Canti brake blocks: length of threaded portion

[Fnaar]

Sorry if this is a numpty question, but with threaded blocks for canti brakes, are there different lengths for the threaded portion?
Well, I know there must be, because I was going to change the blocks on my tourer, and found some threaded ones knocking around in my box of bits, and the threaded portion is significantly shorter than what's currently on the bike.
Going to buy some new ones, but can't (anywhere, online stores) find mention of how long the threaded bit is. Could it be my old ones from the box of bits are for a different types of brake system?

 

[ayceejay]

Modern canti brakes have shaped spacers to help with correct set up - maybe the old ones didn't have spacers or they are still in your tool box.

 

[Fnaar]

Modern canti brakes have shaped spacers to help with correct set up - maybe the old ones didn't have spacers or they are still in your tool box.

Thanks... I don't have the spacers, if they ever were there, but I was intrigued by how much shorter the threaded posts are than the ones on the bike.

 

[Brommyboy]

It may be that the shorter ones are in fact calliper blocks!

 

[Fnaar]

It may be that the shorter ones are in fact calliper blocks!

Aye, could be, good point...