Phosphorus Bronze Bushes-Soaking in Oil

There are various sleeve-type bearings that might work. "Oilite" is an oil-impregnated type like the soaked phosphor-bronze. There are also some plastics; "Rulon" for instance. McMaster-Carr has several such types, typically at a few $ each. Yours will need a moderate to high P (pressure) rating, but a light V (velocity) rating.

how can a plastic bear such crushing forces on the bush?

what velocity has to do here? i think we need high torque bearing stuff.

P.bronze is more friendlier than other metals to the ss (in my opinion) so it should last longer as well.

1. By having a suitable pressure rating, as stated.

2. Not much: as stated, a light velocity rating.

3. I wasn't rejecting "Oilite", just adding some other choices.

Generally following information is required to decide on suitable bearing:

1) Shaft and housing diameter (mm or inch)

2) Bush length (mm or inch)

3) Radial load on the bearing (ksc or psi)

4) Surface velocity of shaft (m / min) or shaft rpm

5) Application details such as location of the bush, if lubrication possible (oil, grease, water or self lubrication), temperature, presence of abrasive particles, etc.

6) Details of existing bush, lubrication and life of the bush

You can provide whatever information from above available to you to this forum or contact any bush manufacturer directly to guide you in selecting suitable bush for your application.

Please note, if your quantity requirement is small, a manufacturer may not show interest in solving your problem.

shaft dia= 1 inch (fix)

bush length= 1 inch or as described/needed

dia. of a plate where shaft has to be inserted= 1 inch (fix)

Radial load= unable to calculate, how to calculate??

surface velocity= how to calculate?

bush will be installed in an ss304 plate, will support ss316L shaft which will be busy crushing sugar cane. Aim is to use no oil+no grease bush (maintenance free) made by P.Bronze.

No existing bush exists.

Does sound like you want a Permaglide bush, or better still the newer INA version, rather than an oil/sintered solution.

You'll need a good finish (polished) on your shaft for any of these bushes to last.

You wrote I will need a good polish/finish for the shafts to last long.

What about Hard-chrome? epoxy paint? or simply a good buff? any other suggestion

I gather the shaft is stainless steel? If yes, and it a fairly good finish, polish it in a lathe to a mirror finish - being careful not to make it out of round. Or have it ground N3* or lower

*per ISO 1320 This is probably the easiest link to understand

A rough or scratched shaft will eat any kind of plain bearing, not just the 'plastic' ones.

You are right about the plain bearing being stronger (assuming this is low rpm)

You don't need oil with the Permaglide or INA bushes I linked earlier (again, assuming low rpm).

So you need to find the surface speed of the shaft (rpm x ∏d = units/min) and compare that to the bearing data sheet maximum allowable for each type.

tell me something..do we have to put oil, at some point, in a PTFE coated sintered bearings which they claim need no oil?

When the coating wears off a PTFE coated bearing you have to replace the bearing. Pay me now or pay me later.

SO..don't you think its better to go for old-fashion P.Bronze-wet type technology?

If you read the INA link you will see the bearings are impregnated with a 'plastic lubricant' which acts much like oil, in oil impregnated phosphor bronze.

Not quite the same technology as the original solid backed 'PTFE film coated' designs.

Hi bob02,

For your application, assuming shaft rpm 28 and radial load on the bush 300 kgs., I think you can go for bushes of self lubricating reinforced plastic material grades of `Orkot' or `Tenmat' or any other similar material available in your country and run them without any external lubrication. These materials should be available in tube or rod forms which can be easily machined on a lathe. Try to maintain good finish on the contact surfaces - shaft od and bush id with fine emery paper. You can maintain bush id 25.15 / 25.20 mm, bush od 32.10 / 32.15 mm and length 25 mm. You have to press fit these bushes into a metal housing / shell and try to maintain a decent shaft alignment to avoid edge loading. This is a simple and economical solution; you should get a good bush life and bush replacement is also easy, if required.

that's well said.

How did you calculated 300kg of load on the bushes??

the length of the shaft is 25mm.

I still dunno how to calculate the actual load on the bush and the shaft inserted into it.

