Page 397 - Gear Technology Solutions

Torquing the truing screw much higher will quickly result in an overshoot
and the bar increases its length to the right side and turns red again. Merely
turning the wrench backwards until the bar turns green again will not
achieve the desired result. The blade will set during the first chip removal
and subsequently will lose its radial positioning accuracy. In such a case of
an overshoot it is required to rotate the wrench all the way back to zero
torque and start the sequence again.

The described sequence is repeated for all remaining blades. It will be noted
that in comparison to the original Pentac-RT building procedure by using 5ft-
lbs (7 Nm), the torque applied to all adjustment screws is on a significantly
lower level with the new procedure.

28.7 Summary

If the recommended procedure is followed, it will be noticed that the truing
sequence of an average cutter head can be done in 30 minutes. If this is
compared with the conventional axial shifting of blades until a reasonable
radial deviation is achieved, then a significant time savings of 20 to 30
minutes per cutter building including truing can be recognized. However,
only a radially trued cutter provides perfect tip and radial runout which will
be noticeable in the gear production. The key points of building and trueing
a Pentac-RT cutter head which generates evenly spaced and smooth flats
and shows no signs of chatter or premature tip wear are:

► If the new truing procedure should be performed on an older Pentac-RT
cutter head, replace the conventional trueing screws with the Teflon in-
serted self-locking screws
► Continue to use the springs behind the adjustment screw heads
► Place the torque wrench especially for the clamp screws as shown in
Figure 3
► Use a low initial torque on the adjustment screws (0 to 1ft-lbs (1.5 Nm))
► Never back out an adjustment screw if the trueing overshot (turn it all
the way out and start over again)

28.8 Literature

®
[1] Stadtfeld, H.J. “Trueing Manual Procedure for Building Pentac Plus-RT
Cutters with Self-Locking Trueing Screws”, Company Publi-
cation, The Gleason Works, Rochester, New York, June
2019

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