Hollowing rig

Re: Hollowing rig

John Trant (Baltimore/DC area)

>I made mine originally with very little play but I have since altered it so that it has a significant gap (1/8" to 1/16"). Smoothness of movement is the most important character on which you should concentrate and too fine of a tolerance can work against you. To enhance smooth movements, I have put a 1/8" drill rod on the bottom rail on which the D-ring can ride. I origianlly used teflon tape but if would not stay permanently stuck to my secondary rest.

The top rail doesn't have to be real beefy either because the weight of the D-ring counters most of the torque. Primarily, the top rail is important if you get overly aggressive with your cuts.

John

Re: Hollowing rig

John Lucas

>Bud

The whole idea behind the hollowing rig is to orient the cutting tip so that it is cutting on the center line and producing as little torque as possible. That's what the bottom rail does. The top rail is there for those times when you do take a hogging cut or hit something hard. It doesn't have to be snug against the bar. I left about 1/16" but it could be more and wouldn't hurt anything. John

Re: Hollowing rig

Duane C.Leach

>You might want to make it with height adjustment to fit more then one size lathe.

Just helping wood go round.

Duane

Re: Hollowing rig

MP Wall

>My rig has 1/8" wall square tube that I have mounted on 5/8" threaded rod and moves up and down to change lathes and sizes of the rig. So it will fit anyones lathe and anyones rig from 3/4" on up.

MP Wall

Re: Hollowing rig

Jim McTavish

>Mine is similar to this. It is 1" square tube, 32" long and 1/8" wall thickness. One inch in from the ends a 7/16" hole is drilled, and a 3/8" bolt that is 3 1/2" long is used. Between the 2 pieces of tube I have a spring that is 1 1/2" long and the bolt goes thru it. If you use a nylon locknut on the bolt (or double nut as I did for the picture), you can adjust the fit anytime you wish.

Re: I prefer round pipe for the secondary rest.

Al Crandall

>Round bar for the boring tool riding on a round black pipe secondary rest from the home center has such a small contact area that when lubricated with a quick rub of a candle the feel is like that of an air hockey puck. I suggest that you increase the size of the mounting plate for the restraining bars and offset the mounting hole toward the headstock 10" or more. Leave the bolt just loose enough so you can pivot the mounting plate in use, and you will quickly see that those two restraining bars can be made a lot shorter and less ungainly. The unit I made for my Jet mini pivots to the front so I can thread a long offset tool through a small hole and then pivots to the back so I can undercut a wide rim.

Re: Hollowing rig

Bud Gabaree

>Thanks everyone for the input and descriptions. When done, I'll see about posting a photo.

Bud