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tonybroad - n/a
4-Oct-06, 09:52 AM
Nylon HTD bottom pulleys - any good - will they take 50Hp comfortably - it's just that they weigh less that i'm interested



comments please



Tony

pest619 - n/a
4-Oct-06, 11:30 AM
well ken seemed to think so when i bought mine... but the pulley makers wont go down to that size at that rpm/belt speed even with a steel pulley in their catalogue if i read the confusing table right...

nickyd - n/a
4-Oct-06, 01:23 PM
Hi Tony,



Should be fine I'd say. I've had one on my 503 all year and it hasn't given me any trouble. It's not even showing any signs of wear yet, but I have noticed a fair bit of wear on my top aluminium pulley. (Obviously that's the expensive one!) After time they will absorb moisture and can swell slightly, but this is after a fair few years. Belt tension plays a part in pulley wear I believe.



As for the manufacturers, I'm pretty sure they will make you any size pulley you like to order. They did an h pitch one for me and it arrived inside a week!



Nick

pest619 - n/a
4-Oct-06, 03:53 PM
as in they dont recomend using that size pulley for that size gearing and speed in industrial applications so it doesnt matter for us

1clue - n/a
5-Oct-06, 02:46 PM
Tony,



I have a spare nylon pulley for my craft, but I haven't used it yet.



I'm making a UH-18sp, and the pulley in question is about 12" diameter and maybe 4" or 5" thick. 8 grooves, it's a V-belt instead of a timing belt like you guys use.



This nylon pulley was given to me by someone, and it shows signs of being compressed/deformed near the hub. We use a 10:1 taper to tighten the pulleys down, where the pulley bolts onto the taper and compresses it, which grips the shaft. The outer area seems fine, the taper looks like it was squished and then trimmed flat again.



This is more horsepower than you're talking about. Designed around a Subaru EA81, which has 85 hp or so. Probably nylon is good enough for what you're doing, but you're starting to push it a bit maybe.



-- Edit: --



My machine has 119 hp, so chances are this nylon pulley will only be a spare. We usually use wood pulleys here for the big one, which by the way work surprisingly well. Probably not for a timing belt though http://hovercraft.org.uk/images/icons/smiley_icons/icon_biggrin.gif

tonybroad - n/a
6-Oct-06, 08:10 AM
thanks Ken but i'm looking at the bottom pulley predominantly with a HTD tooth profile



thnaks anyhow



Tony

1clue - n/a
6-Oct-06, 02:02 PM
Tony,



I suspected something like that, but I thought my pulley was a good example of where nylon starts to deform. I can't say for sure if the forces on your smaller drive pulley would be more or less than near the hub of my driven pulley, but my guess is that the forces on my situation are higher.



My post was intended only as a data point.



Have a nice day.

Jonathan - n/a
27-Oct-06, 12:35 AM
where can I get a Nylon Pulley?

I need to reduce weight, but can't face a diet...