favourite tool for hollowing

[hughie]

Just knocked up another one of my favourite tools for hollowing. Have made a few of them now for myself and friends.

This one has a 3/4" carbon steel shaft 9" long with a 3" tang 3/8 in dia. The HSS tool bit is 1/4x1/4x2.5" held in by a 6mm set screw. I drilled the set screw hole right thru to give me a spare tapped hole just in case down the track I damage the first one and the ferrule is stainless 1" dia.

 

[john lucas]

similar to mine but I taper the first 4 to 5 inches on a 12" long 3/4" shaft. Since I now have a forge I'm going to try to make a new one that is only tapered on the sides, the top and bottom will still be close to 3/4".

 

[Wyatt Holm]

Homemade tools? Good idea!
I have tried making a boring bar, 1/2 " diameter steel bar too narrow. I will try it with 3/4 next time.
thanks
Wyatt

 

[Gil Jones]

Good looking hollowing tool, Hughie! Same idea as the one I use.

 

[Joe Greiner]

What they said. My Olands are 1/2" shank with 1/8" cutters. Movable Vise-grip pliers for an auxiliary handle on the 45-degree offset. Forging a question-mark shape for the next (when/if) would allow the main handle to be in line with the cutter, to reduce torque requirements - similar to some commercial versions for undercutting.

Joe

 

[hughie]

my version

This what I came up with so as to maximise the versatility of the tool.

 

[Ken Grunke]

If I can suggest an additional improvement to your great tool, add a moveable/removable stabilizer arm to the shank.
Get or make a setscrew collar to fit the main shaft and weld an L-shaped round bar to it, like the Johnston/Basham tool.

A further improvement would be a depth gage on the end of the stabilizer bar. I'll get a pic later today, but it's a 1/4" rod sliding through the end of the stabilizer bar, and held by a setscrew. The inner end on mine has a flap of plastic from a milk jug which is supposed to straighten out when your desired wall thickness is achieved, but the milk jug stuff has too much "memory" so I need something a bit stiffer and more forgetful 🙂

 

[hughie]

Hi Ken,

Something like this I guess you mean.Tried the milk jug stuff, useless your right.

The best by far is the old curtain type rod, the one that looks like a long tightly coiled spring with a plastic coating on it. Failing that use a laser

 

[Ken Grunke]

hughie, you are pretty fast on the draw 😉
The laser is reserved for my Jamieson bar, so I can keep my Johnston/Basham-style hollower simple and without another fixture.

I forgot I had replaced the milk-jug flapper with a piece of polypropylene from a yogurt container, which seems to have less memory. It's crimped into the end of the brass rod in my unit which is not exactly convenient for replacing the flap when it cracks. Oh, well, here it is--there's a setscrew into the end of the L-bar holding the brass rod, and also holding the L-bar to the tool's shaft:

 

[hughie]

Hi Ken,

Not so quick as I had made that one a couple of years ago.The smaller one is a bit more user friendly on small stuff.

Cant find a pic the springy curtain hanger stuff...darn it!

In the case of my Basham type I have welded the extra support bar on, plus installed a small swing arm with a tungsten cutting tip to it. This gives me great versatility and allows me to get under the lip etc and of course with the support bar torsional forces are not much of an issue.

 

[Ed_McDonnell]

If you need something springy, why not use a spring (with a soft tip on the end). A spring could be easily attached to the type setup Ken showed using a dowel.

Ed

 

[Ken Grunke]

Good one, Ed. I'll try piano or guitar wire sometime--don't think a protective tip is needed for something like .015" or .020 (at the most) wire unless you have done the final finish cut on the vessel's exterior, which isn't too likely. Thanks!

 

[Joe Greiner]

Ordinary shirt-hanger wire can be used for springs if you add enough coils to reduce its climb up the stress-strain curve, to preclude yielding. This is a captive safety-pin-like doodad, but the idea is the same. For your application, I'd suggest coating the end in something that won't melt to prevent damage to the finish; or allow a final pass with the highest grit if sanding. I often find a need to do another pass to remove wheel prints from the steady anyway for deep turnings.

Joe