Crankshaft dismantling stand |
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Here we have a
simple stand that you can use for dismantling and rebuilding the crankshaft,
not only on M20's but also most of the BSA pre unit singles. I made
this particular one out of box section, but you could just as well make it
from channel or angle iron, (about 3 inch minimum). I have found
that when making these stands that using exact measurements are no good, as
when you weld them up they pull slightly, so the best way is to make it
around the crankshaft that you have, that way, you are sure that it fits
perfectly. I make these stands from anything I have lying around, and
usually you can use the same principle on many other bikes that have
split crankshafts. This particular one cost me £3 for the steel (new) and
took me about 10 minutes to knock up the only thing that helps is a
welder, but you could equally drill and bolt one together. The first thing
to do is grind into the box in the centre to clear the main shafts,
then weld (or bolt) the bit that goes into the vice, then all you have to do
is weld/bolt on the tube or round bar that fits through the holes in the
flywheel, I found that welding these are on is the best way to do it
as you can tack weld the tube (which incidentally is a bit of old
handlebar) whilst the crank is sat on the assembly that way you
are sure that it is all going to fit together properly. Now you have made
the stand! To make the truing clamp you do really need to make this from
channel section, this part allows you to hold the crank true to
within a few thousandths of an inch prior to final truing the threaded bar
that I've used in this particular one is 16mm diameter stock studding. When
you've made the stand, don't think that you can instantly true the
crank , it takes a little experience, in a couple of weeks I'm rebuilding an
M21 crank and I'll do a step by step "how to do it".
I hope you all find this useful, if you need any more information on making one or any aspect of crank truing please email me at davmax@ntlworld.com |
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