Vacuum Pumps for Vacuum Chuck and Stabilizing

[Rich Aldrich]

I plan to finish what I started last year. I want to make a vacuum chuck and be able to stabilize pen blanks. I want to buy one vacuum pump for both applications. Stabilizing typically requires 29" vacuum (75 microns max). Also, a 2 stage vane pump is best for the vacuum level required for stabilizing according to the Turn Tex website. I would think this would be fine for a vacuum chuck as long as the CFM is sufficient - 4 CFM? If anyone experienced anything different please let me know. This is all from research, not from actual practice or experience.

Does anyone use a Robinair or JB Industries pumps? If so, how reliable are the pumps? It is very difficult to find a used Gast pump for less than the price one of these pumps - unless I am looking in the wrong spot.

[Bill Boehme]

If you can find a vacuum chuck with an open port flow rate of 3 CFM I think that you should be OK. Just make sure than system leaks are kept as low as possible. The larger 4 CFM is usually stated because it is more tolerant of leaks. Get a high quality rotary adapter such as the one that JT Turning Tools (http://www.jtturningtools.com/vacuum-adapters) builds. The cost is around a hundred bucks depending on your lathe model.

[Shawn Pachlhofer]

I've stabilized a few hundred pen blanks with just a Harbor Freight vacuum pump. The only problem with the HF pump is that it exhausts oil mist into the air in the shop, so I've had to install a filter (that just "kinda" works) and then also cover than with blue paper towels.

I might upgrade pumps in the coming year.

If you have a Powermatic lathe, I have a Oneway rotary vacuum adapter that I will list for sale soon.

[Jeff Walters]

Check out Frugal Vacuum Pump. I and any members of my club have this unit and I use it for chucking and stabilizing. It's an excellect, reprised medical vacuum pump at a very good price. Bob is also a great guy to do business with.

Jeff

[John K Jordan]

I find Joe Woodworker an excellent resource on all things concerning vacuum pumps, chucks, clamps, and presses.

I bought a new pump from him and am building the system he designed. I really like some of the features, things missing on many systems. After a great deal of research, I can't imagine trying to get by with a bare pump without adding a reservoir, sub-reservoir, Mac valve, etc. He also has good information on other things that work or don't work, like vacuum quick disconnects.

Look at his Project: EVS
He also discusses the pros and cons of various vacuum pumps, used and new, including the Gast. Some of his advise is based on the experience of customers who tried different pumps.

http://www.joewoodworker.com/veneering/faq.htm

He has a kit which I mostly bought, with some modifications. Hope to get the thing finished this winter.
http://www.veneersupplies.com/products/Project-EVS-Auto-Cycling-Pump-Vacuum-Press-Kit.html
You can skip the kit and just build from his plans but when shopping around I found his prices on fittings and things pretty good.

I don't have any connection with this company but their service was prompt and complete. I have talked with Joe on the phone and he took the time to answer all my questions.

JKJ

[Thom Sturgill]

Be sure to put in a bleeder valve to control the vacuum delivered to the chuck - 25" can crush a thin bowl. I typically use as little as 12-15" and take very light cuts. CFM is only important if you have leaks or porous bowls. I often seal the inside as my pump has very little in the way of cfm. IMHO anything that meets the requirements for vacuum pressing or stabilizing is probably overkill for chucking.

[Joe Bradshaw]

Rich, if you are into modifying tools, an air compressor from California Air Tools will work great. I saw one in use as an air compressor and noticed that the compressor was the same as the vacuum pumps sold by Frugal Vacuum Pumps(I have his setup also). I swapped the intake and exhaust ports around and it works great. Real quiet to. I bought the entire stabilizing system from Duro Tools. I got the 5 gal. size. I have stabilized 2 bowls so far. The whole setup was less than $300.00. Of course, I had to buy a toaster oven that would hold 10" bowls. It's always something.
Joe

[Jeffrey J Smith]

I've got both a Gast 0523 series pump and an older Thomas Reichle rocking-piston style pump that was used as an aeration pump at one time. Both work for vacuum chucking, but the Gast will peg the gauge while the rocking-piston pump with a fresh rebuild will only pull about 25" at most. I use the Gast on the lathe and the Thomas is setup on a pro-cut carving stand that uses the same chucks (also use it for vacuum bagging when needed). Haven't used either for stabilizing, but I'd tend to use the Thomas just to save wear and tear on the Gast. Both were bought for reasonable prices on EBay - the Gast was new/surplus and sold for $85.00 (it was a steal - never used). The Thomas was only $35.00 and another $12 for a rebuild kit.

