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Metric polybushes
drt - 18/5/14 at 09:41 PM

Hi guys,

I am searching for a supplier of Metric (M12) polyur. Bushes.

The rallydesign PB121/122 are 0.5 inch (12.7mm)
So are most (if not all) on Ebay...
Checked all the most used kit car parts webshops...
And MK has them om their wishbones, but can't find them on the webshop.

thanks

iank - 19/5/14 at 05:32 AM

quote:
Originally posted by drt
Hi guys,

I am searching for a supplier of Metric (M12) polyur. Bushes.

The rallydesign PB121/122 are 0.5 inch (12.7mm)
So are most (if not all) on Ebay...
Checked all the most used kit car parts webshops...
And MK has them om their wishbones, but can't find them on the webshop.

thanks


Just because MK has M12 bolts doesn't mean they don't use 1/2" crush tubes.

[Edited on 19/5/14 by iank]

Slimy38 - 19/5/14 at 07:16 AM

Mine were M12, or at least they're a good fit on the M12 bolts I have. Unfortunately the supplier is no longer a user on Ebay, but these are similar and they specifically point out they use a measurement that is closer to 12mm;

Haynes Roadster Locost Wishbone Bush set - Rear in Black Polyurethane

Minicooper - 19/5/14 at 09:10 PM

These bush/crush tubes are for 12mm bolts, the crush tube is mild steel zinc plated and not stainless as they are supposed to be but other than that they fit the 12mm bolts pretty snug


Haynes Roadster Locost Front Wishbone Bushes in Poly

Cheers
David

drt - 20/5/14 at 12:24 PM

Thanks guys

I saw all of these articles.
They all stated 12.5 or 12.2 mm.
That put me off.

Slimy38 - 20/5/14 at 12:43 PM

quote:
Originally posted by drt
Thanks guys

I saw all of these articles.
They all stated 12.5 or 12.2 mm.
That put me off.


12.5 I agree might be a bit much, but why are you put off by 12.2? The movement in the bush itself is likely to be more than that? I'd have thought you need to go for rose joints if you want things to stay exactly where they are.

Or is there another reason why you want the tolerances absolutely spot on?

I think mine are 12.2mm but there's virtually no lateral movement. To me the gap is just enough to allow a thin smear of copper grease so the bolt can come back out in five years time. Any closer and I suspect I'd have trouble working with them.

loggyboy - 20/5/14 at 12:51 PM

Any reason for sourcing 12mm bushes over sourcing 1/2 inch bolts?

drt - 20/5/14 at 01:02 PM

Oh and,

A m12(1,75) bolt has a production tolerance between;
11,966 and 11,701 mm

A 12.1,12.2mm crush tube will not do.

loggyboy - 20/5/14 at 01:26 PM

If your that concerned with tollerances you should be looking at rose joints and rod ends.

drt - 20/5/14 at 08:10 PM

quote:
Originally posted by loggyboy
If your that concerned with tollerances you should be looking at rose joints and rod ends.


The chassis end of the Wishbones are rod ends...
This is the hub side...

drt - 20/5/14 at 08:14 PM

quote:
Originally posted by loggyboy
Any reason for sourcing 12mm bushes over sourcing 1/2 inch bolts?


Good point,
The used upright (hub) uses an M12 bolt.
retapping might be an option-ish

DIY Si - 20/5/14 at 08:46 PM

What do you need polybushs on a hub for? Every one I can think of is either a ball joint or a bolt..... And even if they are designed for a bush, if you've got rose joint inner ends, poly outer ends seems a bit odd as it will just introduce movement where you don't want it, especially if you're that fussed about a 0.5mm tolerance on a crush tube.

drt - 20/5/14 at 09:12 PM

quote:
Originally posted by DIY Si
What do you need polybushs on a hub for? Every one I can think of is either a ball joint or a bolt..... And even if they are designed for a bush, if you've got rose joint inner ends, poly outer ends seems a bit odd as it will just introduce movement where you don't want it, especially if you're that fussed about a 0.5mm tolerance on a crush tube.


What do you mean by a bolt ? Just a bolt in a tube welded to the Wib (wishbone)?

Then... :p I could have guessed it woud come to this ...
Rose joints, rod ends... if they are the threaded shaft type, so not uniballs.
must never be use in shear !
To do so is a bodge (and a sin)

When I move from pull-rods to push-rods -directly on the hub- than its ok.
Seems that is the best solution

drt - 20/5/14 at 09:13 PM

quote:
Originally posted by DIY Si
What do you need polybushs on a hub for? Every one I can think of is either a ball joint or a bolt..... And even if they are designed for a bush, if you've got rose joint inner ends, poly outer ends seems a bit odd as it will just introduce movement where you don't want it, especially if you're that fussed about a 0.5mm tolerance on a crush tube.


