Question for those with an articulated or captive bar hollowing system

[Glen Blanchard]

When using a swan neck/bent/curved hollowing tool along with a hollowing rig, where do you position the tool rest?

a. under the straight portion of the tool (as when hollowing by hand)
b. under the bent portion of the tool to minimize tool overhang?

IOW, does having a hollowing rig, due to its rotational resistance, safely permit the user to ignore the rule that dictates that the tool rest be placed only under the straight part of the tool?

[Reed Gray]

The tool rest is ALWAYS under the straight part, and no difference if it is an articulated system, or a captured system. The whole purpose of the curve in the neck lining up with the straight shaft is to fool the set up into thinking it is still straight, so there is no torque to the system as you hollow.

robo hippy

[Glen Blanchard]

The tool rest is ALWAYS under the straight part, and no difference if it is an articulated system, or a captured system. The whole purpose of the curve in the neck lining up with the straight shaft is to fool the set up into thinking it is still straight, so there is no torque to the system as you hollow.

robo hippy

Thats the way I have always done it but I saw a video today on the 'Harrison Specialties' website where he points out that he ignores that rule when using his captive bar rig. I began to wonder if I was the only one applying the rule to the use of hollowing rigs.

[Peter Fabricius]

I have the Monster Hollowing Jig and have always ignored the "rule". No adverse effect.
When doing the neck the tool is not over the toolrest very far and light cuts are the norm. As you go deeper the curved tool is resting on the straight part of the bar naturally so there is no issue.
Experiment a little and see how your tool reacts to the different positions and go from there.
Good luck and please let us know what your findings are.
Peter F.

[Dale Miner]

It depends.

I use a homemade Jameson type capture system that is more robust than his.

If the gooseneck is a short tight curve and the vessel has a small opening and is rather flat on top, then the tool rest is usually near the opening without regard to the curve. The smaller radius does not allow the cutting action to generate enough torque to cause issues. If the bar has a long sweep gooseneck with a good deal curvature, then the tool rest is usually under the straight portion of the bar. BUT, the longer sweep bar is not used until the hollowing has progressed to a fair depth, and the tool rest is able to be near the vessel opening with the straight section on the rest.

Keeping the overhang of the bar to a minimum is more important to me than keeping the straight section on the rest with the system I use.

When using hand held tools (no capture or torque restraint), any venture onto the curved part of the bar requires a very fine touch and is usually avoided.

[Steve Schlumpf]

I agree with Dale -
It depends.

Keeping the overhang of the bar to a minimum is more important to me than keeping the straight section on the rest with the system I use.

I use the Monster captured system more than anything else and the amount of overhang has always been my main concern because the tool itself is designed to counter any rotational forces - within reason. So, you need to have control over the amount of cut and that becomes difficult the further the cutter is from the support.

[Reed Gray]

You can 'cheat', more with some systems, and less with others. But, it seems that cheaters always get a catch eventually. For fine finish cuts, probably not much risk. For heavier roughing cuts, much more risk.

robo hippy

[Peter Fabricius]

I made two cutting bars from 3/8" steel drilled to hold the 3/16" sq cutters. These fit into the bushing in the Monster Bar. The bars are bent to 90 degrees for one and beyond that for the other. They both work just fine and I can get all the way to the edge of as almost flat HF about 6" dia.
The laser allows very precise cuts to get thin walls.
When extended out so far and at 90 degrees light cuts are clearly necessary, but then there is no time limit, so go slow and get a nice smooth surface. I think my opening was <1".
Peter F.

[Robert Willing]

I have the 'Harrison Specialties' system and it is very easy to use. I used the weixy angle gauge to set the recommended angle of 35 degrees that he said to use on the non-flat carbide tip. I even use it on bowls which he also recommends. Great set up.

[Glen Blanchard]

Sounds like there is not much wrong with ignoring the rule when making lighter cuts. Interesting. I'm glad I asked.