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9" SM Utilathe Restoration

I can't see you making it worse but that's just an opinion, hopefully one of the ninja's reamer experts can add more clarity to this.
 
If you are deeply cutting, as in this case, the taper will not be in alignment with the bore. As I said before, it has to be removed, cleaned up by boring, and the last .002 to .005 taken with a reamer. The ONLY way to ensure concentricity and alignment.
 
What if we were to mount the reamer in the spindle with a collet and the advance the quill to ream?


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The problem is that the reamer will follow the hole's least resistance. The damage certainly isn't symmetric, and the large flakes that will come off will tend to divert the reamer. It doesn't take much to get it off center (or worse ream an oblong hole - I speak from experience here).

It is surprisingly easy to chuck it in a 4 jaw chuck, set up the taper, and take a skim cut with a boring bar. This will take out all the random scratches and potentially hard spots from compressing the chips into the bore, and make reaming the way you suggest a dream.

Another tip: when you chuck the reamer and ream, don't do it under power! doing it by hand is far more controlled, and you can 'feel' the reamer work. Don't take more than 2 turns before removing, cleaning the reamer and bore, and then continuing... That way your reamer will last for the next time you need it.

I have a MT3 reamer that has restored 5 or 6 tailstocks, and it is still very sharp.

BTW, if your boring is off a fraction of a degree, it doesn't matter, the reamer will restore the correct angle. If you are off, say a half degree on a MT3, it is out very little over the length, which is easily corrected by the reamer. The .020 - .030 depth of scratches is far too much to ream alone.
 
Hey Craig,

here is what is left :

i think you wanted the main spindle?

54EAB4B4-81BD-46CC-8BB3-33CCC7E46B69.jpeg

What ever Craig doesn’t want is up for sale. The little gear for the apron drive handle is there but the spindle is bent. Would take a bit to get it working.
 
What is the main spindle bearing like? If no one "needs" the spindle and the bearing is good I'll could relieve you of that as well.
 
Dabbler said:
If you are deeply cutting, as in this case, the taper will not be in alignment with the bore. As I said before, it has to be removed, cleaned up by boring, and the last .002 to .005 taken with a reamer. The ONLY way to ensure concentricity and alignment.
Click to expand...

With this in mind I setup to try boring which is something I have never done before...

BOREATTEMPT1.JPG


This is not goodo_O A very light pass made a big mess of the bore on my test piece.

What's going on here?
 
I’m guessing that your tool is rubbing. There doesn’t look to be a lot of clearance. Personally I wouldn’t use carbide.


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I ran into the same thing with a KMS boring bar. From the tip of the tool downward it needs to ground so the bottom of the tool doesn't hit the inside arc of the bore. I was having the same trouble trying to do an inside thread until I notice the the bottom of the bar hitting the inside of the bore. It took quite a bit of grinding but I got it done.
 
Darn, I have a spare Southbend quill but it’s 1.065x5 ¼” key way.

I also have this at 0.94”OD with an unused 2Mt socket in the end.
It could possibly be sleeved up to 1.18” but you would have to improve your boring significantly for it to work. . I think a deeper key would be needed.

F137CEF7-0933-4E3E-96A8-E0BEFD798282.jpeg
 
Craig, I agree with @Johnwa , your tool is probably rubbing. You could try to change the tool angle to give you more clearance. Also, raising it might work.

if you want, we can try to repair it using my SM1340. Your TS quill should fit nicely into the 4-jaw and we can first bore it as @Dabbler suggested (and you are trying) and then we can ream it with the reamer you have.
 
RobinHood said:
Craig, I agree with @Johnwa , your tool is probably rubbing. You could try to change the tool angle to give you more clearance. Also, raising it might work.

if you want, we can try to repair it using my SM1340. Your TS quill should fit nicely into the 4-jaw and we can first bore it as @Dabbler suggested (and you are trying) and then we can ream it with the reamer you have.
Click to expand...

Thanks Rudy, I'll contact you once I have a reamer in hand.

In the mean time, I'll keep poking at this boring challenge. Raising the tool helped but not to the point of being acceptable. What kind of boring bar do you use?

Craig
 
I just have cheap cemented carbide and shop made HSS ones. The carbide ones I did regrinding the clearance angles much like @YotaBota did on his. Much better result.

here are some (l to r: shop made hss, bar with hss tool, cemented carbide set - angles reground)
03C6CB4C-DC04-49B3-A685-D01822C2E1DC.jpeg
 
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More tips for boring: reduce stick out as much as possible while you are learning. Use the largest diameter boring bar that will fit into the bore to reduce flex in the bar. For practice cuts, try less than a 2" stick out, to minimize variables. The tool should have, if possible neutral rake - boy this one got me for a while when I was learning. I tried to set the point at the center line with a positive rake and it was a disaster! Positive rake pulls in the point, which leads to vibration. Negative rake can vibrate, but to a lesser extent.

One more thing: don't worry about scratches or bad surface finish. The reamer will polish it up well enough. If you have galling or ridges, you can clean them up with a 1/3 plug, cut to a MT, and covered with 300 or 600 wet and dry. REMEMBER the bore is for straightness, the actual taper (or .002-.004 of it) will be cut by the reamer.

To make the 1/3 plug you cut your MT in wood, and check for fit. cut it in half. sand off remainder so it is around 30=40% of the circle. Now use it as a hone to take out the ridges, or the galls. Galls will spoil the reamer finish if left in....
 
ChuckTapers.JPG


Chuck taper damage. On the left is the 3/8" that came with my lathe. On the right is the 1/2" I purchased from BB.
The 1/2" was damaged first usage, so the tail stock spindle flaw was already there.

The spindle damage aligns with the recessed area of the original chuck?

So.... what caused this in the first place? Swarth in the spindle taper?

Should I trash these tapers?
 
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The damage to your chuck tapers was most likely due to the fact that they were not seated properly in the quill because it in turn has internal damage.
The quill in your TS does not have a flat for the anti-rotation tang of the taper to engage in when fully seated. It relies entirely on the self-locking property of the MT2 itself. So if in the past, there was swarf in the bore and the taper tooling inserted on top of it, the taper did not lock properly. When the rotational forces were large enough, the tools would spin and gall the softer of the two materials (it seems that was the bore). It’s like when a drill bit starts turning in a chuck that was not tight enough: the drill shank galls and rolls up a burr.

i would just stone your drill chuck shanks carefully to take all the burrs off and use them in the refreshed quill.

When you use taper tooling that does not have a draw bar, give it a little tap with a soft mallet to seat them properly. This ensures that they lock.
 
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