The last couple of nights I have been doing a couple of seat post rebuilds and ended up with a few questions. In this photo is a view of the upper end of 1936 to 1957 seat posts. I was curious as to when the seat post with the threaded on top was used. I had always assumed that the top was silver soldered to the tube. I have a theory on this but will hold off so that I can hear what you all have for ideas.
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I happened to have a junk post so I tried to unscrew it with no success so then I put the top of the post in the lathe and made small successive passes until I could in fact see the braze. You can actually see the braze line in the center seat post in the above picture.
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The second question pertains to when did they change the chamfer on the top from a rounded chamfer to a straight 45 degree chamfer. I checked my original 47 EL and 48 FL and they both have the rounded chamfer.
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The third question is when did they change the fitting that screws into the bottom of the post and acts as a guide for the spring rod. There is actually a third one that has no provision to be unscrewed with a tool but every post I had with this type of rod guide was for a later swing arm seat post.
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I happened to have a junk post so I tried to unscrew it with no success so then I put the top of the post in the lathe and made small successive passes until I could in fact see the braze. You can actually see the braze line in the center seat post in the above picture.

The second question pertains to when did they change the chamfer on the top from a rounded chamfer to a straight 45 degree chamfer. I checked my original 47 EL and 48 FL and they both have the rounded chamfer.

The third question is when did they change the fitting that screws into the bottom of the post and acts as a guide for the spring rod. There is actually a third one that has no provision to be unscrewed with a tool but every post I had with this type of rod guide was for a later swing arm seat post.

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