Setting accurate grinding angle

[cbwx34]

Many thanks to all for this incredible discussion. Well done!
I  have found the Tormek online chisel sharpening class referred to above, and noticed that the AngleMaster has a flat base that sits on the chisel back when setting the angle. On my old Supergrind 2000 the bottom of the piece that sits on the back of the chisel is curved, and I  am never sure of the exact position where it should sit on the chisel.
Should I  get a new AngleMaster to start with?

If the rest of the AngleMaster is OK... you can just purchase the individual piece to replace the curved one... if you think that's the only issue with it....

https://advanced-machinery.myshopify.com/pages/replacement-parts-for-wm-200-anglemaster

... shows the parts, (and there you can click on the individual parts as needed).

[cbwx34]

...Almost all of my screen time is with my ipad. Tonight my grandson "liberated" my ipad. Several years ago I replaced my photo darkroom with a macbook pro.
I watched the Tormek online class on the macbook. What a difference! The larger screen was tack sharp. The video was well shot, so the larger screen really showed the information.
...

Wait until someone tells you that you can watch it on a TV screen... 

[cbwx34]

Hello,

I think we are talking about deviations in the grinding angle caused by the roundness of the wheel.
This means that if you grind the exact angle at the apex (eg. 20°), the angle at the edge heel will be higher and it depends on the blade thickness. For single bevel grind done with wheel dia 250 mm and 3 mm blade thickness is the angle at edge heel 23.7°.
This can cause the problem with Veritas MKII because it is designed for flat grind and if you set 20° you will grind the edge heel only, because there stays ungrinded material due "wheel roundness". Pictures from Gilles "Polishing Angle Calc" and other posted by cbwx34 illustrate this.

Part of TormekCalc2 is EdgeCalc where you can calculate and see deviations caused by the roundness of the wheel vs flat grind.

The most important is that you get exact angle at the apex but you have to count with ungrinded edge heel material which interferes if you want to grind or hone on flat stones.
You can grind off edge heel, you can start with sharper angle, hone at higher angle or something between.

IMHO generally hollow grind isn't disadvantage because there is no material in the middle and therefore is easier to maintain the edge even on flat stones because you have to grind/hone very few material to get fresh apex.

jvh

Thanks for the confirmation, and additional info!

p.s.  I also realized at some point that matching the "chord angle" I posted earlier, would be incorrect.

[Segovia123]

I am a newbie, wouldn't it be easier to add a Japanese Waterstone wheel for your Tormek?

[cbwx34]

I am a newbie, wouldn't it be easier to add a Japanese Waterstone wheel for your Tormek?

I can think of a couple of reasons... money may or may not be one issue, but another reason IMO, is that it's easier to "touch up" a blade vs. using the Tormek to do it.  For example, I now finish my knives on a flat Diamond Resin Stone, which is almost always out, so I can walk in and touch up a blade in just a few seconds, when needed... vs. setting up and using the Tormek.  (You can do quick touchups on the leather wheel, but I still find the stone easier, and a better result).

I think some also like the edge left with a flat stone with a slight hollow behind it.