Jet Mini-Lathe motor woes

[Jeff Myers]

Hi All,
First let me admit i know absolutely nothing about electrical motors.
With that out of the way...
Last week I had the Beall buffing wheels mounted on my mini lathe and had been running it about 2-2.5 hours continous trying to polish things for an upcoming show(big success btw) when i heard something a little off with the motor,,,turned it off and noticed the belt had a twist in it, since i'd been buffing, it must've gotten the twist a while back when turning and had a nice catch is my only guess... either way, the tension was very tight and when i straightened it out and powered back on,,,only getting about 10% power to the spindle and after 5 seconds that drops noticibly, probably in half. It wasn't over heated cuz i cooled it and same problem.
My question is, can the capacitor attached to the motor be at fault or
do you think the motor got burned up? I opened the cover to the capacitor hoping to see it obviously fried but it doesn't show any signs
that it burnt in any way on the outside.
Has anyone else had this happen?
Can i check the capacitor with a meter or something to see if it's the culprit? Can i bypass the capacitor and check the motor somehow to see
if it's the problem? .....be easy on me, i told ya i knew nothing about motors. :o

[Ken Fitzgerald]

Jeff.........I went to the Jet site and looked at the manual for your lathe. They really don't give an electrical schematic. That makes helping you a little tougher. Most motors have a centrifugal switch. When you turn on the motor, the switch puts the starting capacitor in the circuit to start the motor turning in the right direction. Once the motor gets up to proper speed, the centrifugal switch opens up it's contacts and the starting capacitor is removed from the circuit. The first thing I'd try is taking an air compressor and blowing out around the motor. Dust and wood chips can get into the centrifugal switch and cause some really strange symptoms. If that doesn't help........without a schematic, it's hard to help but you might remove the motor and take it to a motor shop for analysis. Based on the symptoms you relate, it sounds like possibly a burned motor. I'd try cleaning/blowing out the centrifugal switch first, however.

[Lee DeRaud]

Ok, random thoughts in no particular order...
1. A twist in a Jet Mini belt?!? I can't for the life of me think of how that could happen, but I wouldn't expect it to work that way. For that matter, I wouldn't expect the belt to be any good after running that way for more than a few seconds.
2. I was under the impression that the capacitor was only there to get the motor started...oh, I see Ken has confirmed that.
3. When you say "10% power to the spindle", do you mean the motor has no torque (bogs down easily) or just doesn't come up to speed? Try removing all tension from the belt and turning on the motor...does it come up to full speed?

The idea here is to eliminate the belt as the problem...got a feeling you're in the market for a new one regardless.

[Jeff Myers]

Thanks for the replies.
Ken, that motor is sealed up tight as a tick, i removed the cover from the fan and there was a few shavings but nothing that would impeed the fan. The fan just seems to cool the end of the motor which is a solid plate. Doesn't have any holes to speak of that dust could get in. Never seen
a motor so protected.
Lee, the 10% was referencing what appeared to be the speed it should be turning, and there is absolutely no torque,,,i can place my hand on the buffing wheel and stop it immediately. I removed the tension from the belt and let the motor spin freely and same problem exists,,,will not spin up to speed , only gets going about 10% what it should be and then in a couple seconds, it drops down even slower,,,never stops completely but sure won't spin up to speed.
The belt actually "looks" fine as odd as that seems. I have no idea how
it twisted either, it was in the proper groove on the pulley as compared to
the other pulley but had a half twist.
Well I ordered the capacitor since it seems simple enough to replace and
is worth the $17 to the door cost before i drop $150 for new motor.
If it turns out the motor needs replacing,,,I believe i'm going to get creative and pull a Tim Allen and mount a 1hp motor i have access to, on the stand below the lathe to power this thing,,,bring on the purple heart
stock!! :rolleyes:

[Jim Underwood]

Good call on the capacitor. I've fried one before, they do go out from time to time. They are actually a "start/run" capacitor as they are hooked into the windings 100% of the time. Using an aftermarket "run" capacitor will only net you another fried capacitor. Don't ask me how I know this.

