looking for a clamping solution - WarmGlass.com

looking for a clamping solution

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Keikeoki
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Joined: Fri Aug 14, 2020 2:52 pm

looking for a clamping solution

Postby Keikeoki » Fri Aug 14, 2020 5:09 pm

I don't have access to a wet belt sander, so I'm wanting to use my pneumatic 4" wet polisher to do some cold work on fused glass bowls and other items. It is working well to hold the glass down with one hand, and use the other hand for the polisher, but I would rather use both hands on the polisher.

I am thinking of building a padded table to use with some padded screw clamps, or to use machinist style clamps with some sort of padding, or even a c-clamp with a 12" throat... Anything that can offer the clamping force to hold the piece down while I use both hands on the polisher.

I haven't lost anything yet, but there have been plenty of close calls... It takes two hands to turn the polisher on, so it is a risky business just trying to make two hands do what really takes 3 or 4. I know a nice wet beltsander like a Covington 760 is the right tool for some of what I'm doing, but that and a lap table are a couple of tools out of my price range right now... I already spent my budget for the rest of the year on the gear I have now, so I'm trying to make do with my 4" polisher. The polisher is working really well, I just don't have enough hands, and I'm not flexible enough to use my feet... ;)

If anyone has solved this problem, I would enjoy seeing what you came up with.


George

Brad Walker
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Re: looking for a clamping solution

Postby Brad Walker » Fri Aug 14, 2020 6:45 pm

We have a stainless table that we put padding on top. We use the padded shelf liner you can buy at Harbor Freight or probably most hardware stores.

https://www.amazon.com/padded-shelf-lin ... helf+liner

Normally we have one person to hold the piece and the other to use the air grinder. If you don't have a second person, I would try WOODEN clamps (that is, clamps made of wood) to hold the glass in place. I haven't done that, but I believe that wooden clamps would work better than metal ones.

https://www.rockler.com/wooden-handscrew-clamps-clamps

Keikeoki
Posts: 4
Joined: Fri Aug 14, 2020 2:52 pm

Re: looking for a clamping solution

Postby Keikeoki » Sat Aug 15, 2020 2:38 am

Good advice, pretty much what I was going to do... For padded surface I have a large supply of the half-inch foam used in exercise studios, but I also have a supply of the tool drawer liner type... And the paded screw clamp I was referring to is the woodworker's wood clamps with two acme threaded rods referred to as screw clamps or handscrew clamps... So for the most part we were using the same thoughts. The thick padding I have has a high density, is half an inch thick, and you can carve into it to help give some lateral hold in addition to the handscrew pressing down. The only problem with that plan is I can't find really large handscrews, they top out at a little over a foot, and the screws take up half of that room. But that is the best clamp for smaller pieces. For larger ones I may just have to make a larger clamp with some lumber. I was going to use bench dogs against the glass under the clamp, the dogs are like hockey pucks with a quarter inch of foam on either side.

I'd love to have my wife be my clamp, but she isn't going anywhere near my compressor and pneumatic polisher, she doesn't do noise...

Yeah, I was hoping there was some tool out there that everyone but me knew about.

I really want a large lap and a wet belt sander, but that isn't going to happen any time $oon. The pneumatic polisher cuts fast and leaves a good finish, and gets me to where I want to go for a cost under $100. It's no lap table, but it will do.

In my back yard I have a motorcycle tire mounting station set in concrete left by the previous owner with access to water and power, I'm thinking that would make a great conversion to a grinding station, I'll just weld a steel plate to the top at a convenient height. Being a solid mono pole table, I'll have open edges on all sides to clamp to.

Thanks for validating that I'm not crazy for trying this. I actually AM crazy, but that's off topic here...

Brad Walker
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Re: looking for a clamping solution

Postby Brad Walker » Sat Aug 15, 2020 7:44 am

I'm pretty sure you can make larger wooden clamps. Try Googling "make your own wooden clamps"

And it's entirely possible that both you and I are crazy....

