vacuum pump - distance away from lathe?

[Hugh]

OK - Yesterday I was turning the bottom of a nice bowl. I should have quit while I was ahead and when I had a 1/2" spiggot left holding it. Thought I would be cool and make it about 1/4". Less to carve away. What a mistake. The spiggot broke and the bowl banged around a bit and then off the lathe. Ruined that bowl. What a waste. I am ready to hook up the vacuum pump that I have had for a year or so. But I want to put it up near the ceiling about 10' away from the lathe. The idea I have is to make a shelf up near the ceiling and put the vacuum pump up there and then run copper pipe down to a place near the lathe where I can easily reach the lathe from the wall. Is it going to be a problem having the vacuum pump that far away? I am going to be using a Gast 1/4 hp 110v pump. My thought is that I may loose a little bit of vacuum power but not enough to cause me any problems. Am I right? Thanks ahead of time.
Hugh

 

[Mark Mandell]

No Problem

I've had friends who put them in the next room. Samo samo. In fact, the longer run of pipe will act like a vacuum reservoir to even out any fluctuation. What you MUST have close to the lathe (actually within arm's reach of the workpiece, are a vacuum guage and bleeder valve set up so you can adjust the pressure on your piece. Look in the HOW TO section here on the 2nd page of posts and you'll find a good compilation on lots of vacuum issues.

good luck

 

[Bill Turpin]

What Mark said is true, but for future reference: The volume (cfm) of a vacuum is inversely proportional to the square of the distance or oriface. In woodworkers language: twice the distance, one fourth the volume. Half the oriface (ID of smallest fitting used) one fourth the volume. Remember that the oriface is figured in cross-sectional, internal area, not pipe size. A 1/4" pipe will suck only 20% of what a 3/8" pipe will!

Bill in WNC mountains

 

[Martin Braun]

Assuming you have things fairly leak proof, you should be alright. It may take a little more time to pump down. Once it does, the *nearly* static vacuum should be fairly close to what you have with a short run of pipe.

 

[john lucas]

I think it's advantageous to have a longer hose. It takes a tiny bit longer to build up the vacuum but that's an advantage if you lose power. It takes a little bit longer for the vacuum to fall off so maybe you can get your hands on the bowl before the vacuum drops off completely.
I had that happen once. Power went out, house went dark, vacuum died and bowl went flying, in the dark. It sounded like I was in a pin ball machine. I didn't even know which way to duck.

 

[Mark Mandell]

Hugh,

With Bill's post in mind, your vacuum line should be 1/2" so that you don't restrict flow. If you were going more than 10-12 feet away, I'd recommend you go to type L copper, but for the distance you're considering, type M will work just fine. I also counsel people away from using compressed air disconnect fittings, but if you must, be sure to get "hi-flo" type which have larger internal diameters. I much prefer making the last connection with a ball union compression fitting that will seal but still remain moveable.

mm

 

[Hugh]

Thanks for the info Gang! I do not have anyproblem using 1/2" or even larger diameter copper pipe - even if the price of copper pipe has doubled or more in price. I did not think there would be a problem, I am just trying to get the pump out of the way where I do not have to move it and store it somewhere on the floor of the shop. The plan is to put the pump up close to the ceiling where it will be out of the way - run a 1/2" pipe to a spot near the headstock of the lathe with the proper fittings and then have a valve to regulate the vacuum, and also a way to connect the vacuum up to the lathe. This will work. Maybe I can save a bowl or two and it will pay for itself.

Mark - I take it (and I should know this) that "L" copper pipe is stronger than "M" copper pipe? I will roll for the stronger of the two - as I like over kill when possible.
Thanks again.
Hugh

 

[Mark Mandell]

L vs M

Thanks for the info Gang! I do not have anyproblem using 1/2" or even larger diameter copper pipe - even if the price of copper pipe has doubled or more in price. I did not think there would be a problem, I am just trying to get the pump out of the way where I do not have to move it and store it somewhere on the floor of the shop. The plan is to put the pump up close to the ceiling where it will be out of the way - run a 1/2" pipe to a spot near the headstock of the lathe with the proper fittings and then have a valve to regulate the vacuum, and also a way to connect the vacuum up to the lathe. This will work. Maybe I can save a bowl or two and it will pay for itself.

