Straightening Leadscrew...

[Fatboy]

I built my Joes 2006 last November and originally used 1/2" single starts for leadscrews from Enco. They were like pretzels, so I ordered 5 starts and Dumpster nuts. The Y and Z were great but the X had a wiggle in it so the cuts were not the cleanest. The wiggle also kept my speed down to about 100 ipm on the rapids.

About a 2 months ago I got another lathe that is far better than the Enco 3n1 I've had for 10 years. Being a little bored I decided to tackle the X screw and true it up. I chucked it in the 4 jaw with 6" exposed and supported the extended end through the headstock with a centering bushing. I marked the thread with a blue marking pen after dialing it as close to zero as I could get.

Then I moved the dial indicator to the end and tweaked it until it was close to zero also. (I used a long piece of shim stock on the threads so the indicator had a smooth surface) I rotated the lathe by hand. Next I loosened 2 jaws enough to slide the screw out and align the pen mark with the indicator. Moved the indicator back to the chuck and repeated the entire process again.

After a couple of 6" sections I was able to use the steady rest to help support the screw on the chuck side. Took about 4 hours to do the entire screw and I managed to get it within .002". After carefully reinstalling it in the router I was able to boost my rapid speed to 180 ipm (200 was just on the verge of skipping steps) and no decernable shake...I so happy.

Now the Y is a little off, I just think that it's jealous. Maybe I'll straighten it tomorrow....it would sure take less time, maybe not.

Guess I shoulda taken at least one picture...thought about it but then forgot. Maybe tomorrow....maybe not.

Fatboy

[joecnc2006]

Originally Posted by Fatboy I built my Joes 2006 last November and originally used 1/2" single starts for leadscrews from Enco. They were like pretzels, so I ordered 5 starts and Dumpster nuts. The Y and Z were great but the X had a wiggle in it so the cuts were not the cleanest. The wiggle also kept my speed down to about 100 ipm on the rapids. About a 2 months ago I got another lathe that is far better than the Enco 3n1 I've had for 10 years. Being a little bored I decided to tackle the X screw and true it up. I chucked it in the 4 jaw with 6" exposed and supported the extended end through the headstock with a centering bushing. I marked the thread with a blue marking pen after dialing it as close to zero as I could get. Then I moved the dial indicator to the end and tweaked it until it was close to zero also. (I used a long piece of shim stock on the threads so the indicator had a smooth surface) I rotated the lathe by hand. Next I loosened 2 jaws enough to slide the screw out and align the pen mark with the indicator. Moved the indicator back to the chuck and repeated the entire process again. After a couple of 6" sections I was able to use the steady rest to help support the screw on the chuck side. Took about 4 hours to do the entire screw and I managed to get it within .002". After carefully reinstalling it in the router I was able to boost my rapid speed to 180 ipm (200 was just on the verge of skipping steps) and no decernable shake...I so happy. Now the Y is a little off, I just think that it's jealous. Maybe I'll straighten it tomorrow....it would sure take less time, maybe not. Guess I shoulda taken at least one picture...thought about it but then forgot. Maybe tomorrow....maybe not. Fatboy

Good thinking on holding the screw to straighten it out.

[pswayze]

Whatever you have done sound pretty slick but I can't quite picture what you did. Can you link to a video or diagram of what you did?

[Fatboy]

Good thinking on holding the screw to straighten it out.

Thanks Joe and also thank you for designing the 2006 and posting it here.

pswayze,
You're in luck because I straightened the Y last night and took a couple of cell phone pictures. Note that the shim stock is there just provide a bridge across the tops of the threads and this allows the dial indicator to gage the deflection of the screw. The lathe is being used just as a holding fixture that I can rotate by hand. With the 4 jaw chuck I can adjust the screw to zero run-out and then extend the screw 6" and move the indicator to the mark and check the run-out there. If there is then I apply a little force to remove as much of the run-out as possible. The steady rest keeps the screw from sagging so that I can get a better reading. Also, there is 24" of spindle length through the chuck that needs to be supported, especially for the 62" screw. I made a adapter to center the screw in the spindle.

The blue pen marks are there to set the amount of screw extended from the chuck. There are 9 marks on the X screw. The dial indicator is mounted on the cross slide so that I can move it long ways to a pen mark and in or out to set the zero on the dial.

I wish that I could explain this better, maybe if someone understands they would put it in better words.

I might get out all the 1/2-10 one starts and true them up too.

Hope this helps,
Fatboy

[pswayze]

Ah! Very nice. Thanks for the pictures. I'll keep that in mind.