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I was the one that brought the old thread back up to the top.  I am very sorry to hear about Jan.  He was very helpful in helping me to get up and running using the Dutchman formulas for knife sharpening.

I will do some experimenting with his simple drill bit jig to see if I can get satisfactory results.

I know this is a very old topic, but I hope I can get some clarification on Jan's diagram that he posted on January 8, 2017.  His jig looks very clever, and I want to try it out.

From geometrical point of view there are no limits to the drill bit diameter. If you use my method to set clearance angles please keep in mind that the height of the aligning bar has to be equal to the drill bit radius. 

Jan

The 10 degree and 20 degree lines are shown on the edge of the stone.
a) I am interpreting Jan's explanation to mean that the top face of the bar would be at the same line as the top of the drill bit?
b) Does this mean that I would need a different bar thickness for each different diameter of drill bit?
b) Would the zero degree mark pass through the center of the drive shaft, or is zero degrees at the edge of drive shaft?

I never seem to be able to keep my stone round after a few iterations of grading between fine and coarse.

I was going to try using the diamond plate method as shown in Wootz's post.  I already have a few diamond stones (the heavier type, not the thin credit card type). 

This might be a dumb question, but I would rather find out the easy way than the hard way.  Is there a reason why the heavier stones, clamped in the square jig, would not work?  Would using them for stone grading affect them for other uses?

I have the Tormek Supergrind.  I would like to try to use the USB elevation/position settings from jvh's TormekCalc spreadsheet.

Can anyone tell me if the geometry of the Supergrind will be compatible with TormekCalc?  I don't know if updated Tormek models shifted the location of the center of wheel, or the location of the USB supports that could affect USB settings.

Thanks.

I experimented with TormekCalc a bit more.  It is really nice.

It seems that all of the calculators are geared toward knife sharpening, and the variable "jig diameter" accommodates knife jigs.

I have had to establish an artificial diameter to accommodate my SVH-60 straight edge jig to use those calculators.

Not a big deal, but I might have to establish several variations of the SVH-60 jig properties in TormekCalc to accommodate different thicknesses of chisels and plane irons.   

Thanks smurfs!  That is a great resource.  I am very encouraged that the spreadsheet that I wrote, which was based on Dutchman's spreadsheet, matches the results of TormekCalc.

I am going to keep both handy!

Steve

Thanks Jan.  That is good to know.  It seems to have worked okay so far, but sometimes small chisels are hard to set square.  I am hoping my setting jig will eliminate that issue.

Steve

cbwx34,
Thanks for posting my pictures!

Jan,
I read the thread that you linked above.  That is very informative, and it sure looks simple (and repeatable).  I think if I had read that a week ago, I would have already adopted that method.  And I will certainly keep it in mind.

BUT - now that I have started down this path I have noticed the possibility of elevating my results.

For example, switching over to the honing wheel, which will require me to re-set the USB on that side and try to achieve the same angle.

Or even jumping to another machine...I noticed that wootz has paper wheels in his collection.  I happen to have 8-inch diameter paper wheels (which I have never used) and a spare bench grinder.  I was thinking about setting up a USB mount on that system.

The idea would be to be able to achieve the same grinding (or honing) angle on the second wheel.  I may be chasing diminishing returns, but I don't know that yet.  So many ideas, so little time.

I will follow up when I have time to try my ideas out.
Steve

Thanks Jan, I will definitely read that thread.

Over the past few days, I have discovered old threads that cover some of the things I have been inquiring about.  I can see that I am dragging you, Dutchman, cbwx34, Ken, and others through topics that have already been hashed out!

I am not sure if you noticed in my earlier post - my square edge jig does not resemble yours at all.  I tried to post a picture, but I cannot shrink it enough for the forum to accept.

Steve

The quote in blue (from p.12 of Dutchman's book) and the referenced figures is how I interpret it...

cbwx34,
Thank you for pointing that out.  I don't know how I missed that.  It makes much more sense now.

