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Slipping speed control on Jet 1442

3K views 27 replies 7 participants last post by  OSU55 
#1 · (Edited by Moderator)
The lathe at the woodworking school for young people where I teach woodturning in Mexico has a defective speed control. When turning at 750 rpm it suddenly slips into 2,000 or higher. I've tried everything I can think of to get the control to stop slipping but nothing has worked. So I rigged up a temporary fix using a chain to hold it in place. See photo. It now runs at about 750 rpm, but to increase the speed I have to undo a wire holding the chain in place. I was hoping someone could come up with a more practical solution. Any ideas?
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#2 ·
I have the same one. It operated by a reeves drive, which is a system where the lever slides one half the pulley away, widening the distance. This allows the belt to drop to a small diameter thus slowing down the speed.

I would recommend cleaning and lubing the shaft. I believe you can access by removing the belt cover.

If the bore has wobbled out and is binding it needs replacing this is what happened to mine. Its a bit involved but not impossible.
 
#3 · (Edited by Moderator)
Thanks, Robert. I have given up trying to fix the speed control. I started working on it a year ago and nothinig has worked. I want to keep the lever chained to the lathe but want to figure out a less cumbersome way to do that, i.e. without the wire that has to be unwound when I want to raise the speed. Maybe a small clip of some sort?
 
#4 ·
I would figure out what is causing it. You might check the springs that help control the Reeves drive. Maybe they have lost some of their spring or they were replaced with the wrong kind?

If you don't want to fix it, then my idea would be to drill some holes in the front of the casting that you could use some pegs to prevent it from turning past the point you want it set.
 
#5 · (Edited by Moderator)
There should be some kind of locking device there. My old delta had 2 positions on the handle spindle.
It would either lock or or unlock the handle so it could be rotated for speeds.
On that chain setup, looks like you almost have it. It looks like that block of wood with the eye bolt is a weight??? The chain could be cut in such a manner that when cut, looks like a hook. You could do that and end the wire unwinding…......Jerry (in Tucson)
 
#7 ·
Reeves drive lathe I had I believe had a pin that held the lever at each speed. Something has to hold the handle to keep it from rotating (and not some chain or something, waste of time). A method was designed and existed on the machine at one time. The fact that the lathe changes speed as the handle is rotated says the pulleys etc are not the issue. You have been attempting to fix the wrong cause, so I would not have expected you to have been successful.
 
#8 ·
The index pin on the handle will not stay in the hole it is set at. The index pin slips out of the hole and the handle climbs to higher speeds. Very dangerous in a school for young people. I don't know what you mean by "fixing the wrong cause."
 
#9 · (Edited by Moderator)
The index pin on the handle will not stay in the hole it is set at. The index pin slips out of the hole and the handle climbs to higher speeds. Very dangerous in a school for young people. I don t know what you mean by "fixing the wrong cause."

- kmetzger
This is the 1st explanation of the problem provided. Previous post described the effect not the cause, and actually the above does not fully describe the problem.

Apparently the pin is present, the holes the pin fits are not wallowed out (the pin fit properly and if the handle is held in the down position, the speed stays constant). There should be a spring on the other side of the handle pivot strong enough to hold the handle down to keep the pin in position. Sounds like the spring is missing allowing the handle to lift the pin out. Replace the spring. A temporary option is something wedged under the opposite side of the handle to hold the pin in the hole. It needs to be easily removable to allow speed change.

Wedges or chains or whatever "band aids" you end up with are unsafe in a multi user environment of young people.
 
#11 ·
Parts diagram shows a couple of springs behind the speed selection lever, so that is most likely your culprit. I have the smaller JWL1236 which is very similar and the speed lever is indeed spring loaded - you have to pull it out to disengage the hole, move to the desired speed, and then let it snap back. Once it's in it's hole, the spring loaded lever will not disengage until you yank on it again. BTW: I'm not sure if you can do it on the 1442, but there is a mod where you can drill an extra hole and get a lower speed on the 1236… the mechanism looks the same as yours, so you might be able to do the same if desired. Great if you turn a lot of bowls.

Cheers,
Brad
 
#12 ·
Thank you Brad. I found springs for the 1442 at e-replacement parts but there was no indication as to which spring belonged to the speed selector. In any case I am very grateful for the help I am getting here and will check the lathe in the school tomorrow.
 
#15 ·
The springs on the handle are working fine. But the shaft to the handle slips in and out. I don t know how to get into the mechanism to see if there s a way to secure the shaft.

- kmetzger
Have you been able to find a manual for your specific lathe? I dont remember just how that shaft was retained on the reeves drive I had. Could have been a cir-clip or a collar with set screw. You should be able to remove a cover over the pulleys to gain access,
 
#17 ·
The manual shows 2 screws that hold the collar of the speed control assembly to the headstock casting, with the control shaft going thru the casting.

The decal on the collar may be covering the screw heads. That shaft insert into a mechanism that, when twisted, causes one of the spindle mounted pulleys to move along the spindle shaft, changing effective dia of the belt position.

It appears removing the screws will allow the entire speed control assembly to pull out as one piece. The shaft rotates within the collar, but should not move in and out.

Troubleshooting is a process of understanding how something is designed to work, and then determining why it does not perform as designed. Good luck!
 
#20 ·
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The springs are working fine but they don t keep the lever indexed. The shaft to which the level is connected slides in and out. I don t know if that s what it s supposed to do.

- kmetzger
I guess I didnt explicitly state it above- NO. The shaft turns, it should not move in/out. Follow directions above, based on the manual you say you have, to remove the assembly to determine the problem.
 
#24 ·
I removed the screws covered by the decal and it allows me to pull out the entire speed control assembly. The shaft rotates within the collar and moves in and out. The lever does not stay indexed. That's why I've got it chained down.
 
#25 ·
I removed the screws covered by the decal and it allows me to pull out the entire speed control assembly. The shaft rotates within the collar and moves in and out. The lever does not stay indexed. That s why I ve got it chained down.

- kmetzger
Understood. Its called troubleshooting/root cause analysis. The shaft is held in place by some method, either behind or within the collar, or at the end of the shaft where it fits into something to move the pully. Seek and ye shall find the problem and figure out whats broken/missing and correct the problem.

One possible solution, if you are unable to determine the actual cause and fix it, is a shaft collar with a set screw up against the control hub to keep the shaft from moving in/out. This distance hand holding is an interesting methodology.
 
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