MTFCA Forum

Tried to adjust my magneto horn, barely put any pressure on the stuck nut and the brass bolt snapped right in half. The lower half of the bolt is still in there. How difficult is this gonna be to fix? Is there an easy way to replace the bolt or should I get to soldering?

Haven't repaired a magneto horn before, but others have.

Took this photo off the web, and it shows the mag horn with its pieces apart.

That brass bolt perhaps is part of the piece that drives the diaphragm. Maybe the photo helps.

This is what the my mag horn nut looks like. It crimps into the diaphragm. I don't have the screw and 1/4-28 won't go all the way through. It might be extra fine.

Maybe it's 14-24 bolt. Try a bendix cover screw or old brass magnet clamp screw if you happen to have one lying round.

I found the screw. 1/4-32. I was in error when I measured the thread. The OD was .240 and I mistook it for #12 and got the thread count wrong. I'm confident it is 1/4-32. I will inform Martynn Vowell.

Yikes. Where am I gonna find a 1/4-32 bolt/screw?

John Regan may know, he's still serving the model community as JRC Products, LLC. piewagon(at)gmail(dot)com jb

The Vowell Art mag horn diagram shows 1/4-32 x 1 1/4 " long center bolt. app.php/gallery/image/2257

McMaster-Carr
https://www.mcmaster.com/screws/thread-size~1-4-32/
They may have a minumum order.
Rich

PaladinBirdy,
Finally checked my messages.
Sent you a reply. I still have what you need.
Jim