Crazy Threads...

[Tozguy]

I would think that defining the problem as specifically as possible would help determine if we need a closer look at the primary drive or the gear box and what part of the gear box.

Yes, testing each of the A,B,C and X, Y, Z settings in the gear box for inch threads would be a helpful at this point.
The numbered settings 1,4 and 5 seem to work so for now we can expect that the problem is not at that level.

Regardless, there is also a lot to be said for opening up the gear box just to see if all is clean and tight. I opened up the spindle drive gear box just out of curiosity and was glad I did. There was a screw holding a key in place that had worked loose. It was just a thread or two from falling out. The idea of a screw falling into spinning gears does not please me. A catastrophe was avoided but it was also good to learn how sloppy the gear shifting mechanism is and to see how gear alignment was more or less complete depending on how I worked the lever.

 

[Hukshawn]

Take a break from this for a few days. I work all weekend and have some woodworking prototypes to do in the evening. I'll see if I can find the time to run the tests and if no avail, pull the gear box off. I'll try to document my travels.

 

[RJSakowski]

The lathe was made by Mysore Kirloskar manufactured in Yantrapur, Harihar, India . They ceased business in 2003.

 

[brino]

Regardless, there is also a lot to be said for opening up the gear box just to see if all is clean and tight.

While there, I would also carefully count and then re-count the number of teeth on each gear in the gear box.

Yes it can be awkward holding a mirror and a flashlight and a pencil while standing on your head, but only by knowing exactly what's in there can you make 100% sense of what's going on and where the problem is. The "easy" stuff has already been ruled out.....that just leaves the rest! I did mine that way from below by putting a paint dot on one tooth and turning the gear-box input shaft by hand and carefully counting each tooth.

I made spreadsheets of all gear for my last two lathes, and it was a great exercise in completely understanding it. Now I know exactly what to do if I need to cut some goofy thread that's not even on the lathe charts.

Since we suspect a previous owner swapped the lead-screw from metric to inch, but did NOT swap the thread-dial gear who knows what other surprises are in there.

-brino

 

[Hukshawn]

So, I did not run every single pitch, I don't have that much bar stock and I'm running it by hand to keep the noise down.
However, I made sure I ran a thread from each gear cluster combination. all metric threads are correct, all inch threads are wrong... I'm going to pull the gear box...

 

[Hukshawn]

Here we go...
First roadblock... can't get the wick pan out...

 

[Hukshawn]

I just noticed there appears to be set screws and an adjustment block for the gear box... the two change gears ate already adjustable... why would the gear box need adjustment screws?

 

[Hukshawn]

Never mind about the adjustable gear box...

 

[Hukshawn]

So I found the backlash in the lead screw. I was right before, it's a union. there's two of them. I assume there is "backlash" so the gears have room to mesh.

 

[Hukshawn]

I would think that defining the problem as specifically as possible would help determine if we need a closer look at the primary drive or the gear box and what part of the gear box.

Yes, testing each of the A,B,C and X, Y, Z settings in the gear box for inch threads would be a helpful at this point.
The numbered settings 1,4 and 5 seem to work so for now we can expect that the problem is not at that level.

Regardless, there is also a lot to be said for opening up the gear box just to see if all is clean and tight. I opened up the spindle drive gear box just out of curiosity and was glad I did. There was a screw holding a key in place that had worked loose. It was just a thread or two from falling out. The idea of a screw falling into spinning gears does not please me. A catastrophe was avoided but it was also good to learn how sloppy the gear shifting mechanism is and to see how gear alignment was more or less complete depending on how I worked the lever.

Ok tozguy, I need you to tell me what you want to see... I cannot see anything wrong in here and I have no idea what I'm looking for