Keikeoki
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Joined: Fri Aug 14, 2020 2:52 pm

Re: looking for a clamping solution

Postby Keikeoki » Mon Aug 17, 2020 1:31 pm

I saw a sewing pony used in a leather factory... Essentially a very specialized type of wood jaw clamp vaguely similar to a screw clamp but with "c"jaws rather than parallel jaws... I don't need a sewing pony per se, but it has inspired me on a potential idea for the jaw design I need. And I can integrate it into the work surface. Machinists have clamping systems for holding work for milling and other operations, and typically the foundation for these systems is integrated into the table. For CNC you build a table with a grid of threaded inserts in your spoil board. If I use one of my thick rubber pads as a spoilboard-like surface, I can have an underlying array of threaded holes in the steel table underneath, and then create an assortment of bolts padded in rubber tubing as well as padded wooden "machinist clamps". Sort of how we use a morton table to set up glass cuts, with pegs and stops, but in the style of a spoilboard grid.

In case you don't know what machinist clamps are or a spoilboard, here is a video https://www.youtube.com/watch?v=bpJyqLoqV04 of a CNC guy demonstrating machinist clamps on a CNC spoilboard, but he goes on to show some other clamps he is developing. The point is that a machinist clamp is like a one-arm screw clamp, using the table as the other arm. And for all practical purposes this is a milling operation, but we are machining glass, so a machinists style of clamping is appropriate but needs to be adapted to the glass. In the video he does not show any overhead type clamps because in CNC, you can't have things projecting over the work. However we are not doing CNC, opening up additional types of machinist clamps that are possible.

I don't think I'm going to build a grid of tapped holes, but I will probably have a strategic set of holes I add one at a time for each piece I work, until I no longer need to add them. To start with I think I'll just use a sheet of 3/4" marine grade plywood, and use wood screws for the clamping force so no tapped holes or extra advanced work is needed, and after I use that a while I will either love it or hate it, and I will evolve the idea from there. For pegs, I'll get some thick rubber tubing, and some copper tubing, and make rubber coated 2" pegs I can run a wood screw through. By the time the plywood is affected by water damage or screw-hole wear, I will know if it was a good idea or not. I have a large supply of the rubber mats, so wear and tear on those won't be a problem, but they will probably last longer than the plywood. For long-armed clamping arms, I will cut those out of hardwood, I have some oak that would be good for that. Instead of acme threaded rods, I will use lag bolts, as those come in long enough lengths, I'll just have to pre-drill pilot holes for those.

Thanks for the brainstorming help, solutions and ideas always come faster when bouncing and sharing ideas. But I'm actually thinking the CNC spoilboard with half-clamps and pegs is what I was looking for, when I put it into practice I'll post some images... Time for a curbside order from The Home Depot!

Keikeoki
Posts: 4
Joined: Fri Aug 14, 2020 2:52 pm

Re: looking for a clamping solution

Postby Keikeoki » Mon Aug 17, 2020 2:15 pm

Here is a sketch of one possible clamp style, many are possible...[img]
glass_clamp_fixture.png
[/img]
Attachments
glass_clamp_fixture.png

Buttercup
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Joined: Mon Jan 28, 2008 5:22 pm
Location: S.E. Queensland Australia

Re: looking for a clamping solution

Postby Buttercup » Thu Aug 20, 2020 11:22 pm

Love this DIY stuff. Some years ago, before the WGB meltdown, we had a lively DIY thread where members contributed their plans, photos and suggestions for making equipment from scratch or recycling and modifying existing items, saving lots of cash

Maybe this thread could trigger its rebirth?

Ed Cantarella
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Joined: Mon Feb 26, 2018 3:49 pm
Location: Highland, Michigan, USA

Re: looking for a clamping solution

Postby Ed Cantarella » Wed Oct 21, 2020 4:40 am

Old thread but maybe this is "out of the box" - if your ceiling is low and this wouldn't be destructive, maybe running something down that is adjustable, with a pad at the end, would be the ticket. Less obstructive than trying to essentially build an arm that can reach out onto the table AND provide good downward pressure. Sort of like arm wrestling.
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.


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