Mystery Machine Tool

[nigelr2000]

Need any engineers out there to tell me what this is. My dad used to be a toolmaker and we found this amongst a set of micrometers and a setting out tool. I know how to use the mic's and they will come in usefull to measure the journals and bores on my mog when I strip the engine. This however is some kind of thread cutting tool but other than that a name would be usefull as I intend to sell it on ebay. It consists of a main unit which looks like it would fit on a lathe, this is spring loaded and has a little handle that can be inserted to release the spring action, there are several sets of 4 teeth which fit the 4 sections at the front of the tool. I have fited one to show this and when the spring loaded bit is released the teeth bit moves in and out.

ID wise it says Murchey Mach & Tool Co. Detroit Mich. Patented Type G 7/16

Looks a bit complex as a simple die would perform the same job so any ideas welcome please.[frame][/frame][frame][/frame][frame][/frame][frame][/frame][frame][/frame][frame][/frame]

[d_harris]

Looks like a thread cutter to me, but I'm sure someone will come and prove me wrong.

[Dean]

Yes they were fitted to capstan lathes.. you can also fit them in the tailstock of normal lathes using a morse taper.

You set the depth or length of thread by winding the tool in the tailstock over the bar (locked in the jaws) to be cut, wing the saddle against the tailstock and lock down the saddle.

Wind in the tools using the screw so the teeth will cut on the bar and push the tailstock hard onto the bar.

The tailstock will then follow the screw cutting action, when the tailstock hits the saddle the attachment snaps out and you can pull it off the bar.

Check the thread for size and adjust.

Once you have a size you can cut a thread in two passes... one big cut, then a fine one.

All the teeth are numbered, make sure the number on the cutters matches the one in the holder. I used to love using these things... but then the CNC came along and made them obsolete for mass production. Still good for repeatability work though.

Far superior to a die finish.. by a country mile.

[nigelr2000]

Thanks for that info Dean knew somebody would know

Whats its official title ?

[Budgie]

i concur with Dean,as an ex toolmaker myself it,s basically a "thread cutting tool" to give it a simple tag,those in the know will click straight away what it is as i and Dean did.

[Dean]

The "official" term is a Coventry Die Head. Well that's the one we used anyway.


http://www.youtube.com/watch?v=wS73c1FU7ys

I cringe watching his fingers by those rotating parts... the things you do for cash eh?

[Budgie]

carry on like that and he,ll have stumps not fingers