I posted this on another site, figured I better post here too. Seems there may be more diy tollsters here like me than the other place. Hope this is helpful to you. Let me know if you have any questions. I'll try to answer them. Also the jpg of the diagram is a little small. If you can not read it, email me and I can send you a larger file to allow you to read it. I put a 14" diameter bowl on this the other day, put it to 13 psi and could not budge it. I hogged some off the bottom of the bowl and the chuck or the piece never once budged. This system works extrodinarily well, much better than I hoped.
I've been seeing some posts on where to get a chuck system and how much. There may be cheaper systems out there than $150, but this was to much fun not to build myself. It pulls 23"-24" of mercury where I live, but of course YMMV depending on the compressor and where you live (elevation matters when it some to vacuum). This system does not take a genious to set up. Just a bit of tinkering and some basic knowledge of how to attach pipe fittings.
I used an old york compressor from an old ford/volvo vehicle. You can get it from a junk yard for under $50. Only get the York compressor as it uses oil to lubricate the system not freon. No freon lubricating system will work for this. This is what you are looking for.
Other items needed:
pipe fittings (see diagram below)
vacuum gauge (most auto stores will have one)
small motor to run the system (1/3 hp 1075 works great, but most anything will work)
switch to turn the unit on and off (light switch works fine)
2 seal bearings
1 bolt to match threads of outboard spindle (not needed if modifying your existing handwheel)
handwheel (or midify you existing one)
1 bolt to match threads of inboard spindle (not needed if using a face plate)
neoprene gasket material (or suitable substitute)
1. Take of the flywheel and the electromagnteic clutch. Weld the drive and pully together so the belt will now run the compressor. Clean the unit up of rust, dirt and grime (does not need to be perfect, just makes it look nicer) Take the covers off the fittings at the top of the compressor
2. Connect nipples, ball valve, vacuum gauge and hose as seen in the diagram. Be sure to seal all connections appropriately. Any leaks will lessen the productivity of the system.
3. Make sure on the seal bearings that you get them where they almost fit on the nipple just not quite, this will ensure a good tight fit. Take the nipple and mount it on your lathe. Sand one end of the nipple till the bearings and able to be hammered on. Put both bearings on the same end, this just gives you plenty of surface to be able to get the handwheel attached to the bearings. It should take some effort to get them in, but not enough pressure to crimp the nipple. Drip some ca glue around the nipple to complete the seal.
4. Turn handwheel to suit you lathe. Epoxy bolt into handwheel to attach system to your lathe. You can also modify your existing handwheel if you like (I did, and added quick connect for ease of use. made a new knockout rod to fit inside the quick connect).
5. Epoxy bearings and nipple in place in the opposite side of the handwheel from the bolt. They can be butted up next to each other, just make sure the bearings are still able tu turn freely.
6. connect hose to nipple.
7. Mount motor and compressor the a stable surface or boards (check the length of crive belt you purchased to set the distance between the compressor and motor). Wire motor to switch, attach drive belt to motor and compressor.
8. Create plate to be screwed onto the face plate usinig bolts or screw face plate onto mdf material and turn round. Make hole through to allow vacuum. Attach gasket material to face of plate with contact cement.
This is just a quick and dirty description of the system, if you have questions please ask. I have build this, as well as several others in our turners club. It workds great!!! You can create face plates of different sized and shapes as needed. The more stuff you have lying around that you can use to build this, the cheaper it is for you. I had the motor and some other components, but added the quick connect system. Total spent was less than $125, so I figure you take the quick connect system off ($12) and add the motor price, your probably right around 150.