Vacuum Pump Help Please

[Griesbach]

Several months ago I bought a Gast vacuum pump from the Surplus Center and a Oneway vacuum adapter for my PM3520B. Well, this afternoon I finally got around to begin setting some things up and I wired a cord and plug for the 220v outlet and removed the lathe hand wheel and put on the adapter.

Pump ran just fine, hose hooked from the inlet side of the pump to the adapter and pulled some vacuum. BUT there is not enough vacuum to hold anything. :mad: I put my hand on the spindle end (carefully because I didn't want to get stuck) and there isn't enough holding power for anything at all.

Checked as best I could for leaks (made some smoke), covered the spindle opening and couldn't find any. It wouldn't even pull any smoke into the spindle.

I know this isn't a complete setup yet but shouldn't it pull something tight to the spindle end.

Need some help here and offering my appreciation in advance.

 

[Mark Mandell]

Start at the pump. Disconnect it from the piping, turn it on, and see what it pulls at the inlet port. To do this you really should have a vacuum guage which you'll NEED for your final system anyway. That pump should immediately pull 28" of Hg. If it doesn't, you either have a bad pump, damaged vanes, or the housing is not properly sealed.

Remember too that each pipe joint should be doped with thread sealer. A common mistake here is the use of teflon plumbing tape. Problem happens when some of that tape can come loose and damage the pump's vanes.

Don't know what you're using to connect to the adapter, by the quick-connect air fittings are notorious leakers.

PS 28" of Hg. in a 1/2" cross-section won't hurt you so don't think the thing's going to suck your hand in.

 

[Ken Grunke]

Hi Cyril, do you have a guage in the system? That will help with diagnostics, when fiddling around looking for leaks. The needle will move if/when you, for example, wrap your hand around a loose tubing joint.
Possible you have a hole hidden in the spindle somewhere? I drilled a hole in my spindle for a crude lock but didn't realize it had gone deeper than it should, the drill's tip had just begun to enter the hole through the spindle. So I stick a gob of polymer clay in there when I use my vacuum chuck, 'twerks very well

 

[jwtaylor]

I would suggest you get a vacuum gage and "T" it into the line and take a reading to see what vaccum you are getting. You could use an automotive vacuum gage if you have one. Block the end of the spindle to see what vacuum you get. You could also work your way back towards the pump, or for that matter start at the pump and see where you are loosing the vacuum.

You may have a weak pump, Gast has manuals that cover cleaning and rebuilding on their website.

 

[Griesbach]

Thanks for the suggestions. I'll have to get a gauge, I know, and see that it will help in the diagnosis. Can't seem to find one locally so I'll try to order one.

Not using quick disconect (but thought of it) so glad I didn't wase the money. So far all I've connected is the pump directly to the adapter using barbed fittings. The pump is supposed to be new but I guess that may not mean all that one might assume.

Going out of town soon for about 11 days, so I won't have much time to mess with it till returning but I'll keep checking on the suggestions even though I won't be able to post.

Thanks for the help so far.

 

[Mark Mandell]

Cyril,

Since you're using hose, you should make sure you've got no kinks or blocks in that line. Knew one guy who hooked up his system, capped the end of the spindle and got very little pull. Turned out his nice flexible hose would collapse as soon as the vac began to build, but popped back into shape when the restriction was removed. Drove him a bit nuts finding the problem. Make sure you're not getting "hosed."

 

[Joe Greiner]

Barbed fittings alone are probably not sufficient. Are you also using grease as well as hose clamps?

JG

 

[laymarcrafts]

Cyril the advise re the Colapsing Hose is one to look for and also the use of Grease at all joints is advisable, but it must be Vacuum Grease not just any old Grease.

Richard
http://www.laymar-crafts.co.uk

 

[Griesbach]

The hose I'm using is the hose that came with the adapter. It is very stiff and has thick walls. Still, I'll check to be sure it's not collapsing. I did not use clamps on the hose fittings yet but I will. I never heard of vacuum grease so that's something else to locate, or, are you refering to pipe dope?

 

[Dave Beringer]

Add a dust and liquid filter

When you get the system ready I would also filter the intake to the pump. Remember you will be pulling you vacuum through the wood and will be pulling moisture and dust /dirt particles from the wood. I have a filter on the intake so that I don't pass this debris into the pump.

I also recommend a blow off value near the lathe. This will allow you to use a partial vacuum to adjust the piece. You can adjust how much vacum you have at the piece. This valve is also helpful for thin walled peices where full vacuum may destroy your peice. Look at Oneways site they have a good diagram of the setup.

 

[laymarcrafts]

Cyril there is a Special Grease for use with Vacuum Systems, anyone who sells Vac Pumps should be able to sell you a Tube.

On my System I have at least 7 Pipe to Hose Joints and I used a Smear of Grease on all plus a Jubilee Clip to ensure a Goood Seal.

djb's advise on Bleed Valve and Filters is sound advise as you need to control the Vacuum and also protect the Pump.

I have an Inlet Filter [Home Made] on the Bleed Valve and an Compressed Air Ceramic Filter before the Pump, a $10 Dollar Filter can save a $300 Dollar Pump from an early exit,

Richard
http://www.laymar-crafts.co.uk

 

[hcbph]

If I can make a suggestion, take a vacuum at the pump then one at the end of the hose. I've seen in another application where the internals of the hose were collapsing but it wasn't visible from the outside. Kind of like having the plys of a tire seperate (in reverse). Trying to evacuate an a/c system and it wasn't pulling, yet it had a couple of weeks ago. Turned out the hose had failed internally.

