History of Leslie Bronze Tab Chambers

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:46 pm

Many may not know this, however there are actually 6 different variations of the Leslie bronze tab chambers. Rather than try and reword it I am simply going to repost an article written by Joshua Simmons in 2014. The words and pictures that follow are all his.

Leslie Bronze Tab Power Chamber Information
As compiled by Joshua Simmons, 2014
To the best of my knowledge this list is in approximate chronological order, oldest to newest, but I'm sure there are instances of deviation and quite possibly more variations I have not seen. Please see attached photos to better understand the type descriptions. Unfortunately, my 52 S3JR was not readily available to take better photos of that type of bronze head. I had to use older photos from my archives, but they should serve the purpose well enough.
1. S3J/S5D type - small air inlet boss, only 3 small tabs, separate nozzle threaded (pressed?) into head, pinned back cap, orifice pressed into head. The back cap had to be pinned to ensure the diaphragm mounting screw tabs lined up with the 3 corresponding small tabs on the nozzle position of the head.
2. similar to #1, except without pressed in orifice. Not a significant difference with this version, but I thought it was worth listing as a separate type since they were used on various horn models that utilized standard orifice tubes.
3. similar to #2, except 6 small tabs, no longer require pinned back cap.
4. similar to #3, except wide air inlet boss (this type is original to my 54 S5T). I believe this type to be the most common.
5. same as #4, also stamped "Swedish Make" (this type appears to be original to the 56 S3K I just got).
***BTW, I'm of the opinion that 1-5 are all made in Sweden even though most are not marked as such. The original hardware on all these types is marked "BUFO," which is a Swedish fastener manufacturer. Can't imagine Leslie importing only the hardware to assemble the heads and not the heads themselves.***
6. single piece cast nozzles, fat air inlet boss (almost same size as threaded mounting bolt bosses), 6 small tabs, but the 4 small tabs that are over the bosses taper down to the boss. The two I own are also more rose colored than my other bronze heads. Not sure what type of hardware was originally used on these, nor what year horns they may have been on. Neither of mine were on a horn when I got them and the hardware had already been replaced with SS screws. I'm speculating that these single piece heads were probably cast by Leslie here in the states, rather than imported from Sweden.
I think it's also interesting to note that this last bronze head version (#6) appears to be identical to the later cast aluminum tabbed S heads. I would even speculate the aluminum tabbies were cast using the same patterns.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:48 pm

Type 1. S3J/S5D type. Small air inlet boss with pressed in orifice, separate nozzle. Kind of hard to see in this photo, but there is an alignment pin that goes through both tabs located in the 7 o'clock position. Also note that there is no small tab in the 6 o'clock position. The 10 and 2 o'clock positions aren't visible in this photo, but there aren't small tabs there either.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:48 pm

You can clearly see the lack of small tabs in the 2, 6 and 10 o'clock positions. The three small tabs that are there have to line up with the corresponding small tabs on the back cap (where the diaphragm securing screws are located). The alignment pin (barely visible on the tab in the 5 o'clock position) was necessary to ensure all the tabs lined up correctly.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:49 pm

Type 2. This type is pretty much identical to type 1 heads, except it lacked the pressed in orifice. I never measured the OD of the pressed in orifices found on type 1 heads, but I suspect these ones were drilled out slightly larger to accept the standard orifice tube.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:49 pm

Type 2. The alignment pin is clearly visible on the tab in the 5 o'clock position.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:50 pm

Type 3. Mostly the same as type 2, except 3 more small tabs were added and the alignment pin was eliminated since the back cap could now be mounted in any position. These still have the small air inlet boss.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:51 pm

Type 4. Basically the same as type 3, except the air inlet boss was widened somewhat. This was probably done so there'd be extra material around the air inlet hole. I'd imagine with the small air inlet boss, it would have been quite easy to drill right through the side of the boss if it was lined up perfectly during set up. The widened boss would probably be a little more lenient during set up for drilling all the holes. Also worth noting is that this type seems to be the most common (at least within my collection).

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:52 pm

Type 5. Exactly identical to type 4 with the addition of the "Swedish Make" stamp. In my observation, the stamping can be located on any of the 3 threaded mounting bolt bosses.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:52 pm

Type 6. Single piece cast nozzle and fat air inlet boss are the biggest difference from previous versions. Not visible in this picture, but the 4 small tabs located over the 3 threaded bosses and the air inlet boss all taper down into the boss, rather than fall straight off. this can be seen in later pictures.

Mafarnz · Post by **Mafarnz** » Thu Sep 24, 2020 5:53 pm

Type 6 on the left, type 4 on the right. Here you can clearly see the difference in the small tabs over the bosses on bother versions. The type 6 head may have been lightly buffed before I got it, but you can still pretty clearly see the difference in color between the two. Both of the type 6 heads I own are more rose colored than any of the other types I own.