I'm pretty sure the longer ones were used for tom stands. There is a fourth variation that was long and had square holes punched every inch or so. These were used in early tom stands where you ran a carriage bolt through the desired holes to set the height. I bought a new boxed Ludwig double tom mount to convert my bass drum to double toms around '79 or so and it was the short one and the black handle on the diamond mount and came with two classic mounts.

Mid 70's catalogs show the short or middle length pipes when mounted to drums. Mostly the Vistalite pictures are the ones where you can see it. The '80 catalog shows all three versions being used on bass drums.

Catalog art can be a less than desirable source for determining what details were used when because so much art was reused over the years. It is also very possible that things get used during the photo shoots that are not actually was would be supplied to customers. If the drums were being shot at a photographer's studio, everything would be sent there and then setup. If there wasn't the correct length tom mount available they would have just used what they had on hand with what was delivered. Getting the shot is going to be more important than accuracy for a catalog.

I worked in the photography field when I was younger. One of the photographers was doing a shoot for a restaurant chain and they needed a picture of two cornish game hens sitting upright on these little chrome stands. They sent someone over with the hens, stands and an small oven to cook them. They didn't bring anything to set them up on. After a few minutes they decided to take one of the luan hollow core doors off one of the darkrooms and set it on two saw horses. They put the cooked hens on the improvised table and took the pictures. My point being you do what you need to do to get the shots and finish the job.

Also consider that we are talking about Ludwig. We all know they deviated from their standard configurations just to get things out the door.

I have a feeling that the shortest one was used for normal depth toms (8x12, 9x13, etc.)and middle length was for the deep toms such as 10x10, 12x12, etc. As was previously stated, the long down-tube post was probably used for floor stands.

Yeah, I think 'Leedybdp' hit the nail on the head. I've had 4 Ludwig double-tom kits - from 1958 to 1976. All standard size toms and they all had the shorter tube. The exact length of the tubes varied a bit, because the mounting mechanism at the top went thru 3 changes since the initial mount in the 1950s (the one with the wooden block) into the 1970s, but they were all short posts.

But as 'Thin Shell' pointed out, the folks at Ludwig who gathered up the hardware to fulfill an order probably weren't measuring the posts! A double tom mount is a double tom mount, regardless of the length of the tube. Looking at Rob Cook's Ludwig book, page 215, it shows that the part number 781 never changed, from the earliest type to the last type (used in the 1970s).

Regards, MB