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How would you hold this part to mill

richl

Active User
Active Member
#1
I am looking for ideas on how to hold this part, it's a ntmb30 taper er40 collect holder.
On the right is the z collect holder my machine came with. Using er40 collects allows me to use more tooling and they will hold better and more true than the present z collect holder (it has very noticeable runout).

I have a 5" Glacern vice, and a 8" rotary table, and just a basic assortment of holders, bolts, nuts and bars...

Assuming I can get a end mill cutter to work, i need to mill a recess like on the z collet holder...

Any ideas, I am going to do this for another 5-10 taper 30 holders so something I can reuse would be preferred.

Thanks

Rich
 

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JimDawson

Global Moderator
Staff member
Director
#2
I think you should send all of those ntnb 30 holders to me for proper disposal :grin:

I would grab the drawbar end in the RT chuck, the collet end might need to be supported also, but some kind of a simple fixture attached to the table or vice would work. If your mill head rotates, that might be necessary to plunge at the proper angle, can't tell from the pictures. Maybe you would have to shim the RT to get the correct angle.

All of the ntnb holders I have run into are machinable with HSS, but are not soft. Maybe in the RC40 or so range.
 

richl

Active User
Active Member
#3
Thanks Jim
The mill is a 1956 vintage south bend, it can tilt, no noods. Plenty beefy, around 1800lbs

I like your idea though, I locked the drawbar side into the rt Chuck, I'm placing a 1" collect into it, a 1" bar in the collect, I'll weld a fixture to clamp into the vise. Tilting the head on the mill might be the best way. I was trying to think up some kind of fixture to tilt the work, but I just don't have anything here to do that with. Pain in the butt to tram this guy, usually 1 hour of tapping the head one way than the other... fun stuff.

Thanks
Rich
 

richl

Active User
Active Member
#5
End of saga, after a very slow process, 2-3 hours worth. This is a much better collect setup. I have not measured the run out, but I suspect if there is any it's in the mill. And right not I am not looking to spent money on taper 30 reamers and tamken taper bearing for the head of the mill ha!

I now have a full set of er40 collects to choose from when working on the mill or the lathe, very happy camper.

Thanks a million Jim! And if eurotrade er40 nmtb30 holders are rc40.... I don't believe it lol

Rich

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