Packard Forum Index » Pre-War (1899-1942)

Hello everyone,

I am back to query the fountain of knowledge that is this website. I had a welder fill a couple of holes in my Sparton SOS horn many years ago. This is the big horn with the bullet nose back that was used on the senior cars in the late 20's. Someone had drilled a couple of extra holes to accomodate a non-standard mounting bracket. Unbeknownst to me, the welder did not disassemble the horn before welding it, and long story short...he welded the vibration plate to the steel backing plate. I carefully ground the two plates apart, but of course damaged the wafer thin vibration plate. The horn still emits sound, but I wonder if it is correct. Is anyone aware of who may have an old Sparton SOS, or a broker of old horn parts who I may buy this one part from? Any help would be greatly appreciated.

Hmm......thought-provoking. I wonder if that's a niche for service/parts that's never attracted a dedicated specialist? I'd think the diaphragm is either a special alloy and/or has some special heat-treatment. In any case I've made a few queries on your behalf and if I hear anything useful I'll let you know.

Dave

UPDATE: I've scouted around and have not been able to identify anyone who specializes in Sparton horn service or parts; they are so trouble-free and long-lived there probably just isn't a demand. I think your best bet is going to be to locate a replacement unit to use or cannibalize for parts.

Much Thanks Dave. I am beginning to feel like it takes a village to restore a Packard, with all the help I have received from this website! The original was blued and had some sort of coating on the forward facing surface which oddly resembled 85 years of accumulated engine oil and dirt.

If it is blue, I wonder if it might be ordinary blue tempered spring steel and if common shim stock would work as a replacement. That material is magnetic, extremely strong and used for those kind of applications in other things that need to be both a spring and support.

Thickness would be important to get the right note. McMaster carries individual sheets in the low thousandths if they have something close in thickness to yours. Other places carry thinner but quantity sold is in larger sheets or rolls.

Most horns -- postwar at least --have an adjustment where you can fine tune the frequency. If no other horn is found and able to give its guts or nothing else comes up, McMaster might be worth a try. MSC might also carry similar.

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Hi Howard,

Thanks for the suggestion. I am not a metallurgist, but this thing has the look and feel of very thin spring steel to my uneducated eyes. The problem is it has a sinusoidal curve in it similar to the circles emanating from a pebble thrown into a pond, that I have no idea how to replicate. So, while the idea of forging one is great, it is intimidating to at least me.

The Spartan horns with the cylindrical or jam tin like back on my 126 and 633 do not have that rippled diaphragm so if you had to make a new diaphragm from flat sheet at worst it might sound a little different. However I am sure there are still some around that are battered or rusted but with a useable diaphragm that could be salvaged.