Belt grinder vs grinding wheel

K

Ken Daniel

Joined
Apr 23, 2014
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5
I have evolved to the point where I am ready to make hollow ground blades. However, the belt grinders are very expensive. Can I use a !0" abrasive grinding wheel instead of a belt grinder?
Ken
 
You sure can, but I don't think most guys here are going to advise it. Bench grinders can be very dangerous, hurling steel at light speed into your gut. Just be careful, that's all. I don't have much advice to give you....other than to say, sure, go for it!
 
10" abrasive wheels are used to hollow grind many times more knives than belt grinders but, they are on production CNC grinding machines costing hundreds of thousands of dollars. You might be able to do some edge-down hollow grinding on a variable speed bench grinder like the Porter-Cable sold at Lowes. I've occasionally wondered about using one of the 10" wet sharpening wheels, like Grizzly sells, for hollow grinding. Whatever you try, be very careful!

Bob
 
Those machines run too fast and you will generate alot of heat. Theres almost no control with that kind of setup. I'd advise against it.

You could look into a Cone-Loc drum sander setup if you were adamant about not getting a grinder. It's a wheel that splits in half and accepts a piece of shop roll.
 
For hollow grinds, a large (16-24"), low/medium speed (400-800RPM) water cooled abrasive wheel would be nice. A 10" bench grinder would be poor.


If you are shop savvy and can weld, building a large wheel wet grinder isn't too difficult. Having a 24"-36" hollow grinding wheel would make most makers green with envy.
Places like HGR sell top grade grinding wheels that would cost thousands for less than the shipping is. I recall a 48" by 4" Norton wheel that sold for $100...it weighed 800 pounds, IIRC.

Belt grinders are expensive, but the quality is worth it. Hollow grinding can be done on wheels from 8-24". 16-18" is a very good size if you can stand the sticker shock.
You can also hollow grind on curved platens that simulate 36-60" wheel diameters. These are great for hollow grinding razors and Japanese knives.
 
If you buy a good belt grinder it should outlast you but the same can be said for an abrasive wheel grinder but as was pointed out if the wheel grabs a blade it'll send it back at you faster than you can react. I don't have one yet but a good leather apron might save your kibbles and bits from damage. BTW Grainger sells pedestals perfect for mounting twin wheel grinders on for those short on bench room.
 
Out of nessecity (still building my linisher) I have only ever done hollow grinds on my 10" bench grinder and while possible like the other have said there is little control but if you are carefull, go slow and dip in water after each pass the results can be pretty good. The biggest hindrance is the motor obstructs your hand when grinding the blade from the inside out. You also need to ensure that the wheel is dressed perfectly, for safety the tool rest must be just about touching the wheel, and wear the usual leather apron, face protection etc.

A simple belt grinder would be the way to go however and if you can diy not too hard at all.

Here's my last folder blade I ground. This is about as good as the finish will be so lots of hand sanding needed.

wi16.jpg
 
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Also, remember that smaller size wheels can be used to make larger radiuses. I was going through fits trying to figure out the exact diameter wheel to hollow grind a straight razor with a particular geometry, when another more knowledgable fellow enlightened me to the fact that large hollow grinds can surely be had with smaller wheels....and good hand/eye control. The wheel diameter itself doesn't have to dictate the grind radius....as you can move the blade up and down on a smaller wheel to create a larger radius. Heat is a concern with grinding wheels.....as it is with belt sanders. "Pink" and "Blue" grinding wheels being made to reduce heat buildup much better than the regular grey ones that come with bench grinders.
 
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