What is the pitch of this heatsink?

[Faringdon]

Hi,
The heatsink called “SK 145 37,5 STS TO220” (Page A109)
Heatsink…
https://www.farnell.com/datasheets/1734934.pdf

…does the “37,5” bit refer to the pin pitch?

Also, do you think we can heatsink a GBJ5010 Diode bridge to its flat side?

GBJ5010…
https://www.mouser.co.uk/datasheet/2/258/GBJ50005_7eGBJ5010_GBJ_-2510579.pdf

[tooki]

It’s the height.

It’s a bit unclear because of the uncomfortable proximity of dimensions on the drawing. Here’s an annotated screenshot that hopefully makes it clearer.

So no, that bridge rectifier won't fit: it's twice as wide as the channel in the heatsink. (Of course, you could always just mount it on the back of the heatsink.)

[HwAoRrDk]

I don't see how it's confusing - the pin pitch is explicitly labelled on the diagram as 25.4mm.

[MarkF]

The only confusing part is that they use a symbol to indicate height where most specifications use a letter for a dimension.

The hole is high enough to support the bridge rectifier and the width of the heatsink is slightly narrower than the bridge.  So, you could bolt it onto the back side of the heatsink.