Mark - I take it (and I should know this) that "L" copper pipe is stronger than "M" copper pipe? I will roll for the stronger of the two - as I like over kill when possible.
Thanks again.
Hugh

Type M copper pipe (it will be marked with printing in RED INK) was designed for low pressure (40psi max) circulating hot water heating systems. Type "L" (marked with BLUE INK) is for general "normal pressure" (up to 250psi) water plumbing. When the price of copper spiked the last time in the 80's, some States got the bright idea of authorizing type M for general residential plumbing to save a few bucks. Many of this systems, usually in homes with somewhat acidic well water, began pinholing about 10 years after construction. I had to replumb my entire 1986-built house from the well supply to the uppermost shower head. Engineers will tell you that type M is tested to 500 psi, but not over time. When I put in my compressor, I piped the distribution system in type L, not because M wouldn't take the pressure, but because L, a heavier guage, will take more abuse and the occasional hit from flying debris, bowls, or tools, plus will be more resistant to lower pH condensate moisture.

mm

ps: In addition to the bleeder valve and vacuum guage mentioned, you must have a filter on your vacuum line or at the pump's intake port to keep wood dust out of your vacuum pump.

mm

 

[laymarcrafts]

Hugh the only influence Distance has on the Vacuum is the Time it will take to pull the Vacuum.

If you calculate the Internal Volume of your System from the Vacuum Chuck to the Pump [A] in ft³ and then take the Pump Capacity in ft³/sec [Ratings are normally in ft³/min or cfm] and then divide A ÷ B you will get an approximation of the Time to Pull the Vacuum.

Roughly it will take less than a Second to pull a Vacuum on 10ft of ½" Pipe with a 2.5cfm Pump.

Details of my Vacuum Pump System with additional data on Pressures and Vacuum's can be found at http://www.laymar-crafts.co.uk/tip42.htm

Richard

 

[webturner]

Regarding the discussion on 'M' vs 'L' type copper pipe (40psi vs 250psi). Remember that a perfect vacuum will never produce more than about 14psi.
For the small diameters you are considering, plastic tubing works fine for vacuum lines and is a lot easier to work with.

 

[Hugh]

OK - I think I have it now. Thanks everyone. Good discription on "M" & "L" copper pipe Mark. Stan - plastic tubing may work for what I am trying to do but the copper is so much better looking and picks up a nice patina after awhile. I put in copper pipe for my compressed air and will most likely use the copper pipe again. Thanks for all the help guys.
Hugh

 

[Bob Boettcher]

Hugh,

sounds like a lot of good advice regarding the distance. My concern would be transmission of the noise and vibration of the vacuum pump to the ceiling and thus to the rooms (and inhabitants) above. The vacuum pumps can be pretty noisy.

Bob

 

[Hugh]

Bob,
Shop is out back - seperate building with only me as the inhabitant. I sleep in the house and go in to eat when it is time. I have an air compressor that makes more noise than the vacuum. When the weather is nice (and this is California) I open up the garage door and all the windows and put on some bluegrass music and it is the greatest place. Deal with my wife when we built the house was that she got the kitchen she wanted and I got the shop I wanted. I now have a 24' x 40' shop to go hide in. Now I am still trying to fix up parts - ie the vacuum pump.
Thanks again everyone. Good advise.
Hugh

 

[Hugh]

Results ... Well I finally got off my ... and set up the vacuum system. I used copper pipe and fittings. I think I have a couple of bugs to work out on the way I set it up, but it works. The pump pulls 25+ inches of mercury according to the vacuum gauge. The bowl that I wrecked that caused me to start the thread - I fixed it. Only because of the vacuum system - it allowed me to remount the bowl and clean up all the bangs and dents. Thanks for all the help everyone. Good job.
Hugh

 

[Bob Chapman]

vac chucks

Hugh,

Have a look at Richard's website. It's immensely useful and a mine of information. I found it very useful when I built my vacuum chuck system. I used compressor hose and fittings and (despite advice above) they work perfectly.

Bob