Not sure if this is the right bit of the forum?
I recently bought a 1920 The Times Survey Atlas of the World. It's huge -bigger than A3 and has some lovely maps.
The front cover comes off with a small square key, and the maps are removable, they're mounted on plated brass posts.
It's obvious there used to be a knob on the top of these posts that went in to the cover, but they've been lost and someone just tightened the key and crushed the post tops.
I'd like to replace them, but I'm having real trouble with the threaded posts. There are two parts to each post, so there's about 4 or 5 threads to check the sizes
But what I'm finding doesn't match any of my metal working thread charts.
Does anyone know what sort of sizes they would have used in the 1920s on binding posts?
It's almost (but not quite) 1/4" - actually 0.233", about 30 or 32 TPI, or 6mm / 0.8 The OD of the posts is 0.31" / 7.9mm, the are 1 1/4" long with a perpendicular through hole halfway along.
I've ordered a 1/4" 32 UNEF tap & die from Ebay China, only a few quid. I'm not believing 1920 British book binders were using UNEF, but it's not BSW, BSF, BSB or BA, as far as I can tell.
Any ideas please?
I recently bought a 1920 The Times Survey Atlas of the World. It's huge -bigger than A3 and has some lovely maps.
The front cover comes off with a small square key, and the maps are removable, they're mounted on plated brass posts.
It's obvious there used to be a knob on the top of these posts that went in to the cover, but they've been lost and someone just tightened the key and crushed the post tops.
I'd like to replace them, but I'm having real trouble with the threaded posts. There are two parts to each post, so there's about 4 or 5 threads to check the sizes
But what I'm finding doesn't match any of my metal working thread charts.
Does anyone know what sort of sizes they would have used in the 1920s on binding posts?
It's almost (but not quite) 1/4" - actually 0.233", about 30 or 32 TPI, or 6mm / 0.8 The OD of the posts is 0.31" / 7.9mm, the are 1 1/4" long with a perpendicular through hole halfway along.
I've ordered a 1/4" 32 UNEF tap & die from Ebay China, only a few quid. I'm not believing 1920 British book binders were using UNEF, but it's not BSW, BSF, BSB or BA, as far as I can tell.
Any ideas please?