New vacuum setup - It sucks

[Alan Zenreich]

About a week ago, I bought a Gast 0522 vacuum pump from a local Craigslist seller. I paid very little for it... but it needed a replacement carbon vane. Fortunately the repair was trivial, the pump works fine, and I figured it was time to order the rest of the setup from Tom at JT Turning Tools.

I received the oversize handwheel for my Nova DVR XP, a vacuum adaptor that plugs into the handwheel, a vacuum kit (manifold, gauge, hose, filter and connectors), and their lovely chuck hub (uses 2" pvc inserts to create chucks).

I mounted the manifold and switch to a small piece of wood that's attached to a 24" length of 3/4" black iron pipe with some pipe straps. The pipe is affixed to my workbench with a flange. There is also a flange on top of the pipe... I'm considering using it to mount a small shelf there.

The only controls are the on-off switch and vacuum pressure adjustment valve... they are at eye level, and within easy reach.

The vacuum pump is housed below the workbench, behind a door in a closed (but well ventilated) cabinet. The pump is quiet, and I don't feel any vibration transfered to the lathe.

Here are a few of the photos of today's installation

[Alan Zenreich]

The vacuum adapter that fits into an oversized handwheel designed for the Nova DVR XP lathe.

When not in use, the adapter stores on a rod built into the manifold, behind the gauge.

In one photo you can see it pulling 27 inches of mercury. I've seen it go higher, there's plenty-o-suction!

[Alan Zenreich]

The chuck hub accepts 2" pvc couplers. This one is a 2"x4" reducing adapter. I used some sticky backed closed cell foam for the padding in this, my first test. Worked out very well.

[Baxter Smith]

Looks great! I have got to say it makes me want one!

[Alan Zenreich]

Thanks... I can't think of anything I would do to improve upon this system. The components from JT are all first rate (beautifully machined).

I'll be making additional PVC chucks... various sizes and configurations.

I might also play around with some threaded wooden vacuum chucks... I have a 1.25" Beall spindle tap that's waiting for an excuse to try out.

However, I keep thinking along the lines of mounting wood to a pvc coupling and using the JT chuck hub... it's so nice <vbg>

[Ray Bell]

Looks great Alan. Where did you get the sticky back sheet foam?

[Alan Zenreich]

The sticky back sheet foam came from a local Michaels craft store.

[Fred Perreault]

Alan,
I have a similar setup, using JT components on my Nova 16-24. I also have the adapter for PVC collars to use as a chuck, and the Beall 1.25" tap. The only issue I found was that changing the PVC collars in and out of the aluminum adapter was not a very quick procedure. Even using registration marks so as to return the PVC to the same spot in the adapter still required re-balancing and trueing the PVC piece. I also had leaks at the bottom of the groove in the adapter occasionally. A seal of some sort may resolve the leaking. I found that after taking a day and assembling, turning and tapping some wooden chucks to supplement the aluminum adapter that I could then reach for the right size for the job.

[Alan Zenreich]

Fred, I've been wondering how well switching pvc couplers will work.

I'll play with some versions and report back.

I'll also be sure to follow all of Tom's instructions posted in the instalation guide for the hub... useful tips in there (especialy about using the tailstock to seat the coupler)

http://www.jtturningtools.com/files/Installing%20the%20Precision%20Vacuum%20Hub%20and% 20vacuum%20cups-2.pdf

[bob svoboda]

Nice set up, I'm sure you are going to love it.++JT!

[Steve Schlumpf]

Congrats on getting your vacuum system up and running! You have a very clean design - nice job on the layout!

Have fun with your system! They are worth the effort to build!

[John Keeton]

Alan, great looking setup, and it will surely increase the enjoyment factor!!

I do have a question. From what little I know about these vacuum systems (and, it is little!) the holding power is in lbs/sq. in., so the more surface area involved in the arrangement, the more holding power. Thus, a 6" chuck has more holding power than does a 3" - in theory. If that is true, I wonder if the foam you have used with the small hole, has a negative effect on that? It would seem it would not as the negative pressure would act on the foam, and then on the turning. Just curious whether it might to a small degree.

But, with 27Hg, I imagine it hardly matters!!

[Cathy Schaewe]

I have the JT setup (although I bought the pump elsewhere). I decided it was too much trouble to switch out the pvc and rebalance it, so I got two of the hubs (one was a birthday present - my friends are very patient with my new hobby). I've found that if I try hard, I can pull something off the 2" chuck (my pump pulls about 24 hg), but absolutely cannot pull the same item off the 6" chuck, which makes sense. I've tried cutting different sized holes in the foam, but that really doesn't seem to make any difference.

I did find that you don't want to dye something and then put it on the chuck, because the vacuum will pull the dye right through the piece, and stain the foam as well!

[Tom Steyer]

Alan,
I have a similar setup, using JT components on my Nova 16-24. I also have the adapter for PVC collars to use as a chuck, and the Beall 1.25" tap. The only issue I found was that changing the PVC collars in and out of the aluminum adapter was not a very quick procedure. Even using registration marks so as to return the PVC to the same spot in the adapter still required re-balancing and trueing the PVC piece. I also had leaks at the bottom of the groove in the adapter occasionally. A seal of some sort may resolve the leaking. I found that after taking a day and assembling, turning and tapping some wooden chucks to supplement the aluminum adapter that I could then reach for the right size for the job.

Fred,

When you received your vacuum hub there should have been an O-ring in the bottom of the groove. Your posting seems to indicate that the O-ring might be missing or perhaps damaged. Also, if the preparation procedure for the PVC cups is done carefully, you should not have difficulty with alignment when changing cup sizes, assuming that the cups are fully seated in the groove, both during preparation and when changing sizes. I would welcome the opportunity to discuss this with you to see if I can help with your problem. Please contact me at your convenience.

Tom Steyer

[Alan Zenreich]

John,

The size of the hole in the foam really doesn't matter. The foam is flexible and the vacuum is spread to the entire diameter of the PVC's rim.

[Fred Perreault]

A follow up on my issue with leaking around the JT Turning tools chuck adapter. I investigated my adapter, and discovered that it did not have the o-ring seal at the base of the groove that recieves the PVC. I had a message this morning from Tom Steyer, and we chatted about the issue and he is sending me the seal (s) post haste. I should have been more attentive in the beginning.... oh well

[Alan Zenreich]

Fred,

I was wondering about your O-ring (or lack of it)... and was about to question it when Tom chimed in.

Glad to see this is getting resolved.

I also think one of the keys to repeatability is to square off the bottom of the 2" coupler (where it will meet the O-ring).

I see little reason for any difficulty making the rig repeatable. That said, having multiple chucks is always a cool thing... nice to not have to replace jaws and/or cups in any chucking system.