Fred W B
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| posted on 18/5/05 at 02:07 PM |
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Material for machined crank spigot bush
Okay, I did a quick search but couldn't find an answer to the following:
Just phoned a machine shop to order a custom machined crank spigot bush. I asked for "phospor bronze". Guy says, no problem, do you want
it in "LG2" or "PB1"?
God knows, I don't - anyone to the rescue?
Cheers
Fred WB
[Edited on 18/5/05 by Fred W B]
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NS Dev
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| posted on 18/5/05 at 02:21 PM |
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don't think it matters really. Phosphor bronze of any specification is an excellent bearing material. Take whatever you can get in approximately
the right size.
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Alan B
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| posted on 18/5/05 at 02:24 PM |
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I agree with NS Dev...or maybe ask them which they recommend.....
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bigandy
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| posted on 18/5/05 at 02:43 PM |
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are you sure it is TB1? Could it have been PB1? This is a particular grade of Phosphor Bronze that is recommended for use when bearing against hard
steel shafts.
I beleive it is a british standard, but i could be wrong. Do a search for PB! phosphor bronze, and I'm sure most manufacturers of bronzes will
have a spec sheet/data sheet for it.
as for the LGT stuff, then I have never heard of it. It could signify the leaded gunmetal though, which is sometimes used as a bearing material,
especially where a decent seal is required.
I would check carefully the differences though, before you use it. Ask the machine shop's advice first. most of them are pretty
knowledgable/helpful when it comes to specifiying materials.
Hope that helps
Andy
Dammit! Too many decisions....
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britishtrident
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| posted on 18/5/05 at 02:54 PM |
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The other option is an "Oilite" bush this was the material of choice on production cars.
http://members.lycos.co.uk/atlanticbearings/oilite_bushes.htm
http://www.bsaoilite.com/content/index.php?id=5&struid=5
http://mdmetric.com/bbush.htm
[Edited on 18/5/05 by britishtrident]
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flak monkey
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| posted on 18/5/05 at 03:02 PM |
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Oilite bushes are just bronze bushes, but rather than being solid they are sintered. This means they have some porosity. The bushes are submerged in
oil, and this is soaked up by the bush and gets trapped in there. Gives bushes with very good self lubrication properties (ooo err missus  ). They
are however made to size (sintered to size) and so wouldn't be an option in most engineering workshops!
David 
Sera
http://www.motosera.com
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britishtrident
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| posted on 18/5/05 at 03:06 PM |
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Did a quick check in the standard text book "Higgins" "Engineering Metallurgy" Not sure if you want phosphor bronze --
either a bearing brass or ther previously mention "Oilite" might be more suitable when the lack of lubrication is considered.
Standard bearing phosphor bronzes are 89.5% Cu 10% Sn 0.5% P --- also known as PB101
For higher loads the Tin and Phosphorus content is increases
81% Cu, 18% Sn, 1% P --- also known as PB102
Where lubrication is likely to fail brass of 74.5% Cu 5%Sn 0.5% Zn 20% Pb --- also known as LB5 is recommended.
http://www.bronze-ingot.com/leadbronze.htm
[Edited on 18/5/05 by britishtrident]
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David Jenkins
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| posted on 18/5/05 at 03:18 PM |
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There can be problems with Oilite bushes - they are made of a matrix of metal with voids in-between that hold the oil. If you machine it, or force a
bearing into a hole that's a little too small, then you close the pores and it no longer works as intended.
Anyway, will a crank spigot bush ever see any oil, apart from the initial assembly? In which case there's going to be a problem, surely.
I guess this is why Ford went over to grease-filled roller bearings!
Just my 2p's worth...
David
[Edited on 18/5/05 by David Jenkins]
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britishtrident
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| posted on 18/5/05 at 03:30 PM |
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Needle roller bearing only became commom place for this application circa 1970 before that Oilite had been in use since the late 1950s when it
replaced a simple brass bush which had been used for the first 60s years of motoring.
Needle roller spigot bearings have a major downside for competition/kit cars in that they are more easily damaged when the gearbox and engine are
mated --- the problem being it can be difficult to tell if a roller has tipped out of postion.
[Edited on 18/5/05 by britishtrident]
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britishtrident
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| posted on 18/5/05 at 03:35 PM |
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Google shows LG2 is a gunmetal for pipe fittings
http://www.bronze-ingot.com/gunmetal.htm
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Hellfire
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| posted on 18/5/05 at 03:49 PM |
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I used LG2 a lot in the petrolchemical industry. It's used for pipe fittings as BT says. Also it's for valve bodies et al.
If I recall, LG2 has more lead in it. It is also porous, I don't think you would have a problem with either of these materials.
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David Jenkins
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| posted on 18/5/05 at 03:59 PM |
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quote:
Originally posted by britishtrident
Needle roller bearing only became commom place for this application circa 1970 before that Oilite had been in use since the late 1950s when it
replaced a simple brass bush which had been used for the first 60s years of motoring.
I wonder what the correct procedure was for fitting them in those days - when I've used them in other applications I've had to soak them
in oil for a while to "fill them up" (or they've had an oil hole to "feed" them). I don't fancy having something
that could drip oil right next to my clutch!
Mind you, I suppose that it only has to act as a bearing occasionally, while the clutch is disengaged.
As for the bronze - I believe that the leaded alloys were intended for bearing bushes. They machine nicely as well!
David
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Trev Borg
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| posted on 18/5/05 at 05:15 PM |
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bugger and just managed to get the right size needle roller bearings too
Before you judge a man, walk a mile in his shoes.
By that time, who cares.
You're a mile away, and you've got his shoes
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Fred W B
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| posted on 18/5/05 at 05:30 PM |
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Wow, 3 hours and all of the above knowledge comes out. Thanks all.
I did have the id codes wrong when I first quoted them in my first post, now edited to be correct as "LG2" and "PB1"
After I posted my question, I spoke to a nonferrous metal supplier, who described the difference as being that LG2 is "soft" and PB1 is
"hard"
Says he can supply me 100 mm of Dia 25mm LG2 for R30 (currently = UKP 2.58), while PB1 is twice the price, and he is out of stock of it.
So, cosidering this and all advice above, seems LG2 is the way to go. Going to buy 300 mm so have enough to bo my pedal bushes as well
Thanks again all, this is the beauty of LocustBuilders.co.uk!
Cheers
Fred WB
[Edited on 18/5/05 by Fred W B]
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Bob C
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| posted on 18/5/05 at 08:10 PM |
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When I put my RV8/T5 gearbox together I made my own release arm & a spigot bearing out of the softer phosphor bronze. Within 5000 miles I had to
pull the gearbox out & replace the bearing with a ford needle roller item + spacing ring - wear so bad the clutch pedal would vibrate when
pressed. No problems in next 30k miles.... So sintered bronze may well be OK & roller bearings deffo OK but I wouldn't use PB again,
I'd always engineer a needle roller solution.
Sure there may have been other factors in my installation making it harder on the bearings than normal (eg unusual cover plate[rover]/ thrust bearing
[sierra cosworth] combo) - but that was the result
cheers
Bob
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WIMMERA
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| posted on 19/5/05 at 01:00 AM |
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Check that it has generous running clearance after fitting, they can cause lots of grief if to tight ,which is an engine out job to fix.
Wimmera
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Simon
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| posted on 19/5/05 at 06:27 PM |
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LG2 and 3 (we use 3), as well as silicon bronze, are used quite a lot by art foundries for bronzes.
ATB
Simon
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