Hi Sigurd,
Both the male and female beams have a band of epoxy glue at the ends and 400mm from the ends, the bearing thickness being half the clearance. This way when the bearings are not aligned there is plenty of clearance for telescoping. This is important if you want an easy telescoping boat.
Yes I did consider plastic bearings but plastic bearings of half the thickness of the clearance (like the epoxy bearings) become too thin to screw onto the beams and I don't know of any glue that sticks to UHMW-PE (though there may be). If you use plastic bearings of full thickness on the ends only you lose the telescoping clearance with the added problem of the bearings preventing the beams from coming fully apart (and assembly impossible).
The epoxy bearings worked well and are easy to make. I only used bearing pads on the bottom angled faces and not on the top. As it turned out they don't need to be tight when the beams are extended. We tried sailing the boat at folded width which meant the bearings weren't aligned and despite plenty of clearance the beams didn't rattle around at all, even in rough water.
I agree plastic bearings would be a good solution if a way to fix them could be found.
Cheers,
Mark
----- Original Message -----From: sigurd grungTo: harryproa@...Sent: Friday, May 06, 2005 7:17 PMSubject: [harryproa] Telescoping slippery surfaceMark wrote
>The male and female beams will have a couple of bands
of built up resin/graphite applied where they overlap
when extended. This will give plenty of clearance when
telescoping to prevent jamming.
Do you mean a narrow band at the very end of each part
of the beam?
Is this as good as UHMW plastic? I imagine uhmw to
have a bit less friction, wear less on the beams
(since it is softer?), be less durable, easier to
change when worn out. Less chance of jamming since it
probably has less compression stiffness than epoxy and
will also be worn down easier where there is humps.
What do you think, did you consider it, and what were
the reasons for using graphite/epoxy instead?
Sigurd
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