4-6 inch wide grinders

E

elementfe

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May 3, 2008
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After making ten thousand knives on 2" grinders, upon returning from vacation I'm having one of those moments.....

Why are 2" grinders the standard?
I've actually never ground a blade on a wider belt or a large water cooled rotary stone, but as my standards for knives have gone up over the years I'm more and more aware of the drawbacks of using a relatively narrow belt, and the videos I've seen of English, Japanese, and industrial grinding are inspiring me to rethink the whole process as it has been.

Anyone out there using something in the 4+ range? If so, what are your thoughts, if you have experience on the 2x72 as well?
 
2" are the standard because that is what Stephen Bader started with.

You can buy wider grinders, they are used in industry and places like TruGrit has about any size belt you need.
 
Well heck. I've been trying to save up for a 2x72 and now y'all have me questioning whether I should be thinking about 4 inch!
:oops:
 
2" is a size that is controllable for freehand grinding. Industry often uses 2.5" and 3" to grind faster. You can get grinders in these sizes, but they are usually commercial/industrial units and expensive. Look at the Burr King industrial grinders for examples.
4" and 6" are OK for doing some flattening and such, but are too wide to be practical for knives.

If you are building a grinder from scratch, or modifying an older one, you can get a wider drive wheel and wider tracking and idler wheels and make the grinder 2.5 or 3". Obviously, you want to make a wider platen, too.
 
DevinT said:
Some makers like one inch wide belts because they get more use from a belt. They break down better. Technique is more important than the equipment.

Hoss
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That's an interesting point. I got to use a 2x72 and 1x30 in the classes I took. In my shop I have an inexpensive Wen 1x30. The 2x72 certainly was able to remove material faster, but the two main things I liked had more to do with the increased versatility (different contact wheels, etc.) and the variable speed. I know there are 1x30's with variable speed, but is there a good one that has that kind of versatility as well?
 
dwaterfield said:
That's an interesting point. I got to use a 2x72 and 1x30 in the classes I took. In my shop I have an inexpensive Wen 1x30. The 2x72 certainly was able to remove material faster, but the two main things I liked had more to do with the increased versatility (different contact wheels, etc.) and the variable speed. I know there are 1x30's with variable speed, but is there a good one that has that kind of versatility as well?
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You already have 1 x 72 grinder .Just make one inch plate . Also 2 inch belt are very easy to split in half .................
 
i think it would be really hard to grind on a 4" wide belt without a fixture.
I would love to try grinding on a horizontal wheel with water though, those look awesome but it seems they are used on already closely forged to shape baldes?
 
timos- said:
i think it would be really hard to grind on a 4" wide belt without a fixture.
I would love to try grinding on a horizontal wheel with water though, those look awesome but it seems they are used on already closely forged to shape baldes?
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What I'm seeing is, for instance, freehand grinding on a horizontal plate, wide belt, on Blenheim Forge's IG videos- looks nice and controllable for flat to somewhat convex grinds.

Just based on the experimenting I've done on a 2" platen mounted horizontally, it's much easier to keep the blade cool, since after you dunk it in water the water stays on the blade rather than running off, as it would with the blade held vertically against a standard 2x72 platen. (A water cooled setup would be ideal)

The big rotary stones are intriguing, but I'd need a lot of experimentation or some mentoring to understand how to do the slightly convex grinds I like on cooking knives, on a stone that's oriented to make a concave grind.
 
I have seen some makers use old industrial 4" inch grinders with water cooling on large kitchen blades. These grinder have water collection and filter and really flood the work. Looks super fast and practical for large blades without plunges. You could consider using such a machine as a professional maker if you do a lot of large blades. If I am not mistaken there is couple of custom belt grinders in Europe offering the 3" version.
 
Motor power might also be a factor. From memory the recommendation is 2hp per inch, although a lot of us use half that. So a 4hp motor or more.
I can drive a 4hp motor on my 15amp 240v circuit, but going beyond that will need a 20amp circuit.

I am curious about a wider grinder for kitchen knives too, but i don't have the space.
 
I don't post deal spotting here, so I didn't put this up a while back when it was an active auction. There are many companies that resell industrial equipment for pennies on the dollar. Local pickup is almost always a requirement.
Most are huge and you need a fork lift and a flatbed. Others are movable on a trailer or even a pickup truck bed. Mills are very common. Much of this equipment requires three-phase and often 460VAC. Some require a good cleaning and moderate repairs.

Here are just a few of the things people can find on auction sites like eBay.

These dual 120"X3" industrial knife grinders from a closed factory were selling for about the price of a 12" contact wheel by a SC company. They had a lot of them. The eBay sale has closed but the seller, toolpartsetc, probably still has them if someone wants to do some searching to get in contact.
s-l200.jpg


Then, there are larger belt sanders:
s-l1600.jpg


Or, a brand new 4"X193" one:
s-l1600.jpg


Or this 220V single phase combo:
s-l1600.jpg
 
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Here’s my setup with a 1.125” wide platen, I can cut my belts down to 1” and move them to either side for plunges or leave the belt tracking in the middle for a large hollow on my kitchen knives. I can grind a bevel faster and get better abrasive life with the narrow but long belts. Tested this with Norton blaze belts grinding hardened blades completely post ht, same platen but 2” wide and I can get 2-8” chefs out of a simple carbon steel before the belt doesn’t feel like it’s working well and it get switched to profiling, same steel and size knives I was able to grind two of the same chef knives plus 1 more 8” chef and 3 smaller kitchen knives with one belt half. In total I more than doubled my belt life, could grind faster, heat management was easier as the sprayer I have covers the entire 1” width versus not covering a full 2” belt, and I had as much or more control. The belt on the grinder is a 120 zirconium belt and it polished the 36 grit scratches out of 4 chef knives, 2 cleavers, 2 herb choppers and a small utility kitchen knife. It still has enough grit to polish several more small knives.
 
oooh that does look really interesting, Also will make grinding fullers and smaller radius easier to control i would think. thanks for sharing
 
I have been thnking about making 4" long wheels for my grinder for quite some years now and maybe I give it a try soon as I will need to replace my front wheels. It seems like a nice way to save time althogh I suspect it will not be so easy to get used to the wider belts.
 
interested in all answers and information.
wanting to explore blade grinding and looking at a couple second hand burr king grinders
482 2x48 and 960-401 4x60 wet
i am currently negotiating on the secondhand 960-401 --- basically a 2x72 minus the extension bar and with 4" wheels , making it 4x60 and setup for wet.
also come with 5 diamond belts. i am guessing it would be easy enough to make 2x72 buy adding extension bar and switching wheels if 4" belts are too wide, shoot i would think you could run 2" belts on the 4" wheels

i used a bk 2x72 at a grindin, the burr king comes off as the industrial legend that it is, big , tough , harken back to old cast iron machines

i want to hear all the pro's of burr king , talk me into buying and what a great decision i have made.

hoping to be at about 1k for the 960 a little less for the 482
 
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