White Metal Bearings

The method in SEM is more or less that shown in "The Hoyt Bearing Book" which is invaluable and my bible. I have made about a dozen in the last 3 months and take my hat off to the SEM contributor for coping without lathe or mill. At least I am building up a stock of moulds and don't have to do each as a one-off now. dismal day here :-( regards Roland

How is your good lady, everything ok I hope. I had the "Hoyt Bearing Book" once, I lent it to a so called friend who went and disappeared book and all. Weather dry here but over cast, doing some last minute checks to caravan and also trying to find somewhere to put all of my work kit as I want the van empty for my engine paraphernalia.
Martin P

previous posts snipped...........
As most of you are probably aware, I was particularly pleased to see the bearing article, particularly as it was for a Bamford 6hp, and I haven't stripped my barn-fresh one yet.
Obviously SEM have realised that the lack of practical information is a problem. If it wants to carry on into the future, it needs to educate newbies.
Speaking of education, Andy Selfe mentioned he should have used leaded bronze not phosphor bronze for his bushing. Can anyone comment on the different characteristics. PB and white metal are the two plain bearing materials I'm aware of.
Had the afternoon out at Onslow Park Rally, near Shrewsbury as the gods chose to urinate all over my freshly cut 9.5 acres of grass. :-(
I was pleased to make the acquaintance of Matt the Sawyer and saw some rather nice engines. Will post some photos when time allows.
Regards, Arthur G

Arthur,
There is a whole range of bronzes which can be used for bearing applications - cast material is preferred to extruded or drawn material. The addition of small proportions of elements other than copper and tin can modify the properties (as with whitemetals).
Phosphor bronze (AKA PB102) is a very hard bronze containing (as you might imagine) a small percentage (about 1%) of phosphorous, and is best for use with hardened steel shafts, but can take a lot of "hammer" and high rotational speeds provided adequately lubricated. Not surprisingly, it is more difficult to machine than brass or leaded bronze.
For older shafts which are mild steel and unhardened, leaded bronzes are considered to be kinder - softer and having a degree of self lubricating property due to the lead content. Codes to look out for are LB4C and SAE 660. The formula includes 6 to 8% lead and 2 to 4 % zinc - perhaps not surprising that it machines similarly to a brass.
Hope that helps.
John
In message , Arthur Griffin & Jeni Stanton writes