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Chuck adapter machining

According to Boris Beizer :

If you got a BXA toolpost and tool holders made in China, you will want to replace the setscrews in the holders -- and that is the right size 8mm setscrew, so get a box of 100, and you will have enough to change all of the holders's setscrews, plus more to make into transfer screws.

The *original* setscrews in the holders (at least in the Phase II which I got some years ago) tend to be a "mystery metal", and are prone to having the socket split out under torque. A real mess when it prevents you from removing the setscrews once tightened. Somewhere around, I have a box of the original setscrews waiting for a non-demanding task. Perhaps they would make good transfer screws. :-)

But you just said "That's where I'm at" above to the mention of "didn't put a register diameter on the backplate". This is the diameter at the back (spindle side) of the backplate, which should be a precise fit on the unturned part of the spindle behind the threads. For this, you need a spacer to hold it far enough out on the spindle so you won't be cutting the spindle nose when you turn that register diameter.

Were you perhaps referring to the boss on the *front* of the backplate, which fits into the recess on the back of the chuck? That is a different matter than the register diameter.

And you'll want to face the backplate while it is mounted on

*your* spindle, and then turn down a bit more to create the boss to fit your chuck.

I'm not sure what the surface plate will tell you that testing the faceplate on the spindle won't tell you better. After all, what matters is how it relates to the spindle.

Yes -- but if it does not have the register, then your "Assuming" in the above paragraph fails.

If it is excessive, yet the locating boss is a snug fit in the recess of the chuck, then the problem is the jaws, not the fit of the backplate. (Or -- a chip between the chuck and the backplate when you tightened the screws.)

You should not need that.

*And* -- coat it with Vactra No. 2 to prevent rust on the freshly turned surfaces. :-)

Enjoy, DoN.

Reply to
DoN. Nichols
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I use all sizes, from 3/16 to 5/8, mostly dictated by what I pick up at garage sales, auctions, etc. Nothing beats getting brand-new carbide's, say, for about $1 per hundred. If I had to pay retail, I'd probably be using 1/16th bits. However, as a general rule I always use the heaviest tool bits I can fit in my holders. The smaller ones (e.g., 1/4") I use mostly for boring bars and small fly cutters.

Boris

Reply to
Boris Beizer

That too. And the larger holders are more available and cheaper than the smaller holders at the used tool places.

Boris

Reply to
Boris Beizer

I don't understand at all. The problem with my lathe is that to get a

5/8" bit on center, I have to bottom the holder so that it rests on the compound. The problem is that the bits come out above center, not below. How does putting in a spacer help you lower the bit when the holder is already at bottom and the bit is still above center?

Boris

Reply to
Boris Beizer

Mine is a very old (1945 or so) Series 110 Clausing (12.75 x 48). The compound is rather thick. From what I've seen of the newer Clausings (e.g.,

5,000 series) the top surface of the

I landed a Dorian D25AXA-16C, an Aloris AXA 8 (Threading tool) and monster Aloris BX4 boring bar holder all for $7.50 at a flea market... gloat, gloat, gloat. So I'm hanging on to both tool posts.

Boris

Reply to
Boris Beizer

Don't you know? What do you think happens to old garment hangers from the dry-cleaning store? Just thread them and use them as set screws.

I never had that problem with Phase II stuff, although I did find that a problem with stuff made in India. I bought a jeweler's rolling mill a couple of months ago and shortly after assembling and trying it out, I removed all the screws and bolts and retapped the holes as required, replacing them with high-grade US stuff. Problem with India is that they invented steel over two thousand years ago and haven't seen fit to change the formula since.

The backplate was really thick 1-1/4" so the spindle nose was safely out of the way,

Thank you. Obviously I didn't know what you meant by "register diameter." Okay. Now I understand the issue. You are referring to the **inside** diameter of the hole in the plate, which is to mate with the unthreaded part of the spindle. There was no option on that with this backplate. It came finished, with no option to machine, except to make it larger. So this adapter is depending on the flat surface mating. Oh well! I didn't plan to use the four jaw scroll chuck for precise work. My smaller three-jaw is an adjust-through and for precise 4-jaw work I would use the regular four-jaw chuck and indicate in as needed.

Boris

Reply to
Boris Beizer

Boria

Most of my bits are below center. May be the way they were ground and also they have been around for a while. So when I bought my lathe, Brimingham 13" X 40", the provided tool holder will accomodate bits up to 1". Thus the spacers. The spacers are actually the pieces that have to be removed to accomodate the circuit breakers in a power panel face.

When I get my BXA post ready to go, need to mill the base, I will not need the spacers.

Bob AZ

Reply to
Bob AZ

Okay. Now it makes sense. I thought that you were using spacers with a BXA toolpost ..which didn't make any sense at all, since there's at least 1" of adjustment in the holder screw.

Boris.

Reply to
Boris Beizer

According to Boris Beizer :

I think that the quality of the screws from Phase II has improved, and it was probably not as bad as the stuff from India, even with the screws which came with mine. But one screw *did* start to split, so I replaced them all. And while I was at it, I replaced them with 5/16" screws, and re-tapped the holes in the blocks, so the single T-handled Allen wrench is a proper fit on those and the ones which come in the genuine Aloris toolholders. (The fit may have been what caused the split in the first place.) At least, the split was not bad enough to lead to my having to drill out the screw. :-)

:-)

[ ... ]

Correct. I thought, from what you posted, that that was the problem.

Well ... you *can* bore it out, press in a collar, and then bore that to precise size, if necessary. :-)

I normally don't have to deal with that these days, because I swapped my lathe's 2-1/4x8 spindle for an L-00 spindle, so I can turn in reverse without risking the chuck unscrewing.

O.K. The four-jaw universal chuck is nice for dealing with square stock -- as long as it is *truly* square. I've got a nice one for my Compact-5/CNC, but not one for the Clausing -- yet.

Enjoy, DoN.

Reply to
DoN. Nichols

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