Is this the backlash or something else

[Bamban]

Today asI was cleaning the lathe after doing a project, for laughs and giggles I chucked in a test bar and stuck an indicator on the bar to see how well the head to ways alignment I did was holding up. The alignment appears to be just fine, then for whatever reasons I decided to do some checks for anything loose. When I got to the cross slide I pushed and pull and I could hear and feel a definite movement. The indicator verified the movement - 0.006.

The backlash on the cross slide happens to be 0.006 as well. The question, is the movement I noticed the backlash, just displayed/exhibited in a different way?

The video is not very clear, but if you look closely at the indicator by my left hand you can see the hand moving with push/pull. The compound is solid, I was just using the tool post as a convenience item.


View My Video



Thank you.

 

[kd4gij]

That is back lash.

 

[Karl_T]

backlash, and not very much either

 

[Bill Gruby]

You have .006 backlash in the cross slide.

"Billy G"

 

[compsurge]

Mine rocks on the bed from right rear corner to front left (where bed wear is ~0.010"). Do you only have movement along the axis of the leadscrew? Verify the leadscrew nut is tightened to the saddle. Otherwise, 0.006" backlash isn't really anything to worry about and is actually pretty good. That's about what I have after tightening the cross slide nut (0.008" compared to 0.060" prior). I also tightened the gibs on the rear of the saddle to help with the rocking.

Are you getting any odd patterns on the cuts?

 

[rafe]

You could, after you push it away from you the .006 on the dial indicator....go ahead and tighten the handle .006 and you should take out the backlash to where you shouldn't be able to pull it back to you. That really isn't a lot of play I think my SB had around .040 or more before I replaced the screw and nut and I was able to work around that much backlash....

 

[Bamban]

Mine rocks on the bed from right rear corner to front left (where bed wear is ~0.010"). Do you only have movement along the axis of the leadscrew? Verify the leadscrew nut is tightened to the saddle. Otherwise, 0.006" backlash isn't really anything to worry about and is actually pretty good. That's about what I have after tightening the cross slide nut (0.008" compared to 0.060" prior). I also tightened the gibs on the rear of the saddle to help with the rocking.

Are you getting any odd patterns on the cuts?

Thank you.

No rocking L-R nor diagonally, just F-B. As far as cuts, had taper before, took it out by adjusting the headstock using Brian Miller's MT5 test bar. Since I intend to do some barrel work eventually, I set up the set tru chuck with a 1 inch test bar. I periodically check the alignment and chuck run out with the same 1 inch test bar. As I mentioned in the original post, it was in this test when I discovered the movement.

Is the lead screw nut the same one holding the crank?

 

[Hawkeye]

The nut he mentioned will likely be the one that rides on the leadscrew and is attached to the part that moves. Quite a few of them are designed with the ability to tighten them a bit on the leadscrew. Just enough to take out excessive movement, but not enough to make it harder to turn the crank.

6 thou backlash would make a lot of us giddy. I wouldn't worry about it for manual work.

 

[Bill Gruby]

The crank nut is the one you can see on the center of the crank handle. Look closely at it If there is a set screw in the center it will, when loosened allow you to tighten the nut to take more of the back lash out. Once you get it where you are comfortable with it tighten the set screw and it locks the nut.

It may also have two jamb nuts instead.

"Billy G"

 

[Bamban]

The crank nut is the one you can see on the center of the crank handle. Look closely at it If there is a set screw in the center it will, when loosened allow you to tighten the nut to take more of the back lash out. Once you get it where you are comfortable with it tighten the set screw and it locks the nut.

It may also have two jamb nuts instead.

"Billy G"

Billy,

I checked the crank, it looks like there is no set screw and only one nut, and the nut is super tight as it is, could not budge it