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Mark K
03-17-2010, 12:12 AM
Hi, Guys

I'm looking for a 2MT shell end mill arbor, drawbar style, 1/2" arbor diameter.

Eagle Rock makes the front end, but with a 1/2" straight shank. Arrand, in the UK, makes metric versions. Other than those, my search of the usual suspects has turned up bupkus.

I can make one from a blank arbor, but I'd prefer a hardened and ground OEM version. Any ideas?

Thanks much, Mark

Star Date: a few minutes later. A search of Tools4Cheap turned up nada, but they do have a set on ebay. A backup in case I can't source a US made one.

Bruce Griffing
03-17-2010, 01:01 AM
This will be a rare item because any machine with a 2MT spindle is probably not rigid or powerful enough for a shell mill.

J Tiers
03-17-2010, 08:29 AM
You'll be making it, most likely.

As for rigidity, there are shell mills and there are shell mills..... Smaller arbors, smaller shanks, smaller shell mills.

Here is an arbor I made for 1/2" bore shell mills, about 1" OD, which the MT2 is perfectly fine with.

http://img.photobucket.com/albums/0803/jstanley/shellmillarb7.jpg

Black_Moons
03-17-2010, 09:36 AM
You can buy premade MT2 shanks very cheaply online in verious configs (threaded, blank, 'bulk' ends) or make one on a lathe by copying the angle off an existing MT2 arbor for anything (and using prussion blue transfer dye+test fitings to get it 100% accurate if needed)

Mark K
03-17-2010, 11:46 AM
Thanks, Gents, I see we think alike. J Tiers, that's a nice construction, I like the driving collar idea. My plan had been a larger flange and dowel pins for drivers. Believe your idea is better, it even incorporates something of a safety clutch.

Arrand makes 2MT arbors (with the pin drivers) for 16mm bores and will quote for cutters to fit. I'll ask for prices and also a quote for a custom half-inch arbor. Will post results.

Mark

J Tiers
03-17-2010, 11:27 PM
No collar on mine..... It's all solid.

The driving pins are set in slots on the side and held in by screws, like this larger one. No clutch action, the pins have to shear, or somehow pop the retaining screws and escape the slots

http://img.photobucket.com/albums/0803/jstanley/shellmillarb1.jpg

EdC
03-18-2010, 07:35 PM
Tools4Cheap has a 3 piece set for $60

http://www.tools4cheap.net/proddetail.php?prod=mt2shell

The pic looks like maybe 3/8, 1/2, and 3/4 arbors...?

Mark K
03-18-2010, 10:53 PM
Thanks for showing your designs, all. It always spurs thinking to see another's work.

I also found the t4c set, asked and he won't break up a set. I have a request in to Ed Jackson, of Arrand, to see what he can do. Will post his answer.

Mark

J Tiers
03-19-2010, 12:17 AM
Yah..... of those 3, for $60, most folks could only use 1, maybe 2.

Victor machinery has the cutters, with shanks of 0.5", 0.75" and 1".

The tools4cheap set includes at least one that is rather uncommon, and therefore generally useless. maybe 2, depending on the real diameters...

They also appear to be the type Mark K thought I had made.

EdC
03-19-2010, 05:22 PM
Yah..... of those 3, for $60, most folks could only use 1, maybe 2.

Victor machinery has the cutters, with shanks of 0.5", 0.75" and 1".

The tools4cheap set includes at least one that is rather uncommon, and therefore generally useless. maybe 2, depending on the real diameters...

They also appear to be the type Mark K thought I had made.


Yeah, its hard to tell what diameters they are by the way the pic is taken.

The only advantage would be to get a taper that is ground and re-machine the arbor to a more useful size.

Mark K
03-19-2010, 06:10 PM
I have a reply from Stewart Jackson, of Arrand. They have discontinued the small 2MT arbor (16mm spigot) and are selling the larger ones from existing stock only. Also not available are the insert cutters to fit these metric tools. He blamed "cheap imports flooding our home market." Not that anything like that has happened here.

He quoted a price of 300GBP for a one-off 2MT x 1/2" arbor. I'm sure it'd be an absolute jewel and I now know what to expect from a tool shop doing a job like this. I have replied with appreciation and regrets. I will send them another order soon though. The tools in their regular line-up are just first rate.

As for the shell mill arbor, it'll be made in the shop. Thanks, J Tiers, for clarifying your design. I guess I shouldn't pretend I can see through metal.

Mark

ARFF79
03-22-2010, 01:58 AM
Why not buy one of the straight shank holders and adapt it. 3/4" shank, drill and tap the end then set between centers and grind to a 2 morse. Or, Critiron used to have 2 Morse shanks for their boring heads. Buy one and make up a set of pilots for it. I believe it was the 7/8-20 thread shank. I have an old B&S shell mill arbor that works on this same principle. Thread off the 1/2" pilot and thread on the 1-1/4" without pulling the arbor from the mill.

Mark K
03-22-2010, 06:30 PM
All workable ideas, thanks. I'm going to go with a one-piece 2MT arbor with the straight stub machined while the taper is seated in the lathe spindle (TIR less than 0.0001"). Best concentricity this way, and better stiffness with less overhang. I'm likely to have just the one insert shell mill, so the lack of a hardened arbor will be of scant concern after all.

Thanks to all who offered ideas.

Mark