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Hold fast vacuum chuck

Joined
Jan 23, 2020
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I just got a hold fast vacuum chuck system and have tried it on a couple pieces; I found that I could even use it for reverse chucking a hollow form, as it held a tight grip. I got both the 3 1/2" and the 6 1/2". It uses what they all a "generator" and your compressor. I know many have made up their own system with a vacuum pump, which I'm sure is much quieter than my rattling compressor (it's a 60 gallon quincy). I'm asking if anyone has any tips for using a vacuum chuck?
 
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I've got pretty much the same setup, though my compressor is smaller. I'm pretty happy with it, but I have problems centering the bowl even with the adapter to mount the four jaw chuck in the tailstock.
 
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I've got pretty much the same setup, though my compressor is smaller. I'm pretty happy with it, but I have problems centering the bowl even with the adapter to mount the four jaw chuck in the tailstock.
It is tricky to center, took me like 10 minutes to get it just right on a hollow form. Even having a center mark on the bottom only helps a tiny bit.
 

Bill Boehme

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The trick is to find a seal material that is thick enough to get a tight seal against the wood and thin enough so that the piece won't squirm when the vacuum is increased. Fun Foam sheets (AKA: Ethylene Vinyl Acetate craft foam) works pretty well, but it isn't very durable. I have settled on weatherstripping that has a D cross-section. The bad news is that I haven't been able to find it at my local hardware store.

The Hold Fast uses a venturi the create the low pressure, but the downside is the noise.
 
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On the AAW Explore resource page, if you search in the Category=Chucks, and Keyword=vacuum chucks, you can find 25 articles with additional information. I recall John Giem, who is an engineer, writing a pair of very thorough articles and was shocked to see they were published in 2011 and 2014. Seems like last year. In any case, there is a treasure trove of help available.
 
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I found them. Very informative. I made the mistake of not researching how to center the bowl. I found a simple invention called a tail stock chuck adapter that allows me to easily center the bowl on the vacuum chuck. It was from Robust tools and fit my robust live center.
 
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Vacuum chucks are great for sanding and light cuts. However be careful. I have used masking tape to secure it further when necessary. This was the case where I discovered a small crack in the rim of a bowl about 1/4” deep. If a finished piece comes off a vacuum chuck there will be damage.
 
Joined
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I found a simple invention called a tail stock chuck adapter that allows me to easily center the bowl on the vacuum chuck.

And here's another useful trick. If you need to leave a piece mounted to a vacuum chuck for an extended period, say overnight, mount a faceplate on that tailstock adapter. Then you can use the tailstock and faceplate to hold the piece in place against the vacuum chuck so that the vacuum can be shut down.
 
Joined
Nov 4, 2011
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Bay Settlement, WI
One more useful trick ... I use a wooden wedge to center up workpieces on my vacuum chuck.

I bring the tool rest up close (less than a half inch), bring up just enough vacuum pressure to hold the piece, and turn the lathe on slowest speed (25-30rpm). I insert the wedge between the workpiece and the tool rest and gradually move the workpiece until it runs true. I withdraw the wedge, and crank up the vacuum.
 

john lucas

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Use the largest vacuum chuck you can. The larger the chuck the more holding power it has. That being said wood moves when you thin bowls out and sometimes even though it was perfectly round when you finished turning it may not sit perfectly flat on a 6" chuck and will not pull the full.vacuum. several times I've had to change to my 3" chuck to get the full vacuum. A 3" chuck doesnt hold as strong so you have to take lighter cuts and as was suggested above use the tailstock as long as you can. Another tip.with the larger chuck. I keep a square of high density foam just a little.larger than the 6" chuck. It has a 1" hole in the middle. When you get a bowl.that has warped a.little you can put this square over the chuck and put your bowl.over it. The square corners are easy to grab to adjust it so it fits fully over the chuck. Then turn on your compressor. The extra thickness of foam will.often be enough to seal against the warped bowl.
If you have.a bowl that has some work holes or other defect that leaks air you put stretch wrap.around the bowl.and it will.seal.these holes. Of course that wont work if the holes.are.in the area that needs to be turned.
Www.bestwoodtools.com sells.a non rotating tailstock chuck adaptor. I find it faster to use than the Robust or Oneway tailstock adaptor.
 
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