Thinking of custom horn/driver adapter - must be non-ferrous? Already available?

[Goldenvoice]

Hey, new guy here with my first set of questions. I have a set of PA speakers needing a horn driver update/upgrade, and I'm leaning toward 2425J, possibly with radian diaphragms. The cabs were Fender branded, and built by Panasonic in Japan; 2-way 12".

The horns resemble (if only slightly) baby-cheeks. The rear of the horn is female-thread, but instead of the 'industry standard' 1 3/8", it's 1 1/4".

So, I'll need to get creative in my own shop, or hire a local machinist.
? Does the material need to be non-ferrous? (non-magnetic?).

I'm thinking flat 3-bolt flange, with the necessary 1-1/4" male nipple...
? Does anyone already offer such an adapter?


Any other thoughts before I take the plunge?

[Don Mascali]

Welcome to the Forum.

Take a look here;
http://www.parts-express.com/speakers.cfm There are some adapters in the Horns and Drivers section.

[Goldenvoice]

Thanks Don.

I don't see anything that hits the 1-1/4", so I'll plan on visiting local machinists. I also came to realize if I purchase 2426 units with the included adapter, the machinist will have a choice about how to go about making the fit.

[John W]

You might try visiting the plumbing dept of your local box store to see if your threads match a standard pipe size. They may have a flange or something that could be re-purposed easier than starting from scratch.

[Goldenvoice]

And I correct in thinking the adapter I construct needs to be non-magnetic?

[toddalin]

I've been using two machinists for my current project; producing custom alternator brackets for 1955-1969 Chevys with headers and no accessory bolt holes.

One does CNC/plasma cutting and the other does aluminum milling. Both are very hungry and eager for work (= not much $$$ and fast turnaround).

As an example, I am having 1/4" steel brackets turned out at $12 each in lots of 20 (was only $25 for the prototype) and billet aluminum spacers also at just $12 each in a lots of 10 with no setup fees. There is no minimum. A singleton of a new design, with set-up, would be ~$25.

I'm in So Cal (Orange County). If you are in the area, I would be happy to share my sources.