I want to run an Oilite-type bronze bushing. 1/2" diameter shaft, rotating as high as 4000RPM.
When I look at McMaster's bronze bushings, they are all rated for various loads at 120RPM. No other mention I can find of RPM ceilings, etc.
I looked around on the internet as well and haven't found any further references.
This shaft/bushing will be inside an automotive engine and will spend its life in motor oil. so the Oilite might not be the best material. a plain bronze might be better. There will be moderate radial loads but let's consider them 'minor'.
So my question is. surely bronze/Oilite bushings must be able to handle more than 120RPM, right?
I once made a pivot bushing for a motorcycle shift lever from a bar of "Oilite" I had. Don't know which variety it is but for a foot shift pilot on a motorcycle I didn't think it would matter much. It wore an eccentric within 6 months or so leaving it a rather sloppy fit. I realize that it was only rotating on a segment but the force/frequency didn't seem to be enough to have worn it useless in that amount of time. My suggestion is to consider the difficulty of getting at that bushing and how you'll check/know the wear on it. I'd also wonder about any bronze particles traveling to other components in the motor. I'm sure there are several flavors of "Oilite" bronze but I wasn't impressed with this one at all. I've used it on the job for fully rotating spindles on small electric motors, no radial load. Your call.
Consider the surface finish and hardness of the shaft. The smoother and harder, the faster it can go without wearing out.
["That's what she said" joke goes here]
I want to run an Oilite-type bronze bushing. 1/2" diameter shaft, rotating as high as 4000RPM.
When I look at McMaster's bronze bushings, they are all rated for various loads at 120RPM. No other mention I can find of RPM ceilings, etc.
I looked around on the internet as well and haven't found any further references.
This shaft/bushing will be inside an automotive engine and will spend its life in motor oil. so the Oilite might not be the best material. a plain bronze might be better. There will be moderate radial loads but let's consider them 'minor'.
So my question is. surely bronze/Oilite bushings must be able to handle more than 120RPM, right?
Never, never use oilite except for very low speed applications. Even 120 RPM is too high. Use a ball bearing.
On a more serious note - check out PEEK as a polymer bushing. Heat tolerant, oil tolerant, great wearing, etc.
But again - smooth, hard shafts make it last longer.
All plain bearings are limited by a PV value. Pressure * Velocity. Pressure is Load divided by bearing diameter and length.
Velocity is Surface Feet per minute.
I found an oilite brochure using googlefu.
https://www.bearing.co.il/OILITE.pdf
Regular oilite is the high speed stuff, PV max = 50000.. Max SFM is 1200.
Example automotive application - early (fifties) Chrysler hemi distributor drive bush - no not plain bronze, but Oilite - 2200 RPM at stock max HP - and substantially above that with higher performance versions - incidentally about 1/2 dia
Have one laying around here somewhere
Regular oilite is the high speed stuff, PV max = 50000.. Max SFM is 1200.I'm certainly no expert on bronze bushings, but oil-lite in an oil bath seems rather redundant. Maybe something like this if you have the means to accurately turn and bore your bushing to size?
Well if it's going to live in oil then at least you don't need oil grooves. That's a good question about using oilite or bronze. I would probably use oilite since I have a lot of it and also I know it is the proper composition for bearings. I have a tool post grinder that has oilite bearings and I am not sure what the rpms are but it goes like a bat out of hell. I also have one that has preloaded taper bearings and both have about the same amount of side play. If done right you can get some pretty close tolerances with bronze/oilite bearings. I'm no expert on bronze alloys best for bearings but I have made a lot of bushings from worn out bronze propeller shafts and they work well. This sounds kind of critical so I would check what type of bronze would be best.
Use a needle bearing they are about the same size as a bushing but they have rolling elements. 4000 is pushing it for a plain bushing.
Example automotive application - early (fifties) Chrysler hemi distributor drive bush - no not plain bronze, but Oilite - 2200 RPM at stock max HP - and substantially above that with higher performance versions - incidentally about 1/2 dia
Have one laying around here somewhere
Note that 1200 SFM occurs at somewhat above 9100RPM on a 1//2" shaft
John, I think your example is not in line with the OP's application. In your Chrysler example, the bushing was splash oiled from the cam/distributor gear set. The OP made no such oiling reference.
John, I think your example is not in line with the OP's application. In your Chrysler example, the bushing was splash oiled from the cam/distributor gear set. The OP made no such oiling reference.
lol. The application is in fact a Chrysler oil pump driveshaft. But it's not an early Hemi, it's a later 340.
