making a special vacuum chuck

[erasmussen]

I needed a way to turn flat thin pieces 5 or 6" in diameter
Thought a new vacuum chuck was in order.
I'll try to show how I did it as best as I can:icon_scra
first the parts a nut with a washer welded to it 2 pieces of mdf one with a 1 1/4 hole the second one has a pocked turned to just fit the nut and washer in notice the inside corner is cut away to clear the weld its just deep enough so the washer sits flush, not shown in the picture (my bo bo ) is a piece of pvc pipe one I had on hand 3 1/2" od and 1 1/2 " tall

I set the nut and washer in a bed of epoxy leaving the washer seting high just a bit so it will be pushed down when the 2 pieces are clamped togather, and then TBII onthe MDF.

And then of course the 2 pieces of MDF are clamped togather

After the glue is set up 30 mins. or so I turned it round, and cut a pocket that the PVC pipe will just fit into

Next i gooped the PVC pipe in place it dont have to be super strong as the vacuum will pull it tighter in use but it does need to be air tight.

Next sflattned and smoothed the edge you can see the sanding stick in the picture :gar-La;

What I forget to get a picture of is gluing on a piece of closed cell foam (sorry)
But thats easy.

Then I tried it out it hold a flat piece great

It even holds a flat bottom bowl :gar-La;

 

[jhreed]

Earl, the engineer and inventor at work again. Looks professional, but who would expect any less from Ear.
James

 

[woodArtz]

Great job Earl. :icon_thum:icon_thum:icon_thum Tell us about the other end of the vacuum operation. How do you have the vac pump set up? What do you use to deliver the vacuum through the headstock? Inquiring minds... :wink_smil

 

[Trent Mason]

Great job Earl. :icon_thum:icon_thum:icon_thum Tell us about the other end of the vacuum operation. How do you have the vac pump set up? What do you use to deliver the vacuum through the headstock? Inquiring minds... :wink_smil

+1

Thanks for sharing this Earl. That is something I'd like to try. :eusa_thin

 

[erasmussen]

Ok I'll try to explain what I got.
The rotary joint is made from 2 bearings, lamp rod, and a PH housing.

The pump is a HF unit (I have used it a lot and it works great), however its a wet pump which means
you have to pump a closed system to keep the oil clean, no air leaks to adjust the vacuum to the chuck, I tried using a ball valve before the chuck and found it was too touchy, then I changed to a gate valve and its easy to adjust now.

of course theres a filter in line and the gauge is on a tee between the gate valve and the rotary joint
as close to the chuck as passable

And the tank is just pvc pipe, nothing in the system is fancy or expensive but it works great
pulls over 700 mmhg at the chuck :eusa_danc

Hope ya'll can understand how it works

 

[woodArtz]

Thanks Earl! Now that's some serious ingenuity there. :icon_thum

 

[Bob Alexander]

Earl, when Don and I were there the other day , you had added something to the pvc pipe to proect the workpiece from the edges of the pvc, I think. Can you tell us what that was? I failed to take careful notice. I think we will have to try to copy your idea. It is a great job and makes a vacumn chuck so much more affordable. Before we do it we would like your permission, as inventions can be patented and sold.:gar-Bi