Atlas 12-36 Headstock Question

ChuckB

ChuckB

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I have disassembled my headstock of my Atlas 12-36, Model 3986, in an attempt to get rid of some play/noise in the headstock. Most of the play is from the two holes in the spindle pulley that the back gear lock pin slides in. Both of those holes are wallered out oval shaped.

Here is what I am wondering about. On the spindle shaft there is a deep indent where the back gear allen screw makes contact and secures the gear. Should it be there? It seems like the back gear should be a little more to the left, but when I slide it to the left and tighten down the allen screw it forces the gear to go back to the right. Is this normal? Thanks.


IMG_1259.jpg
 
I was thinking of filling it in with a weld and then grinding down.. gotta get this together before I can work on the South Bend. Thanks
 
If you had a Longer set screw, you could mill (As little as possible) a flat spot in the shaft so the back gear could Line up with that gear
 
Thanks everyone for the help. I think I'm going to abandon the welding idea and and elongate it with a dremal.
 
Chuck, just a reminder, just one single speck of grinding grit in that bearing will ruin it. A flat rather than a divot is preferred. A recessed flat is better yet. Look at the recessed flat on a HHS end mill shank.

Also, I suspect from the looks of the divot, that an incorrect set screw has been used. If it were mine, I'd replace the one in use with either a "flat point" or a "cup point" (actual mfg. designations). If I had my druthers, "cup point" cause they tend to resist skating.
Might even get a cup point first, mark-up the shaft with a Sharpy and see where the cup point hits with the gear properly positioned. May not have to grind at all but even so, seeing the actual contact point will keep grinding of filing to a minimum.
 
Ended hitting it with the mig for about 2 seconds. Put in the freeze ahead of time so it was ice cold. Carefully filed it smooth. Didn't want to pound the spindle in so I used a piece of all thread along with washers and spacers and slowly pressed it in.. the left Timken was very tight.. then I had to do it over.. I forgot the belt! Anyway got rid of the side play and the clanking noise.
 
Another source of wear or movement in the headstock spindle pulley (assuming that the spindle bearings are properly pre-loaded and have no play) is wear on the three steel-backed pulley bushings.
 
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