vacuum pumps

Anyone have experience with this model? Pro's?/con's?

Harbor Freight is usually not my first choice, but I'm looking there now.

vacuum pump model #98076-2vga. 2.5cfm, rotary-vane

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Reply to
Joe
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Atmospheric pressure 760 torr 101.3 kPa Low vacuum 760 to 25 torr 100 to 3 kPa Medium vacuum 25 to 1=D710-3 torr 3 kPa to 100 mPa High vacuum 1=D710-3 to 1=D710-9 torr 100 mPa to 100 nPa

Reply to
Robatoy

I'd go for it. Rotary vane pumps aren't rocket science. I doubt it would pull 75 microns, but it should do what it was intended to, pull moisture out of refrigeration lines. Just keep the oil fresh. Better yet, invest in some high grade vac pump oil. If you can replace the

1/4" fitting with 3/8" and use corresponding sized hose, that would work better. Besides, the worst you can say about it is, "it sucks".

nb

Reply to
notbob

B.

Reply to
Buddy Matlosz

LOL. You're confusing function with size.

Yeah, *this* isn't gonna start a whole new direction for the thread....

Reply to
Joe

Well, you never did say what you were trying to accomplish...........

B.

Reply to
Buddy Matlosz

Fair enough. Veneering and holding small workpieces in place for production routing.

Reply to
Joe

That won't be enough vacuum IMHO.

Reply to
Robatoy

Pshaw! Then you are wasting your money. You'd be better off using an old vacuum cleaner thru vacuum cleaner hose.

nb

Reply to
notbob

I might as well. Ran it for 10 seconds and it started rattling and smoking. first and last tool I ever buy from HF.

Reply to
Joe

Venturi based vacuum generators are cheap and reliable.

Reply to
Robatoy

For production, think Gast, thet are in a league by themselves.

HF vacuum pumps are toys.

Lew

Reply to
Lew Hodgett

That's what rotary vane pumps do when they've pulled a vacuum. The smoking is oil vapor backstreaming. You should have said what you were going to use it for in the first place. I thought you were going to use it for pumping down refrigeration lines, its intended purpose. Maybe HF will take it back. Tell 'em you didn't know about backstreaming and can't tolerate any oil on the work.

nb

Reply to
notbob

I use a recycled refrigerator compressor with shop-built vacuum pucks for holding (not small) workpieces for CNC routing with a 5 hp spindle.

The higher-volume shops like the vacuum pumps from

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're more expensive but those who have 'em, love 'em.

Reply to
Morris Dovey

Try one of these. (Btw.. the claim of 27"Hg is optimistic)

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Reply to
Robatoy

You are paying insane amounts of money for vacuum overkill. A simple vacuum cleaner will provide all the vacuum mecessary for holding down verneer pieces, even lager ones. The mechanism at work here is not vacuum. but the air pressure acting on the pieces to be held. IOW, it's not the level or rate of vacuum, but the atmospheric pressure on the other side of the work. You can buy a $10 million dollar vacuum system, but the air pressure holding down the pieces will never exceed

14.7 psi.

nb

Reply to
notbob

Yup, those are 'drool-grade'. Used ones are quite reasonable...and parts are available all over. One day, dammit...

Reply to
Robatoy

I don't do veneering, so you won't get any argument from me in that context.

Joe mentioned production routing small parts - and in that context, the choice of equipment will depend very much on the particular set-up (whole table, with vacuum being pulled through a permeable spoilboard; vacuum pucks on an impermeable spoilboard; or something in-between); the material being routed - parameters will be very different for, say, Lexan, baltic birch, and MDF workpieces; and how aggressive the feed is.

I've been pretty happy with pucks and an old recycled refrigerator compressor - but I don't use vacuum hold down for parts under 16 in^2, and I can't even consider vacuum hold-down for leaky materials like 1/4 in MDF. (If I really needed to do that I'd spring for a real vacuum pump

- probably a reconditioned Becker.)

I have a how-to for making inexpensive vacuum pucks at

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- I just daisy-chain 'em together and connect to the intake side of the refrigerator compresor with 3/8 in vinyl tubing.

For non-production (very small) quantities, I'm more likely to use carpet tape - or for in-between (small) quantities, a purpose-built clamping fixture like those shown at

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Reply to
Morris Dovey

Bill Noble, one of the participants of rec.craft.woodturning, usually has a few reconditioned Gast pumps on his web site at a decent price:

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"GAST 0523-IDQ-G21DX

220V, single phase, weighs 30 pounds

I measured 22 inches vacuum

Oilless carbon vane pump, if I read the spec sheet right, this is a 3.2 CFM free air flow pump, 10 psi max, 26 in vac max, so my 22 inch measurement says it's in really good shape.

manual is here:

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$165."

Reply to
Nova

Were you operating the pump with no load or connected to the intended device?

I've rebuilt several direct and belt drive types. They can be a bit noisy and smoky. Give it another try with the inlet completely blocked (max load). Better yet, connect a vacuum gauge to the inlet and see what its actually pulling.

John

Reply to
John Wood

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