The socket cap heads that fasten the foot peg mounting brackets to the frame are, 3/8-16 x 1-1/8" long. However, they are not threading in correctly. I bought this bike used and tried all the socket cap bolts I have from previous projects and the ones that came with he mid controls. It's like they start to thread in but then stop. I sprayed with WD40, cleaned the holes out, cleaned the bolts off. No go. I'm not going to force it as I don't want to strip anything. What would the next, smallest bit size down from the stock socket head cap screw? Maybe a slightly smaller thread size, diameter, etc would thread in there. The previous owner may have done something funky to those two mounting holes in the bracket on the frame. It doesn't appear to be stripped. Need some help to get these mid controls monthed safely and securely. Any help would be appreciated. Of course the left side went on with no problems....

Thanks, BK

 

How about running a 3/8-16 tap in there?

 

Preferably a thread chaser if you can get your hands on a set. It's worth the investment if you work on older vehicles. Taps will work if your careful but it can be a bit risky.

 

What's the difference?

 

I ordered both, thread tapper and thread chaser. Should I start with the thread chaser? Go by hand, power drill, or impact wrench?? I really don't want to make the situation worse. I've never used thread chaser or thread tapper before.

 

Thread chasers are designed reshape damaged threads and taps are designed to cut new threads. Start with the thread chaser and do it by hand slowly. Unless the thread is really bad it should do the trick. Taps will work but because they are designed to cut they will remove some metal. Your dealing with steel so its not as bad as with a softer metal like aluminum but what can happen with a tap is the threads become thin and you end up with a weaker/looser engagement between the bolt threads and whatever your threading it into. Or in a worst case the threads get hacked up all together.

 

I answered my own question, LOL

 

I figured you might have by now.

 

Thread chasers and thread taps are totally different tools, a thread chaser is a single tool which is used for re-dressing an existing thread. As you can see in the image below, the threads don't go to the end of the tool, so it is better for through holes rather than the blind holes which you are dealing with.



Thread taps normally come in sets of three, they are used for creating a brand new thread, see the image below. For your purpose of redressing blind threaded holes, a number 3 or "bottoming" tap is the one to use as the threads go to the very end , A the threads on a number 3 tap will reach to the bottom of the threaded holes.


I would recommend you using a "bottoming" tap for your purpose.

 

I have never seen a thread chaser look like that. The ones I own and all the others I have encounderd have threads all the way down. Interesting. Maybe there are bottoming and non-bottoming thread chasers as well?