriages. But the machine sure is "perty", but I am biased.

Thanks for your time.

Joe

[msimpson99]

It looks like CNC Router Parts has pulled the original nut.

In any case the new nut is not a direct replacement. The problem is that it needs more clearance. You need about 1/16" more clearance for the nut to keep from hitting the Y-beam. I did this by inserting a small piece of 1/16" thick aluminum between the supports and the main frame.

Refer to Step 7 in Chapter 5. I cut a small piece of aluminum 1" x 2" x 1/16" from 1" x 1/16" aluminum bar. You will need to mark the holes to match those in the main frame and support. You will need four of these for each carriage When installing the supports to the main frame, the aluminum spacers go between the two. This will pull the supports about 1/16" further away from the beam when the carriage is attached to the rails. As for the screws I still used the 1/4" bolts. You can use the 5/16" bolts but will have to drill larger holes. If in doubt use 1/4" bolts.

The motor/bearing mounts have enough play that you should be able to easily compensate for the 1/16" difference before tightening.

It has been awhile since I did this mod so keep us informed.


The key is to have a little play so you can line up the nuts.

[WJHildreth]

Michael,

Thanks for the help. I drilled them at 3/8" and will use the supplied 5/16" socket head bolts that came with them. I also think I have some 1/16" sheet aluminum that I can cut the spacers from. I will document the changes on my website. I hope you don't mind but I quoted you above. You can see it at CH5 - Y-Carriage Construction

Regards,

Joe