I guess that it could very well be unfinished...it just seemed odd that the convex "pimple" on the end was perfectly rounded like it was done so intentionally for a function. Also, it seems that further machining of the end would create a flat surface too narrow for a SAT blade unless they shortened the shaft considerably more than any SAT I currently own. Actually having an error/unfinished screwdriver, if that is the case, seems kind of neat to me too.I'm no expert but to me it just looks like an unfinished screwdriver. The taper is to get the tip to the right size before grinding the flats (which obviously) was never done. Look how all your other screwdrivers have that same taper as you move toward the tip. I'm not sure how the taper was created but I think the pimple is just left over metal from the machining, not something that had a purpose. Again, no expert, but that's my guess. You might have to get hold of S&W to confirm what exactly that is.
Seth,
Is the "pimple" of proper dimensions to engage a roll pin? I don't know what S&W would have used a roll pin for, but that came to mind when you mentioned the bump. You already have the correct procedure in progress though, ask Roy!Please be sure to let us know what he says... curious minds...
Froggie
Seth
Unless you speak with a long time employee at Smith & Wesson, you may be disapointed in their answer. Remember screwdrivers were discontinued some 20 years ago. They may not be aware that screwdrivers were included with guns. Anyway here are some of my Smith & Wesson screwdrivers
I called Customer Service to speak with a friend that worked in that department. My call was answered by a young lady. After she told me what I wanted to know, I thought I'd have a little fun. I asked her if they had any grip screws left for the Revolving Rifles. She told me that they had sold the rifle and shotgun lines to Mossburg. I told her it was from a rifle that they made back in the 1870's. She said,"Oh, were we in business back then". I thanked her for her time and hung up. So, good luck calling them. By the way, I thought about your trade proposal, No thanks.