Contact wheel corner

[mknife]

Hi Steve,
In Italy there are two Schools: the first one that use contact wheel as is and the second scool that rounded corners of the wheel.
I'm interested tho know how you proceed with a new wheel: if you use it as is or if you rounded the corner. If you rounded the corner please can you tell me how you make it.

Riccardo

[Steve]

I leave them as they arrive from the factory. At one time I would round the corner with some 100x wet/dry sandpaper while it is running, but find that I can "sculpt" the curve at the top of the grind just as well with the sharp corner. You have to decide what you like best.
Perhaps you can start with the regular corner and then, perhaps, find another maker with rounded corners and try his? Practice is the answer with either type of corner.

[michaellovett]

I have found that some times the wheel isn't quite true when new. When they grind the wheel,because th thicker center is a little harder or firmer,it will be ground a little deeper. The softer edges will be a little higher at times. This will be a slight concave shape when looking down on the wheel. I do like to true them up, and very slightly give the face of the contact wheel a slight convex shape. I take very,very little off. This is only a few thousand ts. It can do away with that dreaded two inch mark on the blades many have talked about in the past. I then only slightly break the sharp edge on the wheel edges. It will wear in on its own is a few weeks of grinding. I'm just not patient! Mike

[mknife]

Hi Steve, hi Mike,
thanks for your answer.
I tryed with both corners, and effectively I haven't see particular differences. I'm happy for your answer because here I have a little dispute with other knifemaker. In my opinion the really important step is to put the belt 3-4 mm out the corner.

[Steve]

That is correct, Riccardo, the belt must overlap the corner approximately 3-4 mm, as you have found. This allows you to make a nice radius at the top of the grind, just in front of the ricasso. Sometimes, the edge of the belt will get too soft, or mushy, and you need to get a newer belt. However, it's helpful to have the edge of the belt a little broken in, or pliable, in order for it to make that rounded cut. Sounds like you are doing very well!

[mknife]

Thanks Steve.

[michaellovett]

Yep! What Steve said!!! Mike

[mknife]

Grazie Mike.

[Steve]

I hope it helps. Everyone has their own way of doing things, some things work well for me while other ways of doing it may not, or may not right now, but work later on, after I've thought about it for a while........

[cliff fendley]

I leave mine square on the edges also but I really never even thought about rounding it. Now that I read this I have an old 12 inch wheel that I got with a used grinder I bought one time and it has been rounded.
I've never used it for hollow grinding because its so big but I may have to try the rounded corner just to see. Most of the time I like a rounded plunge at the ricasso so maybe a rounded one may work good for me.
I did just made a knife for a guy and he wanted the grind line very sharp in the corner of the ricasso. One thing is I can always sculpt a radius with a square wheel but I'm not sure I could have got the corner that sharp with a rounded one even with a new belt.
I'm sure this is one of those things that whatever works for you is the right way of doing it.