Abrasive Belt On A Surface Grinder?

[intjonmiller]

This morning I saw a video on YouTube where a knife maker was using an abrasive belt on a rubber grinding wheel on a surface grinder. He only had very tight shots, just barely wide enough to show that the belt does separate from the wheel, confirming the obvious assumption that it's a larger belt than the wheel. It appeared to be an older machine, not a purpose-built "surface grinder". Fascinating. Searching I'm having trouble finding much information about this. I see that Tormach has an attachment for their surface grinder that does this, but it seems to be much more involved than this other guy was using, and it's made for a specific machine.

I have a good assortment of grinding wheels for precision work. But sometimes I just want to remove machining marks and make it look good, and that can be very time consuming with grinding wheels. A ceramic belt would be ideal there. I've been building a 2x72 type grinder (I started 18 months ago, then it was put on hold when I had a series of commissioned woodworking projects, and I just resumed it this past week) which I had expected to use for that purpose, among many others, but it's difficult to keep a part flat when moving it across the belt. I had planned on coming up with a jig for that (most likely utilizing two ball bearing drawer glides, mounted perpendicularly to each other to provide reasonable alignment in both axes), but now I'm thinking this would be a better solution since I already have a surface grinder with excellent table movement. It just needs a way to mount/tension/track an abrasive belt. And there are at least six threaded bolt holes plus t-track mounts on the spindle housing.

Has anyone here ever seen such a retrofit?

I'm typing this on the computer, but the link to the video is on my phone. I'll add it in the first comment below. I did ask the guy in a comment on his video, but he hasn't uploaded anything in 2 years so I don't expect a response any time soon.

 

[intjonmiller]

 

[intjonmiller]

By way of comparison, this is a machine I installed and used at a shop where I used to work. It was like $9,000 and removed metal like nothing else I've ever seen. It had a silly little work rest for freehand grinding on the end, so I fabricated a decent, rigid table in its place. But with a 36 grit zirconia belt it ate through steel like it wasn't even there, and by comparison it practically didn't even heat up the metal. I mean it would get hot, but neither as hot nor nowhere near as fast as any other grinding method I've ever used.

https://fein.com/en_ca/belt-grinding-machines/grit-gi-modular/grit-gils-0332032/

But its main function was as a sort of thickness sander for metal. After setting the height with the handwheel at the very top and setting the material guides with the 8 black levers you can see there, you inserted the metal into the left side (by this image) and it came out the right. We used it to apply brushed steel look to A36 flat stock for decorative products. More consistent look and WAY faster than other methods we tried. Like if you had enough pressure for it to make contact but not enough for it to dig in and grind it would launch the part at horrifyingly high speed, straight across the shop. A week after installing it the rep came by and said they got a report from another shop that theirs had launched a part which flew 20 feet and THEN went straight through a rolled up carpet remnant and embedded in the OSB wall behind it. I set up some plywood "targets" for it, and before anyone could turn it on they had to announce to the entire shop that they would be using it, so no one was allowed to cross the part of the shop in its path. And still one part ended up getting launched, went through my two plywood backstops, and still made a heavy dent in the powder coating oven I had so carefully set up. It's a mean machine.

It's a modular system. I can't find an image of the work rest on the full longitudinal power feed setup above, so here's one of the same work rest on the base grinder module:

See what I mean? Pathetic on a $9K machine. The work rest on my little $100 Ryobi belt sander is more effective.

ANYWAY, the point is that I know that abrasive belt surface grinding is very effective and efficient. And I think that with a magnetic chuck, a 1/2 HP 120V motor (rather than a ~5 HP 3-phase), and a steel crap catcher mounted on the "exhaust" side of my surface grinder, it should be safe enough. And it would be a really cool project (as if I'm lacking in ideas for projects).

 

[derf]

I think it would be easier to use one of those convoluted rubber wheels that belts fit on snug. that would eliminate all the other components like an idler and tensioner.

 

[TOOLMASTER]

should be easy enough to make a plate for the tensioner on top and change the wheel into a belt sander

 

[intjonmiller]

I can picture a number of ways to do it. I'm wondering if anyone has seen it done, and if they remember where, so I can see one or more successful implementations.

 

[TOOLMASTER]

https://www.google.com/search?q=bel...ved=0ahUKEwiQ3Laar_jMAhXKbz4KHdtZBgEQ_AUIBygC

 

[intjonmiller]

How funny that I didn't do a google image search. That's where I usually start. With the regular search I was finding countless results that were related, but not what I was looking for. Not even close. These are great.

Thanks!

 

[TOOLMASTER]

if the grinding isn't critical ...you can get inflatable hubs that hold round sanding sleeves.

 

[intjonmiller]

I didn't know about those "inflatable" wheels. That's really cool.

Those serrated wheels are so expensive. I need to figure out how to do that myself. Too bad I don't have gearing to get below 4 TPI on my lathe. I've wondered about accomplishing the same effect (or close to it) with a pattern of drilled holes instead. Casting the urethane or rubber isn't particularly difficult. Hmmm...