Spindle galling

T

Tuba Dave

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I have a new to me Logan 1825. The spindle taper is pretty badly scarred up, a collet fixture has .002" runout, as does a dead center. Using a chuck on the threads seems workable. Tell me how bad this is and should I learn to work around it (eg., turning my own centers) or consider having it ground. I may want to use collets on this in the future, but I could probably use a threaded ER chuck rather than the drawbar type. I do mostly small diameter turnings in less demanding materials, but need the length of the bed and tolerance of no more than .001"

20220130_115541.jpg
 
Tool post grinder mounted on the machine. Clean and Blue the area, go slow as your trying to remove only the high spots.
Dress the wheel frequently as the high spots will start to groove the grinding wheel.
Check your progress frequently as you wish to remove as little material as possible.
 
I know it's probably hardened.
So either get a tool post grinder, and re-grind the inside, Or try both a roughing and finish MT taper reamer.

My choice would be the tool post grinder. It means your tapers will just fit deeper in.
Is that an MT3?
 
I used an Aircat die grinder in a boring bar holder on my toolpost once to clean up a Chinese 5c collet chuck and the Jaws of a 3jaw chuck. It got me down to about .0005" on the collet chuck.
 
You can get by with jawed chucks and a screw-on collet chuck. If you need to turn between centers then just make one that is held in a 3 jaw and it will be accurate. You don't really need that Morse taper nowadays.
 
mikey said:
You can get by with jawed chucks and a screw-on collet chuck. If you need to turn between centers then just make one that is held in a 3 jaw and it will be accurate. You don't really need that Morse taper nowadays.
Click to expand...

Ha! Confirmation bias at its best. I think this is the answer I wanted to hear, so it is the advice I will heed.LOL

BTW , I do appreciate all the other advice I received. However, grinding a Morse taper in a critical part is a little beyond my confidence (and, indeed, equipment) at this point. (Hence the post in the beginner's forum) Eventually, yes, but right now I need to get cracking.

Thanks to all
 
You might actually confirm that it _IS_ hardened. A carbide MT reamer might cut it even so.

That said, I only used my spindle taper once (and had to spend a crap-load to get a dead center in the right taper family, for it that I THEN had to modify it, since Jarno-15 is completely unobtainable), and that was only because I otherwise didn't have enough bed length for the project I was on. Otherwise, I'd have just turned a center on a 3 jaw.

I suspect the inside of most spindles is pretty terrible, since most of us use the spindle pass-through without being particularly careful about pushing the material into it.
 
I use my taper a bit. I like turning on centers if I can.
I do put sometimes a center in the 3 jaw and true it up, but I have a carbide tipped center that it dead on, and with it I can pressure turn between centers.

I agree, if you don't have the skills yet, leave it. Wait until you do, or you need it. You can also pressure turn by making your center for 3 jaw with a flange to ride on the jaws to prevent it from being pushed in.
 
A lot of times very careful use of a morse taper reamer can solve this. Don't turn the reamer, apply light pressure with a center in the tail stock and turn the spindle. That will keep from putting pressure on the reamer off center. Oil well, and don't turn backwards obviously. I never clean up the taper 100 percent, just 80 percent or so and take all the high points and hickeys out. Rarely do you have to grind. Most of the time with a lathe if you have out center runout issues i find if you clean up with a reamer and still have them there might be a good chance its bearings as well.

Never had a small lathe that a hss reamer wouldn't clean up
 
Emory paper, a dowell,, masking tape and a sharpie...

Place strip of masking tape around spindle and another on the opposite side of your taper.

Find the correct male taper and paint it with a sharpie or marks a lot.

Gently insert it and give it a slight twist.

Draw a witness line across tape on spindle and taper.

Remove and notice where ink is gone.

Look inside and observe where ink is.

You can secure the Emory paper to the dowel with tape then wrap it.

Now you can use this to work on the high spots.

A sharp file may work too but the paper on the dowel allow you to focus on the end of the Dowell to get small spots.

Repaint and repeat, work on just one spot to see how it improves.

It is likely a smear where somehow whatever was the taper got hung up while spindle kept turning.

Usually this results in a small ring that balls up so you may cut lucky.

In the mean time just use handy round stock in 2 jaw and true it up as needed.

Most do this anyway as removing chuck smacks of effort...

Sent from my SM-G781V using Tapatalk
 
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