maybe bad MT

Frank Fusco

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Mountain Home, Arkansas
Pictured below is the mandrel I use for pens on those rare occasions when I use a mandrel. It is one of the 'professional' adjustable styles. Lately, when using it, I cannot remove by tapping from behind. In fact, some hard whacking won't budge it. I have to lock the indexer and turn the MT with a wrench to bust loose. Not a happy thing to do to my lathe.
I acquired this thing used and suspect it got spun at some point, or two, or twenty. :eek:
Wadda y'all think, should I try to just clean it up with sandpaper or something, or is it toast? I'm leaning towards toast.
 

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Frank, cleaning it would be my first thought. Also cleaning the spindle interior as well. Sometimes gunk can seize things...:doh:
 
Frank,

I think taking some coarse emery cloth strips to the mandrel first to clean it up and then going finer and finer to polish it up. Cheaper than replacing it right away.

My greater concern would be with the lathe collet, the interior surface might have been marred by the mandrel. Take a close look with a flashlight or, if you have one, a pistol/rifle bore light. It might need to be lightly reamed if the surface has been damaged.

Cheers.
 
i say yu need to go to flat work and drop this spinny stuff, and this is just the first hint frank:) i would also sand it morse tapers are made to fit all the way around and once yu clean it some it should regroup itself and fit nice agian..
 
Not what you want to hear, but it sure looks galled to me, and you say you had to use a wrench to break it loose only confirms my suspicions. Morris tapers work by friction and rely on a perfect fit to the taper. there's no way you'll fix it with sanding, you just can't hold a perfect angle on both pieces which you'd need to fix it right.

Bite the bullet and pick up a new mandrel and MT2 finish reamer. It's much easier to fix the damage now with a finish reamer before it gets too severe.

Mike
 
Mike, the inside of the MT on my lathe is OK. I checked with my pinky last night. But, I agree, the galling is bad news for the lathe if I keep using it. My first instincts are probably safest way to go. Bad toast. Will get tossed and I'll buy another.
BTW, since I acquired this used, fergit where, probably a trade with someone here, I don't know the make. But, I'm sure the steel is softer than what my lathe spindle is made of and that is what prevented damage.
 
Mike, the inside of the MT on my lathe is OK. I checked with my pinky last night. But, I agree, the galling is bad news for the lathe if I keep using it. My first instincts are probably safest way to go. Bad toast. Will get tossed and I'll buy another.
BTW, since I acquired this used, fergit where, probably a trade with someone here, I don't know the make. But, I'm sure the steel is softer than what my lathe spindle is made of and that is what prevented damage.

Frank, I have successfully dressed the morse Taper on spindles before with the following procedure:

Chuck the spindle in something, (lathe or DP)
make a sanding block by wrapping (or gluing) a piece of Good quality emery cloth tight around a short flat block of wood, then with the spindle turning, press the sanding block "FLAT" against the taper and slide it back & forth about a 1/4" along the taper to keep from getting any grooves as it turns. Graduate to finer grits until you get the degree of polish you want.

I have also fitted and glued a fine grit emery cloth around a spindle to clean the taper inside a collet as it turned.

The secret on the spindle is keeping even pressure on the sanding block so it remains FLAT against the full length of the taper, which isn't hard to do.

I would give it a try if I were you.
 
Frank, I have successfully dressed the morse Taper on spindles before with the following procedure:

Chuck the spindle in something, (lathe or DP)
make a sanding block by wrapping (or gluing) a piece of Good quality emery cloth tight around a short flat block of wood, then with the spindle turning, press the sanding block "FLAT" against the taper and slide it back & forth about a 1/4" along the taper to keep from getting any grooves as it turns. Graduate to finer grits until you get the degree of polish you want.

I have also fitted and glued a fine grit emery cloth around a spindle to clean the taper inside a collet as it turned.

The secret on the spindle is keeping even pressure on the sanding block so it remains FLAT against the full length of the taper, which isn't hard to do.

I would give it a try if I were you.


Thanks. Really nothing to lose. Will try.
 
Frank, if someone local has a Metal Turning lathe why not get the taper section turned Parallel, then you can just grip it in your 4 Jaw, saves the trouble of keep removing chuck. I turn all my home made mandrels with parallel shanks, you should have plenty of meat there to be big enough diameter to fit the chuck even with auxilliary jaws fitted.
 
Frank, if someone local has a Metal Turning lathe why not get the taper section turned Parallel, then you can just grip it in your 4 Jaw, saves the trouble of keep removing chuck. I turn all my home made mandrels with parallel shanks, you should have plenty of meat there to be big enough diameter to fit the chuck even with auxilliary jaws fitted.

Good idea. In fact, I have a large 3-jaw chuck that is useless for wood. I do the occasional piece of plastic or brass with it. Thanks.
 
Charles, your tip put my mandrel back in business, even without the necessity of turning the morse taper to a parallel.
I simply chucked it up in this, otherwise unused, three jaw machinists chuck and it turns just fine.
A new adjustable mandrel is about $20.00. I believe my machinist friend would have probably charged about that same amount. If this didn't work I was just going to buy a new one.
But, you saved me the money. :bow:
Thanks.
 

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Glad it triggered a solution Frank, as you might gather I'm not one for spending money where a simple fix exists.

Sad that a little turning job like that 'costs' we tend to help each other out on a goodwill basis around here.

Often arrive home to find several feet of redundant steel bars from some worn farm equipement, drive shaft, hay lifting spikes, 20kg of 1-1/2" nuts and bolts etc. propped by the shed.

Far outway my spare time labour outlay.

Sorry for any delay responding, been returning from Bavaria.
 
Charles, your tip put my mandrel back in business, even without the necessity of turning the morse taper to a parallel.
I simply chucked it up in this, otherwise unused, three jaw machinists chuck and it turns just fine.
A new adjustable mandrel is about $20.00. I believe my machinist friend would have probably charged about that same amount. If this didn't work I was just going to buy a new one.
But, you saved me the money. :bow:
Thanks.

Frank if that doesnt work bring it with you on your next trip this way and we will give it a try on my little Grizzly metal lathe wont cost ya a cent.
Jay
 
Glad it triggered a solution Frank, as you might gather I'm not one for spending money where a simple fix exists.

Sad that a little turning job like that 'costs' we tend to help each other out on a goodwill basis around here.

Often arrive home to find several feet of redundant steel bars from some worn farm equipement, drive shaft, hay lifting spikes, 20kg of 1-1/2" nuts and bolts etc. propped by the shed.

Far outway my spare time labour outlay.

Sorry for any delay responding, been returning from Bavaria.

Charles, as a former farmer, I know the value of a good 'junk' pile. I believe farmers are not only the most resourceful business people anywhere but they have always lead the way in recycling. Today, farmers are considered the villains.
 
Frank, I have delt with this a time or 2 as a die maker because we used morse taper drills nearly every day. The best way to fix a male morse taper is to use a hard, flat india stone to knock off any dings. The flat hard surface helps to keep the taper surface true. Personally I would NOT use sand paper because it is to easy to get the line of taper out of whack. I clean the inside (female) morse taper with 3M abrasive scotch brite type pad, usually red or blue. This stuff works well for cleaning and sometimes I soak it with WD-40. It will not remove that much material by hand, so it won't hurt the taper.(Be careful using it with power tools)
 
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