cat40 toolholder with 3/4-16 internal thread

[joesimmers]

Hello, I am looking for a cat40 toolholder that has a 3/4-16 internal thread to mount an attachment (jig grinder) and cannot find one.

Anyone know of a source for these?

I would also be interested to know if you can buy a generic (soft) cat40 holder
and machine it yourself to your liking?

Thanks, Joe

[Milacron]

Originally Posted by joesimmers

I would also be interested to know if you can buy a generic (soft) cat40 holder
and machine it yourself to your liking?

Back when I manufactured tapping machines, we used to take Bilz QC tap chucks that were no. 4 morse taper, turned a groove in the MT shank with carbide on a lathe to get below the case hardening and could then cut at that groove, the MT shank off on a bandsaw to length. The newly exposed "meat in the middle" was not hardened and easy to drill and tap. I should think similar would be possible with CAT holders.

Either that or buy the cheapest Chinese CAT holders you can find as they probably aren't hardened anyway !

[Mark McGrath]

Buy a Weldon/Sidelock holder and screw a sleeve on to your attachment.
Example : Buy 1.1/4" holder,make 1.1/4" od x 3/4"x 16 tpi bush.

[Milacron]

Originally Posted by Mark McGrath

Buy a Weldon/Sidelock holder and screw a sleeve on to your attachment.
Example : Buy 1.1/4" holder,make 1.1/4" od x 3/4"x 16 tpi bush.

I thought about that but presumed he wanted the least overhang possible (since a jig grinder attachment is typically a rather bulky long thing), such that the ideal might be to cut a CAT holder flush and drill tap from there.

[smallshop]

We used to recut tool holders all the time. Milicron is right...once you get under the case it cuts good. Watch crossing screw holes.....

Old holders with worn bores make good custom tools. Flycutters, etc.

[joesimmers]

Milacron you are 100% correct with the minimum overhang thing, I already tried alerting an existing cat40 holder but thought it was hard all the way thru.

Perhaps I will take another shot at it.

thanks, Joe

[Milacron]

Originally Posted by joesimmers

I already tried alerting an existing cat40 holder but thought it was hard all the way thru.

"alerting" ? Re hard all the way...possible I suppose but that wouldn't be a good way to make a tool holder as it would be too brittle. Back when we modified tap holders the only company that hardened their tap holders all the way thru was TM Smith. These were also the only tap chucks we ever had trouble with the ends shattering after alot of use. We complained but they refused to change them. Now they are out of business...wonder why...

[metlmunchr]

Agree with the above suggestions. You'd need an 11/16 hole to chase your thread, but I'd avoid the temptation to start with a 5/8 toolholder because taking .03 per side might not get thru the hard part, and if you happen to hit the transition area and have hard and soft spots, then getting a decent thread will be a real bear. Probably better to start with a 1/2.

If you have to bore and thread across a setscrew hole, you might want to torch anneal a setscrew and loctite it in place first, to get rid of the interruption.

[charlie gary]

I've bought blanks from YG1 before, but now I don't see them listed on their web site. You might be able to call a tool vendor and ask about them. This guy sold me one a few years back. Mike Hedwall 1-800-929-3321

[Limy Sami]

I know it's UK but J&L?

Soft cat 40 blanks page 593

Browse the UK Master Catalog

[joesimmers]

Milacron, I meant ALTERING Haa Haa!

Yes indeed I was able to cut into an existing cat40 holder, bore it to .687 and chase a 3/4-16 thread.

Thanks for all the replies, you guys are great!!!!

[i_r_machinist]

Jump over to the classified forum. I just bought some nmtb40's dirt cheap.
have fun
i_r_