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Vacuum pump vs Vacuum Generator

Joined
Mar 8, 2023
Messages
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Location
Reedsville, PA
I currently have and use, a ”Hold Fast” vacuum generator and it works just fine. I’ve been thinking of switching over to using a dedicated vacuum pump I could locate closer to my lathe. Also, I would not have my compressor firing up to fill the tank, even though the tank is large enough to handle the vacuum generator’s requirements.

I see a lot on Amazon for sell but I am not sure which type I should be look at. It seems the ”oil” type are the least expensive but can spew oil about the shop when used of an extended period of time.

I would appreciate any advice offered.

Brian
 

Tom Gall

TOTW Team
Joined
Feb 20, 2013
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Hillsborough, NJ
Definitely a vacuum pump. Most are continuous duty fractional HP motors (mine is 1/4HP). Cheaper to run than a 2+HP compressor....and MUCH quieter!. Mine is about 20' away from the lathe (quieter and less dusty) and connected with an air hose. All controls are right at the lathe.
 
Joined
Nov 15, 2020
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Location
Huntington, VT
The Gast rotary vane pumps are very reliable and as said are available used. I have one dedicated to my lathe and one for pressing veneer and general clamping with shop made fixtures. They are far more efficient and quieter than running a compressor.
 
Joined
Mar 8, 2023
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Location
Reedsville, PA
Thanks all for the input. I’ve started looking for a Gast pump on eBay. Just not familiar enough with them to know if one is a better than the other and what to look out for.
 
Joined
Mar 17, 2019
Messages
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Location
Warrenton, Virginia
You can also look for a used Thomas 2660 pump. They are also very dependable,quiet and easy to rebuild.

There are lots of pumps with varying capacities out there so make sure you check ”cfm” to make sure you get one with enough capacity. The 2660 has about 4 cfm which has worked really well for me so far.
 

Tom Gall

TOTW Team
Joined
Feb 20, 2013
Messages
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Location
Hillsborough, NJ
The Gast rotary vane pumps are very reliable and as said are available used.
Thanks all for the input. I’ve started looking for a Gast pump on eBay. Just not familiar enough with them to know if one is a better than the other and what to look out for.
I have a Gast #G588 EDX that I purchased from Oneway 20 yrs. ago. Never had a problem ... it has been maintenance free. Prior to that I had a no-name (noisy) pump (still works) for about 10 years. Just be sure to have filter(s) in place. Bad news! - prices for a new Gast pump have about doubled since 2003 .... and I complained then. My first brand new pump with 3/4hp motor was $80 from the Surplus Center.
 
Joined
Dec 26, 2022
Messages
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Location
Bartlesville, OK
Website
www.prairiewoodart.com
I purchased a used Thomas 2668 pump to use with a vacuum chuck. It also made it simpler to use my vacuum bag with which I used a vacuum generator along with my noisy pancake air compressor in the past. The 2668 is roughly 3 cfm and has been adequate thus far. I did not want the maintenance and potential mess associated with a standard oiled vacuum pump. The used pump was ~$200 on ebay. New are about 4 times more.
 
Joined
Mar 8, 2023
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Location
Reedsville, PA
I will look into the Thompson pump and see if there is deal out there lucking about. Seems like I’m always late to the party when I want to try something new or different.

Thanks again for all information and suggestions.
 
Joined
Dec 26, 2022
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Location
Bartlesville, OK
Website
www.prairiewoodart.com
That's the one I was seeing!
The fittings should be 1/4-18 NPT (standard pipe thread). Brass fittings from anywhere will work. Nothing special is needed since this is very low pressure. Just make sure to use some teflon tape to seal the thread joints. I used parts from Harbor Freight to add suction filters to the valve and pressure gage set up. There is a filter for intake air into the pump/gage area with the release valve is opened. There is also a separate, larger filter (again Harbor freight) plumbed between the valve and the pump. I also purchased an inexpensive 3/8" air hose (it has 14" NPT hose ends) from them to connect to my vacuum chuck hard line. I cut off the end of the air hose and it simply slides onto either the vacuum chuck hard line or my vacuum press line. Both joints are leak free. The pump already had an exhaust filter on it. IMG_1607.JPG
 
Joined
Mar 8, 2023
Messages
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Location
Reedsville, PA
Good information! I just found a person selling a Gast pump local that I’m going to look at tomorrow. He says it draws 24“ Hg.
 

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Joined
Aug 14, 2009
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Location
Peoria, Illinois
I run a tube from oil pump exhaust into a 1 gallon metal can and then put a couple of paper towels over the top of the bucket. No oil being spewed all over the shop. In fact before I used the bucket, I didn't see any spewing either.
 
Joined
Sep 12, 2017
Messages
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Location
Marietta, Georgia
Good information! I just found a person selling a Gast pump local that I’m going to look at tomorrow. He says it draws 24“ Hg.
Look at the cfm rating. For stabilizing you can get away with 1 or 2 cfm but as mentioned a 5 will give you more reliable results. My first Gast was a 7cfm model and held quite well. The motor died on it for some reason and I found a 15 cfm unit and it will hold in spite of bug holes and minor leaks.
 
Joined
Apr 20, 2006
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Location
Erie, PA
I use the pumps out of refrigerators or dehumidifiers. The one I have had for over 15 years is still running great, pulls 27" Hg. I run a line from the pump to a plastic jar with a hair type product to collect any mist (have not seen much if any at all).
 
Joined
Feb 16, 2021
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Location
Parkersburg, West Virginia
I have the same vacuum Chuck and generator. The vacuum generator didn’t last me one year. I went to Harbor Freight and bought a cheap vacuum pump. It works much better and have not had any problems with oil.
 
Joined
Aug 6, 2009
Messages
704
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Location
Lummi Island, WA
I use a gast rotary vane pump for chucking - works great. I found mine on ebay - it was sold as surplus stock from a hospital and was new in the box and sold for $89 14 years ago…the seller explained to me at the time that hospitals are required to have backups available and this inventory is rotated periodically. The company he worked for liquidated old stock for them. New gast RE pumps go for about $400 - pays to look around.

I also use a Thomas/Reichle rocking piston aeration pump that I bought used on ebay for $59. It had been used for aeration on a large pond. Its extremely quiet and pulls a great vacuum for my carving stand. These rocking piston pumps used to be sold by Frugal, but they were getting hard to find for him (I heard).

Both pumps have rebuild kits easily available and are rated for continuous duty.
 
Joined
Jan 11, 2022
Messages
111
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107
Location
Roanoke, VA
Here's how simple Gast pumps are. 1/4 HP is marginal, but a 1/2 HP is better seeing how wood is porous and leaks.
The vanes are some sort of phenolic squares that simply ride in a slot and centrifugal force pushes them against the chamber walls.
Two different Gast models shown below.

1           gast - 1.jpg

1           gast - 2.jpg

1           gast - 3.jpg
 
Joined
Mar 8, 2023
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Location
Reedsville, PA
Mr. Vaughan, there is not much to them at all. I will continue to shop around and see what I can find. I am nervous about getting on with a dead ac motor. Rebuilding the pump looks easy enough.

Thanks for the advice.
 
Joined
Jan 11, 2022
Messages
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Location
Roanoke, VA
Burned out windings are possible but rare. Many of the motors gast used do have a thermal overload in the centrifugal switch area. Its that cylindrical thing on the left.

1           gast1 - 1.jpg
 
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