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Rockwell 21-120 Horizontal Mill back gear issues

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Registered Member
Jan 27, 2015
I have the manual and read how to adjust the backlash but I am confused and I can't get it to go into back gear,
does anyone have experience with this adjustment. Also my mill doesn't have jam nuts it only has cap screws, so I will get those soon.


H-M Supporter - Premium Member
H-M Supporter-Premium Member
Nov 27, 2015
jdjax, are you still having trouble with the backgear? I have a Rockwell horizontal/vertical combination mill. I think the backgear is the same as the 21-120 horizontal model. I've never tried to adjust the backlash, but I can get it in and out of back gear. On my machine, the back gear hadn't been engaged for quite some time, so the engagement lever was kind of sticky. Also, the PO had mounted a VFD in a position that interfered with the engagement lever, such that the lever couldn't be turned quite far enough to allow it to be pulled out to engage the gears. After I re-positioned the VFD mounting bracket and lubricated the backgear lever, I was able to get it in (and out) of backgear fairly easily.
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