Questions for you vacuum chuckers

[Brad McCollum]

I am in the process of building a vacuum chucking system. I want to use it for all of my finish turning, not just to finish off the base. What size vac chuck would you use for utility bowls that are 14" - 15" in diameter? What about bowls in the 10" - 12" range? Would you use something different for the outside vs the inside? How much vacuum would you suggest for these bowls? Thanks for your help.
Makin' m round in Memphis

[Jim Becker]

The rule of thumb is a bigger drum is better. Dave Lancaster turns all of his 12" bowls using the 8" OneWay drum. I am already finding I need to get one that size as my 5" is a bit small now that I can actually turn larger objects since buying the Stubby.

As to vacuum, I very rarely turn mine down with the bleed, but Johnny Tolly has an excellent document that will give you the numbers you need based on size and thickness.

[Brad McCollum]

Now that is what I call a quick response! Thanks for the info Jim. Where can I find Mr. Tolly's document?

[Jim Becker]

Email him...he's in the AAW directory.

[Richard Allen]

Hi Brad

The vacuum chuck is a terrific device and you should get a lot of good use out of it. There are woods that you can't use a vacuum chuck on and some situation where a vacuum chuck is a poor choice for holding a bowl. Woods like ash and red oak don't vacuum chuck well because air can be pulled right through the wood. A thin walled bowl can collapse in a vacuum chuck.

A 5" chuck should hold the bowl sizes you mention with a death grip. An 8" chuck will hold anything you mention and it can do so with less stress than a 5" chuck provided you bleed off some of the vacuum. A vacuum chuck drum can be used for jam chucking.

Good Luck

[Andy London]

I would suggest a 5" drum, the bigger the better. I run mine around 15 to 20 HG on bowls up to 12" which is the largest I have turned so far. You need to be careful if the item is thin as these things will suck the bottom out of a bowl in a fast...learned that the hard way on a beautiful spalted birch bowl.

I have put a couple of pages on my website together on the process, based on the way I set it up.

http://www.picframer.ca/vacuum_chucking_on_the_jet_mini.htm

http://www.picframer.ca/vacuumchuckjet.htm

Andy

[Steve Stube]

Andy, thanks so much for the informative write-up and photos on vacuum chucking.