Vacuum Chucking Advice & Questions

[Jack Tyree]

First the background:

My lathe is a Oneway 12/24 currently with a Talon chuck. I have been reading a lot of threads and posts here lately about vacuum chucking. I was interested in it when I first purchased the lathe and accessories to start turning, but because of the expense to outfit it at the start, it was put on the "back burner". You all know about this vortex and the expense involved when you first start out turning. I thought the money was better spent on a good grinder and the Wolverine sharpening system.

After reading Steve's tutorial about his vacuum system, I realized that you didn't have to buy a $440 pump and some of the other toys and that a vacuum system could be set up at a reasonable cost.

Now the questions:

I would like to set up a system in the near future and here's what I'm tentatively planning. I probably will purchase the rotary adaptor and chucks from Oneway because they are fairly reasonable in cost and will not cause any fitment issues. As far as the pump goes, I have been watching ebay, and am wondering what is the best kind of pump to get? Is a Thomas 120 volt pump OK? Is it best to have an oil less pump? What about CFM? Is 2.5 to 3 CFM enough? I assume you would want be able to hold 25 inches of vacuum or better? Is it of any advantage to have a 220 volt pump? I have the ability to install 220 on a seperate circuit, but because of the lathes location and the breaker boxes location, not the ambition. I already have the tools to turn and thread wooden chucks for the headstock. Would they hold vacuum if they were sealed say with several coats of poly and installed with plumbers tape, and then use craft style foam or cork on the sealing surface? And last but not least, are these systms real noisy?

[Nick Mastropietro]

Jack
I purchased a Thomas 120v Wob-L oil less vacuum pump from e-bay 3.5-4 cfm and it works fine. As for the chucks, many here use either wood or PVC and seal the edge with fairly dense closed cell foam, I purchased 2 Hold Fast chucks on sale 50% off from Redmond Machine. Initially the vacuum pump run as a standalone unit was a bit noisy, however when connected into the completed system it was significantly quieter. I too referred to Steve's procedure for the build. Here is a link I just posted of my completed system.> http://sawmillcreek.org/showthread.php?t=143148
I mounted the system to a 3/4 piece of plywood that mirrors the shape of my lathe's leg and attached it to the leg, that way it moves with the lathe and is a more compact system then having another cart taking up floor space. Hope this helps.

[Jack Tyree]

Nick, I read your post yesterday, and was in awe of how neat a job you did, in particular the control panel & valve. I think that's a two stage Thompson pump, isn't it? I am thinking about mounting everything to the side of roll around tool box that I have my sharpening system mounted on. Probably to a piece of 3/4 plywood. Is it best to have the pump mounted horizontally or does it matter?

[Mike Peace]

I am no pump expert but the users manual for a Gast 523 says it doesn't matter how you mount the pump. For other types of pumps download the manual from the manufacturers web site.

I put mine on the wall high enough to not get shavings on it. Makes it easier to cleanup after turning with one less thing to move out of the way or to sweep around.

[Thom Sturgill]

<snip>...am wondering what is the best kind of pump to get? Is a Thomas 120 volt pump OK? Is it best to have an oil less pump? What about CFM? Is 2.5 to 3 CFM enough? I assume you would want be able to hold 25 inches of vacuum or better? Is it of any advantage to have a 220 volt pump? I have the ability to install 220 on a seperate circuit, but because of the lathes location and the breaker boxes location, not the ambition. I already have the tools to turn and thread wooden chucks for the headstock. Would they hold vacuum if they were sealed say with several coats of poly and installed with plumbers tape, and then use craft style foam or cork on the sealing surface? And last but not least, are these systms real noisy?

I'm not the expert either, but I will try to answer a few of the questions as best I can.
120v works fine, the more CFM the better as unfinished wood leaks. My pump does LESS than one cfm, and hold fine if the wood is at least coated with sanding sealer on the vacuum side. With unsealed wood, I have trouble getting enough vacuum to hold safely.

Holding force is a factor of vacuum * area so a larger chuck requires less vacuum, but the ability to get at least 20" is essential.

I use an mdf backing, 2 layers, drilled and threaded to fit the spindle. The threads are sealed and hardened with CA glue. I have a PVC coupling attached to that in a groove with part of the mdf fitting inside the coupling. I attach with epoxy to seal and varnish the mdf. I have used silicone caulk to insure a tight seal between the pvc and mdf. Craft foam acts as the seal/cushion against the bowl or hf.

My system is not very noisy compared to the vacuum or DC, but is slightly louder than the lathe. Its also a vast improvement over using the hold fast with a compressor in close proximity.

