Choose the Oneway Vacuum Adapter!
Ed:
I've had a vacuum chucking system on my 1642 for about 2 years, and I love it! It makes doing all sorts of finishing operations wonderfully fast and efficient. I just demonstrated its use to our turners group on Dec. 3rd. Mine uses the same Gast direct drive pump sold by Packard and Craft Supplies (I got mine 'new' via eBay for about $170 - It was completely unused and still in the factory crate - a shameless GLOAT! But check there for possible bargains), a home-brewed valve/filter/gauge, air-leak system, and the Oneway vacuum adapter. You may also uncover the "vacuum pump bargain of a lifetime" if you search for the Surplus Sales (Nebraska) vacuum pump written about so widely - these pumps work great, but are wired for 220V - if you have another outlet at this voltage (or want to install one) this is an economical way to get a reliable vacuum source. BTW - you DO want to put a filter inline between the lathe and the pump somewhere to protect the pump from dust and debris. I bought an in-line air filter on eBay for about $ 12 (including hose fittings). Filters are not often sold as part of vacuum system kits (and I really think they should be), since protecting the most costly part in the system should be a priority.
I thought I'd correct a misconception included in Dave Somers' reply to your question:
David Somers said:
I have a 1642 with a vacuum attachment.
I based it on the Gast pump and Oneway Vacuum Cylinders with the appropriate spindle adapter for my spindle size. Because Oneway's Vacuum adapter is specific to Oneway Lathes I left that out and used the EZ Vacuum adapter that Craft Supplies carries. Part 314-1050 around $80 if I remember right.
To correct this misconception, Oneway's vacuum adapter is NOT SPECIFIC to Oneway's lathes, and uses the same threading adapter that is used on their scroll chucks and vacuum drums - these are available in all standard spindle sizes and threadings - even custom from Oneway, if you have an oddball lathe spindle. Since the Jet 1642 does not have outboard threading on the spindle shaft left extention (which fits the hand "wheel"), a special, non-threaded adapter is necessary to fit the Oneway vacuum adapter to the unthreaded, bored-out spindle shaft on the Jet 1642. At the time I got mine, these were not available directly from normal suppliers of lathe accessories, so I got mine directly from Oneway for nearly the same amount as a "normal" threaded adapter. Now you can buy the necessary adapter for the Jet 1642 lathe right off the shelf at Packards; this item is now in their catalog and also available online.
I chose the Oneway adapter because I really liked the fact that the hose connection comes off at 90 degrees to the lathe spindle axis and makes for easy hose positioning when you slide the headstock right to make a shortbed lathe for bowls. The engineering of this adapter (in my opinion) is better than anything on the market, including the EZ-adapter (continuous threaded hollow-rod type) which relies on the seals of an air hose quick disconnect to maintain vacuum; I didn't like this feature or design, and chose the Oneway which has proven reliable over 2 years, and an accessory that I think is "built tough" (....with apologies to Ford).
Another benefit of the Oneway adapter (not available on the EZ-adapter) is that the body of the vacuum adapter replaces the same function of the hand "wheel" (i.e. you can still turn the spindle easily with the vacuum adapter in place) which you cannot do with the EZ adapter. This is a BIG plus in my book.... My vacuum adapter never comes off the lathe. When using any MT2 taper accessories in the headstock, I have a machined MT2 adapter for use with scroll chucks that has a taper in it; the tapered accessories are held in place with a chuck and the adapter instead of using the MT2 hole in the lathe spindle....this adapter is quick and easy to use (...essentially the same principle as the chuck-mounted Steb-centers...). Therefore, I never need to use a knock-out bar, and the vacuum adapter stays in place all the time, ready for use whenever I need it without having to set it up!
There are a number of other vacuum-chucking possibilities, but after you assemble the basic system, you can build some custom vacuum plates and drums to assist your turning. Once you get started with this technique, you'll wonder why you didn't do this sooner - it beat's the heck out of reversing bowls in cole jaws, etc. although these are necesasry for pieces which are not solid, and can not hold a vacuum due to sidewall voids, natural edges, etc..
One word of caution when using vacuum systems.... - it is not a good idea to put on liquid finishes while the piece is under vacuum. One of my friends learned the hard way when applying oil to a piece, and was wondering why the piece was taking so much finish.... Needless to say, the vacuum pulled the oil right through the walls of the bowl and into the vacuum chuck/system - quite messy to say the least!! My advice is to finish pieces with liquid finishes
off the lathe, or at least until you are confident that the porosity of the wood thas been reduced by multiple applications of finish, and this be done not under vacuum.
Good luck getting your system together, and don't write-off the Oneway vacuum adapter - it is a VERY good choice!
Rob Wallace