Rotary Table Quick Centering Mandrel

darkzero

darkzero

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Another quickie planned years ago that I finally got around to. Centering tool for quick setups. Will be good for 90% of the stuff I do. If I need higher accuracy I'll indicate.

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Here's what I started out with. A threaded drill chuck arbor purchased years ago, (luckily I didn't loose it), a piece of 4140, & a piece of 6061.
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Tapped the 4140 to thread onto to the arbor, machine, & sand/polish to final size.
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Making the "emergency" sleeve & washer.
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Here's how I use it. Mount the mandrel in a collet. Rotary table bolts are loose. Drop the the quill to seat the mandrel in the RT MT taper, then snug the RT bolts.
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TIR of the mandrel in the mill spindle is .0004"-.0005".
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TIR of the RT after simply using the mandrel to center is .0007"-.0008", this was on the very first try. If I'm more careful about it I can get it lower but the point of this tool is for quick & dirty centering which will be fine for me in most cases.
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The reason for the long mandrel is after centering & snugging down the RT, with the mandrel seated in the RT, I can quickly center my chuck. Tighten the jaws on the mandrel, then snug down the chuck. Again, if I need higher accuracy I'll indicate the chuck in also.
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To eject the mandrel I use the washer & bolt.
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And in any case the mandrel might get seated to where I can't simply pull it out by hand, I use the sleeve, washer, & bolt.
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And finally storage.
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Thanks for looking! :big grin:
 
I've been wondering how I was going to manage that. Thanks for the how to...
 
Thanks Will, another project on my list.
 
Another good accessory for the RT is a tappped slug for the center so you can use as a hold down hole. I made two one with a flange that sits in a recess on bottom of RT hole then put a threaded rod to bring to top surface after alignment process, and a expanding one in case I forgot to put the other one in BEFORE I mounted the RT to the mill. Nice job!
 
Nice job, Will! As usual, very high quality pics that make it simple to understand.

I mean, its not like I don't already have a huge project list already ...
 
mikey said:
Nice job, Will! As usual, very high quality pics that make it simple to understand.

I mean, its not like I don't already have a huge project list already ...
Click to expand...

Haha, thanks Mike!
 
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