Author Topic: unintended reshaping  (Read 1446 times)

Offline Ken S

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unintended reshaping
« on: November 11, 2018, 02:42:52 pm »
Yesterday I started to sharpen my grandfather's turning tools. They are a 1930s vintage Sears Craftsman carbon set of eight tools. They are true garden variety tools. My grandfather used them very skillfully making chairs and tables. They were carefully sharpened with clean straight bevels. I hesitated to grind away my grandfather's skilled sharpening, however, they were no longer sharp.

I started with the one inch straight ground skew chisel. I used the Multi Jig with the standard settings: hole B, 65mm protrusion, and 20° skew. This would make resharpening very fast in the future. I scribed a line on the grinding wheel with a fine tip marker using the support bar as a straight and sauare edge. The skew angle seemed very close. I also used a black marker on the bevels. The bevel angles did not exactly match the Uniform standard Tormek settings, but seemed close. I marched on for a bit before adjusting the microadjust.

I was using my SG-250. (My diamond wheels are presently on loan, which gives me a chance to get reacquainted with my SG.) Getting my skew to the exact Tormek profile will take some time. I am reminded of a wise comment Jeff Farris made in the Tormek turner's video, approach reshaping gradually. I knew that, but had temporarily forgotten it. In hindsight, I should have noted the variance of the skew from the Tormek profile and tweaked my set up to come closer. Within two or three sharpenings, I would be on target with minimal steel removal and less time spent.

I used the horizontal, grinding away support bar set up. (I should have tried the vertical position.) Using the horizontal position, I also set up my TT-50 truing tool in a separate support bar left in place (but raised) in the vertical sleeves. I have found that very light truing exposes fresh, sharp grains more effectively than using the stone grader.

The operation took longer than I had planned. The SG can handle the operation, but not quickly. Once the profile is matched, just sharpening goes much faster. Good preparation of the grinding wheel is essential.

Ken

I finished sharpening that one inch skew and also completed work on the half inch skew. Only six more tools to go.......

Offline Ken S

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Re: unintended reshaping
« Reply #1 on: November 12, 2018, 12:07:35 pm »
follow up:

I later realized something which increased my skew grinding time. My grandfather sharpened his tools with a six inch grinder; I was using my 10 inch Tormek. The arcs are different. Like any other reshaping factor, this is a one time constraint.

As part of my "post mortem" analysis, I watched the skew sharpening section of the TNT-300 DVD. Jeff Farris suggested switching to the more aggressive vertical grinding position. I had just rewatched the entire DVD a couple weeks ago. I think that somethings are not absorbed into my brain until I need them. I do believe in the value of reviewing really good instructional material (both printed and video) occasionally. I think of it like grading my SG-250; I can refine the scratch pattern and pick up some finer points.

Ken

Offline Ken S

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Re: unintended reshaping
« Reply #2 on: November 12, 2018, 09:04:54 pm »
I would add two more suggestions.

The first one, again from Jeff's Tormek Turning DVD, is his suggestion for sharpening a very worn skew, using a stop block and playing cards. My Craftsman turning chisels don't have too many sharpenings before they become too short for the standard set up. The back up method is good to know.

The second suggestion is to keep a green Scotch-Brite pad nearby to buff the surfaces. My tools are not stained or rusted, however, more than eighty years have dulled the metal a bit.

Ken