Regardless, Chrysler used these in millions of engines for over 50 years. My post was to try to understand what material they used. it looks a lot like Oilite but I'm not sure. I want to be able to make my own for a few reasons. they're kinda pricey if you buy them and I want to be able to make them to my own dimensions.
In this application, I considered a needle bearing and even ordered a few to look at but I'm not at all convinced they'd be any better and I know they'd be a lot worse if they decided to come apart. The bronze bushings last 'forever' which is good enough for me.
If you do use Oilite, Boston Gear has a page about both machining (don't use "dull" tools that close up the pores) and sizing - with non cutting tools
Thanks. I read up on that last might. no grinding (to avoid embedding abrasive particles)or dull tooling. Of course, if the Oilite will run in hot oil I'm not sure the closing of pores would matter that much.
I have a factory 'burnisher' for these that basically is a mandrel. It 'smushes' the bushing to size once it's installed.
Another reason I like the bronze bushings over needle bearings is I'm a believer in the idea that bronze, being softer than the steel shaft, is far less likely to damage the shaft.
Another reason I like the bronze bushings over needle bearings is I'm a believer in the idea that bronze, being softer than the steel shaft, is far less likely to damage the shaft.
Depends on debris floating in the oil. If clean, no particle to embed in the bronze. If dirty (the sump) then there's lots of small metal fines that can turn the bushing into a lap, cutting the shaft OD.
Never, never use oilite except for very low speed applications. Even 120 RPM is too high. Use a ball bearing.
This must be a joke.
'Cuz oilite has to run faster to actually work. That's why the lever application did not work.
They are used in motors all the time at 1750 and 3450 rpm. They need to warm up some to get the oil to come out and lube the interface.
lol. The application is in fact a Chrysler oil pump driveshaft. But it's not an early Hemi, it's a later 340.
Regardless, Chrysler used these in millions of engines for over 50 years. My post was to try to understand what material they used. it looks a lot like Oilite but I'm not sure. I want to be able to make my own for a few reasons. they're kinda pricey if you buy them and I want to be able to make them to my own dimensions.
In this application, I considered a needle bearing and even ordered a few to look at but I'm not at all convinced they'd be any better and I know they'd be a lot worse if they decided to come apart. The bronze bushings last 'forever' which is good enough for me.
Ninety years already - not just "over fifty", nearly double it.
Chrysler invented Oilite 1930, Super Oilite 1932. Both existed because MOPAR needed them, went straight into use, and they are night and day different goods.
Oilite was classical Copper-Tin Bronze, just sintered for a lot of Oil-holding void spaces. Oilite Plus, the rather WEIRD Copper-Iron Bronze for higher loading pressures. Think water pump bearings.. or maybe it was a seal face? Been a while.
More variations on a porousity theme have been added since Oilite left its MOPAR home. See Oilite II and very much harder Oilite 16, (what the motorsickle mentioned actually needed) add yet-another variant - Oilite Plus - with PTFE involved.
WHICH of the classical or present-day oilites do you really need? They have modest, but nonetheless "special", considerations as to machining, lest the "pores" become occluded from cutting tool rub/smear. OTOH, it has become HARD to find a size not stocked, ready to use. Because "ready"- stock items adopted as design wins - is how they ARE most commonly used.
Why invent a new size, when all I had to do was select from existing ones and go sort a tougher challenge ,"Autopen" signature machines and their first-gen automatic document feeders, the rice-bowl of that era.
A few boxes of a hundred, various types and sizes, (from W.W. Grainger, "back in the day"), and formerly wore to flinders sheet-offset printing presses - chock full of 'em, so long as not under-roof at TIMROSCO HQ [1] - rode again. Stable as houses, and jam-free, even at the full gallop.
The maker has their characteristics and the maths for matching to applications right on the website for load pressure vs surface velocity differentials.
"olite.com" finds it. Actually a Beemer Precision brand now, nearby Pennsyltucky.
MMC has a ton of 'em - prolly all those Beemer makes - just not necessarily all in local stocks in any depth, if at all.. same as Grainger was doing.. and probably still are?
Many Oilites worth. OK Brethren. That's a cheat. I have been researching use of Copper Iron Oilite for back pressure fed void-through lubed wear plates- that mostly WONT. "wear" - underside of a 10EE carriage . for "some years already".
[1]Harry Timken had an OCD fetish. Ignorant printing press or mimeograph machine came in the door at Timken Roller Bearings Co HQ? Harry's orders, any bearings IN the hapless f**ker were replaced with his beloved tapered rollers. Damn the re-Engineering and machining expense!
Exit Oilite. Enter a thousand-year-capable mimograph machine, obsolete the year before it left the factory, brand-new.
