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[nhp651]

Is it possible to make the frame [normally made in brass] from 6mm thick high impact polystyrene, using brass bearings for the shafts to run in.
the bearings would be glued in to the styrene frames, and the initial shaft speed would be about 2500 rpm turning two lay shafts at a reduction of 2.5 ; 1.
i have the technology and machinery to make it all, but just wonder whether after going to all the hassle the hips would melt around the bearing holes.
i know some will argue for and others against, but would like to hear from someone who has actually made one, please, and did it work or did it melt

i would like one similar to that in bill's Arun lifeboat, but in plastic.

cheers,

neil.

[chingdevil]

I would have thought that was possible as long as the bearings have some form of lubrication, preferably light grease this should keep the temperature down.

Brian

[malcolmfrary]

The model railway lads were doing this back in the '60's in plastic kit conversions, admittedly with much lower power levels.  As long as the bearing surfaces are lubed to keep the temperature down, and there is enough area of the bushing exposed to air to give what heat is generated somewhere to go, there shouldn't be a problem.
There are other plastics than styrene, some should stand more temperature.  When you think of it, styrene is a top choice for vac forming, mostly because of the ease with which modest temperatures encourage it to deform.  Maybe acrylic?  SRBP?

[HS93 (RIP)]

hear are two ideas that would probably  work with your materials, but you may consider the material they make some model car chassis from a type of fiberglass sheet that is very rigid , if you use flanged ball races they are easier to fit. both ideas do away with couplings so you just use a longer shaft , the larger one does not need to be as big but it was made so it could be used direct drive as well if the gearing did not work , they are both 2.45 to 1 so near as damit 2.5 to one, the gears are from MFA we use the bigger gears as you don't need to tighten the belt as much.

the fiberglass can be got hear  http://www.mickreevesmodels.co.uk/~mickreev/Access/accessories.htm  go right to the bottom he also sells some nice other  stuff like very small self tappers i use the very thin fiberglass to clad and ply as you can get a good paint finish

[nhp651]

thanks for the info chaps.that has helped a great deal..........i'm going to try it and see.i have  also some nylon blocks that can be cut, so will have a play around.
many thanks, and will let you know how i get on.
neil.

[RaaArtyGunner]

hear are two ideas that would probably  work with your materials, but you may consider the material they make some model car chassis from a type of fiberglass sheet that is very rigid , if you use flanged ball races they are easier to fit. both ideas do away with couplings so you just use a longer shaft , the larger one does not need to be as big but it was made so it could be used direct drive as well if the gearing did not work , they are both 2.45 to 1 so near as damit 2.5 to one, the gears are from MFA we use the bigger gears as you don't need to tighten the belt as much.

the fiberglass can be got hear  http://www.mickreevesmodels.co.uk/~mickreev/Access/accessories.htm  go right to the bottom he also sells some nice other  stuff like very small self tappers i use the very thin fiberglass to clad and ply as you can get a good paint finish

Great link. 

Maybe there should be a section where links such as these can be stored.