brightspark
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Cast iron bearings perform better than Bronze in many applications.
yep graphite in the cast iron is self lubricating
- Thread starter ukracer
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When overhauling old fashioned vehicle dynamos & starter motors etc. after getting the bushes out the end cap and off the front end , we had to drop the new bushes in very hot clean engine oil , oil almost hot enough to burn . and let it cool, down to barely warm then with a brass mandrel drive the new sintered bushes in place .
I had my suspicions knowing what they do there..
But i am only guessing... LolI can get it cored locally but not till Wednesday. But i will get a price though. Cheers
Interesting..
These lasted 11 years..
I was not sure but decided there must be a reason they dont use steel. That said it wa only going to be a temp fix till the new year.
oldbikedavey
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Might be cheaper....Apparently gold is just as good as bronze for making bushes
oldbikedavey
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Would casting something up in aluminium bronze be a valid solution ?
Brad93
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Aluminium bronze is quite hard. It doesn't make great bearings in many applications.
Agroshield
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Without the pins that go in the bush, it may be difficult to make things fit well. Given the wear in the bush, it would be wise to check that the pin is not also worn, or similarly out of round. A bush which is sized to, and has to pass over, the unworn part of the pin will be loose on a worn part.
Any sloppiness in the connection is going to lead to premature failure. That sloppines could be between the pin and ID of the bush or the OD of the bush and the hole. Hence the bushes would normally go in the link with a slight press fit and then be bored insitu on a mill.
A simple 50 ID 60 OD item is a bit risky if anything other than a short term fix is required.
Monkey Harris
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Re bronze type bushes on small motors,
fans on ovens and boilers..
Often getting hot,
when they get stuck I oil and free them seem to work well afterwards..
Is this common practice..
Why do they get stuck..?
fans on ovens and boilers..
Often getting hot,
when they get stuck I oil and free them seem to work well afterwards..
Is this common practice..
Why do they get stuck..?
Seadog
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The lubricant dries up and becomes more akin to a lacquer.
Munkul
Jack of some trades, Master of none
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Not sure if you can buy them in the sizes you need, but we've had some amazing success with the spotted graphite impregnated solid bronze bushes. In a horrible high torque, high side load, high impact application where regular oilite sintered bronze gave up quickly.
Cast iron, unlubricated works in some applications. We use them on oscillating rams in one of our machines - 12 per head, maybe 14 heads in a machine, heads rotating at around 260 rpm, the rams banging backwards and forwards at the same time, once per rev - it has a pretty complex lubrication system.
If the lubrication fails, it doesn't take long for things to pick up and wear.
In other parts of the same machines, we use some stupidly expensive plastic bearing material, runs dry and lasts years. But eye wateringly expensive.
If the lubrication fails, it doesn't take long for things to pick up and wear.
In other parts of the same machines, we use some stupidly expensive plastic bearing material, runs dry and lasts years. But eye wateringly expensive.
Not enough lube so the bush heats up & expands onto the hot shaft that will also have expanded ..even worse if there is a bit of scoring on either part , when you lube it , it will have lost a bit of heat so with luck it will act as a bearing once again ...for a while if it wasn't too damaged.
My antique 1943 back gear lathe had true sintered phosphor bronze bearings on the cross shaft mounting bushes , It never appeared to reach full speed in any ratio , one day I happened to rest my left hand on one of the bearing as I was about to change the drive belt ration . It was *%^$£ing hot I can tell you the motor wasn't that far behing either.
On stripping it down I found dozens of tiny scores in both bearing sets of the shaft .. Someone in its earlier life had been turning cast iron brake drums ???
I ended up putting in two new bushings with two high speed roller bearing in each bushing and also had a new precision drill rod as the cross shaft turned down a 1/2 thou so I could get a good push fit on assembly .
For those with an enquiring mindset ....
There are two main types of graphited cast iron one is spheroidal or ductile good for bearings.
https://www.bing.com/search?q=What+...gEJMTg1NjhqMGoxqAIAsAIA&FORM=ANNTA1&PC=EDGEDB
And the other is flake cast iron which is good for compression & strength .
What is flake graphie cast iron used for ? - Bing
Intelligent search from Bing makes it easier to quickly find what you’re looking for and rewards you.
oldbikedavey
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Babbited, its characteristics would change.
