David C. Roseman
12-10-2015, 9:45 PM
A few weeks ago I added the new Grizzly G0766 22 x 42 lathe to our shop. I’m a big fan of vacuum chucks to finish-turn the bottoms of bowls and platters, and to remount finished pieces later for rework or repair. So, one of the first orders of business was to outfit the lathe for use with our shop-built vacuum chucking system. I knew JT Turning Tools in Omaha made nice vacuum adapters, handwheels and other accessories for several models of lathes using CNC milling equipment. Their Precision Vacuum Adapter is the adapter that Robust is now shipping with its line of lathes when a customer requests that the lathe come vacuum-ready. So, I called Tom Steyer to see if he could get me up and running quickly.
Tom knew about the new G0766, but did not have details of its outboard spindle configuration. I sent him some photos and measurements by email, and we talked a couple of times on the phone. In short order, Tom sent me a Precision Vacuum Adapter Kit that fits the new lathe perfectly. The kit contains his Precision Vacuum Adapter and a handwheel beautifully machined from a billet of aircraft aluminum to replace the Grizzly factory handwheel. The new handwheel extends beyond the outboard end of the spindle enough to receive the vacuum adapter and assures a perfect seal. The G0766 is not yet listed on JT Turning’s website. The cost was $149 for the kit.
I'm very impressed with this setup. My vacuum pump is a rebuilt GD Thomas (RietschleThomas) 3.15 cfm double-piston pump. With the JT Turning Tools adapter and handwheel, and one of my shop-built vacuum chucks made from hard maple, sch. 40 PVC and gaskets cut from 1/8” neoprene craft foam, I pull a full 25 inHG on mounted bowls when my manifold bleed valve is fully closed. That’s enough vacuum to do some serious damage if not throttled down for some workpieces.
I am also now a big fan of JT Turning Tools’ “Precision Vacuum Hub”, which I did not know about until Tom brought me up to date. It is a nicely-machined hub that mounts onto the spindle inboard to allow the use of several different sizes of sch. 40 PVC connectors to make interchangeable custom vacuum chucks. Very slick. An O-ring assures a good seal between the connectors and the hub. It, too, produces 25 inHg vacuum with my system, without the work involved in making your chucks from scratch.
I’ve attached some pics of the new vacuum adapter, handwheel and vacuum hub on our G0766. Also a few pics showing how I make gaskets for the mouth of the PVC connectors. I use a 2” wide strip of 1/8” neoprene craft foam (Walmart, Michaels, etc), secured on the outside with only vinyl electrician’s tape, then folded over into the mouth and held in place with a DIY “split ring” made with a 5/8” ring cut from sch. 40 pipe, with a 3/16” section cut out to allow space for the neoprene. When snapped into place, the ends of the split ring butt tightly together, yet the ring is easily removed for eventual replacement of the gasket. I’ve always used black craft foam for my gaskets, and have never had any problems with color transfer.
Gaskets for the Precision Vacuum Hub PVC connectors can also simply be disks of craft foam cut slightly bigger than the connector mouth, with a hole in the center, then just sandwiched between the connector and the workpiece when vacuum is applied. That works fine too. I just prefer making custom gaskets.
Tom knew about the new G0766, but did not have details of its outboard spindle configuration. I sent him some photos and measurements by email, and we talked a couple of times on the phone. In short order, Tom sent me a Precision Vacuum Adapter Kit that fits the new lathe perfectly. The kit contains his Precision Vacuum Adapter and a handwheel beautifully machined from a billet of aircraft aluminum to replace the Grizzly factory handwheel. The new handwheel extends beyond the outboard end of the spindle enough to receive the vacuum adapter and assures a perfect seal. The G0766 is not yet listed on JT Turning’s website. The cost was $149 for the kit.
I'm very impressed with this setup. My vacuum pump is a rebuilt GD Thomas (RietschleThomas) 3.15 cfm double-piston pump. With the JT Turning Tools adapter and handwheel, and one of my shop-built vacuum chucks made from hard maple, sch. 40 PVC and gaskets cut from 1/8” neoprene craft foam, I pull a full 25 inHG on mounted bowls when my manifold bleed valve is fully closed. That’s enough vacuum to do some serious damage if not throttled down for some workpieces.
I am also now a big fan of JT Turning Tools’ “Precision Vacuum Hub”, which I did not know about until Tom brought me up to date. It is a nicely-machined hub that mounts onto the spindle inboard to allow the use of several different sizes of sch. 40 PVC connectors to make interchangeable custom vacuum chucks. Very slick. An O-ring assures a good seal between the connectors and the hub. It, too, produces 25 inHg vacuum with my system, without the work involved in making your chucks from scratch.
I’ve attached some pics of the new vacuum adapter, handwheel and vacuum hub on our G0766. Also a few pics showing how I make gaskets for the mouth of the PVC connectors. I use a 2” wide strip of 1/8” neoprene craft foam (Walmart, Michaels, etc), secured on the outside with only vinyl electrician’s tape, then folded over into the mouth and held in place with a DIY “split ring” made with a 5/8” ring cut from sch. 40 pipe, with a 3/16” section cut out to allow space for the neoprene. When snapped into place, the ends of the split ring butt tightly together, yet the ring is easily removed for eventual replacement of the gasket. I’ve always used black craft foam for my gaskets, and have never had any problems with color transfer.
Gaskets for the Precision Vacuum Hub PVC connectors can also simply be disks of craft foam cut slightly bigger than the connector mouth, with a hole in the center, then just sandwiched between the connector and the workpiece when vacuum is applied. That works fine too. I just prefer making custom gaskets.