If you look over stevec's photos, you'll see that his toolholder has two different ways to add spring to the base metal. There is a circular insert, obviously spring steel, at the 'give' point. A more common addition is the screw at the back end of the tool. It presses on a strong spring that pushes on the 'movable' front part of the tool and also provides a measure of adjustability to the stiffness of the whole thing. If you have enough thickness in the shaft on yours, you could easily add a plunger, spring and pressure bolt.
(02-12-2017, 01:22 PM)Roadracer_Al Wrote: [ -> ]I made one for my shaper. I clearly used the wrong material... it took a permanent bend after the first use.
I was entertaining the idea of squirting some silicone caulk into the spring gap in order to offer some damping and get the chatter down.
Al, I don't think the spring tool holder is right for a shaper. On a lathe with a workpiece turning in a circular motion and the tool at or slightly below the center line the tool would move AWAY from the workpiece. on a shaper the linear motion woud cause the tool to dig into the workpiece.
Isn't the idea that the workpiece can push the tool away, preventing dig in? If so, wouldn't this be true an a shaper?
Keep in mind that, in a shaper, the shaft of the tool would be vertical, not horizontal as in a lathe. It is possible that it would function in a shaper, if it had the proper spring action.
In a shaper, the top of the spring tool needs to be in line with the axis of the clapper box pivot to function properly.
Andrew..
I struggling to visualize quiet what you mean.. please elaborate
Thanks
Tony.
I actually had the tool tip *behind* the vertical line extending from the clapper box so the clapper would stay closed during the cut. The idea of the spring tool is that it will be stiff enough to take a cut, but if the tool digs in, it springs back and up (the "loop" of the spring must be built so it's ahead of the cutting edge), preventing chatter.
After my first effort, I realized that what this tool really needs is a way to fine tune the spring rate to match the depth of cut, the toughness of the material, etc.