tilt-a-whirl positioning fixture

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tilt-a-whirl positioning fixture

Postby Bob Hammond » Sun Nov 08, 2015 3:34 pm

Hello, here's something that might be useful, and I could use advice about. I wish I could have an Emmert patternmaker's vise, but that's a bit beyond my means and needs.

(I'm sorry, you'll need to tilt your head to the left; I can't get the pics to cooperate clockwise.)

I'm getting to an age where I like to position a workpiece so that is comfortable to work, for my eyes, hands, neck, and spine (It's Hell getting older!) So I made this Plumbers' Special positioning fixture from ~$25 of 1/2" pipe fittings and some scraps. It allows me to position a workpiece at a comfortable height and attitude. There are two floor flanges, two unions, and a few nipples. The captured service wrenches are made of baltic birch. I haven't decided how and where I will permanently mount this fixture, and so for now it's just screwed and clamped to the corner of my bench. Also, I suppose 3/4" or 1" pipe & fittings might be heftier, but I'm not chopping wood here

As for my question, it occurs to me that it would not be difficult to install a vacuum clamp system. Somewhere I could install a Tee with a hose-barb fitting for a vacuum line, and then rout a groove around the plantilla/plate for a vacuum gasket. My question is, would that be secure enough so that an instrument would not slip, or catastrophically, fall off?
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Re: tilt-a-whirl positioning fixture

Postby Jason Rodgers » Sun Nov 08, 2015 7:52 pm

This is cool, Bob! I like the captured wrenches... I never would have though of that.

And yes, a vacuum clamping platen should be able to hold a guitar securely at any angle. I made a very crude vacuum hold-down for carving solidbodies, and I could chisel and plane and torque it roughly, and that's just using weather stripping. This guy is doing what you're talking about http://blog.customguitars.com/scotts_gu ... xture.html

One word of caution: depending on the back wood you're using, vacuum sucks right through porous woods and will not get a good grip. It's easy to test: put your guitar on the fixture, turn on the vacuum, and give it a jiggle. A splash of shellac, which you might have on there anyways at that point, will seal it up.
-Ruining perfectly good wood, one day at a time.
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Re: tilt-a-whirl positioning fixture

Postby Greg Steil » Mon Nov 09, 2015 9:30 am

That is so cool, I love home made tools etc.
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Re: tilt-a-whirl positioning fixture

Postby Gordon Bellerose » Wed Nov 11, 2015 10:18 pm

You and I must be close in age Bob. I also spend some time thinking about ways to make the work easier. :-)
That is a cool little vise. Allows you to position your work pretty much any way you want it.
I need your help. I can't possibly make all the mistakes myself!
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Re: tilt-a-whirl positioning fixture

Postby David Robinson » Sun Nov 15, 2015 11:43 am

I love vaccum clamping, but you have to use a reservoir system pump, that constant running pump will drive you mental.


I am making one of these to clamp/bolt on my stewmac stand.
http://www.jerryhartzell.com/wood-carvi ... ving-vise/


I have seen other made from 2" trailer hitch balls.
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Re: tilt-a-whirl positioning fixture

Postby Bob Hammond » Sun Nov 15, 2015 2:13 pm

David, I like the Jerry Hartzell design, maybe better than what I've done. The height is adjustable, which could be a very useful feature. I suppose that the eyebolt is is strong enough (it certainly is if it's forged).

About using a 2" hitch ball, I wonder if that is too small and too slippery. I remember a carver's station that I saw in FWW several decades ago. It was a bowling ball that was fitted into a clamping leg system (3 or 4 legs?), and the ball had been drilled and tapped to fit a nipple or bolt so as to mount a platform to it or a workpiece. Maybe a bocce or croquet ball might be a more convenient size.
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Re: tilt-a-whirl positioning fixture

Postby Bob Hammond » Sun Nov 15, 2015 2:42 pm

I guess this is what is known as "going large":

http://www.monsterballvise.com/floormodels.htm
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Re: tilt-a-whirl positioning fixture

Postby David Robinson » Mon Nov 16, 2015 8:19 am

Bob - I can see it is a real rabbit hole once you go bowling ball size, with all the hydraulics involved.

