R8 Arbor With Jacobs Taper

Is the male taper bottoming out in the chuck?
 
The biggest part of the chuck is .618" to the best I can measure on a taper. The small end of the taper is all that is contacting. The arbor moved around in the chuck like a clapper in a bell.
 
I thought about lapping them together but if the arbor is correct I hate to screw it up. I might be able to turn a taper on a scrap piece to lap it in but I'm not that sure of my turning skills. I usually don't do anything that requires that degree of accuracy.
 
That is a 2° 26' ( 2.439 ) included angle, maybe you can match that up with something. It may not be a Jacobs taper on the arbor. I can't match those numbers to anything standard.

kingmt01 said:
I thought about lapping them together but if the arbor is correct I hate to screw it up. I might be able to turn a taper on a scrap piece to lap it in but I'm not that sure of my turning skills. I usually don't do anything that requires that degree of accuracy.
Click to expand...

The more you do precision turning the better you get at it. It seems that in it's current state the arbor is useless anyway so if you screw it up, all you are out is your time.
 
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Just grabbed a good arbor out of the shop and the .618 dim looks good on the large end.
 
What is the angle of a Jacobs? What else would they have included an arbor for. I'm thinking (& I may not remember correctly) before I got this chuck that I used a chuck from my lathe on this arbor. I hate to start pulling chucks of arbors but I guess I'll have to. I have the arbor that came with this chuck somewhere. I should try to find it to check it as well.
 
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