I am collecting all the hardware for a modified Joe 2006.

I have the R8ZZ 1/2"x1 1/8"x5/16" bearings and today received my
1018 Carbon Steel Precision Acme Threaded Rod 1/2"-8 Acme Size, 4 Turns/Inch, 6'L, Rh Thread from McMaster Carr part #99030A716

The bearings will not go on the rods!

I have the Dumbstercnc parts on the way, I just saw on there website that they are for McMaster Carr Acme Threaded Rod part #98940A629

I did not see any differnce in the two Acme Threaded Rod part numbers other than that they are made from differnt metals.

Am I going to have a problem with this, or is there a way to make all this work?

travisc,
others have seen the same. Most have turned down the screw slightly with a lathe setup and a file. Some have made a homemade lathe ( just a drill to turn the rod) and a file to remove a small amount of material.
I have the same materials and plan to do the same. I have a wood lathe, and will use it to turn the rod so I can file off enough to fit the bearings. I haven't measured mine yet, but I believe reported oversize is about .003

It looks like you bought 1/2-8 screws and nuts for 1/2-10 . Are you sure you have those nuts, because they won't work. :(

As for the bearings, try spinning the screw in a drill, and lightly filing or sanding it until they slide on.

Thanks,
BobF
I will make a lathe setup and fix the screws
Ger21
I copied and pasted the wrong part number in my post, it should have been 98940A623, for the nuts that matches the 1/2"-8 ACME 2 Start
so, I did order the correct one.

yup, i had the same problem, i posted a picture of my simple jig with a drill as shown in the Mod section Post #32

http://www.cnczone.com/forums/showthread.php?t=29977&page=3

Joe

I did what joe did as well, it's a common problem. Once you sand it down consistently (or file it) the threads will be a little off. I found after jogging the machine around a bit it will work those threads back into place well and it will be smooth riding again.

yup, i had the same problem, i posted a picture of my simple jig with a drill as shown in the Mod section Post #32

http://www.cnczone.com/forums/showthread.php?t=29977&page=3

Joe

http://www.cnczone.com/forums/showpost.php?p=294093&postcount=32