What is babbitt?

[JD Kelly]

Hello to all. I am a frequent visitor to this site, but I have never really posted because I am not a blacksmith and I am not even sure that I would even be classified as a "blacksmith wannabe". (Oh, for the record, I have no interest in swords or knives.) I am a woodworker with a mild interest in blacksmithing...well "mild" may be too mild of a description of my interest. Over the last couple of years I have been gathering and storing the necessary equipment to dabble in the profession a wee bit. I have a small Trenton anvil, a Buffalo machinist/boilermakers forge, various hammers, coal, a post vice, an assortment of junkyard steels to learn with and two pair of ratty old tongs to help me build the tongs that I will need. I have dressed the hammers to what I think I will need and did some very minor work on the horn of the anvil, but the forge blower is what is needing some work. With retirement looking good for next year it is time to get these things ready and get all this stuff in one pile, so to speak.

The blower is going to require new paddles on the impeller, a new shaft and a good balancing. The bearings are babbitt and I have elected to use a tin-based babbitt. Pricing babbit at McMaster, 89% Tin (Sn), 7.5% Antimony (Sb) and 3.5% Copper (Cu) was an eye opener...roughly 130$ for a 4.5# brick plus shipping. Hm, I would have to pour a lot of bearings for that price and quantity. On the same catalog page they listed a leadfree pewter at 92% Sn, 7.75% Sb and 0.25% Cu for about 15$/#. Being a resourceful person (okay, okay, read cheap) I had this idea to go to the local flea market and purchase a post 1970 (leadfree) pewter plate or saucer for a buck-two-ninety-eight, chop it up, melt it down and infuse it with an additional 3% Cu (by weight). Granted, there would no surity on the analysis, but it should be close enough, right? That brings about the question in the title of this thread. I am looking for more information than a "...low friction white metal comprised of Sn, Sb and Cu used for bearings..."

There appears to two schools of thought on making babbitt/pewter on the net. The first suggests to bring the Sn to 400 degrees C, add the Cu, stir to dissolve and add the Sb and repeat. Since 400 degrees C is well below the melting points of both Sb and Cu this appears to be very akin to throwing a handful of milo and soybeans in a quantity of flour and stirring. All you have is a mixture of flour covered milo and soybeans, ie tinned Cu and Sb no smaller then the particle size you threw into the mix.

The second school is to melt all the metals in separate crucibles, mix and pour into an ingot cooling quickly (relative term) to fix the grain size. Cut the ingot into pieces, re-melt to pour temperature and pour. This would not distrub the Cu or Sb grain size

The latter just appears to me to make more sense and I have a liquid (diesel) fueled burner that can easily achieve a ceramics cone 10 temperature (roughly 2300 degrees F), would you think that this would be the way to go? I know, I know, just go find a small quantity of tin-babbitt and pour the bearings, light the fire and hit the metal, but that would take all the fun out of it and aren't hobbies supposed to be fun?

As I said earlier, I have been a guess in your house for long time and I have shown up to feast at your table empty handed for all that time. It is time to rectify that with the following link that should take you to a page with the title of Primary Metallic Crystalline Structures (BCC, FCC, HCP). It's a good read.

You folks have an excellent site and know that I will continue to read it even if this blacksmithing thing does not work out.

JD


Primary Metallic Crystalline Structures

[irnsrgn]

I think there is a babbiting BP somewhere, just buy some babbit and save yourself a lot of headaches. you can also use old babbit from old farm machinery.

Where in NE, Ks, I am 17 miles north of Hiawatha

[Candidquality]

I would recommend melting out what you've got and simply re-using it. Just plan for the fact that some may have worn away, so it might not fill up the entire cavity. The self lubricating properties of the babbitt are still there just below the surface. The original company magnolia, is still in business. I must have take the information home as I cannot find it now, but there are several grades of babbitt with varying uses. With the amount of research you've done i've no doubt you've noticed that. Good luck and let us know how it turned out. I'll try to get that information if I can find it before my wife packs it away.

[skunkriv]

BABBIT INGOT USED FOR GRT LKS ORE BOATS PROP SHAFTS - (eBay item 110190153667 end time Nov-13-07 18:09:47 PST)

Babbit on ebay. Bid of $9.95 with a day and a half to go. I agree with the above, melt out what you have and melt and add enough new with it to make sure you have enough for a good pour.

[waianvil]

Kelly there was a article in the woods magazine on making a babbit bearing if you would send email to the woods magazine they could tell you what month issue it is the are rebuilding a old table saw that they are installing new babbits on the unit

[HWooldridge]

Another alloy that will work is linotype lead - especially if you simply need a little extra to replace the old stuff. Linotype used to be available as scrap from newspaper printers but it's getting hard to come by now. Used wheel weights will also work in some applications.

I repoured a 25 lb LG with straight linotype and it worked just fine. A lot of what makes babbitt work over the long term is proper lubrication.

[habu68]

http://www.owwm.com/files/PDF/FAQ/Magnolia.pdf