Bosch Stabilizer setup for different bars

[Kevin Jenness]

I recently got one of these excellent hollowing rigs which I use with several different diameter boring bars. Adjusting the tool rest height so that the cutter advances parallel to the ways is a bit fussy as it must be right on the money. After a couple of changes using steel spacers and shims I decided to set the rest permanently for my 1 1/4" bar and make shim blocks for the thinner ones. I used plywood and plastic laminate because that's what I had on hand, but steel would be more durable. I bored them with 1/2" holes on 6" centers and pin them to the tool rest with the supplied fulcrum pins.

I also realized that I could turn the setup around in the banjo and use another toolrest and banjo to extend support into a large mouth form. This can be useful both to prevent chatter and to get the tool precisely on center at the bottom of the vessel.

 

[Lou Jacobs]

Adjusting the tool rest height so that the cutter advances parallel to the ways is a bit fussy as it must be right on the money. After a couple of changes using steel spacers and shims I decided to set the rest permanently for my 1 1/4" bar and make shim blocks for the thinner ones. I used plywood and plastic laminate because that's what I had on hand, but steel would be more durable. I bored them with 1/2" holes on 6" centers and pin them to the tool rest with the supplied fulcrum pins.

I’ve been doing the same thing with my Bosch stabilizer to move between 1/2” and 3/4” bars. I cut a piece of 1/8” steel bar stock and it provides a perfect “shim” to move between the two sizes without having to adjust the post height.

 

[John Hicks]

The post is a pain to adjust every time you switch bar sizes. Great idea

 

[Ricc Havens]

Great idea. Thanks for sharing!

 

[Jim McLain]

Very good idea. I’m thinking Trent needs to offer some.

 

[Alan Weinberg]

Very good idea. I’m thinking Trent needs to offer some.

Exactly!

 

[Lou Jacobs]

I’m thinking Trent needs to offer some.

I was at Trent’s shop last August (‘23) and mentioned it to him. (Visited when we were in Fort Collins for a family party). He said they were working on something similar. His manufacturing, all on site, is amazing!!

 

[Jim Reynolds]

Okay, at the risk of appearing totally uninformed of the reality the situation and not owning this piece of kit, would a correctly thick bushing on the tool post under the lock collar and resting on the top of the banjo accomplish the same height adjustment that a plate on the tool rest does in the recommended solution. Admittedly changing the height would require removing the Stabilzer hollowing system from the banjo (a disadvantage in comparison to the plate on the tool rest alternative), but I am guessing that you don't change the bar thickness in the middle of the hollow form (perhaps a naive assumption).

 

[Dave Landers]

Okay, at the risk of appearing totally uninformed of the reality the situation and not owning this piece of kit, would a correctly thick bushing on the tool post under the lock collar and resting on the top of the banjo accomplish the same height adjustment that a plate on the tool rest does in the recommended solution. Admittedly changing the height would require removing the Stabilzer hollowing system from the banjo (a disadvantage in comparison to the plate on the tool rest alternative), but I am guessing that you don't change the bar thickness in the middle of the hollow form (perhaps a naive assumption).

There are 2 adjustments to make.
One is the relative height of the arm that holds the tool vs the tool rest portion of the stabilizer - needs to be changed for different bar (tool) diameters. It's kind of awkward to adjust. That's what the spacers Kevin and Lou made address.
The other is the height of the whole unit in the banjo, which sets the height of the tool cutting edge vs the wood. Also needs to be adjusted with different tools. Spacers like you suggest would address this (I would make them U-shape so you can just slip them in).

I've thought about making various spacers, but never got around to it - and have just got used to resetting the heights.

 

[Kevin Jenness]

There are 2 adjustments to make.
One is the relative height of the arm that holds the tool vs the tool rest portion of the stabilizer - needs to be changed for different bar (tool) diameters. It's kind of awkward to adjust. That's what the spacers Kevin and Lou made address.
The other is the height of the whole unit in the banjo, which sets the height of the tool cutting edge vs the wood. Also needs to be adjusted with different tools. Spacers like you suggest would address this (I would make them U-shape so you can just slip them in).

I've thought about making various spacers, but never got around to it - and have just got used to resetting the heights.

Actually, using the spacers on top of the tool rest does not require changing anything else The center height of the boring bar holder remains at the same height regardless of the bar diameter. It's when you adjust the tool rest height on the main post that you have to change the height of the main post in the banjo. I used shaper collars and shims to make the double adjustments but it was a nuisance.

 

[Dave Landers]

Actually, using the spacers on top of the tool rest does not require changing anything else The center height of the boring bar holder remains at the same height regardless of the bar diameter. It's when you adjust the tool rest height on the main post that you have to change the height of the main post in the banjo. I used shaper collars and shims to make the double adjustments but it was a nuisance.

Yes I see now! Cool!

 

[Lou Jacobs]

The other is the height of the whole unit in the banjo, which sets the height of the tool cutting edge vs the wood. Also needs to be adjusted with different tools.

Whoops, already addressed as I was writing. I’m too slow.
My various tools (admittedly a narrow selection) all have the cutting edge at centerline of the tool, so no adjustment necessary other than the shim.