Page 329 - Gear Technology Solutions

22.9 Tolerances for Blade Grinding and Cutter Building

All Gleason recommended tolerances for blade grinding and cutter head build-
ing are compiled in the table, shown in Figure 29. The following list with bullets
gives recommendations of how to apply the tolerances in Figure 29.

● The surface finish of the cutting profile of the blade should be
Ra = .25microns or less.

● Care must be taken to avoid burning during the grinding process. Burned
blades usually exhibit reduced hardness resulting in poor cutter life.

● Also, carbide blades can show burn marks when the cobalt binder is ex-
posed to high grinding flash temperatures.

● Burned blades must be topped down by re-grinding in order to remove all
areas that have soft spots.

● Blades should be ground in batches to the tolerances specified. Sets of
blades should then be selected and sorted based upon the variation within
one set.

● Master blades should be made equal or better than 70% of the tolerance
indicated in the Guidelines under Variation within one Set (Figure 29) and
should be marked with the differences from the nominal dimensions

● For GR&R studies use tolerances defined in the columns marked Set to Set
Variation

● The Set-to-Set Variation is the maximum allowed range a blade parameter
may vary from the theoretical Nominal as specified on the blade grinding
summary

● Blade depths vary among different cutter sizes. Often there is more than one
depth for one particular cutter size. Therefore, the Profile Depth is used to
determine the absolute tolerance of the Set-to-Set variation for blades
measures on the No. 562, the GBX or BIM machines

● To determine the correct Profile Depth bound tolerance for measurements
performed on a No. 562 machine, subtract Y2 from Y1 as indicated under
No. 552 Blade Checking data, shown in the blade grinding summary.

● Unless otherwise specified, clearance side tolerances may be increased
above their pressure angle side equivalents

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