Situation 6：Aperture Reduction or Increase.

Reasons for shrinkage:

①Too low cutting speed.

②Too large feed.

③Too small main declination angle of reamer.

④Inappropriate selection of cutting fluid.

⑤When sharpening, the worn part of the reamer is not worn off, and the elastic recovery reduces the aperture.

⑥When reaming steel parts, If the allowance is too large or the reamer is not sharp, it is easy to produce elastic recovery, which reduces the aperture and the inner hole is not round, and the aperture is unqualified.

Reasons for Increase:

①Cutting speed is too high.

②Improper feed rate or excessive machining allowance. 

③The main declination angle of the reamer is too large, and the reamer is bent.

④Chip edge adhered to the reamer cutting edge. 

⑤When sharpening, the swing of the reaming cutting edge is out of tolerance.

⑥Inappropriate selection of cutting fluid.

⑦When installing the reamer, the oil on the surface of the taper shank is not wiped clean or the taper surface is bumped.

⑧After the flat tail of the taper shank is offset into the machine tool spindle, the taper shank taper interferes. 

⑨The main shaft is bent or the main shaft bearing is too loose or damaged. 

⑩Reamer floating is not flexible.

⑪When the axis is different from the workpiece and the force of both hands is uneven when reaming by hand, the reamer shakes from side to side.

Solutions:

①Appropriately reduce the outer diameter of the reamer according to the specific situation.

②Reduce the cutting speed to properly adjust the feed or reduce the machining allowance.

③Appropriately reduce the main declination angle to straighten or scrap the unusable reamer that is bent.

④Carefully trimmed with whetstone to pass.

⑤The control swing is within the allowable range.

⑥Choose cutting fluid with better cooling performance.

⑦Before installing the reamer, the reamer taper shank and the inside of the taper hole of the machine tool must be wiped clean, and the taper surface with bumps must be polished with whetstone.

⑧Grinding the reamer flat tail to adjust or replace the spindle bearing.

⑨Readjust the floating chuck and adjust the coaxiality.