• LInsufficient lubrication at lower slides causes slides to hang and jump.
  Lubricate per manufacturers "Lubrication Instructions and Specifications". Be certain to adjust size again.
• Worn spiral gear on slide adjusting screw.
  Move spiral gear on screw to new contact face and lap gears together.
•  Slide adjusting screw thrust bearings loose.
  Tighten adjusting screw.
• Worn gears in hand feed unit.
  Replace with new gears.
• Worn or loose lower slide gib allows side movement of slide, cocking regulating wheel.
  Reset gib
• Loose work support blade allows deflection.
  Tighten blade in body and tighten body to lower slide.

FAULTY SIZING - Work Out of Round

• Work piece over size (generally), or under size a few tenths of a thousandth.
  In a majority of throughfeed jobs, grinding should be done with ‘upper slide clamped, lower slide unclamped, and adjusting screw set in middle of backlash so there is no strain on screw. If infeed screw is under strain either way any considerable jar on machine, such as from a passing industrial truck, nearby trip hammer or a light blow to machine, etc., may cause a slide movement of a tenth of a thousandth. Also unclamping or clamping either slide might cause a slight movement.
  To adjust slide either way a few tenths of thousandths do so with a 0.0001" dial indicator mounted against slide.
• Loose regulating wheel spindle bearings.
  Adjust bearings. If sizing still out, after checking every other possible source of trouble, scrape bearings.