Hope that helps.

[Nick Mastropietro]

Mike's got it right, I don't think it matters, on oil to worry about.

[Steve Schlumpf]

Jack - I am not an expert on vacuum chuck systems either - I just happen to build one and post about it.

Like Thom mentioned - the holding force applied to your turning depends on the area of your chuck and the amount of vacuum applied. There are charts available online that can give you an idea of what force is applied per given size chuck and hg reading. If you can't locate one - let me know and I should be able to dig something up.

So far, the chuck I use the most is 4" diameter and I turn the hg reading down to about 20 hg when turning. You can apply more vacuum but then you take the chance of distorting or even imploding your turning! 20 hg has been more than enough for any turning so far!

As far as voltage, get a pump that you can just plug in. No sense running a separate drop just for your pump if you don't have to.

Volume level has no been a problem - mainly because I wear ear plugs when turning. I can hear the vac pump - and the dust collector - and they are noisy but no where as irritating as the high pitch whine of a shop vac! Noise level will really depend on which pump you end up with and where you have it mounted. I wouldn't worry about it until you get your system running.

As far as adapters for your lathe - I highly recommend checking with Tom Steyer and see if he has one that will fit your lathe. The advantage of Tom's adapter is that it is plug and play - unlike the Oneway version in which your vac hose remains attached. Worth checking into a far as I am concerned because once I am done using the vacuum - I want it out of the way.
http://www.jtturningtools.com/vacuum-adapters

Good luck with your system! Looking forward to seeing the photos!

[Jack Tyree]

Thanks, everybody for all your help!
Steve, I looked at the link you recommended, and while his stuff looks well made & well engineered, I don't think he has anything for the 12/24 available. The rotary adapter Oneway sells comes with an adapter just like you put on their chucks & stays with the rotary piece. I think the 12/24 is a "oddball" in the line because you have to remove the hand wheel to install the vacuum adapter. It screws on the outboard threads and you give a light whack to tighten it up just like you do a chuck. The handwheel center is cross drilled for a bar so it's easy to remove and reinstall as is the rotary adapter, so it's not a big deal to get it out of the way when not being used. The only drawback is that you don't have a wheel when your using vacuum. That's kind of a"bummer" but on the plus side, the Oneway pieces are only $110 which is about half what Tom's would be. I am just thrilled that there are other options than the Gast unit Oneway sells for $440! That's what put the brakes on doing it sooner, I just couldn't justify that expense. I would rather spend that money on the Monster hollowing system I so DESPERATELY need! I see what you mean by vortex...

But now here's my other question, and you will have to go to Oneways website to see what I'm talking about. When you pull up the page for vacuum chucking, you will see a link to a PDF of their system's plumbing and layout
http://www.oneway.ca/vacuum/images/vaccuum_kit.gif
and it looks vastly more simple than the one I've seen both here and on other sites. I can understand the addition of a filter and maybe two filters for a two stage unit and can understand how that would help a pump last a lot longer. Am I thinking along the right lines or am I full of it?

[Tim Rinehart]

I am surprised the pdf didn't show a filter. That's pretty much a guarantee to have your pump need a rebuild or replacement without filtering all the dust and gunk that may get sucked in. I'm very surprised. Perhaps the pump is 'implied' to have a filter built in...but I doubt it.

If you have a pic of what your handwheel and opening looks like, rough size of opening, etc. , I may be able to suggest a handmade option for the rotary adapter that would save you a few $$. Take a look here, this was where I got the idea on how to build mine... http://www.joewoodworker.com/veneeri...umchucking.htm

[Thom Sturgill]

Tom Steyer's price may be higher for the adapter, but his pump is half the price of the Gast sold by OneWay. Tom's adapter includes a replacement hand wheel, which stays on the lathe. Simply plug the adapter in and go, pull it out when done. Its held in place just by the o-rings.

The layout is actually about the same. I use two Ts, Steyer makes a small manifold. but essentially all of the diagrams I've seen pretty much boil down to the same - vacuum chuck to adapter through headstock - adapter to meter and valve then to filter and pump. Place the meter and valve close to the headstock for control. Some place a small filter on the inlet side of the valve and a silencer on the outlet of the pump - both are optional.

IMHO, at least one filter should be used to protect the pump. If you use an oil type pump you also need one on the outlet to keep oil from spraying the area.

[Keith Burns]

Jack another option to consider. I use this on my Oneway 2436 and it has given me no problem and allowed me to keep my handwheel. I got it at Packard, catalog #111210. I leave it permanently on the lathe as it has a quick disconnect for the hose.