holdrich style radius cutter that mounts in a quick change toolholder

[markknx]

it works ok, one change i would make to my design is to perhaps shorten the inner, moving frame. made it a little long and it doesnt seem to cut much smaller than a 1/2" radius without having to over extend the tool. otherwise, i am happy with it. i just guessed on the dimensions based on some pictures i saw online, but it works ok. been wanting one for a while. i kinda want to make a rotary broach too, but the cutter bits for it are pretty pricey even if you do make the broach tool. http://www.polygonsolutions.com/rotary-broaches/

you can make the cutters from drill rod if you have a mill. there is a site that has instrction. I am not sure if I can name it. The guy made a rotary brotch for his lathe that had a built in 2 deg. bevel and a indexing dial. It was not as complicated of a set up as it sounds. as a matter of fact I think you could do it with just the lathe. I made one and I am in know way a machinist. Mark

 

[markknx]

So I guess it is OK to post this link http://mikesworkshop.weebly.com/rotary-broaching.html Check out all of his site for some nice simple projects. He told me when I ask him if he minded me copying his roto broach , to go ahead and if I had any question just ask him. Chuck he uses his on a mini lathe and I use a 10 x 22 so I think you should be OK as long as you set it up right and don't force it. I cut my bits with a spindexer shimmed to give me the 2 Deg. relief needed. Mine is posted here some where if I find it I will add a link. it fits in my 4 way tool post. one couldbe made for QCTP.Mark

 

[chuckorlando]

I have no real need for one, but something is cool about rotary broaching. Like gear hobbing or shapers.