Paul

 

[Malcolm Smith]

Oneway pump

The pump than Oneway sells is very ideal for their vacuum system. A gage is definately need. Granted, the pump is fairly expensive but if You can't find an alternative, you might do well to order theirs. They've clearly given thought to exactly what is needed.

Malcolm Smith.

 

[Mark Ost]

Vaccum pump question

Cyril: I had the same problem when I purchased a used Gast Pump. I finally opened the pump end and inspected the graphite vanes. They were cracked and would not draw much of a vacuum. They are available from John Henry Foster Company in St. Louis, MO (314-427-0600). For my pump, the Gast repair kit was numbered 17-B-04. I have the Parts List and Operating instructions for model numbers 0322, 0522, 0822 and 1022, if they would help you. Send me an email with your full name and address, and I could send a copy to you, as needed.

Mark Ost.
Pineville, MO
(417)223-4435

 

[CA Savoy]

Adaptor

Cyril:

What size adaptor did you use to connect the ONEWAY Vac. adaptor to the outboard spindle of your 3520B?

CA

 

[Tony Reynolds]

If you need a pump check out joewoodworker.com. He's got some rebuilt dual piston pumps for a good price. I run one on my set up and for my veneer bag. It pulls about 25.5"hg and works great.

 

[Bill Boehme]

If you need a pump check out joewoodworker.com. He's got some rebuilt dual piston pumps for a good price. I run one on my set up and for my veneer bag. It pulls about 25.5"hg and works great.

A piston pump is fine for veneering because it is capable of greater vacuum than rotary vane pumps, but it is not a good solution for lathe use because the flow rate is too low to maintain vacuum where there are leaks -- and there always will be some leaks. You should get a rotary vane pump with an open port flow rate of about 4.5 CFM or greater and a vacuum capability of around 26 inches of mercury with a blocked port. A quarter horse GAST pump will fill that bill nicely. BTW, there are two types of rotary vane pumps: oiled and dry -- make sure that you get the dry type -- the oiled type will be a mess and the really fine dust that gets through the filter will mix with the oil and make a mess in the pump.

Bill

 

[Tony Reynolds]

These have a flow rate of 3.15cfm, plus I use it with a reservoir system with lots of reserve so it hasn't been a problem having enough vacuum. It pulls 25"hg then kicks back on when vacuum drops to 21"hg in reservoir. Joe's site shows how to build a complete system for veneering and or chucking.

 

[W.C. Turner]

Cyril the advise re the Colapsing Hose is one to look for and also the use of Grease at all joints is advisable, but it must be Vacuum Grease not just any old Grease.

Richard
http://www.laymar-crafts.co.uk

<<"Are you also using grease as well as hose clamps?">>

Please advise. What does the vacuum grease do?
W.C.

 

[W.C. Turner]

Grease

On page #1 of this thread, vacuum grease was mentioned, & I posted question there. In case that is not seen, here it is again.

What does the vacuum grease do, form a seal, or what?

W.C.

 

[Tony Reynolds]

WC it's to form a seal.

 

[Frank Alvarez]

dirty pump

I have to thank you guys. I read the thread and took my Gast piston pump apart. When I first got it I eagerly and foolishly had tried it out before putting a filter on it and later used plumbers tape to make the seals. I found not only pieces of dust but also plumbers tape in the piston and in the little flap valves. I cleaned it up and works great now. Thanks again, this is a great service to all us want a be's.

 

[lumpy]

I'm in the midst of setting up a vacuum chuck and was wondering what any of you are using for a filter?
Thanx
Brad

 

[Mark Mandell]

I'm in the midst of setting up a vacuum chuck and was wondering what any of you are using for a filter?
Thanx
Brad

Follow the link but if the filter doesn't show, put 4-1565 in the search box.

http://www.surpluscenter.com/item.asp?UID=2006110807490831&item=4-1565&catname=

 

[laymarcrafts]

Brad I used a similar filter but sold as a In-Line Compressed Air Filter, after all it is only Air we are Filtering, I used the smallest available which was rated at 35cfm way above the 4.5cfm of my Pump.

I also made a Filter for the Air Intake to the Regulator Valve and I detail the method in the Hints and Tips Section of my Web Site.

Both Filters are very effective and my System runs as clean as you possibly can get it.

Richard
http://www.laymar-crafts.co.uk

Look under Hints and Tips ~ Vacuum System

 

[webturner]

I didn't have an air filter onhand when I set up my vacuum pump. So, I grabbed an old inline fuel filter from my lawn mower. The ends happend to fit into the air hose exactly and it works so good I've never gotten around to getting a real air filter.

Stan

 

[Richard Preston]

When you get the system ready I would also filter the intake to the pump. Remember you will be pulling you vacuum through the wood and will be pulling moisture and dust /dirt particles from the wood. I have a filter on the intake so that I don't pass this debris into the pump.

Yes, and I have sucked in CA glue as well. Then had to soak the cylinder which attaches to the spindle in Acetone to get the glue off.