Picked up my logan 9" today

strantor

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Ok, I got my Logan home today and I'm reading .0050" movement on the chuck as I rotate it by hand. Is this OK? Seems like a lot to me. The guy I bought it from said that the bearing preload might need to be tightened after transport. I haven't even cracked up the manual yet. Will see if I can figure it out in the morning.

How would you guys go about getting a lathe out of the back of truck by yourself? You can see how I did it, looks like a kludge. Had to let the air out of the tires and load the tailgate full of bricks to get into the garage, then air the tires back up and get as close to the rafters (with temporary shoring) as possible, then chain it off to the comalong jack, and lift it as high as it would go (not high enough) let the air out again, drive out, then let it down.

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I took a video of my testing with the dial indicator. I cannot upload it for some reason, but here are some pictures. I snapped pictures at the high and the low reading. I started at zero and it went up to 1.5 and then back past zero 7.5.

EDIT: I can also read about .003 shift when I put a 2X4 under the the chuck and put a little upward prying pressure on it.

I'm not sure what the name for this measurement is.

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On the 4 jaw .005 won't make a differnce. I would take the chuck off and check the spindle for runout and endplay.
 
OK, first, take the chuck off! that is no place to take a reading... Remove the chuck and then repeat what you have done on the spindle itself. The lifting part will then be done with something that will slide inside the spindle bore. If indeed the fella did replace the spindle bearings, then it would not be uncommon to have to go back and do a slight adjustment on them after some run in time. I dont know what the specs on it should be but would think it should be under .001, maybe around .0005?

Run the lathe for some time - 10min? - or so and keep a feel on the area of the bearings, there should only be a very slight warmth there (with no load) and then check the run out again.
 
It's worth doing some research on Logan spindle bearings.
The "correct" bearings for that are a high precision unit that is around $300 per bearing from Logan or Timken.
Some people think lower grade bearings of current manufacture are probably as good as high-precision 50 years ago, and use the standard bearings. I could argue that either way.
If the previous owner replaced the bearings, it would be good to know what he used, and if he knew how to orient them if he used the expensive ones.
 
Which model of 9" is it? Does it use standard ball bearings like the 9B? Is there belleville washers in the head that puts preload on the spindle, or just a take-up nut.

Now reading the run-out on the outside body of the chuck does not show much, You need to remove the chuck and read against the spindle itself. Read to the spindle register and to the inside of the spindle and compare. If someone bored too deep, they could have chewed up the internal taper so check face of register, OD of register and ID.

0.003 lift under spindle could be loose tolerance in bearing, improper preload, or just needs to warm up. Try this after running for about 10 minutes. There was a manual shown with the pictures of the lathe, check carefully how the unit is supposed to be put together.

As for moving the lathe, usually use an engine hoist, to lift in and out of trucks. etc.


Walter
 
Took the chuck off and read only .0003" play on the spindle. MUCH better. I guess the chuck is not perfectly round? This doesn't matter since its a 4 jaw chuck, right?
 
Also, with the chuck off, I put a bar in the spindle and lift up and down with ~50ft*lbs. I get .0010" in the up direction and .0012" in the down. so .0022" play up/down or side/side when acted upon; is this acceptable? should I make any attempt to adjust the preload?
 
Which model of 9" is it? Does it use standard ball bearings like the 9B? Is there belleville washers in the head that puts preload on the spindle, or just a take-up nut.

It's a 9B, and looking at the parts page of the exploded view, I see 2 ball bearings and a takeup nut but not anything called a belleville washer.
 
So did you actually pay less than $1k for this? If so, I think you made a good buy.
 
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