Tempered glass platen

Feb 6, 2001
Try as I may I cannot find a glass shop in NE P.A. who can get a piece of tempered glass 2" wide. I recently got a grizzly grinder and would like to have a flat platen to go with it. Since I didn't want to wait for the ordering, grinding, hardening of a steel platen(even though that's what I would eventually like, but I'm impatient and have a couple orders)I thought I'd go the tempered glass route. If anyone knows of a supplier I would appreciate the info. {Also, how thick 1/4", 1/2", ?.} Thanks.

As R.J. Martin is sure to step in and tell us again, the glass does not have to be tempered. Just go to a place that cuts glass and buy several pieces a hair over 2" wide and as long as your platen. Super glue the piece onto your platen. Eventually, the glass will crack. When that happens, knock it off and glue on another piece. RJ has probably posted this info a half dozen times. Good and cheap knifemaking tip.

Danbo, soul brother of Rambo
Danbo: When I clicked on the post, I was thinking "here we go again..." I almost fell off the chair laughing when I read your post.
In the interest of safety, please don't run the belt super fast, and don't put all your weight into it. You'll get a flatter tang, if you use a new, sharp belt.

RJ, I was thinking the same thing!!!


[This message has been edited by C L Wilkins (edited 04-18-2001).]
About how long will untempered glass last if you don't abuse it. I have a 1 hp grinder without variable speed so the belt speed is constant.
Also, how thick should the glass be. I tried a piece of 1/4" laminate glass and it cracked in less than an hour. Thanks.

I'm not familiar with using laminated glass. I guess my glass is about 5/16 thick-maybe a bit less.

I usually run 3000SFM or less, using belts with a smooth back. YOU NEED TO BE SURE THE PLATEN IS SETBACK JUST RIGHT.

I have had pieces last for months, other times days. I take the bulk of the material off with a contact wheel, so, I'm not on the platen for long. This keeps both the glass and me from wearing out.

I just ordered a few cut pieces of 1/4" annealed glass for my platen. The guy at the glass store said Tempered glass is the kind they put in large door windows etc. When they shatter they break into small pieces, annealed is just regular glass and will break like normal glass. I tried some 1/8 glass from the harware that broke almost instantly. I am thinking the 1/4" will work better, and with my platen I can move it back so the belt isnt running way over 1/4" of glass. I will see how this works soon.. Darrel Ralph has mentioned someone that has Pyrex glass for this purpose but have not heard anything more about it...

Trace Rinaldi
I've been using 1/2" plate glass. Most commercial glass shop have it or can get it. The thick stuff seems to last a little longer and handle mechanical and thermal shock a little better.

As was mentioned earlier, for safety reasons I try to keep the belt speeds slower on the glass platten. I use a steel platen for 90% of the grinding the then switch to the glass for finishing the surface. Also, I'm real picky about making sure the glass is fully bonded to the mounting surface. I blast the glass and the mounting surface with aluminum oxide to prep it and then use high strenght epoxy to bond it...making sure I get 100% epoxy contact to the glass. It's a pain when you have to change glass but this way it's less likely to throw a chunk of glass if/when you do get a crack. Maybe I worry too much but I keep thinking about the physics of glass slivers at high speeds...


Cecil Self
SELF Knives
Arrow-Dynamics Cutting Tools
The glass to use is called neoceran. I know several people using it .None of them or me have had it shatter or even crack badly.As a matter of fact I am the only pne who has had a piece crack on him, and this only happened after I turned it over to use the opposite side. It will give great service under hard use and for part time makers will probably last over a year. Fank.
I've been using a piece of 1/4" thick plate glass as a platen for a grizzly grinder for a couple of months now. It has a couple of cracks in it which don't go all the way across the glass. I JB Welded the glass to the platen. So far it has worked really well for me. I bought a few pieces of that glass, and I've also been using a piece of it as a sanding block when I do hand sanding.

Hi J.

I went through the same thing with my Grizzly. After all the posts here about tempered glass, I went to all three of the local glass shops for info.

The smallest piece of tempered glass I can buy is 14 inches by 14 inches.

That is a little large for my platen.

I learned what Frank just shared:
"The glass to use is called neoceran."

That is what I bought and epoxied on to my platen with light pressure.

It broke within an hour- the platen was not flat, and the grinding pressure [I don't lean on ANY of my equipment]against the bowed platen was all it took to break.

I took the platen to our local machine shop and had it straightened and then ground flat.

I need to pick up and mount another piece of the ceramic stuff- whick LOOKS just like glass.

It is real pricey, but the local shops have pieces the size of the platen that are just scraps to them. I think they charged me 4 or 5 dollars.

In the meantime I am learning to hollow grind.

Please post again and let us all know how you do with it after you start grinding.

Dave Evans
Tenino, WA
Dave, I attach my neoceran with two layers of two way carpet- the kind that does not have any fabric in it. One of my friends has used silicon which would probably allow for a little distortion and I understand J.B. weld will do a good job. I pay $10 each for my pieces-that's Canadian of course but I've found this to be a real help especially since up until recently I only did flat grinding and I was doing quite a few hunters. Frank.
Dave, my piece is still holding up nicely. Not nicks, cracks or errors. I used JB weld and it seems to have done the trick. Of course it hasn't gotten very much use lately. I will keep you posted (sigh) Terry
A quick fix that will work in a pinch is to run a 100 grit belt inside out and use a piece of barstock to press the belt flat against the platten. Don't forget to clen your contact wheel before using it again though.

Bleeding, it's a hobby of mine.