Hold fast vacuum chuck

[John Hicks]

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?

 

[Karl Best]

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.

 

[John Hicks]

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]

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 to create the low pressure, but the downside is the noise.

 

[Mark Jundanian]

What difficulties are you encoutering in using the vacuum chuck?

 

[Dean Center]

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.

 

[John Hicks]

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.

 

[William Rogers]

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.

 

[Mark Jundanian]

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.

 

[GRJensen]

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.

 

[Gerald Lawrence]

Leaving the revolving center mark from turning the tenon has always worked for me. Just place the bowl on vaccum and bring up tailstock to center mary. Oh by the way light cuts and use the tailstock support till at the final cut and sanding.

 

[john lucas]

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.

 

[Ken Hunter]

I sometimes have a problem getting the vacuum up to pressure, mostly with the 6inch chuck.

I have the 3.5 and 6 inch chucks. Normally the 3.5 inch chuck works fine but there are times I need to wiggle/twist the hose connection at the head stock to get the pressure up. The 6 inch rarely works.

Any suggestions?

I like the system for reaching the botttom of the bowl but I still use the tailstock whenever I can

 

[Sam Fleisher]

I sometimes have a problem getting the vacuum up to pressure, mostly with the 6inch chuck.

I have the 3.5 and 6 inch chucks. Normally the 3.5 inch chuck works fine but there are times I need to wiggle/twist the hose connection at the head stock to get the pressure up. The 6 inch rarely works.

Any suggestions?

I like the system for reaching the botttom of the bowl but I still use the tailstock whenever I can

What kind of wood is giving you problems? Any little defect in the wood will leak a little or a type of wood like oak for example you'll get less vacuum.

I mostly use a 18 inch disc I've made and the rim of a bowl goes onto it like a set of Cole jaws. I've found that it doesn't take a maximum vacuum all the time to hold something very well. That said it will only work if my rim is flat and no holes in the bowl.

 

[Dave Landers]

I sometimes have a problem getting the vacuum up to pressure, mostly with the 6inch chuck.

I have the 3.5 and 6 inch chucks. Normally the 3.5 inch chuck works fine but there are times I need to wiggle/twist the hose connection at the head stock to get the pressure up. The 6 inch rarely works.

Any suggestions?

I like the system for reaching the botttom of the bowl but I still use the tailstock whenever I can

Wood leaks. Some more than others. If I have leaky wood, I use pallet wrap (i.e. Saran Wrap) around the piece (including the chuck body). That helps with the leaks (and also provides a little support, just in case). If there's bug holes or etc I'll usually bridge them with painters tape before wrapping, to keep the wrap from being sucked in. Sometimes tape over strategic areas is all that's needed.

Also, by the time I get something on the vac chuck it might not be entirely round anymore. So the seal around the chuck might not be best. I use a ring cut from craft foam (1/16" thick "fun foam" or whatever they call it) to give a bit of extra help sealing up the imperfections.

 

[Tom Gall]

there are times I need to wiggle/twist the hose connection

If wood leakage isn't the problem as others have mentioned, then maybe add a hose clamp if there isn't one, or replace the hose. Do you have good vacuum at the spindle without the chuck?

 

[Charles Cadenhead]

Be sure you have the twist on fitting facing the right way. If it's backwards you won't get a tight seal and have leakage. Took me too long to figure that out.