# boring question



## SE18 (Sep 18, 2012)

Hi all, I'm making an MT3 to MT2 piece with taper. Outside is completed except for cutting off both ends used for holding in the chuck. It's aluminum. 

So now I'm working on the inside (MT2). I got through fine with a 3/8 followed by 1/2" drill. Then, I had to go out and buy a 5/8 drill ($17). Purpose is to widen the hole so I can then use my boring bar to make the taper (so the boring bar has room inside to back out).

So I finally got the 5/8 through but had a lot of difficulties, mainly these:

1. The bit got caught inside once
2. The bit started turning inside the tailstock chuck
3. The MT2 on the tailstock chuck which fits into tailstock started spinning

I was able to get through with light cuts and frequent backing out and used kerosene to cool the bit

So here are my questions

1. Is this typical?
2. Would the chuck's MT2 spinning in the tailstock hole cause damage?
3. Would the drill spinning in the chuck cause damage?
4. Is there a better way to do all of this?

Much thanks; you probably can tell I'm a beginner. LOL

DaveV


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## Tony Wells (Sep 18, 2012)

Hi Dave, I'll try to give a little input.

1. Is this typical?

No, it is not.

2. Would the chuck's MT2 spinning in the tailstock hole cause damage?

Potentially yes. Look inside the tailstock to see if there are any marks or damage. Feel with your finger. It should be very smooth. If it is damaged, you will want to correct it.

3. Would the drill spinning in the chuck cause damage?

Usually only to the drill. Drill shanks aren't typically hardened, so the chuck can get a good bite on them, so the drill can get kind of ugly if allowed to spin much. It's possible, though not as likely, that the jaws may have been damaged. They are hardened.

4. Is there a better way to do all of this?

There are other ways, let's put it that way. The preferred way for me is to use a MT shanked drill with a tank that locks in the tailstock to prevent spinning. It sounds like maybe you didn't have your chuck fully seated. My way of doing it is to ease the chuck into the tailstock to align myself, then draw it back about half-way, then slam it in as hard as I can. This takes a bit of practice not to put dings on the morse taper from not being lined up right, but it can be done. The taper will hold quite a bit of torque if properly seated.

I also prefer to use a reamer to finish the ID of anything I make with a morse taper socket. Just easier and faster to get an accurate ID. Especially on smaller tapers. And I don't recommend aluminum for a morse adapter. 

If you do the ID first, you can mount the piece on a proper factory taper from a drill or reamer and turn the OD between centers using it as a mandrel. Your concentricity will be better than chucking one end. Also, on the aluminum, it's too easy to crush and egg in the lathe chuck once you have drilled through. 

There are, as usual, many ways to remove the pelt from the feline. Those are just a couple of my thoughts. Others will add to it.


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## SE18 (Sep 18, 2012)

thanks for your very detailed reply


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