what type of vacuum pump/chuck

[curtis rosche]

ok, so after make enough bowls, and being satisfied with my skill, now i am disgusted witht he way the bottoms look. i am looking at vacuum pumps over at the Bay. they have cheap pumps. what type should i be looking for? and once i have the pump, what do i need to use it with my lathe? my spindle is 3/4x16tpi

[curtis rosche]

here are a couple i found,

GAST Model DOA-P704-AA Vacuum Pressure Pump!!

This pump is in very good physical and functional order. It has two working gauges. These retail for over $700 new. This is a fairly new pump and hasnt been in service for long (maybe one year).
Free Air Displacement: 1.1cfm
Electrical: 115v/ 60 Hz/ 4.2 Amps
Ultimate Vacuum: 25.5" Hg
Pressure: 60 psi

--------------------------------------------------------------------------------------------

GAST Vacuum Pump NEW 0523-101Q-G582DX Compressor

Vacuum Pump Power Rating 1/4 HP Voltage Rating 115/230 Volts Current Rating 4.6/2.3 Amps NPT Inlet (F) 1/4 Inch NPT Outlet (F) 1/4 Inch Phase Single Length 13 1/2 Inches Width 5 1/2 Inches Height 6 Inches Free Air Flow @ 10 PSI 3.9 CFM Free Air Flow @ 10 Inches Vacuum 3 CFM Free Air Flow @ 15 Inches Vacuum 2.2 CFM Free Air Flow @ 20 Inches Vacuum 1.4 CFM Free Air Flow @ 25 Inches Vacuum 0.5 CFM Free Air Flow @ 5 PSI 4.4 CFM
----------------------------------------------------------
SPX Robinair Cooltech Vacuum Pump Model 15600
Specifications:

Free Air Displacement:

6 CFM

Number of Stages:

Two

Factory Micron Rating:

20 microns

Intake Fitting:

1/4" MFL

Oil Capacity:

15 oz. (445 ml)

Motor Size:

1/2 HP

Voltage:

115V, 60Hz

Weight:

27 lbs (12kg)

Dimensions:

9 ¾" H x 5 5/8" W x 15" L
(24.7 cm x 14.25 cm x 38.1 cm)

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[Mike Minto]

So I use the HF 2.5 cfm vacuum pump, and am getting over 25 HG on the vacuum gauge - and it's MUCH less $. mike

[curtis rosche]

also this one

SARGENT-WELCH SCIENTIFIC CO., SAR-VAC MODEL 8804 VACCUM PUMP

if one of these will work please let me know. if you are one of the CL addicts around here who constintly searches it, let me know if you find any thing good on your adventures. my computer is to slow to do the search of multiple craigslists at one once.

[curtis rosche]

so, i take that as a vote for one of the gast pumps? which one?

[Richard Madison]

Curtis,
From everything I have read here, the 1.1 cfm capacity is probably too small if your bowls have much porosity. Have you tried doughnut chucks or jam chucks? Certainly a vacuum chuck system would be very handy, but you don't actually "need" one to make bowl bottoms look good.

[curtis rosche]

well, Rich, i looked at donut and jam chucks, but heres the problem. most of my bowls latley, and all of the future ones that i am going to make from the reclaimed wood i got, fit my lathe exactly, i take a file to the blank just to get it to spin. i leave them as big as possible, and because of that it would mean that a chuck would not fit around the bowl to hold it.

dont vacuum chucks work better anyways? except for really pourous woods (what woods are they?)

[Richard Madison]

Jam chucks would still work. They are not necessarily larger diameter than the workpiece. Having never used a vacuum chuck, I can not say if they are "better" or not. For very porous pieces one can cover most of the outside with plastic wrap film to help seal it while on the vac. chuck.

[curtis rosche]

these were all under $50 Mike

[curtis rosche]

i also found this one, from the place that Steve sites in his how to article on SMC
http://www.surpluscenter.com/item.as...4-1669&catname=

1/4 HP Rotary Vacuum Pump/Compressor
Used, GAST model 0522-P335-G509DAX. Direct drive, oil-less rotary vacuum pump/compressor. Thermally protected motor.

SPECIFICATIONS

• HP 1/4
• Voltage 220 AC
• Amps 1.5
• RPM 1725
• Duty continuous
• Ports 1/4" NPT

4 CFM at 0 in. Hg
20 in. Hg max vacuum
PSI 10 cont.
PSI 15 max.
Size 11" x 5-3/4" x 8"
Shpg. 31 lbs.

[David Walser]

Curtis,

Most of the Gast pumps available second hand are 220v (because they are used in commercial applications). Every now and again you can find the 110v version on ebay or surplus supply center (or whatever). In general, you are looking for the rotary vane model in either an oiled or oil less version.

Several forum members have bought the 2.5 CFM vacuum pump from Harbor Freight. It's a rotary vane model that requires oil. (Be sure you keep the oil reservoir full, or the pump's life will be shortened.) This is a relatively new item at HF, so we don't know how reliable these pumps will be. (Gast pumps have a great reputation.) Here's a link: http://www.harborfreight.com/cpi/cta...emnumber=98076

As for how to hook the system up, take a look at Steve Schlumpf's excellent tutorial and search the forum for photos and descriptions of other forum members' setups.

Good luck!

[Jason Clark2]

I ordered a Gast 0522 (http://www.surpluscenter.com/item.as...-1669&catname=) last week and expect to receive it on Monday.

I'm making my own rotary adapter and vacuum chuck this weekend and plan to use Steve's tutorial as a guide to acquire and assemble the remaining parts.

Jason

[Mike Stephens]

Where can I find Steve's article? I did a quick search but could not find it.

[Jason Clark2]

It's been moved to the articles section:
http://www.sawmillcreek.org/showthread.php?t=84279

Jason

[Mike Minto]

hey, i'm glad you found a pump for less - wish i had found a 110 gast for that price, i would have bought that. mike