Shifter threads

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Murray

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Just got my shifter handle and mechanism back from Passon. Stick was rechromed. The chrome shop screwed up the threads so that now they are 'less' than the 3/8" fine thread they should be, but larger than 5/16". They now are "mystery" threads. Now stock knobs will not thread on. I need a suggestion on how to repair the threads without damaging the new chrome. This is a very rare stick- '68 cuda 4-sp with console, so must find a way to repair this one. My only idea is to build up with epoxy and then re-tap back to 3/8" NF. Got any other idea's? Help!
 
Call Passon and ask them what they can do for you. If the threads worked before you sent it out they should work when you get it back. I'm sure the rechroming wasn't cheap, but that how some business roll they just don't seem to give two sh*ts about what goes out there door.
 
Passon did offer to take back to chrome for repair. I don't blame Passon for anything, just thought it would be simpler for me to repair than wait another six months for them to do it. Otherwise stick looks good. I got $500 into it.
 
Passon has always been good to me. I wasn’t blaming them but they picked the shop to use It should have never been sent out if it wasn’t right and they should get it fixed. if you mess with it and can’t fix it then the shop is not going to do anything to make it right
How about some pictures so it easier to understand what the problem is
 
Send it back. There is next to no one in the US doing real chrome plating. It likely went across the boarder. I had my bumpers replanted and one of them was pealing chrome the day it showed up. It had to go back.
 
The way the threads are now- 3/8"NF die will chase extremely loose, too loose to 'bite' and tighten, will spin free. A 5/16" die will not start- the shaft diameter is too large. Metric doesn't seem to work either, thats why I refer to it as 'mystery' threads. The bolt in the photo is 3/8"NF.
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You are saying that the chrome plating made the threads smaller? I don't see how that's possible. Typically they get a few .0001" bigger from the plating. Still should be well within tolerances for SAE threads like that.

What does the O.D. measure?
 
You are saying that the chrome plating made the threads smaller? I don't see how that's possible. Typically they get a few .0001" bigger from the plating. Still should be well within tolerances for SAE threads like that.

What does the O.D. measure?
I have had this happen before with chrome platers.....the handle got left in the tank too long when the chrome was stripped. I have repaired lots of damaged threads by machining the handle down, then drilling a 3/8 -24 bolt out and pressing it on like a reverse heli-coil. Tig weld the end to keep it from coming loose. Have always done this before chrome though...
 
I would fill the ball with the stuff (looks like molding clay looking material) that is sold that is totally machinable, can be drilled and taped. Why deal with the handle?? I guess the threads on your shifter now measure a metric size ?? what ever metric size is between the 5/16 and 3/8..
 
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Appreciate everyones input. Yes threads are now smaller because the chrome shop chased them incorrectly. Provided new photo if that helps. 3/8"NF OD is .370 while the current OD on shaft is .330. The difference is small but important. My original idea of epoxy to make up the difference I thought could work if I could find a release agent to first coat the threads of the knob, fill it with epoxy and let it harden on the stick, then unscrew it after hardening. The trouble with that idea is that I don't know of any release agent. Maybe someone out there knows how to do this. Or maybe I'm completely wrong. Help!
 
If you have the correct material, you can fill the ball and drill and tap it just like if it were steel. I am also NOT a metric guy, but I bet .330 is darn close to a metric size Bet that is how they boogered your threads anyway! If I was a computer guy I would find it for you, but I am not!
Persevere!
 
You can't go to any metric size. Because: A) .330" is 8.38mm. No such thing. B) The thread pitch on metric threads does not match up to SAE threads. M1.0 is = 25.4 threads/in., M1.5 is = 16.9 threads/in. So even if the size was right, it would never screw together.
 
I got nottin'. But if I was the OP I'd be PISSED. Actually that difference is NOT small considering the size of the piece.

"Back then" I had a stripped shifter. I just "JB welded" the ball on and forgot about it. Not real handy if you need to change the boot!!
 
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