Angle Grinding Calculator Help Please...

[darita]

I see that there is Calculator 1 and 2.  I have an old Supergrind 2005 with a Tormek Diamond Wheel.  Which calculator should I be using and why?  Also, how does this calculator compare with the KnifeGrinders calculator?  Thanks for the help.

[Ken S]

Derek,

You posted this earlier:

10
Knife Sharpening / KnifeGrinders Fprmula Question...
« on: November 15, 2021, 10:57:35 pm »
I'm trying to use my Supergrind 2005 to do regrinds to finish on my guided knife sharpener.  Problem is, I set up the Tormek using KG app, for a 16*dps, but when I check the angle on my other sharpeners, it comes up 17.5*.  What am I doing wrong?


Based on what you posted, what would happen if you set the KG app for 14.5° to end up with 16°? You may have to do some experimenting; however, if the error is constant, all you need to do is put in the corrected angle reading.

Ken

[darita]

Do you think I'm getting an error in the dps angle because I'm using an old Supergrind 2005?

[cbwx34]

I see that there is Calculator 1 and 2.  I have an old Supergrind 2005 with a Tormek Diamond Wheel.  Which calculator should I be using and why?  Also, how does this calculator compare with the KnifeGrinders calculator?  Thanks for the help.

If you're talking about the Calcapp calculator... all the calculators give the same results.  There's more than one so you can, for example, set one up for sharpening, and one for honing. (I recently added a "2in1" calculator that does both on one screen, so you can use the other 2 calculators for something else... if you use more than one machine for example).  But all work the same.

It doesn't matter what model Tormek you're using in the Calcapp app.

I'm on the record saying that KGs calculator contains "differences" (with the addition of "blade thickness"), so all I can say is, don't mix the two.  I also seem to recall that there are two versions of the "Supergrind" model and the KG app only worked with one of them.

Do you think I'm getting an error in the dps angle because I'm using an old Supergrind 2005?

Not in the Calcapp app (or any app that measures directly to the wheel).

[darita]

Thanks.  Good information.  Why then do you think I'm getting bevel angles that are about 2*dps off of what they should be?  The measurements seem to be pretty straightforward and I do use a digital caliper.

[cbwx34]

Thanks.  Good information.  Why then do you think I'm getting bevel angles that are about 2*dps off of what they should be?  The measurements seem to be pretty straightforward and I do use a digital caliper.

Probably measuring directly to wheel? There's some examples in this thread...
https://forum.tormek.com/index.php?topic=4326.15
... of some ideas to try until you're familiar with it.  (Rubber band, string, etc.).

Assuming of course the error is with the Tormek setup....   

[RickKrung]

Thanks.  Good information.  Why then do you think I'm getting bevel angles that are about 2*dps off of what they should be?  The measurements seem to be pretty straightforward and I do use a digital caliper.

Probably measuring directly to wheel? There's some examples in this thread...
https://forum.tormek.com/index.php?topic=4326.15
... of some ideas to try until you're familiar with it.  (Rubber band, string, etc.).

Assuming of course the error is with the Tormek setup....   

There are many ways to use a digital caliper... and many ways to misuse one...   But I doubt that is where your issue is.  One assumption being made is that the guided sharpener is correct.  Do you have an independent method of determining the bevel angle, such as a laser goniometer? 

Regarding the message CB linked, I have long ago figure out how to use the direct-to-stone method and now exclusively use it.  Any variety of tools can be used for making the measurement.  I have settled on a modified woodworker's marking gauge.  The real key, however, was adopting the use of a rubber band stretched between the machine shaft and the USB. 

Rick

[darita]

Thanks.  Good information.  Why then do you think I'm getting bevel angles that are about 2*dps off of what they should be?  The measurements seem to be pretty straightforward and I do use a digital caliper.

Probably measuring directly to wheel? There's some examples in this thread...
https://forum.tormek.com/index.php?topic=4326.15
... of some ideas to try until you're familiar with it.  (Rubber band, string, etc.).

I have that marking gauge and will try using it, along with the rubber band.  I do have a laser goniometer and use that and it does pretty closely agree with my guided system.  I've been using both to determine how close I'm getting with the Tormek. 

Assuming of course the error is with the Tormek setup....   

There are many ways to use a digital caliper... and many ways to misuse one...   But I doubt that is where your issue is.  One assumption being made is that the guided sharpener is correct.  Do you have an independent method of determining the bevel angle, such as a laser goniometer? 

Regarding the message CB linked, I have long ago figure out how to use the direct-to-stone method and now exclusively use it.  Any variety of tools can be used for making the measurement.  I have settled on a modified woodworker's marking gauge.  The real key, however, was adopting the use of a rubber band stretched between the machine shaft and the USB. 

Rick

[Ken S]

Rick,

I remember when you first posted your idea of using your modified marking gage. At the time, it struck me as a clever and logical idea. (it still does). I have not tried it, however, I believe Lee Valley sells a replacement shaft for my metal marking gage which is calibrated in millimeters. That would seem ideal to me.

I use 12mm Baltic birch plywood for my kenjigs. The "footprint" which rests on the grinding wheel is approximatele 12x18mm, large enough for consistent readings and much larger than the thin rods of digital calipers. With the large Tormek grinding wheels, I can easily "eyeball" equal enough distances above the arc of the grinding wheel with the kenjig. If I had to use digital calipers, I would use your rubber band.

Good thinking, Rick!

Ken

[cbwx34]

...
The "footprint" which rests on the grinding wheel is approximatele 12x18mm, large enough for consistent readings and much larger than the thin rods of digital calipers.
...

This is my experience too.  I started using the "depth rod" (the thin part of the caliper that comes out the back), thinking this would be the most accurate, but eventually switched to using the front side...



... which I found easier to "line up" and like you said, more consistent readings.

I have that marking gauge and will try using it, along with the rubber band.  I do have a laser goniometer and use that and it does pretty closely agree with my guided system.  I've been using both to determine how close I'm getting with the Tormek. 

I think, with a little practice, you'll find things line up nicely.