Vacuum Pump

[Bernie Weishapl]

I have a quick question. I can get a Gast Vacuum pump for a decent price. In fact there are two of them both 115 volt. One is new and the other is used. The spec's say they will pull 27/29.5 in-hg. I know there will be some loss but was wondering if this would do the job for bowl turning? Thanks.

[Lars A Stole]

Bernie,

The Hg measurement is fine, but you will want to have at least 3 CFM I think and a decent sized chuck. As a reference point, I had a small Gast pump from Joe Woodworker that was rated at 1.1 CFM (and 25.5 inches) and it just wasn't strong enough to hold on a bowl with a 5" chuck (although it was fine for veneering). I later bought a surplus 220v 3.5 CFM Gast (also 25 inches, I htink) and it holds great.

Lastly, I am assuming you have about a 5" diameter chuck in mind. The strength of the hold is proportional to the area of the chuck, which is proportional to the diameter squared. My 1.1 CFM gast would might have worked if I had an 8" chuck. I'd be nervous using a 3" chuck on a large bowl, regardless of the pump.

Hope this is helpful.

Lars

[Matt Haus]

What's the model number? If it says it will pull 27/29.5 in-hg then your fine. Make sure you test it on a guage right at the pump to make sure it's what your getting. The amount of vacuum will also depent on the size of the chuck you are using. The larger, the more pull per square inch.

[Bernie Weishapl]

It says the "free air flow range" is 1.75 to 3.3 cfm on the one and model #SAA -V110-NB. The other one I am looking at says 115/220 rated at 27.5 in-hg at 5 cfm and model #4VCF-14-M400X. I am not wired in the shop for 220v so that is why I was looking at 115 V. Thanks again for the replys.

[Stephen Mushinski]

Bernie,

The one with the high CFM would be the best buy if they are the same price. You wrote that it is 115/220 so that means it can be wired for either voltage. Pretty simple to do as it should be labeled inside the cover or on the outside label.

Having said that I think either unit would function ok.

[Kevin McPeek]

I know a lot of people have bought the one from the surplus place and it is rated for .5 CFM @ 26"HG but 3.6 CFM @ 10 PSI cont. This would be the first I have heard of that not having enough vacuum.
I am currently using the shopvac on the Nova with their coupler and it seems okay at best. I was planning on getting the pump from surplus supply, but maybe I should pony up some extra bucks..?

[Dennis Peacock]

Either one will work just fine Bernie. I have 3 teeny-tiny vac-pumps daisy-chained together to give me what I need at the lathe. Either one that you are looking at would do you just fine.

[Bernie Weishapl]

Thanks for the help. I am looking at both pretty hard. Have to make a decision soon.