Mitutoyo Tailstock DRO for my PM1236

darkzero

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Another loooong overdue project. The Mitu scale has been sitting around for way too long, I got it from Enco during a sale, that's how long it's been. :confused 3:

Warning: There's a lot of photos in this post!


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My tailstock has 4" of travel. To maximize the use of travel for drilling, I shortened my arbors so they eject when the quill is close to fully retracted. With full length arbors I loose quite a bit of travel. I made my bracket to mount on the quill using set screws so it doesn't affect any loss in the travel I had before.

I use the Bison keyless chuck pictured above most of the time. My Jacobs 14N sits a lil bit closer than the Bison chuck before it ejects. Although I didn't need to, I matched the taper of the 14N on the face of the bracket to give me more clearance for the future if I ever need to ream the TS quill.
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This is how much room I have before my drill chucks eject.
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Bracket mounts on the quill with exactly half it's thickness, sits right at the 0 mark but not that it really matters. :)
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The following are WIP pics if interested.

Making the bracket.
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Used my "cheater" machine to chamfer the flats to match the chamfer on the radius done on the lathe.
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Finished bracket. I'm using brass tipped set screws.
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Made a spacer for the read head. Yes, I am using double sided tape to mount it. I've found Duck brand carpet tape is really strong stuff. Not critical here anyway but it's strong enough to give good measurements. I've actually got my mill quill DRO mounted with the same stuff & it has been holding up great for many yrs now.
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Before I could mount it all up, I first had to address the rotational slop for the quill. The slop has always bothered me but it didn't affect anything so I never got around to fixing it. Now I needed to. Made a new key to take care of that.
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And finally, shortened the scale to appropiate length.
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Thanks for looking if you made it this far! :big grin:
 
In regards to the groove on the original quill key. At first glance I thought it was caused by repeated impact when drilling over the years. But after looking at it closer I don't think that's what it's from. Looks like it was put there intentionally to make it a shear pin?

I was originally going to make the key out of drill rod or 4140 cause that's what I have. Then thinking about it, my quill is not hardened so I didn't think it would be a good idea. Thought it would be best to have the key fail before damaging the quill if something were to ever happen. So I made the key out of mild steel.

Should I cut that groove on the new key? Rotational slop is pretty much gone so it won't see as much impact as it did before.

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Nice job, Will, and a Mitutoyo to boot! Thanks for showing us how to do something that's been on my list for years.

I honestly don't know of an instance where you would have enough load or impact to shear that key. I guess if you used a really big drill and it suddenly got stuck then that might do it but I would imagine the Morse Taper would slip before the key snapped. Personally, I wouldn't bother purposely weakening the key, especially if you fit to the slot closely. Just an opinion.
 
Nice job, Will, and a Mitutoyo to boot! Thanks for showing us how to do something that's been on my list for years.

I honestly don't know of an instance where you would have enough load or impact to shear that key. I guess if you used a really big drill and it suddenly got stuck then that might do it but I would imagine the Morse Taper would slip before the key snapped. Personally, I wouldn't bother purposely weakening the key, especially if you fit to the slot closely. Just an opinion.

Thanks Mike! And thank you for the advice on the key. Ok I'll leave the key alone. The largest drill I have is only 1" so I doubt my lathe could ever shear that pin.
 
Very nice looking project!

Can you kindly say a bit about your chamfering rig? Homemade? Thanks.
 
Very nice looking project!

Can you kindly say a bit about your chamfering rig? Homemade? Thanks.

Thank you!

It's a commercial unit from KBC Tools. These things are surprisingly expensive. I originally wanted to make one like Stefan Gotteswinter. The KBC one went on sale for $500 something ($790 normally) & it was a Taiwan model so I splurged on it. Well built, runs smooth, & very quiet. I don't regret paying for it at all, I love this machine.

https://www.kbctools.com/itemdetail/1-548-100

There are other styles on ebay too (search chamfering or deburring machine).

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Thank you!

It's a commercial unit from KBC Tools. These things are surprisingly expensive. I originally wanted to make one like Stefan Gotteswinter. The KBC one went on sale for $500 something ($790 normally) & it was a Taiwan model so I splurged on it. Well built, runs smooth, & very quiet. I don't regret paying for it at all, I love this machine.

https://www.kbctools.com/itemdetail/1-548-100

They're are other styles on ebay too (search chamfering or deburring machine).

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That adds a very nice "finished” touch !
 
The style points that machine adds to a project are so money: since it's only midday, I fear my impulse may win and I might have one on order before night falls!

Just Need To Stay Away From The Buy Button !!!
 
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I was recentering my tail stock a couple of days ago & when I tried to use my larger Skoda live center, it wouldn't fit. I forgot to check that one. My other live centers fit fine but now I needed to modify the the DRO bracket. Made an expanding mandrel to hold the bracket which worked out great (too great). This time I machined 2 tapers on it.

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I didn't need any precision to make the minor modification but just for kicks I put an indicator on it. Needle didn't move at all. Ok, so then I put a tenths indicator on it, needle didn't move again. I must have 2 broken indicators! Well it really shouldn't have any runout cause of how I machined the mandrel & the bracket but it's always a trip to see the needle not move.

 
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