Thread: Hollow grinding smiling blades, 1" or 2" belts

I recall Charlie uses 1" belts for grinding smiling blades (i think all his blades), and prefers them over 2" belts.
other folks have said that 2" belts are commonly used for grinding razors as well, and very common in knife making.
to those that use 2" grinding belts: how useful or difficult is it to grind a smiling hollow compared to a 1" belt?

Thanks.

I think Charlie is building a 2" setup...but I'm not sure he's got it going yet.

I myself wondered the same as I don't have my 2" grinder finished & have never made a smiling blade. I have a feeling that no more of a "smile" a razor has, it wouldn't effect it much. On some knives I've done I use different parts of the belt for different purposes & have a feeling that's how it would work on the razor. Will be interesting to hear someone with experience here chime in.

You can grind a smile on either 1" or 2". I used to think 1" was easier. I think that was because I was so used to a 1" belt. Lately I have been grinding smiles on a 2" belt. Either size belt will work. It is the technique that matters not the tool.

Charlie

Originally Posted by spazola

It is the technique that matters not the tool.

Correct. As I was always tought. Try to master your work with the tools you have. I started with 2" belts and that's what I'm used to. Works flawless. I do however like quality tools to start with.

It is easier to grind the curve of a smiling blade with a 1" belt and wheel, especially if the spine has a lot of curve to it as well. But, it is easier to make a smooth transition to the honing bevel with a 2" belt and wheel. Like Charlie said, " It is the technique that matters not the tool."

okay, next question..

i'm considering a Bee Metal Grinder from knifemaker.ca

someone had said that as little as 1/4hp per surface sq. inch was sufficient to grind a razor, and 1hp per sq. inch surface was more than enough.. so a 1hp motor on a two inch belt and an 8/8 blade gives you 1/2 hp per sq. inch.. should be enough right?

others seem to think that you need more than 1hp on a 2" belt and would go with a 2hp motor.

i'm going to go for the variable speed model if i get a Bee as folks say it is a better option than working with pulleys, and i wont need to modify the grinder. the difference between 1hp and 2hp is only 400$, all in all more money spent, but maybe well spent as i'd like to be able to make knives with this grinder also.. 2hp might be nice, but it would require 220v i think, whereas the 1hp might run on 110v which has its advantages..

i know this is a ymmv thing, but is the advantage of a 2hp motor enough to bother with the inconvenience of needing 220v?

any thoughts on the Bee Metal Grinder? its supposed to be a very good grinder, but the options are 8" or 10" contact wheels, 2" and 1 5/8" contact wheels on on the multi platen, and a flat platen and slack grinding, as well as the option for a small wheel attachment for 1/2" to 1" wheels.. it seems like the only thing missing is the ability to run a 6" or 4" contact wheel..

i'm happy to hear that a 2" belt will still work alright for smiling blades, and i planned on starting out with thicker grinds anyways, so i was curious to know what you guys think about the Bee Metal Grinder..

I can answer part of your question. When running variable speed and lowering the rpm below "normal", you loose torque. If you think about stock automobile engines it normally takes a larger more powerful engine to launch you from 0-60 mph: Toyota Camery 4 cylinder vs 6 cylinder. The 4 cylinder is more than adequate to handle the job, but you have to get the rpm's up a bit more to merge onto the highway. Same principle with the electric motor, larger motor = more torque at lower rpm's. Lower rpm's, less heat when grinding.

Variable speed is nice, I would use it if I could afford it.

The bigger the motor the better, especially with variable speed. I can and do use smaller motors, but most of my grinders are built from stuff I have laying around. If I were buying a new grinder I would get the biggest motor I could afford. On the other hand if I were building a grinder on the cheap with found materials I would use whatever I could lay my hands on.

The Bee grinder looks nice to me.

Charlie

Agree with Charlie - get the 2hp if you feel you can afford it. I use mine for a lot of things that require more power that needed to grind razors. I have a 3 phase motor with a variable frequency speed control - runs on single phase 220 - and this set up does not lose power at lower speeds. Good luck

All my grinders are 2Hp/220V variable speed. Definitely helps with fast stock removal and the variable speed is the bees knees at lower speeds. I'm thinking about picking up another grinder and it will be the same 2HP/220V variable speed, without even a second thought. In the end you'll be glad you got the heavier HP and VS.