Threadsize of an 1951 fork tube plug ?

Raytag
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Re: Threadsize of an 1951 fork tube plug ?

#16

Post by Raytag »

Hi Roo,

sure I have the manual and I leafed thru the pages concerned but I was a bit hesitant about this new technology LOL
I need to get going with the bike so I do what I feel comfortable with: Cutting the new used tubes, thread them on the lathe and I`m done.
I`m surprised about it how encouraging you`re reg that straightening job. Sounds easy enough and one day I`ll try that!

I guess some fellas here used to work as machinists or taught themselves on a lathe still
for those who haven`t heard about threading tubes on a lathe I tried making some vids with my manual lathe from 1966.
The retard speaking is me. Kinda complicated for me looking thru a lense and trying to see my manuevering my hand thru the lens .... Fumbling with a smartphone gives me fits anyway

Basically it`s like this:
The used tubes I found are 1,4" longer than standard and not 2" as I mentioned before
1. Cutting the tubes on the lathe close to 1.4" (note the screeching noise. Thats for not removing the chromelayer before = silly idea)


2. Facing the tube will achieve the final length


3. boring the short recess at the beginning for a seal or whatever (no vid)

4. Boring the minor diameter of the thread needs. 1.333 dia and 1" deep


5. Cutting the internal thread to 3/4" depth. Because it`s an internal thread
I cannot see where the tools is and this is why I`m watching a dial on the carriage. At a 3/4" depth I have to retract
the tool quickly and stop the lathe for not crashing into the carriage into the pipe. Then I`m reversing the direction of the lathe and therefore
the carriage with the tool returns. This process I have to repeat several times because with that type of threading tool I cannot cut the thread in one single pass.
The vid shows the very first pass. Many follow. Every new pass deepening the pitch



6. The vid of the last pass got amiss

7. Finished thread, tissue bits in the thread, maybe a bit to loose. I used 160rpm speed. For a carbide tipped tool like I used it is far too slow
and so the threads won`t fetch an award. What the heck.


I could install the frontend again if I didn`t forget to order a new brake cable ....grrrr
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