Hand Tools

Subject:
Conclusions of abrasive size experiment

Bill Tindall, E.Tn.
Are these conclusions valid?

Conclusions:

1. The resulting surface from 5 micron front and back is unacceptable to someone planing for surface appearance. Surface planers should not further consider sharpening to only 5 micron or equivalent.

2. For both the less abrasion resistant "Ward" and the "Weaver O-1" , 5 micron front and back shaved about 200 feet from the life of the blade for a shaving lifter.

Speculation:

1. 5 micron front and back will leave the edge more venerable to initial wear than 5 micron bevel and polished back.

2. The price to be paid by a shaving lifter for stopping at 5 micron is an initial loss of 200 feet of edge life.

3. A more abrasion resistant steel might not suffer as much initial loss as a softer steel because of less scratch depth.

4. This initial loss of edge life could be 200 feet or less for any blade, and hence less meaningful for long life steel like V11.

5. A few passes on leather charged with abrasive could lessen the adverse impact of stopping at 5 micron. Ditto for a polished back that remains polished.

Why do I care? I can not go from 120 grit grinder to 1 micron without grinding perilously close to the worn edge. Hence, there is an intermediate step of "Fine" fixed diamond. Hence, I am using the advantage of cheap and fast cutting loose diamond on cast iron in the step where it is the least efficient. It would be best to use loose diamond after grinding.

Desirable would be grind at 120, xx micron diamond on cast iron, strop, Done. 5 micron would do the job removing metal and 3 might.

David's excellent work will cause me to move to PMV11 blades for all my shaving liftings . His work on abrasive size has encouraged me to resurface my cast iron plates and investigate 3 and 5 micron diamond followed by strop for sharpening.

Nobody here will care where I wind up but the furniture makers on the main board and elsewhere might. I will report David's work at our club meeting when we start up in the Fall

Thank you!

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