Small Gloat

[Rob]

Haven't posted in a while so figured I would show my latest acquisition. In the next couple months I'll be building a vacuum chuck. I got the pump From a great guy on SMC. I still need to get the lathe adapter and manifold. I could build a manifold but figured I would order what I need from http://www.jtturningtools.com/ and get everything at once. I'll probably make my own chucks from MDF and PVC, mounted to face plates to start as I have a couple small ones I don't use. Later I might get a tap and use that instead of face plates, don't know yet. Several plans on the web for chucks. I'm thinking I'm going to build a small cabinet w/vent to house the pump and chucks to go behind the lathe. That way the manifold and gauge is within reaching distance, and the pump can be enclosed to reduce noise. Looking forward to this. But the cabinet will have to wait while I finish a couple flat work commissions I'm working on.

View image in gallery​

 

[woodArtz]

Sounds like a plan! Can't wait to see it in action.

 

[LeftyTom]

There are no small gloats, only small screws that you always drop (and can never find). :icon_thum

 

[SgtSnafu]

Not being at turner you're speaking greek to me, but it sounds cool. Once you get it done, I would like to hear how it turns out for you. (no pun intended)...

 

[Dreuxgrad]

I'd like to follow along. Used a shop vac for a couple of go-rounds, with less than desirable results,lol.
Ed

 

[Rob]

I'ii document the build but will be a month or two.

 

[ehpoole]

If you build an enclosure for the pump you will need to take cooling into consideration as, unlike vacuums and such, there is typically very little positive airflow to introduce cooler air into such an enclosure. You may even find that a muffin fan (with a respectable CFM figure) is required for adequate cooling. That, coupled with the fact that most people just run these pumps continuously, means that they can get quite hot after awhile once the vacuum is achieved.

If you add a vacuum reservoir (and check valve) then you can also add a vacuum switch to automatically cycle the pump so that it only runs when needed. You can use simple Schedule 40 PVC (not the lighter-duty sewer and drain) to build smaller vacuum reservoirs. You can also use most any air compressor rated tank as a vacuum reservoir, if more convenient.

You will also want to get a filter suitable for vacuum use to prevent debris from getting sucked into the vacuum pump where it can contribute to premature failure. I ordered mine from the following Yahoo! storefront: VacMotionOrders. Be sure to order spare filter elements to keep on hand, and I suggest ordering at least the next larger size filter so that the filter has less impact on your maximum vacuum displacement (improving your draw-down time) and so that you can run longer between filter changes.

Last year I purchased all the needed parts for a venturi style vacuum pump -- venturi pumps are non-mechanical vacuum pumps that are powered by positive air pressure provided by an air compressor -- so that I can build a proper vacuum press for veneer work (and likely other tasks like vacuum clamping down the road). I haven't felt up to spending much time in the shop lately, so I have not yet gotten around to actually building it (other than a rough test mockup to verify everything works). So, hopefully, soon I'll feel up to getting it built, then I'll have to shell out some money for a couple of good polyurethane vacuum bags.

I wish you luck in your build and look forward to your upcoming thread on the subject!

 

[Rob]

You don't think that a vent on either end will be enough air flow?

 

[ehpoole]

You don't think that a vent on either end will be enough air flow?

Doubtful, once a vacuum has been achieved they really don't draw in much air to circulate, so the motor's fan will mostly end up recirculating the same hot air unless you either add a fan to your box OR create some way to duct the airflow from the motor directly to the exterior of your enclosure (but then you risk also ducting the noise out of your box).

Run your pump for a half-hour or so at full vacuum (just plug the hose) and test to see how hot it gets. There can be a lot of variability in the heat they generate, and some can get quite hot if left running after full vacuum is achieved. Obviously, the hotter your unit runs the more critical cooling will be, the cooler it runs the less critical.

Out of curiosity, how deep a vacuum does your unit pull? You'll want a pump that can pull below about 20-24+" for most vacuum chuck purposes, IIRC, and at least a few CFM to ensure the unit can compensate for leaks or small hairline splits in the workpiece. This range is generally considered "High Vacuum" (as apposed to Deep or Micron vacuum for the full 29.72" vacuum). I mention this because there are basically 4 ranges of vacuum pump/venturi to select from: Low, Medium, High, Deep/Micron.

I don't have a lathe currently, but if I did and I was using a vacuum chuck, I would probably add a (low) vacuum pressure switch that could sound an alarm (and/or automatically kill power to the lathe) if the vacuum pressure falls below a critical threshold where separation of the workpiece is imminent. It adds a little extra complexity (the vacuum switch and a relay or contactor) but it could add a greater margin of safety by slowing down the equipment (hopefully) before the vacuum chuck and workpiece separate from each other.

Just some thoughts that I have had on the subject while planning and researching my own vacuum system.

 

[Vetteman9956]

And to think that you could have spent 7 grand on the new powermatic lathe and not had to go to all that trouble of building your own.:gar-La;

 

[ehpoole]

And to think that you could have spent 7 grand on the new powermatic lathe and not had to go to all that trouble of building your own.:gar-La;

Well, I just don't know *what* got into Rob's head....

Not that I would not mind a Powermatic Lathe myself, might even be enough to tempt me towards the Dark Side.

 

[Rob]

And to think that you could have spent 7 grand on the new powermatic lathe and not had to go to all that trouble of building your own.:gar-La;

For $7k I would rather go with the Robust, I like their head stock much better. Of course no vacuum attachment, but I will have that covered.