Need to borrow a 6mm keyway broach

[MrWhoopee]

'Very clever. This is aluminum, so the cut should be pretty easy. If this was held in the QCTP, why is the tail of the tool threaded? Also, why is the nose of the tool turned down?

It was made from a piece I had lying around. Those were unnecessary, pre-existing features.

 

[lesrhorer]

Ah. 'Clever and frugal.

 

[lesrhorer]

Hey! That gives me an idea. The below design would not be all that difficult to build. I wonder if anyone would be interested in such a broach design? It could be fitted into the quill of a drill press or milling machine, a lathe tailstock, or a press. If the cutter breaks, it can be easily and inexpensively replaced, because it is nothing but square HSS tool stock.

 

[MrWhoopee]

Hey! That gives me an idea. The below design would not be all that difficult to build. I wonder if anyone would be interested in such a broach design? It could be fitted into the quill of a drill press or milling machine, a lathe tailstock, or a press. If the cutter breaks, it can be easily and inexpensively replaced, because it is nothing but square HSS tool stock.

View attachment 374801

Make it with interchangeable shafts for different size bores and you may be onto something. They are much slower than a conventional broach but can be used in blind bores by drilling a hole where the keyway ends.

 

[lesrhorer]

Y

Make it with interchangeable shafts for different size bores and you may be onto something.

Yep, that's the idea. I haven't fully figured out the machining details for interchangeable shafts, but it shouldn't be terribly difficult.

They are much slower than a conventional broach

Yeah. Maybe I can come up with a right-angle setting gear or something so the tool does not have to be removed from the machine to advance the cutting blade. That would speed things up a lot.

but can be used in blind bores by drilling a hole where the keyway ends.

I don't follow.

 

[MrWhoopee]

I don't follow.

A conventional broach can't be used in a blind bore. This one can if a radial hole slightly larger than the keyway is drilled thru the wall at the point where the keyway ends. This allows the chip to break. This is the application where I first saw this style of tool used.