Shaper boring bar holder

[Janderso]

Wow! That is one boadacious shaper! Many thanks, again, for all your work on this.

+1

 

[lesrhorer]

The problem is that with the overhung tool extending so far out from the hinge of the clapper is that the tool dragging in the cut on the return stroke tends to want to lift and try to jam up even more, begging to break something. I am a bit skeptical that the collet will be able to keep the bar tight without slipping axially. There is another type of bar that mounts directly in place of the tool post hele in place with a nut on the outside.

As long as the cutting tool is ground properly, I wouldn't expect the load to be that high on the return stroke, or even on the forward stroke, for that matter. Of course, it rather depends upon the material, the width of the broach, and the DOC. For my project, the material is Aluminum and the maximum slot width is 6mm. 'Not a lot of force there, even with a moderately hefty DOC. Cutting something like a 12mm slot in stainless steel would be much more of a challenge.

A 5C collet can deliver a pretty astounding axial holding force. The combination of a fairly shallow taper with a fine thread can produce an ungodly clamping force. I wouldn't skip the Wheaties before tightening the collet block, however.

 

[lesrhorer]

I'm a little concerned about the collet/bar spinning as well, though the Fireball Tools guy made this and seemed happy with it. I figure worst case, I can pin the bar in place or something.

That's not a bad idea, in any event. My previous post notwithstanding, a shaper is a pretty brutal piece of machinery, as I am sure you are well aware. It puts some serious stress on... well pretty much everything.

 

[ErichKeane]

Ended up using this for the small project and it worked great! I made a fixture plate for the cut to act as a angle plate, and let her rip! I DID end up locking out the clapper on the 2nd one by putting brass inside the spring, but it really made no difference.

The holder itself had no problem, the 5c collet held perfectly. However, the set screw holding the tool in the bar DID seem to back out once or twice.

 

[lesrhorer]

I am very excited to get these installed on my lathe. The spindle will have a maximum speed of 3000 RPM, vs. 2500, with almost twice the torque at any given speed.