And yes the motor is just about bullet proof. After I fried the capacitor the first time, I took the motor apart looking for the centrifugal switch that is usually in a motor with a "run" capacitor. All I found was a solid state armature, bearings, field windings and case. No brushes, no switches, no windings on the armature. There's virtually nothing to go wrong inside these motors and if the bearings go bad, you can buy a set for around $12 from your local bearing supplier.

And don't order a capacitor from Jet online. Call them to order because the shipping on an online order will cost you $20 minimum for a $12 part that is smaller than my cell phone.

[Frank Fusco]

Just a personal observation: In this and other woodturning/working forums, I believe that Jet Mini Lathe 'woes' is the most frequently posted single subject.

[Frank Guerin]

Belt twisted. Put back to normal. Belt now slipping?

[Randy Meijer]

Just a personal observation: In this and other woodturning/working forums, I believe that Jet Mini Lathe 'woes' is the most frequently posted single subject.

Maybe it is because more people own Jet Mini lathes than other brands??

[Lee DeRaud]

Maybe it is because more people own Jet Mini lathes than other brands??Not only more people overall, but many more people new to turning. (raises hand)

[Barry Stratton]

Not only more people overall, but many more people new to turning. (raises hand)

...and if there are many more out there like me, there are a whole bunch of Jet Mini's getting terribly abused way above and beyond the machine tolerances.......:D Whats that high pitched whine??? Oh, the lathe isn't spinning anymore....Huh. Is that gouge supposed to be stuck??? Huh, that must be what they call a "catch". Anyone smell smoke?????:confused:

[Lee DeRaud]

.Whats that high pitched whine???Don't worry about it, it's probably just Tyler.:D :p

[Jeff Myers]

HooWaahh!!! It was just the capacitor folks, motor is running strong
again. Something for other Jet mini owners to try before they opt to replace the motor if they run into this problem in the future. Saved
me about $150 for a new motor if i had to order one!(...now where's
that tool catalog! :rolleyes: )

[Jim Underwood]

I think that the Jet Mini is probably one of the better mini's out there. Like I said before; I've had the motor apart and it's just about bullet proof. There's hardly anything to go wrong with it.

I believe the trouble I had with the capacitor was that it was an older model and had a lot of miles on it. Capacitor had seen its better days. This was a "loaner" that a friend let me use so I could finish up a job making some handles for a guy.

I liked the Jet machine so much I went out and bought one for myself.

The only consistent problem (besides the capacitor) with the Jet is that the tailstock creeps a little and the tool rest breaks a little too easily. Then again, everyone and their dog owns one, especially Newbies such as myself, and they do get abused! Don't ask me how I know this....

I think if I were to make accessories for the Jet mini, and began to advertise I could make some money on it....

[Chuck Nickerson]

The stock under-the-bed piece is round; LV sells one that's square, giving a greater contact surface. (Although my degree is in math, I'm too old to calculate the increased contact surface.)

[Brett Baldwin]

Chuck, the number would be 21.5% more surface area, almost all of which you'll see because most of the missing area would be under the bed and not in the slot inbetween.

What about cutting a piece of flat stock to size and drilling the proper size hole. Maybe rough up the contact surface for better grip?

[Randy Meijer]

.....LV sells one that's square, giving a greater contact surface.....

Could post a link to the item or post the stock number so I can look at it?

LV used to sell a "clamp block" that allowed one to add a
steady-rest to your lathe. Its configuration fit the JET mini rails; but the threaded hole is not compatable with the threads on the locking mechanism of the Jet tail stock. The clamp block is a lot thicker than the OEM clamping disk so I'm afraid you would run out of thread if you just drilled out the clamp block and used the original nyloc nut.

[Randy Meijer]

.....What about cutting a piece of flat stock to size and drilling the proper size hole. Maybe rough up the contact surface for better grip?

Brett: I had the same idea and even purchased a piece of steel stock from HD for the project. This was more a preventive thing since my TS doesn't slip any more. I took about half a turn on the adjusting nut and the problen has gone away.

BTW, there were a couple of people, here or at IAP who use to make a clamp block for the Jet mini with a hole threaded to match the Jet threading. They were asking somewhere around $25. I don't remember who it was and don't know if they are still available. It was a nice little item.....milled out of a single piece of steel.