Is a hollow grind possible without belt grinder?

this thread interests me because you would have thought somewhere along the way somebody would have either developed a way to make hollow grinds without a expensive belt grinder , or have made a cheap machine to do specifically that.

I mean correct me if im wrong but wouldnt two stone wheels right next to each other (spinning upwards toward the blade , not "into" the grinder) Be suitable to make hollow grinds?

Isnt this how they made straight razors in a factory setting (i know sometimes the whole thing is just stamped/dropforged)?
 
Look up "Tormek Knife Jig" you basically want to reproduce that to fit your Bench grinder
 
The problem I see with using two hard stone wheels is that typically a stone wheel will be quite a bit smaller than the contact wheels used to get a proper hollow grind. That combines with the need to be adjustable, and the fact that stone wheels have a tendency to bump and hop on the steel making a smooth or even grind very tough. There are machines being used that do run two wheels side by side for hollow grinds, but even those almost always run belts. I don't have the link but there was a thread on here a couple days ago about them
 
JZknives said:
this thread interests me because you would have thought somewhere along the way somebody would have either developed a way to make hollow grinds without a expensive belt grinder , or have made a cheap machine to do specifically that.

I mean correct me if im wrong but wouldnt two stone wheels right next to each other (spinning upwards toward the blade , not "into" the grinder) Be suitable to make hollow grinds?

Isnt this how they made straight razors in a factory setting (i know sometimes the whole thing is just stamped/dropforged)?
Click to expand...

OK, you stand corrected :D It isn't cheap or easy to make one of these. Here is one of the budget priced double wheel hollow grinders.....a mere $16K.
http://www.truhone.com/store/pc/viewCategories.asp?idCategory=6

There are other commercial grinders that do the job, going up to near $100K. The ones made from two KMG grinders are the cheap units.

BTW, to explain my earlier comment about the knife placement, I was referring to an upward turning set of wheels, where the knife is placed above the wheels. Other systems turn down, and the knife is placed below them.

I have a tru-hone sharpening system that uses 4" wheels to put a hollow ground final edge on a knife. It runs a bit over $1K
 
Stone wheels just suck. They grind slow, vibrate, and heat up the work atrociously, they create deep uneven scratches, and you will have to have at least two stone wheels of different grits, almost exactly the same diameter, to get a medium finish. That's unlikely, as stone wheels constantly get smaller in size as they wear, and wheels of different grits won't wear at the same rate. Did I mention that they suck, too?

Just flat grind with a file for now, would be my advice.
 
I think this thread is a prime example of someone liking the IDEA of something more than truly needing/wanting to do it. I did the same thing when I was a teenager reading knife books. I would read about makers hollow grinding, and think that must be the best way to fly. But I had never done it and didn't truly understand the benefits or drawbacks.


So to the OP... why do you want to hollow grind???

Hollow grinding on a contact wheel is faster than flat grinding. It also allows you to achieve a very fine finish right off the machine.

If you do a bunch of hoaky stuff to try and achieve a hollow grind, you are TOTALLY negating both of those factors.

I could hog out a hollow grind on a 4" hunter with an angle grinder on edge, and then spend hours and hours cleaning and truing that surface with EDM stones and sandpaper... or I could walk up to my KMG with 10" serrated wheel and do the same grind in 2-3 minutes.

A flat grind with a slightly convexed edge makes for a superb cutting tool, and can be done with hand tools MUCH easier than trying to hand tool a hollow grind. My recommendation is to do that and see if you even like making knives. If you do, and you're still hell bent on hollow grinding, then save your pennies for a quality belt grinder. :)
 
You could try 10 inch expander wheels I have 2 of them on a harbor freight grinder I havnt tried hollow grinding on them. They can be found at blacksmith supply stores can't remember where I got mine butt I do know centure forge has them they only have 40 and 100 grit belts for them they also sell 6 inch wheels not sure how to post pics or I would post some of mine
 
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