two belt grinders face to face?

eric brinkerhoff

eric brinkerhoff

Joined
Mar 10, 2013
Messages
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hello,Im new here so forgive me .Im wondering if any of you have seen grinder setups using two belt grinders face to face?Ive seen the guy on you tube using two contact wheels face to face to make hollow ground straight razors and I would like to adapt this method to flat grinding.Any thoughts or info would be great,thanks.
 
Hi Eric... welcome to Bladeforums!

I can't get past the image of steel being shot to the floor or hurled at your face using such a contraption. I'm sure there are a few designs that may work but in my opinion, the average knifemaker would be putting themselves in harms way, playing with that idea.
 
Yes I've seen this, it's a Lewis video I believe, no way I'd try that flat grinding...
 
I just can't picture it working on a flat platen. The edge would need to be toward (into, against) the direction of the belt otherwise the belts would just pull the blade in between the narrowest part of the gap and jam the belts at best. Therefore, in order for it to work at an acute angle the rollers on the top of the platen would need to be nearly touching and the rollers would be the contact area of the bevel and not the platen. The only way I can imagine it working is if you remove the rollers and run it real real slow. Not practical.
 
I'm with Rick, that type of setup would require everything to be fixed into place with absolutely zero movement of the machines or the blade, or you risk catastrophe. Even the belt splices could possibly create enough grab/bind to really screw things up on a setup like this. I'm not saying it's impossible by any means but I see mostly bad outcomes unless the setup was engineered and built specifically for such a purpose by someone with an extensive machining background.
 
Or... you would need to clamp the blade blank into a Sherman tank weighted down with a brick in the trunk.:p
 
Rick Marchand said:
Or... you would need to clamp the blade blank into a Sherman tank weighted down with a brick in the trunk.:p
Click to expand...


A '76 Lincoln Continental might be a good alternative...plus when you're not grinding you could rent out the hood space for concerts and sports events...
 
If you do try it, be sure to get it on video. That should be good for a few hits on Youtube if it goes well.
And a few million if it doesn't. ;)

Oh and make sure you have a truckload of these on hand.

369189183_tp.jpg
 
I think rather than building/buying two grinders for flatgrinding, you'd be a lot better off with something like the TW90 and surface grinder attachment. I saw a vid where the maker used one with shims to set his proper angle. It wouldn't be quite as fast but it would be a whole lot safer and more accurate.
 
Greetings Eric-

As I read this, my thoughts go to this scary shop built "tire-drive" pitching machine we had in grade school. It would give a dozen perfect pitches, then randomly throw a bean ball at your ribs once and awhile. Now put the whole works in your grinding room and replace that baseball with steel. Now play again.

If you have the bucks and the space for two belt grinders and are wanting to increase efficiency/save time on your build process, I bet the good folks here can suggest twenty different ways to better utilize your second unit. I also bet that no experienced maker would suggest face-to-face contact wheels for knife grinding either.

Not saying it can't be done, but that doesn't make it a good idea either.

For what it's worth, the youtube vid you saw is probably by Charlie Lewis. If so, don't follow his example. As with 92% of Texans named Lewis - he's borderline insane. I mean that in a good way though...sorry Charlie.

Good luck to you Eric and please don't let this discourage you from thinking outside the box. It is a fine trait for knifemakers.
 
[youtube]0GVB0qkRF1c[/youtube]

We discussed it at a hammer-in once. We determined that the easiest way to build one would be to take two 24" belt sanders and weld them together. Then again, it's limited on the width of blade you can do and no more useful than any other grinding jig.
 
That set up isn't as crazy dangerous as I expected. Still, you wouldn't want you attention to lax while using it. I would have built a top guard to avoid anything getting sucked into it.
 
The two wheel grinders I have seen all turn upward, not down. You draw the blade down the junction, and get a hollow grind. If you have the blade even, both sides are the same grind height....if not, oh well.
 
I was thinking maybe adjustable platens with rounded upper edges and the two belts going down like in the lewis video.If I knew how to post pictures I would post a couple of drawings.
 
Well dumb me. All I could picture was some guy sticking a piece of metal between two spinning belts and having it shoot to the floor and stick right in the top of his foot.
 
It's no more dangerous than a buffing wheel. I couldn't imagine having the wheels turn up instead of down, you'd light the ceiling on fire! Turning down, you can catch the sparks in a bucket of water.

Rick's idea of a top guard makes sense, especially if you get a lot of visits from other makers wanting to try it out.
 
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