Jack shaft overheats.

I've just read this thread on overheating and maybe can help others in diagnosing heat problems--in your case you could find out what specifically is causing the heat as it is warming up--HF has a hand held laser heat gun that will give instant heat settings on objects aimed at----it is on sale for about $14 now--I've had mine for approx. a year and amazed at all the uses for it---I have it with me in the car for finding overheating of wheel hubs, any engine accessory, trannys- rear ends-radiators-transfer cases-exhaust and intake manifolds-etc---I use it in my shop and home to find overheating breakers-wiring-plugs and wall receptacles- motors-bearings etc.--it makes quick accurate readings of close or far away objects and can help to predict potential problems-I think I will buy another one today so I will always have one within reach --Dave
 
Needle bearings need a hardened shaft. Off the top of my head don't think they would be rated for the rpm your running even on a hardened shaft.

Greg
 
I think the best course of action is to return your machine to "stock" as Logan produced it. There's nothing wrong with the
design of these machines, and with proper pulley sizes, a shaft of the correct length and a suitable motor it should work
fine for you. Small Logans of this basic design have been producing good work since the early 1940's, so why re-invent the
wheel?
 
Pulled it all apart last night and something went very wrong. I will place my bets for the initial problem being the bushings were too tight which was compounded by running too fast. Anyways, things got nasty and both the shaft and the bushings are shot.

...What material would you suggest for the new jackshaft?

I've never seen a jackshaft too rusty to work; mild steel, not SS, would be my preference. Heck, it's 3/4 inch
diameter, there's not a lot of material strength needed. SS has chromium oxide layer, it does NOT
make a good bearing material (CrO2 is abrasive).

2HP motor and higher speed than lube will handle, did score the shaft a bit. But, that's not fatal: you want
some (three mils?) diameter difference in shaft and journal, and you can turn that much off the scored shaft
just fine. It was too tight, after all. Then, lube with high viscosity oil (SAE 90 ?). The scoring on the
bushing hasn't removed enough metal to matter, and a smooth shaft will polish it back to round
in short order.

So, if 'twere my problem, I'd do a very light lathe cut over the scored shaft area (use carbide, there's probably some
workhard stuff there) and try to reuse the shaft. Even if you get a new shaft, consider using emery
on the affected area, and remounting temporarily the one you've got. After all, the new shaft will want new bushings, too,
there's really no loss if you mung the old ones while turning the new 'uns.

Heck, maybe just a few manual swipes with emery cloth, and some white-rouge polishing, can recondition the shaft.
 
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This may be a mistake but i am going to test out the direct drive option first. I of course have the motor and some aluminum laying around already so all it will cost me is my time and a new belt. I started last night cobbling together a 10" tall motor riser and will pull the head stock apart to install a shorter belt. Hope to have it put together some time next week.
 
Success.

Using some scrap aluminum i had laying around i bolted together a 9" tall riser for the 2HP motor. Ugly but it did the job

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I then played around with the step pulley combination and ended up settling for around 1300 RPM and locked the motor down to the bench. If i find this is not enough later i have at least two steps up i can go. Ran the lathe for about 30 minutes testing all sorts of frequencies and both directions and it seemed OK. I am happy with the results and will leave it this way until i find it is lacking in some way.

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Thank you for the help and guidance.

Four things left to do.

1. Finish wiring the RMP gauge. Should be done this weekend.
2. Make a debris shield for the motor. Should be done next week.
3. Locate a 9B for parts to harvest the power apron and install that. (Looking for 2 years now....)
4. Use the darn thing...

Matthew
 
Very nice... I know I have issues with my original motor mount loosening up allowing the mounting plate to "rattle", making it a noisy lathe. I do not like that....
 
I saw that done on a South Bend 10K, the owner used direct drive with the motor on a platform like yours. He said it worked great for him.
mark
 
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