Steve

[center]

but I believe JG should be from the tip of the blade to the center of the USB. 

That actually makes the most sense to me, but it seems that all the diagrams for the knife sharpening jigs illustrate this dimension being measured from the back face of the USB - and it seemed that the only dimension that differentiated the knife sharpening jig from any other jig was the diameter of that jig. 

Maybe I missed it in the "More math" document, but I did not see a note that 6 mm should be added to the JG measurement for jig setting.  The 6 mm additional correction to reach the back of USB was clearly depicted in the original Dutchman document (A vs K).

I don't mean to obsess about this too much, and I appreciate everyone's patience.  After looking into this so much, having a clear understanding of the setting parameters and relationships has become very important to me.

I was not able to download a working copy of Dutchman's spreadsheet for some reason, so I duplicated it myself and I match every one of Dutchman's values.  I would be glad to post the Excel spreadsheet somewhere, but I am not sure it is mine to disseminate without Dutchman's approval.

Unfortunately, I am unable to load photos small enough for the forum.

I have attached a crude sketch that shows my measurement from the bottom of USB to bedding surface.  I am interpreting Dutchman's "More math" sketches to calculate JC as shown.

It is my understanding that for a blade already ground (approximately), then the "sinking" effect could probably be neglected, and the full thickness of the (single-bevel) blade should be used for calculations, as this is the line to the tip of the blade at the grinding wheel.

If I am interpreting Dutchman's sketches correctly, the JG measurement is from the tip of blade contact with the stone to the back face of the USB as shown.  I would appreciate confirmation that I am calculating JC correctly, and interpreting the JG dimension correctly.

Jan, apparently my jig dimensions do not match yours.  Maybe I do not have an SE-76.  Also, mine does not have a notch inside to affect the bedding angle.  I guess this is why my calculations were not matching the ones you posted earlier.

More comments are welcome.  I really appreciate the discussion on this.

Steve

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

The equations in "More math ..." can be used 

Dutchman, Thank you for your excellent work, and sharing this information.  I did not understand immediately what you meant by your comment about "More math...".   Then I realized this was a reference to an update of your original document.  I have now spent some time studying the "More math" document. 

I am pursuing the use of these concepts for chisels and plane irons, with the SE-76 square edge jig.  My question is how to establish the distance JC for this jig - which is for a single bevel blade.

Please confirm if my method is correct, or point out where I am wrong.

Distance from the jig bedding surface/bottom of blade to the bottom of USB = 23.5 mm.
Subtract 6 mm (radius of USB) from this value = 17.5 mm.
Add the full thickness of the blade (3.0 mm).
JG = 20.5 mm.

Thanks again.
Steve

Steve,

So if you find there are errors in my assumptions or calculations, please do elaborate.  I'll be grateful, and happy to fix it,

Kind regards,
Rich

Rich,
Thank you for responding and making that app available.  Sorry I could not recall your name when I referred to this in my post.  I was looking for your name on the website app, but did not see it.

One minor comment on the calculations you shown at the bottom of the diagram - I believe there is a typo.  It seems there is a "2" missing in equation 1, just in front of the parentheses.  I think the quick calculator is using the "2" in that equation.


Once again, I really appreciate the discussion on this topic.  There have been many more responses than I expected.  Great discussion on the effects of wheel wear.  I am hoping to dedicate some time this weekend to dive in.

Steve

Thanks for this discussion.  I hope to have time to review some of your comments this weekend.

One thing I did notice - I made my own spreadsheet based on Dutchman's calculations and assumptions, and I match the numbers in his tables exactly.

I found another website app (from one of the Tormek site members) called Sharpening Handbook.  The math is basically the same as Dutchman's, but there are some slightly different assumptions involved - such as the distance from the top of the USB to the center of jig.

I found that these differences result in minor changes in the results.  I don't really mind the slight difference - I am more concerned with jig settings for repeatability.

Steve