[Shawn Pachlhofer]

for stabilizing - you want a vacuum pump that will pull the MOST vacuum you can get....so in Jeffrey's case above, I would use the Gast for stabilizing.

[Rich Aldrich]

"Be sure to put in a bleeder valve to control the vacuum delivered to the chuck - 25" can crush a thin bowl. I typically use as little as 12-15" and take very light cuts. CFM is only important if you have leaks or porous bowls. I often seal the inside as my pump has very little in the way of cfm. IMHO anything that meets the requirements for vacuum pressing or stabilizing is probably overkill for chucking."

Thom, Good point on the bleed valve. This will allow one pump to be used for both applications with caution.

My thought is that you would need more CFM for chucking, but since it is at a lower vacuum level, the pump might have more volume capacity at the lower vacuum level. With stabilizing and veneer pressing, you have a fixed volume of air to pump out and the vacuum level is more important to remove the last bit of air which might be a bit more difficult.

[Paul Gilbert]

The priority for vacuum chucking is volumn. For stabilizing the priority is ultimate vacuum. Rotary vane (Gast) pumps will only pull about 26" Hg when new and the piston types are about the same. To get to 29" you will need a two stage pump and this means oil. For this you need to look for pumps used by AC repairmen.

[Rich Aldrich]

Bill, That makes sense for the volume requirement. The openings in the vacuum adaptor and chuck are probably a limiting factor as you point out. I did get a vacuum adaptor from JT Turning tools last winter, but got too busy to complete the system.

[Rich Aldrich]

for stabilizing - you want a vacuum pump that will pull the MOST vacuum you can get....so in Jeffrey's case above, I would use the Gast for stabilizing.


I've stabilized a few hundred pen blanks with just a Harbor Freight vacuum pump. The only problem with the HF pump is that it exhausts oil mist into the air in the shop, so I've had to install a filter (that just "kinda" works) and then also cover than with blue paper towels.

I might upgrade pumps in the coming year.

If you have a Powermatic lathe, I have a Oneway rotary vacuum adapter that I will list for sale soon.

Shawn, Agree that vacuum level is the most important for stabilizing from what you and the stabilizing experts have said. I heard the same oil mist issue with the Harbor Freight pumps in my research. My main question right now: Is a used Gast pump better than a new Robinair or new JB Industries pump for similar money? You will probably be interested in this answer as well when you decide to replace your pump.

[Rich Aldrich]

If you can find a vacuum chuck with an open port flow rate of 3 CFM I think that you should be OK. Just make sure than system leaks are kept as low as possible. The larger 4 CFM is usually stated because it is more tolerant of leaks. Get a high quality rotary adapter such as the one that JT Turning Tools (http://www.jtturningtools.com/vacuum-adapters) builds. The cost is around a hundred bucks depending on your lathe model.

Bill, That makes sense for the volume requirement. The openings in the vacuum adaptor and chuck are probably a limiting factor as you point out. I did get a vacuum adaptor from JT Turning tools last winter, but got too busy to complete the system.

[Rich Aldrich]

Check out Frugal Vacuum Pump. I and any members of my club have this unit and I use it for chucking and stabilizing. It's an excellect, reprised medical vacuum pump at a very good price. Bob is also a great guy to do business with.

Jeff

Jeff, It is interesting that you can stabilize with this pump according to what I have read. However, experience is what counts. This would be the most economical system because his kit includes the fittings, etc. Which model pump came with your system?

[Rich Aldrich]

I find Joe Woodworker an excellent resource on all things concerning vacuum pumps, chucks, clamps, and presses.

I bought a new pump from him and am building the system he designed. I really like some of the features, things missing on many systems. After a great deal of research, I can't imagine trying to get by with a bare pump without adding a reservoir, sub-reservoir, Mac valve, etc. He also has good information on other things that work or don't work, like vacuum quick disconnects.

Look at his Project: EVS
He also discusses the pros and cons of various vacuum pumps, used and new, including the Gast. Some of his advise is based on the experience of customers who tried different pumps.

http://www.joewoodworker.com/veneering/faq.htm

He has a kit which I mostly bought, with some modifications. Hope to get the thing finished this winter.
http://www.veneersupplies.com/products/Project-EVS-Auto-Cycling-Pump-Vacuum-Press-Kit.html
You can skip the kit and just build from his plans but when shopping around I found his prices on fittings and things pretty good.

