Atlas/Craftsman 12x36" lathe...questions

[Jason280]

No luck on the SB chuck, it must have a different thread pattern....it will barely start threading on, and then stops.

 

[wa5cab]

They are both nominally the same 1-1/2"-8 threads. The difference has to be in the details. Carefully measure the diameter of the registry and major diameter of the threads on the two spindles.

 

[jwmay]

I’ve read something about them not being compatible, but wasn’t sure enough to say so. Unfortunately, I cannot remember exactly why.

 

[Jason280]

I'll mic them once I get a chance, but a little surprised it wouldn't work.

 

[TonimusMaximus]

I'd be willing to bet the major diameter is different. Ran into the same issue when I re-barreled my Savage rifle. Only went about 1/4 turn then bound up. I ended up knocking down the major diameter on the barrel. Doubt I'd try that on the lathe spindle, though...

 

[wa5cab]

Most likely. If the chuck had to be usable on the Atlas, you would need tp chase the threads in the back plate. An possibly adjust the register bore. But that would make it unusable on the SB. So best bet is go buy another chuck.

 

[Jason280]

Interesting thing I noticed earlier today with the lathe. I've been going through the gears in the quick change GB (while rotating the spindle by hand), but cannot get the left lever into the "E" detent. I can get it close, but not quite all the way. I've also noticed that with some settings on the QCGB, it becomes difficult enough to rotate the spindle that it causes the belt to slip. Now, I haven't actually tried it under power, wanted to make sure all the bugs were worked out first.

I assume I will probably need to pull the QCGB and check it, anything else I should be looking at?

eta: Also, how do I correctly "size" the belt running from the electric motor to the main pulley? I know the length isn't too much of an issue, but how thick should it be and should I use a cog/notch style or standard V pulley?

 

[jwmay]

. I've also noticed that with some settings on the QCGB, it becomes difficult enough to rotate the spindle that it causes the belt to slip.

There will be different levels of resistance between different settings on the QCGB, depending on how many gears are being used to get that feed rate. But I've already lost confidence to continue with this train of thought. I don't have a gearbox on mine, so maybe that idea is all wet. I do agree that you're gonna have to at least get down and look up in there, to see what's stopping your E selector. Maybe it's just full of chips and gunk. Oil gets pretty hard after a few decades of sitting around. It may just be that. Maybe just spray brake parts cleaner up in there, and see if anything changes. The standard application is one full can according to Mr. Lyle Peterson. My Youtube shop teacher.

should I use a cog/notch style or standard V pulley?

Standard V pulley, or link belt. It's been suggested not to be cheap when selecting the link belt. I've got enough faith in the recommendation to agree. While any brand new V belt of proper size will probably do the job equally well. As I've been putting mine back together, I've already realized that once all the extra hardware is on the headstock, I'm not going to want to take it back apart to get the spindle out and change the v belt. So, I'll more than likely be buying a link belt whenever the need for replacement is apparent.

 

[wa5cab]

The Atlas 10F and Craftsman 12" made prior to 1957 use Fractional Horse Power (FHP) V-belts with part numbers beginning with 4L plus a 3-digit number which is the belt length in tenths of an inch. The single digit before the "L" is the nominal outside belt width in eighths of an inch.

There is no good reason to use a link belt for the motor belt unless you already have enough new and good quality links to make one up. Otherwise, you are just spending more money.

 

[jwmay]

Agreed. I wasn’t paying attention to which belt the OP was asking about. What about the gearbox problem Wa5cab? Any historical problems he should be informed of? Are those gears zamak too?