platen material?

C

cory

Joined
Dec 23, 2001
Messages
63
I have been using a mild steel platen for a long time. I need to resurface it as it has a low spot where my table bolts up from profiling. Is there anything a guy can line it with that won't cost much and is easy to get? What about materials that a guy might just have laying around the shop or the garage? Will having something "soft" on the platen like maybe a piece of leather, get better grinds or is it best to keep the platen hard?
 
You might want to try out the pyroceramic platen material. It runs cool, but that too will get the profiling scratches after a while.
What I did, was to buy an extra platen plate which I use just for tang tapering. When I am ready to profile I just switch back to the other platen plate. I think the extra steel plate cost me around $14 from Rob Frink.
 
Cory, don't mess around - get a pyroceram platen liner from Steve Pryor. I can't remember the cost but it was under $30. Just do it, you will be glad.

Why? It's perfectly flat and hard enough not to get uneven with use. I've had mine on for a year and it's still perfect.

Dave
 
Dave, do you do any profiling with the pyroceram? I have experienced a lot of wear with it after profiling.
 
Wayne Goddard says if you really want a hardened platen, he won't argue the point, but he prefers mild steel. Why? Because he can draw file it flat. You can also make a second platen of mild steel or soft knife steel, and use one to flatten the other (check it with a straight edge). If you had three identical platens and applied the machinists rule of three, they would be very flat. Angle iron or similar pieces might also work for a homemade platen. I made a copy of my Burr-King platen with a piece of 1/4" by 2" 5160, and left it soft, although it may have hardened a little on it's own--works fine. $50 Knife Shop has a lot of this type of information in it.
 
If you don't want to go with something harder, just take the platen off, and put it on you disc sander. That will flatten it out, at least for one or two knives. Pyroceram is the best bet, it outlasts hardened D2 as a platen material etc.
As to profiling, why not use a contact wheel? It is a lot faster, quieter, less wear and tear on the grinder. It also saves on your belts. You couldn't pay me to profile on a platen.:eek: ;)
 
I usually start my profiling on the contact wheel and then when I'm close I go to the platen with a work rest to get a nice flat edge, but even when doing just that, I still end up with the wear on the platen, whether it be steel or pyroceram.
 
Rick I think you're talking about one of those steps that feels good but may not be completely necessary. I know just what you're talking about, and in fact have done it like that; I like the 90 degree edge too. But I've found I can eyeball the edge from vertical on the wheel just as accurately as I could with a rest - and it's much faster, quieter like Mike said, and easier on belts. I'm a bit anal about belts, they just cost too dang much! :rolleyes: I do everything I can to make em last longer...

Dave
 
Hold all jokes please. I agree with Mike Hull, having toyed with many different methods myself. I magically thought that there was some "zapper" out there that punxched out knife-like shapes instantly. I have found the contact wheel eto be very good. My platen is only for flat grinding. However, I don't use a worktable on the contact wheel, because my grinder won't fit one. I freehand profile with drawn rather than scribed lines on the contact wheel, then true up the angles to 90degtrees on the disc grinder which DOES have a flat worktable.

My platen is one I made of mild steel constructional bar when I discovered after 3 months that my original platen wasn't even flat to begin with. After 80 knives flat grinding, the platen hasn't even needed any dressing yet. Seems to last, and its no bother to cut and make another piece very quickly. I have another 2 waiting in my drawer, expecting that the first would wear out.

Cheers.
 
The advantage of the pyroceram platen liner is twofold. It's very flat, and it is about 75% cooler than without it. That saves belts and bearings. The top wheel on my vertical platen used to get so hot, it would heat the whole arm, enough to raise blisters if you came in contact with it. I was waiting for the bearings to go at any time. When I went with the pyroceram, I noticed immedietly that it barely got warm, and only that, after extended running. It causes way less drag on the belt also. That correlates into less wear and tear on the grinder.:eek: ;)
 
I admit to running a belt inside out (grit toward the platen) to dress up my platen. Not as good as draw filing but lots easier.
BTW, I should say that I haven't learned flat grinding!
Lynn
 
I've played with the idea of a heat treated tools steel platen...even polished and coated,...say TiN,TiCN....etc. But I threw all of those ideas out the window the day I put a new belt on the grinder and saw sparks on the back-side of the belt. This particular belt had stray abrasive grains on the back of the belt which effectively sliced grooves on the platen. So I guess I look at the platen as a perisable component...same as belts, drill bits, saw blades....etc.

I've never used the pyro-glass but I read enough postive reviews to convince me that it is the way to go.

-Rob
 
I think Rob has a very good point. It seems that where tool meets work there is a replacement cost; some materials just last longer then others. Funny thing, tools always cost more if they last longer. :( A capitalist plot?
 
You must log in or register to reply here.
Back
Top