Hi OldSchool!

There was no real determining factor as to length. However, it does appear that the early aluminum version, as shown in your first picture, came with a shorter arm. My 1968 Buddy Rich 80N kit has the aluminum version and a short down post. The majority of chromed single arms can vary in length. The exception to length came in the late 70's when the Super Setomatic was introduced, which used fairly short down posts.

-Mark

Hi, Mark!

Thanks for your input. So, to see a "long" version, as shown in my 2nd pic, would seem pretty common on kits with 20" and 22" bass drums?

Yes, definitely! I've seen posts with length differences up to 6". I honestly don't know why there was such a discrepancy in length, but it certainly occurred!

-Mark

This just occurred to me... when the Avante kit came out, the post for the single Setomatic arm did need to be longer to get the 14" tom up a bit higher than the 12" and 13" toms mounted on the double setomatic arm.

-Mark

I never even considered that, Mark. Thanks again for your input. I was simply trying to determine if there was actually a valid reason for the difference in lengths. Other than what you just pointed out, regarding the Avante kits, there doesn't appear to be.

In actual fact the short arm was utilized for use with the "Super Set O Matic" mount, obviously the long arm would have created height restrictions with that mount. Many of the short arms are now being sold off and are found to be too short for use with some of the larger hanging toms.

Cheers

John

+1 The shorter arms in general were originally part of a Super Set O Matic holder.