SB 9a gearbox issue

Rd2nowr

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Jan 22, 2017
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This is about to drive me crazy! I don't know what else to do but ask. I just rebuilt my 1937 SB 9a and while everything looks good and it runs very well, I'm having problems with the gear box selector. This is the old single lever with the 3 position top lever style. I very carefully took the gears out, keeping them placed in the correct order, per the instructions, cleaned, de-burred with a needle file, oiled, and re-installed. The gears will spin on the left most position, but not when the top lever is in the center or the right position. What am I doing wrong? I'm trying to cut the inside threads for a spindle thread protector, but even when the back gears are engaged, I have to "help" the chuck to get it to rotate.
Thanks in advance,
Tim
 
How is the shaft held in place? I just had this issue with a dual-lever SB9 gearbox - the tapered pin on the intermediate shaft had been messed up and was causing the shaft to bind - made an abominable mess.

Were it me I'd think about pulling the gearbox and checking the individual shafts and the idler gear in the lever - if the bearing is going bad in that it could lead to binding/nastiness as you describe

Al
 
How is the shaft held in place? I just had this issue with a dual-lever SB9 gearbox - the tapered pin on the intermediate shaft had been messed up and was causing the shaft to bind - made an abominable mess.

Were it me I'd think about pulling the gearbox and checking the individual shafts and the idler gear in the lever - if the bearing is going bad in that it could lead to binding/nastiness as you describe

Al
Thanks, AL. I just pulled the gearbox apart again and checked everything. There was some burrs on one of the gears. Everything works as it's supposed two now.
Tim
 
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