Refurbish G8 belt grinder platen
Refurbish G8 belt grinder platen
I have a 5 HP Porter Cable G8 belt grinder that was manufactured 80 years ago. After all that time, it's in amazing condition, except for wear on the platen, which is something I would like to improve.
The platen itself is a piece of 18.75" x 9" x 1/2" hardened steel bolted to a beefy casting, and has worn several concavities in it's surface. The whole thing is symmetrical, allowing it to be flipped to put fresh surface at the table. Sadly, that appears to have been done in the past. And it can't be flipped front to back because of the countersunk screws for mounting. So it's going to have to have some effort to improve.
My first thought would be to send it out to get ground (probably Blanchard). Then I thought, maybe I can upgrade with modern materials? My first thought was maybe machine a sort of frame/holder for replaceable PTFE wear surface. Not sure how hot it gets on the back side of those heavy 36 grit (typical) Zirconia belts, or if that would even be a problem.
A bit of searching seems to indicate that the KMG guys like the "ceramic glass" (clear ceramic) platens, and price for purchasing such a panel seems like it will be cheaper than having it ground flat. That would still require some sort of mounting frame (just lip at bottom?). Perhaps with plate glued on, then using heat to break the bond should replacement become necessary?
I don't expect the volume of the usage I would put it through will ever result in another worn out platen to replace should it simply be ground, and I haven't gotten prices yet, so just kicking around ideas.
The platen itself is a piece of 18.75" x 9" x 1/2" hardened steel bolted to a beefy casting, and has worn several concavities in it's surface. The whole thing is symmetrical, allowing it to be flipped to put fresh surface at the table. Sadly, that appears to have been done in the past. And it can't be flipped front to back because of the countersunk screws for mounting. So it's going to have to have some effort to improve.
My first thought would be to send it out to get ground (probably Blanchard). Then I thought, maybe I can upgrade with modern materials? My first thought was maybe machine a sort of frame/holder for replaceable PTFE wear surface. Not sure how hot it gets on the back side of those heavy 36 grit (typical) Zirconia belts, or if that would even be a problem.
A bit of searching seems to indicate that the KMG guys like the "ceramic glass" (clear ceramic) platens, and price for purchasing such a panel seems like it will be cheaper than having it ground flat. That would still require some sort of mounting frame (just lip at bottom?). Perhaps with plate glued on, then using heat to break the bond should replacement become necessary?
I don't expect the volume of the usage I would put it through will ever result in another worn out platen to replace should it simply be ground, and I haven't gotten prices yet, so just kicking around ideas.
Russ
Master Floor Sweeper
Master Floor Sweeper
Re: Refurbish G8 belt grinder platen
I like your thinking of new materials for the replacement platen, although I am not sufficiently knowledgeable to make a recommendation.
RussN
RussN
Re: Refurbish G8 belt grinder platen
I've no idea of cost but it shouldn't be hard to check. One other option would be what's commonly used in open pit tailings lines are hardened stainless steel gate valves. They come in a wide variety of sizes and thicknesses to well above what you'd need. Visualize a hardened and ground flat plate with a radius at one end. If there durable in that environment it's doubtful you'd ever wear one out. I know the plates are available separately and without the rest of the valve components.
Re: Refurbish G8 belt grinder platen
According to my calculations, that platen weighs in at close to 24 pounds. Shouldn't be too hard to get another piece of 1/2" plate and replace the old platen. A Blanchard grind is not necessary for that platen as it is not used to produce precision work. It's use is to remove a lot of material quickly. BTW, is that machine 3 ph? Nice machine!
Mr.Ron from South Mississippi
Re: Refurbish G8 belt grinder platen
pete:
Thanks. That's not something would ever have crossed my mind! Exactly why I posted.
Mr Ron:
Yes, it's quite heavy, particularly when attached to it's massive casting. And I realize that the platen isn't a precision surface, but the grinder angle is to deal with it's rather extreme hardness. I pondered cutting it with a fly cutter using a carbide bit. But wondered if the less than polished surface would cause wear/heat in the belt. Of course it could be worked with sandpaper to a finer finish, but the thought of surface plate sanding a plate that big and heavy took my thoughts back to grinding.
And yes, it is 3ph. She's a beast!
Thanks. That's not something would ever have crossed my mind! Exactly why I posted.
Mr Ron:
Yes, it's quite heavy, particularly when attached to it's massive casting. And I realize that the platen isn't a precision surface, but the grinder angle is to deal with it's rather extreme hardness. I pondered cutting it with a fly cutter using a carbide bit. But wondered if the less than polished surface would cause wear/heat in the belt. Of course it could be worked with sandpaper to a finer finish, but the thought of surface plate sanding a plate that big and heavy took my thoughts back to grinding.
And yes, it is 3ph. She's a beast!
Russ
Master Floor Sweeper
Master Floor Sweeper
Re: Refurbish G8 belt grinder platen
I for one would like a pic of this beast. I love old machinery.
Jack
Jack
- neanderman
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Re: Refurbish G8 belt grinder platen
Second that!
Ed
LeBlond Dual Drive, 15x30
US-Burke Millrite MVI
Atlas 618
Files, snips and cold chisels
Proud denizen of the former "Machine Tool Capitol of the World"
LeBlond Dual Drive, 15x30
US-Burke Millrite MVI
Atlas 618
Files, snips and cold chisels
Proud denizen of the former "Machine Tool Capitol of the World"
- Bill Shields
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Re: Refurbish G8 belt grinder platen
You want the platen surface to be as smooth as possible
Too many things going on to bother listing them.
Re: Refurbish G8 belt grinder platen
Sorry, I'm terrible about taking pictures. And just didn't have time to try to make them small enough for the site to allow them. But, here you go. Not real interesting, but you can see the machine and the platen removed. I included a 123 block for scale.
Russ
Master Floor Sweeper
Master Floor Sweeper
Re: Refurbish G8 belt grinder platen
You may notice it still sits on rickety casters. Making a good pallet jack suitable base is "on the todo list"...
Russ
Master Floor Sweeper
Master Floor Sweeper
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Re: Refurbish G8 belt grinder platen
BadDog,
I have a pair of Porter Cable B9 belt grinders that could stand to have the platens redone, so I will be curious as to what you do. These had new platens brazed on at some point in their lifetime. Great heavy duty pedestal type machine that has a quick release tensioned top roller . You can change a belt in under a minute without any fussing.
Nyle
I have a pair of Porter Cable B9 belt grinders that could stand to have the platens redone, so I will be curious as to what you do. These had new platens brazed on at some point in their lifetime. Great heavy duty pedestal type machine that has a quick release tensioned top roller . You can change a belt in under a minute without any fussing.
Nyle
Re: Refurbish G8 belt grinder platen
What about just use a piece of 1/2" steel tooling plate. It comes Blanchard ground.
I'm sure you could find a drop somewhere.
It may not wear as well as what you have, but you may not be needing it eighty years from now!
I'm sure you could find a drop somewhere.
It may not wear as well as what you have, but you may not be needing it eighty years from now!
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!