How to do that?

I just assumed 300 kg vertical load on each bush should be able to crush a sugar cane. I hope I am right. To find out if bushes can run dry, you will have to calculate P and V, which I guess will be a bit confusing for you. I did it from the data provided by you.

You had mentioned bush length as 25 mm. I think shaft length may be 10 -12 inches.

Let us know when your juicer starts working. I may visit you for a glass of fresh and hygienic sugar cane juice... With all your efforts put in, certainly the juice will taste a lot sweeter... Add a piece of ginger and lemon while crushing, it will taste still better..

You will get a glass of juice of your choice only in one condition........if you let me know the secret of calculating or CALCULATE the P and V of the bush.

The Internal dia. of bush is 28mm or so, the dia. of the shaft is 25 mm and its length is 25mm too. The length of roller is 4 inch with 2 inch dia..now how to calculate?

There is no secret involved in all this; if you search the net or contact the manufacturer you will get the details. I did some search now and found PV calculation details on http://www.anchorbronze.com/powertransmission.htm

But, to decide which bush to be used where and what finished bush dimensions to be maintained, you will require some experience and expertise. This information you will not get easily. Since you came with your query on this forum, I gave you the info for your application free without even knowing if I would get a glass of juice... I guess, I got the only good answer score from you. Good luck to you for your juicer.

"Never" is a long time - so no it's not.

Re-oiling periods for sintered bearings depend on an array of service, environment and load factors. If you have space, a good idea is to fit an oiler, or a nipple.

Depending on what you're crushing and the type of crusher you may find that abrasive dust entering the bearings becomes a problem. Regular lubrication will clear some of it out. I've worked with oilite bearing that dust got embedded in the bearing. The wearing was fine, pity the same couldn't be said for the shaft

In bob02's context, this is for a sugar cane crusher. Abrasives are not so likely a problem, but the mild acidity affects the metal choices. Easy cleaning would be needed, and lubricant contamination would be undesirable. There are now several interconnected threads on this, which may be a bit disorienting.

Ahh, I didn't notice it was our friend Bob. Rocol make a range "FoodLube" there should be a suitable one. http://www.rocol.com/corp/index.php?option=com_content&view=article&id=26&Itemid=465

I would be inclined to use Oilite bearings in this case

For solid bearings LM76 has the widest selection and excellent technical staff.

Check out www.LM76.com for their choice of lube free bearings.

Another choice that is excellent for the food industry is Spyraflo self aligning bearings.

Check out at www.spyraflo.com

Sealed roller bearings are susceptible to shock load damage and require exact alignment both of which might make putting them in a crusher apparatus a poor idea.

Oilite has very poor durability and would require frequent replacement. If failure occurred during use systemic damage could occur.

If the bearings do not have to be food grade for contamination reasons monster bearings for your application would be self lube die/mold/forge bearings from Superior Die Set Corporation ( http://www.supdie.com/ ).

I would think sealed roller bearings would be the choice. Why fool around? No lube,

can handle extreme loads with years of service. Just a thought.

They text book says..roller bearings are softer than plain bushes. BTW not a bad idea for an rpm of 28...in that case...yes they should last long.

"Oilite" type bearings impregnated with food-grade lubricant, 1" shaft diameter × 1" long, can be obtained for < US$3 each. PEEK plastic bearings (a few more $) would also work. All of these choices have adequate P (pressure) and V (velocity) values for the application.

That said, this has been a futile and overengineered quest. Just get a Jeff Gallagher watermelon mallet and bash the crap juice out of the sugar cane. That'll be way more fun than turning a crank or switching on a gearmotor. Or just buy a $600 unit from China or India, rather than waste way more than that in "free" design time.

BTW, it's "phosphor bronze" rather than "phosphorus bronze", but that's just a minor quibble.

AHHAAA!!!!! thank you v.much for bringing about the language improvement.

I'm getting a $450 chinese juicer with triple rollers having stand too but the final touchings are not as fine as mine would be. besides they don't use 316L grade ss and some parts of the other metal are also not that good a craftsmanship.