I agree fully on the extra movement.

eddie99 - 20/5/14 at 09:15 PM

Also on the lookout for metric polybushes...

drt - 20/5/14 at 09:23 PM

quote:
Originally posted by eddie99
Also on the lookout for metric polybushes...


metric

Haven't got any luck yet...
currently my hope is floflex.
http://www.floflex.co.uk/

DIY Si - 20/5/14 at 09:36 PM

quote:
Originally posted by drt
quote:
Originally posted by DIY Si
What do you need polybushs on a hub for? Every one I can think of is either a ball joint or a bolt..... And even if they are designed for a bush, if you've got rose joint inner ends, poly outer ends seems a bit odd as it will just introduce movement where you don't want it, especially if you're that fussed about a 0.5mm tolerance on a crush tube.


What do you mean by a bolt ? Just a bolt in a tube welded to the Wib (wishbone)?

Then... :p I could have guessed it woud come to this ...
Rose joints, rod ends... if they are the threaded shaft type, so not uniballs.
must never be use in shear !
To do so is a bodge (and a sin)

When I move from pull-rods to push-rods -directly on the hub- than its ok.
Seems that is the best solution


What hubs are you using? It sounds like nylon, or a similar hard plastic, may be better for you than poly bushes as they'll remove 95% or more of the movement but still allow rotation.

43655 - 20/5/14 at 09:48 PM

any access to a lathe? you can buy polyurethane bar, usually 90 shore A i think.
I'm considering getting some for bushes. i'll use delrin or nylon of somesort in my tube chassis wishbones though.
Would that be any good, if you want to have a precise suspension setup. would guess they'd be between poly and shperical bearings

drt - 20/5/14 at 09:49 PM

quote:
Originally posted by DIY Si
quote:
Originally posted by drt
quote:
Originally posted by DIY Si
What do you need polybushs on a hub for? Every one I can think of is either a ball joint or a bolt..... And even if they are designed for a bush, if you've got rose joint inner ends, poly outer ends seems a bit odd as it will just introduce movement where you don't want it, especially if you're that fussed about a 0.5mm tolerance on a crush tube.


What do you mean by a bolt ? Just a bolt in a tube welded to the Wib (wishbone)?

Then... :p I could have guessed it woud come to this ...
Rose joints, rod ends... if they are the threaded shaft type, so not uniballs.
must never be use in shear !
To do so is a bodge (and a sin)

When I move from pull-rods to push-rods -directly on the hub- than its ok.
Seems that is the best solution


What hubs are you using? It sounds like nylon, or a similar hard plastic, may be better for you than poly bushes as they'll remove 95% or more of the movement but still allow rotation.


Without a crush tube ?
But how would I torque the bolt up without causing stiction ?

DIY Si - 20/5/14 at 09:59 PM

Nylon bushes still need a stainless steel crush tube. They look just like a poly bush set up, but with virtually no play.

My first version engine mounts use nylon, as I have very tight clearances, and they look like this. Just need to fit the stainless crush tubes now, as the one pictured is mild steel.


drt - 20/5/14 at 10:17 PM

aaah, I see.

Yes a PA66 bush would be the dream

Sadly I lost access to (my) lathe.
That is why I needed a supplier

Why do you have nylon engine mounts ?

DIY Si - 20/5/14 at 10:25 PM

Mainly because I had nylon bushes lying about ready for my front suspension. But that's weeks/months off yet, and I didn't want to wait for anything else to arrive in the post. And I only have about 1/2"-3/4" clearance in places round my engine.

DIY Si - 20/5/14 at 10:26 PM

And my bushes and brackets came from Russ (?) at Furore Cars.

drt - 20/5/14 at 10:30 PM

quote:
Originally posted by DIY Si
And my bushes and brackets came from Russ (?) at Furore Cars.


Aaah thanks,

didn't think about furore

(Do not wish to be a pain, a rigid connection to the engine would have been sufficient.
as the nylon will not damp anything out)

DIY Si - 20/5/14 at 10:38 PM

I know, but it gives me a little wiggle room on the bolts. They are also just a Mk1 engine mount, so I can change the bush later on with little hassle.

Also, try this place. They appear to have a minimum order of £50, but their prices seem much cheaper than anything else I've found. Ones the same size as mine are £0.48 EACH, but they do come in bags of 100!

drt - 20/5/14 at 10:45 PM

That is solid gold
thanks!

43655 - 21/5/14 at 06:39 PM

I'm a designer now, but have access to a lathe in work. Some delrin bushes wouldn't be hard to knock up if you like.
by the way nylon is horrible poo to machine, melts really easily compared to delrin's beautiful machinability.
there are a few plastics i've seen, 'nylatron' comes recommended, nylon with molybdenum in i think