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Vacum Chucking ?

M

Mark Warden

Joined
Feb 9, 2009
Messages
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Location
Sinking Spring Pa.
2 Parts
#1 I have a gast vacum pump that was used for medical use.If I hook it up to a gage it's pulling between 25 - 30 (didn't have my glasses on) it seems rather small is there some kind of volume rating or do you think this would be suitable for vacum chucking? If so
#2 I saw somewhere I thought in this forum a home made adapter for attaching to the lathe.I searched over an hour now and can't find it. I did find lots of usefull info and again say thanks to you all for sharing. If anyone knows what I'm talking about can you point me in the rite direction please.
 
Mark Warden said:
2 Parts
#1 I have a gast vacum pump that was used for medical use.If I hook it up to a gage it's pulling between 25 - 30 (didn't have my glasses on) it seems rather small is there some kind of volume rating or do you think this would be suitable for vacum chucking?
Click to expand...

That's plenty. If you can pull over 20 you are OK. The volume rating is CFMs.

You can usually GOOGLE the pump model and find that out.
 
Carl Ford's article

#2 I saw somewhere I thought in this forum a home made adapter for attaching to the lathe.I searched over an hour now and can't find it. I did find lots of usefull info and again say thanks to you all for sharing. If anyone knows what I'm talking about can you point me in the rite direction please.[/QUOTE]


Take a look at Carl Ford's article. Good stuff there. I made a variation that fits to the hand wheel but does not use the lamp tube.

http://www.carlford.info/assets/demos_classes/vaccum_chucks_demo/cbf_vaccum_chucks_demo.html
 
I have a pdf of a vacuum adaptor that I built along with a vacuum chuck. Send me an e-mail and I will attach it for you.
Ideally you need a bridge rectifier to conver ac to dc but they are very inexpensive at radio shack.
 
DanRoscigno said:
Has anyone tried one of these DC vacuum pumps:

https://www.surpluscenter.com/item.asp?UID=2009051421445500&item=4-1801&catname=

They run off 135VDC, Burden (surpluscenter.com) says to run them off 110VAC with a rectifier. Assuming a $6 rectifier this is a $20 vacuum pump. The web site says it will pull 25 inches, but does not list a volume.
Click to expand...

That is a tiny "peanut whistle" size vacuum pump that is rated at less than 1/25th of a horsepower. It wouldn't be satisfactory at all. Also, their statement about using a rectifier is a gross understatement.
 
HoldFast says anything over 12hg is fine. My HoldFast holds very well at 18hg. Finished up a large 15# walnut bowl @18hg. Finished turned at about 600 rpm. No problems.

On the other hand, if you have thin turnings you have to be careful about collapsing them with too much vacuum. So, watch those dials.

Burt
 
Vacuum pump source

Dam near free, if you can get one. My local appliance store gave me a brand-new in-the-box fridge compressor, sucks very well, havent attached a gauge yet, but I will. It had specs for suction that were well in the range of vacuum chucking. It's 1/4 hp, overload protected, how can you go wrong?
 
Burt Alcantara said:
HoldFast says anything over 12hg is fine. My HoldFast holds very well at 18hg. Finished up a large 15# walnut bowl @18hg. Finished turned at about 600 rpm. No problems.

On the other hand, if you have thin turnings you have to be careful about collapsing them with too much vacuum. So, watch those dials.

Burt
Click to expand...

It really depends on the surface area of the vacuum and the surface area of the item being held . 12" of platter will hold great at 12hg, 2" of the same 12" platter, would not.

I have some small 2" chucks that I use for finish work on small hollow forms and even at 26hg, you can pop it off easy. Even if the HF is as big as the chuck.
 
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