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Wooden bearings
Posted: Wed Oct 20, 2021 2:09 am
by lostintime
I know I'm probably asking for a hailstorm of flaming arrows to shoot down the idea, but, growing up I worked with lots of farm equipment that used wooden bearings, from grain augers to hay bailer plungers. My grandfather was what would now be considered a "Mennonite" (German anabaptist) and was very much against owning anything that he couldn't make parts for and taught me how to make "bearings" by weight down the densest parts of hard wood to submerge it under oil then heat it to 250F and hold that temperature a while after it stopped bubbling and let it slow cool. The water fraction of the wood steamed away, and as it slowly cooled was replaced with the oil (grass fed pig lard was his preferred
). Then shape it with simple wood working tools. From what I saw (filtered through the rose colored glasses of time) they worked extremely well, failed gracefully rather than catastrophically, and usually outlasted proper "English" bearings. So..anybody using wooden bearings?
Re: Wooden bearings
Posted: Wed Oct 20, 2021 2:16 am
by TahoeSteam
Lignum vitae was a commonly used wood bearing for cutlass bearings and rudder gudgeons back in the steam ship era and at least into the big WW2
Re: Wooden bearings
Posted: Wed Oct 20, 2021 2:50 am
by Kelly Anderson
I understand that some traction engines came from the factory with wooden link blocks, some of which survived into the preservation era.
Re: Wooden bearings
Posted: Wed Oct 20, 2021 8:34 am
by Mike Rometer
I volunteered for a time working on restoring a flint and bone mill, and the line shafts (10" dia) were set in Lignum bearings. It was said as long as the speeds were slow it was ideal. They had possibly been there since the place was built 150 years before.
Re: Wooden bearings
Posted: Wed Oct 20, 2021 5:26 pm
by barts
You may find this paper on wooden bearings interesting.
https://rogersathre.com/Sathre&Gorman_2 ... arings.pdf
Wooden journal bearings continue to be used in specialized
industrial applications in North America (Steuernagle 2001).
At least three companies currently manufacture wooden bear-
ings in the United States with total annual sales estimated at
$2 to 2.5 million (Steuernagle 2002). The bearings are used in
screw-auger conveyers to transport bulk materials, because of
the bearings’ ability to work well under dry abrasive condi-
tions with irregular lubrication. Wood is also used in roll-end
bearings for roller conveyers and other specialty applications,
where their low cost is an advantage. These bearings are gen-
erally made of hard maple wood (Acer saccharum, ‘rock
maple’) saturated with wax or oil lubricant, and compete suc-
cessfully with a wide range of other bearing materials includ-
ing metals, plastics and ceramics. Accumulated experience
has led to design guidelines regarding radial clearance, grain
direction, load-speed relationships, and other operational fac-
tors (Steuernagle 2001, Anon. 1977).
Re: Wooden bearings
Posted: Wed Oct 20, 2021 6:03 pm
by lostintime
Very interesting! They even tested pork tallow! I've only skimmed it but saw no mention of burnishing them in. I was taught whenever possible(split bearing with a retaining strap or housing) to make it slightly to small of a clearance for the shaft then tighten it down while the shaft was turning, first sign of smoke stop the shaft, douse it with water until the shaft was cooled and repeat until it was tight. It polished the surfaces and when the shaft cooled it left the proper clearance.
Re: Wooden bearings
Posted: Fri Oct 22, 2021 4:49 pm
by RNoe
Kelly Anderson wrote: ↑Wed Oct 20, 2021 2:50 am
I understand that some traction engines came from the factory with wooden link blocks, some of which survived into the preservation era.
The 1910 Altman Taylor 16 h.p. steam traction engine I work on has Wolf valve gear with wooden blocks for sliders.
They are adjustable for clearances and have not required replacement in many decades.
I am not sure what USA species of wood they are made from.
RussN
Re: Wooden bearings
Posted: Fri Oct 22, 2021 5:52 pm
by DetroiTug
Wood bearings used in agricultural implements like disc cultivators were from Boxwood. A Hardwood and naturally oily wood.
Re: Wooden bearings
Posted: Sat Oct 23, 2021 2:38 am
by Lopez Mike
I've seen them in a number of applications. There is one thing in common with all of these successful uses. Low speeds and little resulting heat.
All of the various wood treatments don't do much for thermal conductivity. As soon as there is much heat generated, things go downhill. The smoke gets out!
As Wes and Mike have noted, Lignum Vitae (sic) has a long history in slow speed applications. Myself, I'll take acetal resins. Easier to find hereabouts.
Mike
Re: Wooden bearings
Posted: Sat Oct 23, 2021 5:32 am
by lostintime
I would think that if the wood has given its smoke up that the acetyl would have failed already also
). Then shape it with simple wood working tools. From what I saw (filtered through the rose colored glasses of time) they worked extremely well, failed gracefully rather than catastrophically, and usually outlasted proper "English" bearings. So..anybody using wooden bearings?