I don't have any connection with this company but their service was prompt and complete. I have talked with Joe on the phone and he took the time to answer all my questions.

JKJ

John, I will check it out in more detail. Just briefly going through the site, the pumps he uses for veneer appear a bit small for chucking. Which pump do you have?

[John K Jordan]

the pumps he uses for veneer appear a bit small for chucking. Which pump do you have?

I bought this one:
http://www.veneersupplies.com/products/Vacuum-Pump---55-CFM-120v-AC-240v-AC.html

I have not built the system but I did hook up the pump and some fittings and it was fairly quiet and really pulled a vacuum.

I want to use it primarily on my lathes, for vacuum clamping for the mill and wood, and perhaps for veneer at some point, as well for an occasional need to pull a vacuum to seat or test something. I am also interested stabilizing if it will work for that, but that's not my primary objective. Many years ago I did use a vacuum when potting things in epoxy resin and would like to do that occasionally too (I ran a small metallography laboratory and potted test sections from nuclear reactor fuel plates for polishing and analysis - good fun!)

I spent several months researching and reading everything I could find on this. I discarded the inexpensive venturi method as too noisy and decided to go with a new pump from Joe. I'm sure I could have found a cheaper used pump but I figured this way would simplify things if I ever had an issue with the pump. I really like the Mac valve idea and the sub-reservoir in his plan. I like the inexpensive PVC reservoir so the pump doesn't have to run continuously - I may even increase the reservoir size. If you look around on his site you will find pictures of many people who built systems from his plans - he's evidently been doing this for a while.

I want to build a nice, compact portable self-contained unit like in his plans. I figure when I get too old to play it might be easier to sell and for the next guy to use!

The other issue is the adapter for the lathe. I use Jet 1642 lathes and plan to machine my own adapter similar to the one JT Turning sells, but for a fraction of the cost.

JKJ

[David C. Roseman]

John, I will check it out in more detail. Just briefly going through the site, the pumps he uses for veneer appear a bit small for chucking. Which pump do you have?

Rich, two of the pumps on Joe Gorleski's (Joe Woodworker) site are definitely not too small for chucking. John links to the Gast, which produces 5.5 cfm, way more than necessary for vacuum chucking, IMO. For the last three years, my shop-built system has used the rebuilt GD Thomas (Rietschle-Thomas) double-piston commercial pump that Joe sells for about 1/3 the price of the Gast. http://www.veneersupplies.com/products/Vacuum-Pump---Thomas-315-CFM-120-VAC.html With a bowl or platter mounted using either my shop-built chucks or my JT Turning Tools Vacuum Hub, it pulls a full 25 inHG consistently. That's enough to do some damage to thin-walled turnings, so it's important to incorporate a bleed valve. With light cuts you can finish-turn the bottom of a fairly large bowl quite securely with just 15 inHg.

For connecting your system to the spindle of your lathe, I second Bill Boehme's comment on JT Turning Tools' "Precision Vacuum Adapter". It is exceptionally well made using aircraft aluminum and two double-shielded, double-sealed bearings. It is the adapter Robust ships with it's line of lathes when a customer asks that the lathe be vacuum-ready.

[Shawn Pachlhofer]

Shawn, Agree that vacuum level is the most important for stabilizing from what you and the stabilizing experts have said. I heard the same oil mist issue with the Harbor Freight pumps in my research. My main question right now: Is a used Gast pump better than a new Robinair or new JB Industries pump for similar money? You will probably be interested in this answer as well when you decide to replace your pump.
disclaimer - Curtis is a friend. He gives me no discount on products - other than a Veteran discount that he offers to any other vet.

give him a call. His contact info is on his website. He's always willing to talk about stabilizing and give tips on how to maximize your success using his products.

He's got a page on his site talking about several different pumps that are available on the market: http://www.turntex.com/index.php?option=com_content&view=article&id=61%3Avacuum-pumps&catid=35&Itemid=61

[John K Jordan]

John links to the Gast, which produces 5.5 cfm

Actually, it's not a Gast pump.

But it is rated at 5.5 cfm which, as you imply, is more than adequate. The value of putting that flow on a system with a significantly sized reservoir is that for many applications the pump runs only occasionally instead of continuously like some I've seen, coming on only when the pressure drops enough. This should be quieter and perhaps increase the life of the pump. A switch can make it run continuously if the application requires.

Kind of reminds me of a huge vacuum reservoir in the bottom of a player piano I rebuilt. This evened out the vacuum supply and only required occasional foot pumping to keep playing.

JKJ