Re-tapping holes.

[riseandrun]

Hi everybody,
I'm working on fixing up an old blue 150. The paint on it is in pretty good shape, and I'm guessing it hasn't had a lot of use except... where the shell attaches to the motor top and bottom there are some "worn out" holes..I had to tap them out to 1/4X20. I now wish I had more experience because I would have tapped them to 1/4X28 for the finer thread/ better holding right? I put lock washers and big regular washers just to cover the worn out area's. The question is how do the pro's fix this kind of problem? Is there a minnie heli-coil type of repair plug? The metal is so soft I'm thinking about using teflon tape if it wont melt just to tighten up the treads.
Any advise appreciated.
KW
pics to follow....

[sweepleader]

I think that 1/4-20 is too big for a Helicoil, unless you are talking about putting in that size bolt. Then a 1/4-20 Helicoil would be fine. Of course you need to make the hole even bigger to get the Helicoil in. If you are trying to return to the original screws, there is an insert available that is solid steel with threads inside and out. I think the original is 12-24 if you are talking about the fan/flywheel/ starter housing screws. That is a tough size to match as it is not used much anymore. I did a quick search on line for "thread repair insert" and didn't find anything right away. If it was my own saw I might keep looking. Teflon tape is lubricant and it flows under pressure, that would not tighten the threads for more than a few minutes and then you could never get it out of the hole. You might try JB weld in a very clean hole with a lightly oiled bolt just sitting in with no tension. I have done that on other things in the past and got passable results. Never tried it on a hot, oily, vibrating saw. Good luck, let us know how it comes out.

[sawnami]

Mechanicstoolsandbits.com has an extensive selection of Timeserts. Timeserts make the repair better than new. We use them exclusively at work for all thread repairs with no failures. Having drilled the holes oversize already may pose a problem though.

www.mechanicstoolsandbits.com/machine-thread-kits-time-sert-0124-inch-thread-repair-kit-p-33.html

[riseandrun]

Here's a few pictures of my blue 150. The decals and paint are in pretty good condition.. I just need to get a sprocket to be complete. I think I need the correct gas cap too because this one is leaking.



Here's a close up of the "repair". I used big washers and lock washers to hold the top. I haven't done anything to the bottom yet.

[

The bottom: This is what happens when it idles roughly on concrete? One of the case screws is almost sanded in half. Too bad because the rest of this saw is clean. The two bottom holes are yet to be "redone". I think I'm going to look into the inserts to give them a try.



The saw started really good, and runs smooth and strong. I'm going to use it as a beater...why not?

Thanks for the replies guys.