Vac chuck question

[Dan Forman]

Is there a way to rig a vacuum chuck and still have free access to use a knockout bar in the spindle when needed? A friend has one on his lathe, but says he leaves the connection in all the time, and can't use a knockout bar anymore. I do enough spindle turning to not want a permanent connection, so that I can use the knockout bar. Thanks.

Dan

[Gary Chester]

I've been wrong before... but I seem to remember a somewhat recent post about a connection that used an O ring that slid inside the drive shaft of the lathe that made the seal...

wish I had more detail...

[Steve Schlumpf]

Dan - I think a lot of it has to do with the make of lathe. Mine just plugs into the handwheel when used and unplugs when no longer needed. Very simple and works great. There are a couple of photos of it in my tutorial in the Articles and Reviews Forum.

[Dan Forman]

Steve---That's what I'm looking for. I have a PM 3520, should that fit? Will check out the article. Thanks.

Dan

[Greg Ketell]

Dan,

I found this quote while researching the same question. I haven't yet had time to try it out but maybe you can and report back. :D


When I graduated to the 3520B, I needed to convert.

I discovered that the male quick disconnect that I use on my garden hoses fits quite nicely into the outboard side of the headstock, and with an O-ring seal to boot. I polished up the inside of the headstock thru hole, made an adapter for the sealed ball bearing epoxied in a small block of acrylic, and I was in business.

GK


Steve---That's what I'm looking for. I have a PM 3520, should that fit? Will check out the article. Thanks.

Dan

[Bill Bolen]

Ron Sardo's system is kind of backwards from normal. No rotorary adapter required because he has a long vacuum tube mounted in each chuck and just clamps on the vac hose to the tube end. The whole thing comes out when the chuck is removed.Tutorial is here,,,Bill..
http://www.simplyturning.com/Tips/VacuumChuck/

[Doug Wolf]

Dan, Here is a couple of pictures of one I just made for my 3520B following Steve's wonderful article (Thanks Steve, it is a very
good write up). It's turned out of a 3" piece of 1 3/4" diameter UHMW rod I picked up from ENCO (Cat#319-4773). I drilled a 1/4"
hole completely through, then recessed the face for 2 double sealed bearings (Cat#510-1953). I originally made an adapter with
rollerblade bearings but they weren't sealed and I could only pull 15" of Hg. I bought these which are the same size 8x22x7MM but
double sealed and now I can pull 22" of Hg. I am using 5/16"OD/3/16"ID tubing and found a brass insert at HD that I push inside
the tubing to seal it to the bearing. Because the vacuum pulls it tighter to the headstock the O-Ring at the base of the shaft is
probably all you need but I turned a groove in the shaft for another O-Ring. The UHMW is really slippery and I found out Epoxy
wouldn't stick to it, so I used the E-6000 sealant to glue in the bearings.
PS. I'm using a GAST 522 pump @ 5,000 feet, so a perfect vacuum is 24.9" of Hg.