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What type of plastic for winch hawse


dirtydiesel

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If it's stainless - why do you want to coat it at all? Any kind of coating (pretty much) is just going to wear off - so it might as well not be on there in the first place!

I'm not convinced that mirror polishing is the way to go. I don't have a particularly objective explanation for this - only an empirical one. If you rub your finger over a smooth pane of glass, it encounters more friction than over a frosted one.

The 'physics' behind this as far as I know are this.

A perfectly smooth surface will have less friction than a rough surface. However, no surface is perfectly smooth. Microscopically, the two surfaces look like two gears running over one another. If the 'pitch' of the two 'gears' is similar, there will be a lot of friction as the 'teeth' mesh with one another. If they are different, they mesh less well and friction is reduced.

The surface has irregularities at a molecular scale as well as at a crystalline scale and at the scale of the surface finish - all of which interact this way. For a low friction meeting of two surfaces, you want the pitch to be different at each scale - in fact you want them to be prime numbers so that one will not divide into the other exactly.

A satin finish, like you achieve with bead-blasting, having a fairly random surface and thus the 'pitch' if the irregularities is random, is less likely to mesh with a smoother surface (like the individual fibers of rope). If the surface is too rough, it will start to interact with the fibers themselves - so there is a half-way point between perfectly smooth and rough where the surface friction will be at its minimum.

So, for my money - I would go for a satin finish over a mirror polish.

Si

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  • 1 month later...

probably about £25,

50mm slot up the middle, make the slot at least 40mm narrower than the winch drum to reduce side bunching.

then run around the edge of the slot with a 25mm radius tool on the outside and 5mm rad on the inside.

Sorry to drag this back up Dan...

How narrow do you think It would be sensible to go on a fairlead for an EP9? drum is roughly 230mm wide (measured in the dark!). Would 40mm narrower than the drum be too much?

How wide is the 525 drum?

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  • 1 month later...

Thanks for that Dan, I went with 40mm narrower in the end and its got a 30mm rad for the rope :)

This is the ali prototype after one side has been machined. It was 1 hour of roughing followed by 2 hours of the finishing cut.

D7186D63-87B0-4E0B-B060-2336086FCF18-670

Final version will be in stainless (304) and should hopefully go on the mill monday. (Reminds me, really must buy some beer for my mate with access to the CNC).

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Thanks :). My own design other than shaping of the outside....Barry a.k.a Cwazywabbit suggested adding that shape to it :).

I hadn't thought of that actually. The fairlead is 40mm thick at the moment. its about 48mm to be level with the bumper. Think I'll add some materal to the back of the model... unless he's already blocked it up.

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You can always space the fairlead off the bumper if you're too late Ross.

Whilst you're delivering beer to your mate can you tell him he's a git from all us on here who can't play with nice toys like him all day?? Ta muchly! :P

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Spacer it will have to be... its already been blocked down and machine programmed (the tooling won't reach that far).

I'll pass that on Bish ;). Annoying thing is I have access to a mill and lathe at work, but no CNC stuff :(.

Binned Barry?!!! Don't be so silly! I'd like it to end up on the mantle piece :D. However, I'm sure Mom would have something to say about it....

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