Are these vacuum pumps any good?

[TurnedAround]

A vacuum pump purchased from Highland Hardware, Craft supplies, Oneway, etc. will run around $369 dollars. I was wondering is this particular pump is comparable to the ones that wood turning suppliers sell?

Even with shipping this one comes to about 200 dollars in savings.

Sure would appreciate some info if any of you have it. I'm very interested in setting up a vacuum chuck for the PM3520a.

Thanks, Larry

BTW I am aware that its 220v which is no problem.

http://www.surpluscenter.com/item.asp?UID=2005062006115650&item=4-1540&catname=

 

[Bill Boehme]

A vacuum pump purchased from Highland Hardware, Craft supplies, Oneway, etc. will run around $369 dollars. I was wondering is this particular pump is comparable to the ones that wood turning suppliers sell? ........ BTW I am aware that its 220v which is no problem.

Craft Supply and the others that you mentioned ARE woodturning suppliers. Who else were you thinking about where the price is $200 more? I know that the one that Craft Supply and Packard sell are very commonly used by woodturners. But, you don't need to spend that kind of money when you can find them on eBay for much less. I got the identical one that Craft Supply sells for $25 plus about $25 shipping.

BTW, these pumps run on 120 VAC and NOT 240 VAC as you stated.

Bill

 

[Steve Worcester]

I think you left a link out?

If you do a search in the forums here, there are a couple of suppliers mentioned. In vacuum pumps, HP does certainly play a role in how quickly it can evacuate the chuck, so keep that in mind. Additionally, look at the max CFM capabilities. They will most likely state that number as OPEN, which means that with no load on it. They may also show a CFM at a certain number such as .5 CFM at 26Hg. max. That states how much air it pulls at max vacuum. (For the record, vacuum is stated in inches of mercury, and not PSI). The higher the max, the more vacuum it can pull. A pump for woodturning, 20Hg is sufficient, but the ability to pull more CFMs means it will work better with a leaky chuck or where the seal against the woodturning isn't real good.

 

[Vernon Oberle]

Ebay??

If you are referring to the surplus pumps on ebay and a couple other places that are about 1/3 to 1/2 horse and 220V, mine works very well. The only drawback is not being able to easliy move it around to use for other roles such as vacuum pressing.

 

[Anthony Yakonick]

He means this one

http://www.surpluscenter.com/item.asp?UID=2005062006115650&item=4-1540&catname=

 

[Mark Ost]

vacuum pump

I purchased a Gast vacuum pump like that one pictured, 230v, and found that I had to replace the carbon vanes. No problem there,except for the price. I can now pull 23 to 25 inches of mercury with no trouble. They are great. I purchased a One-way rotating valve for the headstock and a 3 1/2 vacuum chuch from O ne-way. The system works like a charm, just as Johnny Tolly of Austin said that it would. I would recommend that anyone who wants to do vacuum chucking buy one, and the price in the previous web page is great.

Mark Ost Stateline Woodturners out of northwest Arkansas.

 

[Bill Boehme]

......For the record, vacuum is stated in inches of mercury, and not PSI......

Steve,

Inches of mercury is unit of measurement that we frequently think of when talking about atmospheric pressure or refrigeration systems, but it certainly is not the only applicable measurement unit and PSI is just as valid. For the rest of the world that uses the SI system (metric), neither of these would be used. A few other units of measurement that are just as valid, but somewhat dependent upon the field of use are atmospheres, bars, centimeters of mercury, pascals, torrs, and PSF. Some of these units can be stated as absolute or relative to standard day pressure taken at mean sea level, but inches of mercury and centimeters of mercury are always relative measurements when talking about vacuum. When talking about barometric pressure, it is an absolute measuement. Vacuum is essentially always stated relative to standard atmospheric pressure (or some other stated reference) without use of a minus sign (the minus being understood, for instance, 25 in-Hg vacuum is understood to be negative with respect to standard atmosdpheric pressure). There can't be an absolute measurement of vacuum since anything other than absolute zero pressure would be a positve number. Also, pressure in many applications including a typical shop air compressor is normally stated relative to standard atmospheric pressure. Pressures taken outside the atmosphere are normally absolute. So the bottom line is that there is not a "rule" on which units to use, but it would help if it is something that others can relate to.

Bill

 

[-e-]

in addition, check out used medical equipment suppliers (matrixmedical on ebay has some good deals on vacs). i got the following for same price as your link.

"This 220 v pump is new, it was never used. It did sit around for a while so there is some dust on it and a few small spots of rust. It has been tested and works perfectly. Comes as shown with a Fairchild back pressure regulator and inline filters."

the back-pressure regular allows the pump to be restarted under pressure, so ii may use the pump for vacuum clamping and pressing as well. i get 25" hg from it.

according to GAST, the filters are required.

i emailed GAST and asked them about the pump before i bought ... it was used in medical equipment and no longer manufactured but the guy thought it was fine for vacuum chucking as long as the filters were inline.

 

[TurnedAround]

Thanks, -e-

I checked the model numbers and they are pretty much the same. The "buy it now" price on ebay is now $179 dollars. Starting bid is $149. They claim the pumps are new as well.

I may just take my chances with the surplus center and see what happens.

Thanks so much for all the good advice. Really enjoyed your site too.

Larry

 

[-e-]

thanks
just a quick note on some info just acquired:

it is recommended that you let the vacuum pump run a while after use -- this helps to dry the lines and components. moisture in the pump will shorten the life....

makes sense.