As to the eye-bolt - most weld up the return on the eye end. - I liked the idea of having multiple holder types that fit into the eye-bolt part. One with a plate, a threaded end, a clamp, etc.
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Re: tilt-a-whirl positioning fixture

Postby Peter Wilcox » Mon Nov 16, 2015 2:27 pm

Interesting. I have used bowling balls before.

telescope-bowling-ball-1.jpg

telescope-bowling-ball-2.jpg

I still have one rolling around out in the shop getting in the way, and a couple of hydraulic jacks I've never used. Now I've got an idea for them. Thanks.
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Re: tilt-a-whirl positioning fixture

Postby Jason Rodgers » Tue Nov 17, 2015 12:10 am

Peter Wilcox wrote:Interesting. I have used bowling balls before.

telescope-bowling-ball-1.jpg

telescope-bowling-ball-2.jpg

I still have one rolling around out in the shop getting in the way, and a couple of hydraulic jacks I've never used. Now I've got an idea for them. Thanks.

That's cool! How does that work?!
-Ruining perfectly good wood, one day at a time.
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Re: tilt-a-whirl positioning fixture

Postby Peter Wilcox » Tue Nov 17, 2015 2:45 am

One ball is the bearing that sits on a rubber pipe coupling mounted on top of a post. The other ball is a counter weight to balance the weight of the telescope so it will stay in whatever position it is moved to.
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Re: tilt-a-whirl positioning fixture

Postby David Robinson » Tue Nov 17, 2015 8:23 am

I love the ball counter weight!
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Re: tilt-a-whirl positioning fixture

Postby Bob Hammond » Tue Nov 17, 2015 3:00 pm

Peter, is that a shopbuilt telescope? The bowling balls give it a planetarium look. Are you scanning into Area 51?
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Re: tilt-a-whirl positioning fixture

Postby Peter Wilcox » Tue Nov 17, 2015 4:47 pm

Bob, I built that scope probably 15-20 years ago - I can't really remember. The objective is a surplus Kodak aerial camera lens, 36" f/8. I removed the iris diaphragm and shutter. The eyepiece is a huge surplus Erfle about 2" diameter and 1.5" focal length, giving the scope 24 power with probably a 2.5 degree field of view. The tube is some kind of plastic storage container. The telescope weighs a ton, but it's great for nebulae and comets.
Unfortunately I had to take the mounting post down a couple of years ago as my wife wanted a deck there, and since the post was made of alder, I took it apart to make guitar bodies. I have some 8" to 12" diameter creosoted fence posts and telephone poles laying around, so I should make a new mount from one of those, but that entails digging a hole in rocky ground - maybe some day.
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Re: tilt-a-whirl positioning fixture

Postby Jason Rodgers » Wed Nov 18, 2015 1:13 am

Peter Wilcox wrote:One ball is the bearing that sits on a rubber pipe coupling mounted on top of a post. The other ball is a counter weight to balance the weight of the telescope so it will stay in whatever position it is moved to.

It just sits there? There's nothing holding it on cept gravity?
-Ruining perfectly good wood, one day at a time.
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Re: tilt-a-whirl positioning fixture

Postby Peter Wilcox » Wed Nov 18, 2015 2:45 am

Jason Rodgers wrote:It just sits there? There's nothing holding it on cept gravity?

Yup. It just lifts off so you can take it in the house when not in use.
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Re: tilt-a-whirl positioning fixture

Postby Greg Martin » Sat Nov 28, 2015 1:03 pm

Lmi has a vac clamp system and stewmac has the floor stand.both are great if you have a dedicated place in the shop and can afford the 500.00 Plus costs. I like Bobs design although Id hate the captured clamps,they just call to me to get hung up in them ---some how. I carved my archtop using Benedettos carving cradle but by the end I wish I could have been seated. Id like to use something like Michael Lewis's carving cradle which does allow you to be seated.
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Re: tilt-a-whirl positioning fixture

Postby Bob Hammond » Sun Nov 29, 2015 8:36 pm

The captured wrenches can be disengaged from the unions, and can hang loose or be repositioned so that they are out of the way. They're like the wrenches on a bench vise or older benchtop circular saws from the 40s-50s.
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