Atlas Mfc Mill Arbor Drawing ?

[Wheels17]

Wow! They really hogged that thing out! Quite the ripples on the bottom of the keyway. Must have been a big horizontal.
Thanks for the pictures. They are excellent.

The taper is really short compared to the specifications at 2 9/16". I'll have to put a #1 in there and see what spacing I get.

 

[CluelessNewB]

The taper is really short compared to the specifications at 2 9/16". I'll have to put a #1 in there and see what spacing I get.

I'm measuring 0.702" as close as I can get on the large end of the taper and about 0.589" on the small end again using an inexpensive digital caliper. Take those measurements with as many grains of salt you deem appropriate.

 

[Wheels17]

Thanks!! The standards call for .572 to .700 over a length of 2 9/16, at least the way I read it. What is the length of the taper from the end to the driver boss? The mill I bought has a vertical head, and I can't get the %&^*& pulley off to try the arbor driver. A standard MT2 collet slipped in by hand sticks out about .20. (I meant a #2 in the last note).

 

[Rob]

Just returned from a trip to Madison Wi. I might add it was not the right time of year to go there. I did glance at my 7/8 arbor and it appears to have a 1/8 keyway. Will try and get pics and measurements of it and the rest of the measurements in the next day or two.

 

[wa5cab]

Rich,

The drive pin notch has been butchered for some reason.

Wheels,

That should be 3/4"-16 vice 3/8".

 

[Wheels17]

Rob, I'm not sure what you are referring to with the 3/4-16 comment.

I've attached the most recent updates of the drawings. Pictures I've found on ebay all show the keyway running off the end, so I've modified the drawings to show that. One thing I'm still missing on the drawing is the relief between the 3/4-16 thread and the arbor proper. Another interesting discovery, the arbors that are genuine atlas arbors all seem to have the keyway in line with one of the drive slots. The ones formerly sold by tools4cheap have the keyway at 90 degrees to the drive slots, as I've drawn them.

Tools4cheap also appears to have used different diameter nuts for the 7/8" and the larger arbors. The extra wide mcmaster nuts (3/4"-16 1 1/4" 47/64" 10 96460A640 13.35) are 1 1/4 across flats. They would be fine for the 7/8 arbor, and probably for the 1", but a custom nut will be necessary for the 1 1/4 if that one is ever made.

 

[Rob]

Ok here are some more pics and measurements of the arbors.

The relief at the end of the 3/4 thread is 1/8". I don't think that this is critical as long as you do have the relief cut as the nut will go over the end of the main part of the arbor if needed. The nut for the 1" arbor has a 1" and the 7/8" nut has a 7/8" relief cut in them that is 1/4" deep.

The key way in the 7/8 arbor is 1/8". I do not see that it maters where you put the key way.

Let me know if you need anything else.

 

[Wheels17]

Thank you for the pictures. I count 39/16s, or 2 7/16 for the overall length of the MT2, with a 3/16 straight section as often seen on drawbar collets. This makes my proposed arbor 1/8" too long. Right now I can't get the vertical head pulley off the spindle, so I can't do any fitting until I get the driver nut on the spindle. I'm going to have to make an expander wrench for the interior of the spindle to see if I can get it off.

I've updated the drawings with an arbor nut, and the thread relief.

 

[wa5cab]

Rob, I'm not sure what you are referring to with the 3/4-16 comment.

Wheels,

Back in post #19, you wrote that McMaster had a long nut that was more than long enough to use to make the big counter-bored nut on the arbor but you wrote 3/8"-16. Seems that I recall the phone ringing or some other interruption while I was writing that and there are posts in between yours and mine.

 

[Wheels17]

That would be tough to put on.... It's right in the drawings.