Tormek Community

In the Shop => Wood Turning => Topic started by: Ken S on August 09, 2018, 02:57:39 am

Title: reshaping a skew chisel
Post by: Ken S on August 09, 2018, 02:57:39 am
I have a flat, straight ground one inch skew chisel that I am reshaping to an Alan Lacer grind. The Lacer grind leaves a third of the chisel with a straight grind (with no skew) and the other two thirds ground with a radius. From the tip of the straight portion to the tip of the radius portion, there is a combined skew angle of twenty degrees, often stated as seventy degrees. I am doing this on my Tormek. It has been laborious, however, it is a one time project. Resharpening in the future will go much more quickly.

I am new to sharpening turning tools. This project is very educational. It is also humbling. Let me state up front that I don't know how many of my difficulties are Tormek related and how many are operator inexperience. I am making progress.

Switching from the horizontal position to vertical helped. Switching from the Multi Jig to the platform was a big help, at least for this combined grind. Also, I found that turning the platform around helped. The locking screw rides outside the grinding wheel. The platform is offset to the right. This allows the long side of the platform to face between the support bar and the grinding wheel. It keeps the chisel much steadier.

I use two thicknesses of plastic gift cards laid on the platform to allow the Anglemaster to touch the grinding wheel. Alan Lacer describes the bevel angle as the angle which makes the bevel 1.5 timesthe thickness of the chisel. In plain trig, that is close to twenty degrees. I plan to dedicate one of my several support bars to this grind and leave the platform "permanently" set as well as the microadjust set. This will speed up future resharpenings.

My sharpening of the radius portion was not going well. Getting the platform oriented better was an improvement. Using the gift cards with the Anglemaster set the bevel angle properly. I also noticed that I did not have enough skew angle. By the end of today's session, I still had the enduring small flat spot on the radius edge. I did get rid of the multiple bevels and down to one clean bevel. I think the flat spot will be ground away as I correct the skew angle. My next sharpening session will see me much closer to the finish line.

Incidentally, Alan Lacer hones with a 600 grit diamond hone. The DF-250 600 grit diamond wheel may prove to be an ideal honing tool. I am not there yet. I am making progress.

Ken
Title: Re: reshaping a skew chisel
Post by: Ken S on August 18, 2018, 07:42:40 pm
After the second sharpening:

Resharpening went very well. I left my platform pre set on a support bar. I also left the micreadjust set. All I had to do was drop the support bar and platform in the sleeves and tighten.

Most of the time, the ACC solution would already be made up. Today I mixed up 150ml water + 6ml ACC. The T8 can work with 125+5 ml. The extra will not cause any spillage and will lessen the effect of evaporation. Support told me that it is water that evaporates, not ACC. When I was through sharpening, I just lowered the T8 water trough.

I switched to the DF-250 600 grit wheel. Four light round trip passes on each side did the job. I should have more scientific; fewer passes might have sufficed. I finished up using the leather honing wheel. I used another support bar, however, my second platform was cut and modified to be two small platforms. I plat to get another platform so that I can leave both support bars set up. (At this rate, I will soon run out of support bars.  :(

The skew tended to lunge forward with the leather honing wheel. This may have been because of being trailing edge with the leather wheel. Using a standard platform might help. I will try that next time.

The journey is proving longer than I initially anticipated, however, I am making progress.

Soon there will be a slight detour in this process. I live near Rich Colvin. Rich is a very experienced turner. I want to learn his thoughts on the three diamond wheels and Multi Base. I plan to leave the three wheels and Multi Base with Rich for an in depth field test. During that time, I will be back to working with my old friend, the "Original" SG grinding wheel. That should actually provide a more interesting topic, as the SG is our standard wheel.

I will continue to keep posting.

Ken