I have an early 70s Slingerland kit that I am restoring.

Its the tom mounts that are the problem right now. The fastening square headed bolts on the tom mount - I cannot figure out the thread to either retap the insert (looks like this part was replaced with something that just doesnt work) or put a bolt in (luckily i had a random bolt to use on the bass drum mount).

Its 24 threads per inch but its wider than a standard 7/32 tension rod.
its just slightly under 6mm wide on the threaded section.

Is it 12-24?

Hi Monty!

Are you referring to the drumkey operated screw that goes into the Setomatic tom plate? If so, they are 1/4-20 thread. Definitely a size that's popular in the US!

-Mark

Yes thats the one - except it's 24 threads per inch (i have triple checked its not 20 tpi as the size seems about right for 1/4).

Monty,

I'm attaching pictures of a 70's Slingerland concert tom I have. Just took the pictures now. The square-head bolt is original. The "T" bolt is an aftermarket from JP2creations.com. The Aftermarket threaded in perfectly. I then took each bolt and tried them in my 1/4-20 die and each threaded in with no issues. Honestly, I don't know what you have, but it's possible that the hidden strap nut has been tapped to a different thread. They are 1/4-20!

-Mark

When measured on the threaded end: A 1/4-20 fastener measures slightly over 6mm (6.2mm or .244"). A 12-24 fastener measures approx. 5.5mm (5.41mm or .213").

Originally Posted by slingerfan

When measured on the threaded end: A 1/4-20 fastener measures slightly over 6mm (6.35mm or .250). A 12-24 fastener measures approx. 5.5mm (5.41mm or .213).

Thanks for the measurements!

-Mark

Thanks for all the advice. I am not quite sure what is going on with the mounts i think they were bought as replacements by the previous owner and the inserts in no way match the thread of the bolt and are much smaller than 12-24.

I have ordered a 12-24 tap but I am not overly confident this is the right thread so i might be onto either replacing the bolt or putting a new thread on that.

Just as an update for everyone who offered advice.

Firstly the good news- one tom mount was actually just a little stiff and the rod and insert were 1/4 20 and work fine.

The other tom mount isnt 12-24 either so i just bit the bullet and made it and the insert M6. It works anyway and the rod was junk as it was.

The rod does look identical to the one that is 1/4 so i think it must have been rethreaded at some point but even then I cant find any bolt that matches the size and profile of this one.

Originally Posted by Monty

Just as an update for everyone who offered advice.

Firstly the good news- one tom mount was actually just a little stiff and the rod and insert were 1/4 20 and work fine.

The other tom mount isnt 12-24 either so i just bit the bullet and made it and the insert M6. It works anyway and the rod was junk as it was.

The rod does look identical to the one that is 1/4 so i think it must have been rethreaded at some point but even then I cant find any bolt that matches the size and profile of this one.

Glad you got this worked out! Threading the other one to M6 makes perfect sense, too! Sometimes you have to work with what you have. I see that you're from Scotland, so finding replacement parts can get tough! I've had a few 60's MIJ snare drums that were missing some of the original metric tension rods, which can be really tough to find! Tapping the original metric lug inserts to 12-24 was really easy and I was able to use "normal" tension rods!

-Mark