New 101-28910 owner qcgbox confusion.

[carlbob]

I might not be understanding the manual for my lathe. I tried to cut a 16 tpi today and it made threads for sure, but they were a very fine thread. The slip gear was in the outboard position and handle B was in the hole according to the threading chart on the machine. I switched the slip gear to the inboard position and woohoo it cut 16 tpi What the heck am I doing wrong??
Any help with my confusion would be appreciated. Thanks in advance...
I"m a newbie to running lathes but I'm having a blast doing this in my retirement years. This is my 2nd craftsman lathe the first being a small 6" swing 101 07403 It was rough as well, but did the same to it as I did to my current lathe and sold it for a small profit. I learned a great deal from tearing that one down and redoing her. My current lathe is a 101-28910 a 12x36 that was in pretty good shape when I purchased her but a lot of dirt and rust. Took most everything apart, cleaned, oiled and gave her a nice coat of fresh paint. It's looking broke in now, as I have some scratches and oil stains in the paint job. I'm keeping this lathe since I've got it running as close to new as I can. I'm a machinist by trade name only, we were parts changers now a days on the railroad.

 

[mmcmdl]

I switched the slip gear to the inboard position and woohoo it cut 16 tpi What the heck am I doing wrong??

You're not doing anything wrong , maybe other than mis-reading your chart . You made the thread you wanted .

 

[wa5cab]

Take and attach to your next post two photographs. First should be a closeup showing the front of the QCGB with the box levers set to 16 TPI. For the second, open the gear cover on the left end of the lathe. Position the 40T Slide or Sliding Gear OUT and lift and lock the Banjo (AKA Change Gear Bracket) so that the Sliding Gear is engaged with the 16T/32T compound gear that is mounted at the pivot point of the tumbler. Position the camera over whatever that is under the blue tarp so that it clearly shows all of the gears mounted on the Banjo. In the text say what thread the machine actually cuts when set per the photo.

 

[carlbob]

So here is a few pics of the gear train and the handle postion it was set on. I can't find the piece of stock it was cutting those fine threads on, and it's to cold in the garage to turn those threads today. Hope the pictures help.

 

[Rooster]

Greetings, if you look at the chart, when your in row B, the far right position will cut 30 tpi, the far left will cut 16 tpi.

 

[carlbob]

Thanks for the info from y'all, but I figured out my mistake. I did not move the feed rate handle on the right side of the qcgb to the matching down column for the 16 tpi I wanted to cut. Oops. Beginners mistake I guess.

 

[wa5cab]

Right. And another case of a photo being worth a bunch of words. And with the sliding gear IN, you were actually cutting 15 TPI.

On another subject, you badly need some grease on those gears. And some SAE 20 ND oil on all of the bushings.

 

[markba633csi]

Yes, you should have some lubrication on the gear train, it will reduce the wear and noise. Keep an eye on the two tumbler gears just below the spindle. The shafts they ride on can sometimes begin to loosen and the thin hex nuts behind the arm fall off and get lost- consider a tiny bit of removable Loctite (242 or similar) on those
Nice lathe, I have the bench model but still setting it up
Mark

 

[carlbob]

Thanks y’all. I use 90 weight gear oil on all exposed gears and 20 weight nd oil on all the oiling locations. They were cleaned and dried for the pictures to make things easier to see.
This is a great site full of info and a forum for us atlas/craftsman lathe owners. Woohoo. I know it’s not a monarch lathe but mine isn’t making space shuttle parts and didn’t cost as much either.

 

[wa5cab]

OK on cleaned up for church.

But SAE 90 isn't really satisfactory for open gears. It will sling off in just a few minutes. It works fine in gearboxes and axles where there is a sump or a pump and reservoir but not on an Atlas lathe, mill or shaper.