Refurbish G8 belt grinder platen

Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.

Moderators: GlennW, Harold_V

User avatar
BadDog
Posts: 5131
Joined: Wed May 17, 2006 8:21 pm
Location: Phoenix, AZ

Re: Refurbish G8 belt grinder platen

Post by BadDog »

You are absolutely correct. I'm very concerned about durability, at least so far as will cover a "one and done" solution sufficient for my expected usage, gladly going further unless price/effort becomes sufficiently problematic.

In most applications I would be very concerned about the susceptibility to denting. But in my mind it seems that the application as a platen behind those heavy stiff belts would be very unlikely to take an impact that would result in a dent to the normal belt support surface. I suppose it could take a hit on the edge from complex shapes that aren't flat trying to get into an inside angle, but that would be easily addressed with a file if it raised a ding.

I have no idea if that's an accurate depiction, but it's where my thoughts went when saw your post. But I did wonder if the cast alloy or structure would negatively impact the hard anodize, which it seems it will.

For what it's worth, I had some similar thoughts about the "ceramic glass" (aka clear ceramic) as a platen. I suspect anything that would be a risk of damaging a cast tooling plate platen could also crack/chip a ceramic platen. Except instead of a dent, it would be a broken platen needing replacement. Again, magnitude and real world likelihood may place those two in completely different categories of realistic risk, but those ideas have been tallied in the cons column, pushing the ceramic platen somewhat downward relative to other options. Likewise the problem with cost and related for Blanchard grinding has now pushed that topic and all related down my list of preferences. I still haven't found solid prices on some other options, so still trying to wrap my mind around the various options.

I guess in summary, my biggest concern are as follows from most to least.

1) Flat so that my parts applied get relatively flat surfaces resulting.
2) Smooth enough to avoid physical or friction/heat damage to the belt (they are NOT cheap)
3) Cost/effort - if low enough, considered consumable
4) Abrasion resistant to prevent too rapid failure of platen
5) Resistance to other types of realistic risk of damage (normal or negligent)

At least that's what I came up with to help gel and represent my thoughts for this post.

I'm always ready to have my mind changed, and welcome all suggestions. Whether or not I understand them is another thing. :oops: :D
Russ
Master Floor Sweeper
User avatar
BadDog
Posts: 5131
Joined: Wed May 17, 2006 8:21 pm
Location: Phoenix, AZ

Re: Refurbish G8 belt grinder platen

Post by BadDog »

I guess I could add that my current thoughts are leaning to one of my earlier ideas in support of the ceramic platen.

In sizes 1/8-3/16, the clear ceramic appears to be rather reasonably priced, as well as very flat, smooth, and abrasion resistant. It seems to be almost the holy grail for the knife guys with the 2" KMGs.

Likewise I have a ready supply of 6061-T6 plate of suitable size that could be hard anodized, but likely cheaper to buy it already so treated.

For both options, I envision a ~1/4 thick holder replacing the current ~1/2" platen, and having a lip to secure the actual surface material, primarily providing a shelf at the bottom to provide a mechanical stop for the belt traversing downward. The KMG guys do that and secure with glue. When needing replacement, the glue is killed with heat to remove the platen previously occupying that space, and a new platen applied with glue.

That insert holder approach seems to provide the best sum of pros vs cons, though I have not yet successfully found pricing on HA plate.

Given the susceptibility to damage, the aluminum tooling plate might find itself in the same group of possibilities. But with wear issues and cost/suitability for hard anodizing in play, maybe it falls off the list completely unless a cheap source is found making it a cheap consumable?

