Changing Gears

[Gilrock]

Ok I must be doing something wrong. I have the Jet 9x20 metal lathe. I've really wanted to learn how to thread using the lathe but both times I've changed out gears I've managed to break the retaining rings. They seem like cast iron and are really easy to break. Am I supposed to unthread the post that it sits under to get them back into place? The second time I thought I had it in position and it cracked and fell off when I turned the lathe on. Now I'm unable to use the auto-feed until I get them fixed. I would like to find something made with a better piece of metal. If I had a mill I'd do it myself. The replacements I found online were around $9 apiece. Kinda expensive for a cheap washer that breaks when you breathe on it.

 

[randyrls]

Gil; Lets see if the gang here can get you started.
You are talking about the change gears in the gear train driving the lead screw, correct? "Retaining Rings"? Are you talking about "e-clips"? These look like a hippy letter "E". And yes, they are not intended to be put on and taken off very often.

If the retaining ring looks like a letter "U", the clip should not break. It is under no stress at all. It's only purpose is to keep the gear bushings from sliding sideways on their shafts.

I found the manual for the Jet 9x20 online. Do you have the 9x20 N, or W model? These are very similar to but not exactly like other 9x20 class lathes sold by Grizzly, HF, and everybody else.
http://content.wmhtoolgroup.com/manuals/321376_man.pdf

I'm just trying to get my head around what the problem is...

 

[Gilrock]

Yeah its the one that holds the gear from sliding off. I'm not at home to double check which model I have but it looks like the one in that manual and I was looking at the manual yesterday and I'm pretty sure it was the same manual. I had identified the part as Item #8 on the page where the gears are shown.
8 .............. BD920N-2006..........Washer

It didn't seem to want to slide back into place without trying to tap it with something which I found doesn't work cause they are way too brittle.

 

[randyrls]

I had identified the part as Item #8 on the page where the gears are shown.
8 .............. BD920N-2006..........Washer

It didn't seem to want to slide back into place without trying to tap it with something which I found doesn't work cause they are way too brittle.

Gil; OK; So this part looks like a "U" with a grove cut into it? The groove faces out. The part should just slip into the square headed slot on the end of the shaft. These lathes are made to average, but not great, standards. Jet has good tech support so you may want to call them.

There *may* be two shafts where that part is used.
1. The 'a' gear above the banjo.
2. The banjo 120 and 127 gear shaft.
This is one of those situations where the lathes are different between distributors.
(On my Grizzly G4000, the 'a' gear didn't have the 'U' shaped washer, but I fixed that.)

You should not need to turn the shaft to change the gears, just slide the (#8) washer upward to free it and slide the gears on and off.

I would check to see if the bushing/keyway (part #15) is shorter than the gear dimensions. The two gears on the bushing /w keyway should have a sliding press fit. You may also want to back out the shaft a bit to make more space on the shaft. Caution: Some lathes have a set (grub) screw that locks the 'a' gear shaft in position. The set screw hole is in the edge of the headstock casting. You must back off this set screw before turning the shaft or you will strip the threads on the shaft. AND the set screw isn't shown on the parts lists!

I hope this helps. Work cautiously and think things thru before proceeding.

 

[Gilrock]

Yeah I broke the one that held the gears on the shaft that runs the feed screw several weeks ago. The gear was held in place so tight that I ran without the washer. Then when I went to change out the gear on the upper shaft I broke that washer also. So yep it's used in two places and I broke both of them...lol. They weren't sliding back into place without applying force to the back of the washer. They seemed to be about as strong as a Graham cracker.