On 2010-05-19, Richard Smith wrote:
Hello everyone
Capstans - have had a project in mind to make a capstan for some time
now. Anyone any experience or ideas on capstans?
Last summer, rescued a worm-drive gearbox from a machine being
scrapped - had a 15HP electric motor attached - big beast. Gives 50:1
reduction.
Overall idea is that if had small petrol/gasoline (or diesel) engine
attached, would be useful tool.
Anyone have ideas about how to make the capstan barrel with its waist
in the middle?
It wasn't until here in your article that I realized that you
were talking about the kind of capstan used on sailing ships instead of
a lathe turret, which is sometimes called a capstan in the UK. I think
that the distinction is between the bed turret (such as I have on my
12x24" Clausing which can be interchanged with the standard tailstock)
and the built-in turret which lives on a carriage and is coupled to the
feed rods for power.
Bearing arrangement for capstan?
Any ideas how to size the capstan barrel and what shape it should be -
are there "rules" or "rules of thumb" about capstan proportions?
My idea is to take some steel pipe and slice "eye" shaped slits out of
it longways evenly around the circumference then collapse the tube in
the middle until the edges of the "eye" slits touch, then weld up.
Well ... the ones which I have seen on old square-riggers (the
kind powered by a bunch of people marching around them pushing on bars)
were iron castings, including the ridges to help it couple to chain
instead of just rope. (It was used for raising the anchor as well as
for many other things needing a long pull with lots of tension.
Another line of enquiry:
Calculations suggest that if you chose the right size of motor, you
could come near to but not exceed the breaking strength of your rope
by reason that the motor would stall first - for any revs / inhaul
speed. Would make this machine very easy to use if that were the case
- wouldn't need any gauges or whatever.
Now, I'll stop, because the ones which I have seen were purely
muscle powered. :-)
Enjoy,
DoN.
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