Similarly for steel tooling plate, either as an insert, or complete platen in it's own right. Or the stainless gate valves mentioned earlier. Pricing to be identified. No idea if it's possible to purchase already coated hard chromed or nitrided material, but Blanchard options appear to be off my list at the moment. I'm probably missing some, but lots to ponder...
Russ
Master Floor Sweeper
Rich_Carlstedt
Posts: 1754
Joined: Sat Dec 21, 2002 12:16 am
Location: Green Bay Wisconsin USA
Contact:

Re: Refurbish G8 belt grinder platen

Post by Rich_Carlstedt »

If finances are tight , I think you should revisit the Front to Back Flipping of the Platen .
Redoing the flathead holes with a Carbide C'Sink is a viable alternative.
Don't know what tools you have, but doing a 9 inch fly cut is another possibility to counter having a Blanchard grind.

And the last outside the box approach is to find a tin can plant in your area and ask for a sheet of tinplate
a full sheet is usually around 3' x 3' mostly and range from .007 to .0013" thick and are extremely hard steel.
Fill in the gouges on the platen and glue the tinplate to it. The "Tin" coatings vary from .25 to 1.25 , so the thicker coats are the best
FYI , Tin has some of the lowest friction of any metal and tinplate is extremely flat ..just a thought

Rich

post note
I have used Cast Tooling plate most of my life for various purposes at work and love the stuff, but I would not use it for a platen
Too soft for an abrasive application
User avatar
neanderman
Posts: 896
Joined: Mon Jan 09, 2012 7:15 pm
Location: Cincinnati, Ohio, USA

Re: Refurbish G8 belt grinder platen

Post by neanderman »

Is this forum great, or what? I'm constantly learning new things!

And I still love GlennW's avatar!!!!!
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"
User avatar
BadDog
Posts: 5131
Joined: Wed May 17, 2006 8:21 pm
Location: Phoenix, AZ

Re: Refurbish G8 belt grinder platen

Post by BadDog »

It's not so much finances are tight. If it were, I would have to find another hobby. But rather budget's not unlimited, and spending $400+ refurbing the platen alone is taking a lot of money from other projects. Compared to just dealing with the less than perfect platen, and maybe finishing on a smaller machine, the math just doesn't add up.

It may be that I can flip it, but would need to rejigger the countersunk mounting holes, perhaps just offsetting it ~1" downward since I probably don't need that very upper portion for my needs. I've got some reservations, but won't know for sure until I get those locked in place screws out. At this point, my final fall back is rosette welding nuts onto them so the heat shock can help free them AND give me something more to hold.

I happen to have a very large fly cutter more than capable of making that cut width, but I was under the impression that the finish wouldn't be acceptable for a platen. I've produced some very good finishes using that fly-cutter, but it's not ground, and I imagined far too much work being necessary after fly-cut to achieve an acceptable finish. But maybe that's another thing that I mistakenly thought I knew?

I like the tinplate idea. Too thin for an insert approach (like ceramic), but could be doable as described. I have no idea if such a resource exists around here (Phoenix, AZ), but next question on that would be, what glue would be good for that? Something without much body so that it wouldn't clump and distort when the plate is laid up on the flat fly-cut platen, but able to handle expected platen heat levels from both direct belt friction and transfer from grinding operation. Cano seems a good choice, were it not for the heat.

I agree on all points Ed. :D But I kinda miss his old avatar. 8)
Russ
Master Floor Sweeper
pete
Posts: 2518
Joined: Tue Feb 10, 2009 6:04 am

Re: Refurbish G8 belt grinder platen

Post by pete »

While it's not exactly cheap in the size you'd need nor is it all that hard. But as at least one has mentioned that tool steel plate can be had in almost any width, thickness and up to at least 36" long. I believe it's only blanchard ground so probably within .005" of being flat and parallel. If? you can flycut your current platen well enough to flatten the hollows out, shimming one of those tool steel plates until it's square and level and then epoxy bonding a piece of that 1/4" - 3/8" plate to what you have should work well enough. In a production shop and used multiple hrs a day I'd go a more expensive and durable route. But it should last well enough. Multiple ways to solve this, so it's just picking the cheapest, semi durable and least pita solution.
Post Reply