Gasket material for vacuum chuck

[Jay Barker]

Hello all-I am in the process of putting together a vacuum chuck system for my lathe. I’d like to do most of it with homemade parts. I plan on using a disc of wood with a short piece of PVC pipe epoxied to it. This will be threaded with a Beall spindle tap. My question Is what type of gasket material should I put on the end of the PVC pipe?
I was thinking closed cell foam. but not sure what thickness. I understand that if it’s too thin, it may not make a good seal with any irregularities on the piece. If it’s too thick, I think the piece may have a tendency to shift around. Thanks for any advice!
-Jay

[Ben Darrah]

I use the closed cell foam sheets from Michaels. They are a little under 1/8th thick. They work well.

[Peter Blair]

Just like Ben I too am using those thin sheets of closed cell foam. I use contact cement to hold them in place. Seem to work fine. I have a couple of Oneway and use Rubber Chucky gaskets on them.

[Edward Weber]

I would also make more than one chuck while in the process. A couple of different diameters can cover a wide range of projects.
Just a suggestion.

[John K Jordan]

Hello all-I am in the process of putting together a vacuum chuck system for my lathe. I’d like to do most of it with homemade parts. I plan on using a disc of wood with a short piece of PVC pipe epoxied to it. This will be threaded with a Beall spindle tap. My question Is what type of gasket material should I put on the end of the PVC pipe?
I was thinking closed cell foam. but not sure what thickness. I understand that if it’s too thin, it may not make a good seal with any irregularities on the piece. If it’s too thick, I think the piece may have a tendency to shift around. Thanks for any advice!
-Jay

Jay,

The hobby store foam is what most people I know use - may browse in the store if you have one local. Some foam has an adhesive backing but it might be stronger to glue it. Joe Woodworker used to sell a special gasket material specifically for shop-made pvc vacuum chucks but I don’t know if he still carries it. (I bought some maybe 5-6 years ago)

If tapping a block of wood to hold a PVC pipe section (I think a good way to make these, cheaper than using a different face plate for each size) one thing you might do is tap the wood first then mount and turn it flat for perfect alignment, even turn a groove to fit the pipe. I suspect you plan on doing this anyway but I figured it wouldn’t hurt to mention it. I mounted pvc in a chuck and faced off the mounting end as well.

I’ve made several other custom accessories with the Beall spindle tap. This is a wooden chuck made specifically to hold chicken-size eggs to finish tuning the end. I tapped a block of dogwood, hard and strong, turned it round, then glued it into a hole in a block of soft cedar. Turned that to shape (to make it perfectly aligned) then cut some slotted springy fingers to clamp over the egg. Good clean fun! (I'm careful to stay away from the spinning clamp)

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JKJ

[Paul Williams]

My vacuum chucks are similar to those described above including the use of 1/8 inch self-adhesive foam. Several years ago I picked up several chunks of a material I believe to be machinable nylon. I drill and tab a chunk, screw it to the headstock and turn to fit the smaller end of a plastic reducer/coupler. I attach with CA glue. They work great and there is no detectable leakage. I think I made chucks with 2, 3, and 4 inch pipes. The reduced end is 2 inches on the larger chucks. I have one that is 4 inch diameter by 6 inches long. It works to reach the inside bottom of bowls. Seems to be stable enough and runs true at that length.

My only issue is that I used an oil lubed HVAC pump when i built my system and I have not completely solved the oil mist issue.

[Richard Coers]

My only issue is that I used an oil lubed HVAC pump when i built my system and I have not completely solved the oil mist issue.

I run a tube from the exhaust into a coffee can, then put a couple layers of paper towel just inside the top of the can. Simple and works well.

[Robert Hayward]

The Beal spindle tap does a really nice job in hard wood. With my vacuum chucks I use Live Oak, very dense hard wood. The PVC fitting fits into a groove turned in the wood. Then sealed with epoxy mixed with microballoons, glass beads. I also have one large chuck that I used an 1 1/4-8 nut epoxied into a piece of Live oak and then a 6" PVC fitting. A neighbor turned a recess into one side of the nuts so they would snug up against the spindle on my 3520b, just like a commercial chuck does. I had to buy the nuts in a five pack so he turned the recess into all five nuts.

The thin hobby store foam is what I use for a seal.

[roger wiegand]

The closed cell PVC foam that often comes as packing material works great, but for a splurge, try the gaskets that are sold by Rubber Chucky. He makes them for several commercial chucks as well as to fit a 4" PVC drain pipe union. They slip over the edge without need for glue and work very nicely.

[Jay Barker]

So I ended up using the craft store foam and it worked perfect. It was probably 1/16 or 3/32 thick. It was very exciting to see how good it worked. Thank you all for the help.

[Brice Rogers]

I think that there are two thicknesses of craft foam.