[NA]Need tool explained

[Let'sgoflying!]

I’ve watched 10 videos on this but still can’t see how it make the cuts or shapes it does.

Rotary Broaching
and
Wobble Broach

 

[billsgs126]

Well, having read just one post on the subject, I am even more confused than you are.

 

[Bell206]

Rotary Broaching

Are you familiar with how a hollow mortising chisel works on wood? Similar principal. After a pilot hole is drilled in the metal, the square, hexagonal, etc. rotary broach is introduced into the hole where the outer "chisel" broach tool stops rotating but the center spindle continues to rotate. The center spindle center is offset by a degree or two (?) and that rotating offset drives each tool point sequentially into the metal "chiseling" out the same shape of the tool. Better?

 

[Capt. Geoffrey Thorpe]

wiggle waggles it's way into the hole.

 

[Let'sgoflying!]

So it’s just pushing it’s way into the part without spinning?

 

[Racerx]

Correct. It's wobbling so only one edge is cutting at a time.