In the Shop > General Tormek Questions

Using Dutchman Tables with Square-Edge Jig for Plane Irons?

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arnman:
I found the excellent threads discussing the Kenjig and Dutchman tables.  It seems the discussions and Dutchman's tables were developed for the knife jig.

I would like to develop some quick-set jigs for plane irons and chisels.  I have the old-style square jig, if that matters.

I don't see any reason why I could not use Dutchman's equations to develop settings for my purpose, but I thought I would throw this out to more experienced users first.

Thanks.
Steve

Ken S:
Excellent question, Steve.

I don’t see why Dutchman’s tables would not work. In my case, I started what would evolve iinto the kenjig sharpening my chisels and plane blades. This was before Dutchman posted his tables. My goal at the time was to avoid having to measure each blade using the Anglemaster. By keeping the Distance and Projection constant, I could sharpen chisels and plane blades all day without having to remeasure.

I used the two holes in the TTS-100 to set a constant Distance. With this Distance set, I used the Anglemaster to set the appropriate Projection. I then marked this projection (from the front of the square edge jig) on a piece of blank label tape placed in one of the three slots of the TTS-100. I made a mark at the end of the blade in the slot and labeled it (eg. “25 degrees”). Adjusting the Projection instead of the Distance is a bit clumsy, however, I only needed to do it once.

You might have to compensate to use Dutchman’s tables with the square edge jig. I have not tried this, however, I don’t think it would be omplicated. Hopefully Dutchman will post. He is the authority on this. I will email him.

Ken

arnman:
Thanks Ken.

I thought about using some trial and error to set the projection (and make a jig), using a fixed support distance from the wheel surface.  However, I know that over time this relationship would change.  Of course, I don't know how long that will take.

My thought was possibly to develop a spreadsheet using Dutchman's equations, specifically for use with the square grind jig.  As you know, there would be a different range of "S" and "A" values with the square grind jig vs the knife jig.  Also, I thought I may as well use the spreadsheet for the range of wheel diameter I will be working in for the realistic future (which is 230 mm to 240 mm).  I could run the spreadsheet for each 1 mm change in wheel diameter.  At this time, I don't know how sensitive cutting bevel is to a slight change in wheel diameter.  But for the level of sharp we all like to chase, I suppose it would be sensitive.  I guess if I get it really close with the set-up, I can do a slight adjustment using the sharpie method before grinding.

I have a lot of ideas floating through my mind right now about how to implement this.  One of them would be to develop an adjustable projection jig, which would allow the projection to be set to the spreadsheet projection values - which would ALL be established for the SAME distance between the support and wheel surface "S).  I could use a spacer block to set the support bar.

I hope that makes sense.  I have to think through the details a bit more. 

I don't have much experience with the machine, so I could be chasing a bad idea.

Steve

Ken S:
Steve,

I think you are overthinking this. Most bench chisels are sharpened with a 25° bevel. Paring chisels normally get 20°. If you happen to use mortise chisels, they get 35°. Plane blades normally get 25°.

One of the reasons I used the TTS-100 is that the two small wheels are Tormek's patented means to auto correct for wheel diameter changes. (The 250mm T8 wheels and the 200mm T4 wheels use the same TTS-100 with no adjustments.) A plane blade or chisel back is a large enough surface to work well with the Anglemaster. Either the tape mark in the slot or wooden stop blocks work well to set the Protraction.

You have good creative instincts. I just think another project would be better for them.

Keep thinking!

Ken

Jan:
Arnman, Dutchman tables do not work for the square edge jig because the geometry of this jig is substantially different from the knife jig.

Nevertheless you can use the Dutchman’s approach and equations to calculate tables for square edge jig. I have a simple calculator for it, so I can verify your results. Let me know.
 
Jan

P.S. Important guidance resulting from recently closed discussion on this forum: the set up does not depend on the chisel thickness!


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