Q: What is this mounting hole for?

[t-bon3]

Apologies for the noob question but what is this threaded hole for? My google skills have let me down on this one.

It's on the drive side chainstay just behind the bottom bracket:



On an 80's raleigh road bike steel frame

Chainguard mount or something else?

 

[jim haseltine]

Front mount for a fully-enclosed or oil-bath chain case.

 

[keithglos]

More likely dates 50/60s

 

[Jonny69]

It looks more chain-case than chain guard to me too. The chain guard on my 1967 Raleigh RSW is a much more flimsy-looking thing. Agree also that the frame looks a bit earlier, even just from that vague shot!

 

[legrandefromage]

somewhere to keep your loose question marks.

 

[t-bon3]

Confession time. The frame in the photo is not actually my frame it's a picture I found which has the same mounting hole as my frame.

My frame is this one. 25" seat tube, 126mm rear dropout spacing.

Currently prepping for a respray.
There are some other mounts, one on the inside of the non-drive side seat-stay (dynamo mount?); also 2 small clips brazed onto the underside of the down tube. One close to where the down-tube shifters would be and one down closer to the bottom bracket. Not sure what these do exactly.