On another forum, I saw that Lignum Vitae bearings have been used for over 100 years on things such as hydro turbines and ship propeller shafts. Has anyone had any experience using lignum vitae as a bearing?
It is supposed to be a self lubricating wood. Since most of the uses I have seen tend to deal with parts in water, I wonder if it must be submerged in water to work? I also wonder what the practical limit is in terms of RPM to a certain diameter?
My brother worked at the portsmouth naval shipyard for 30 years and we had some pieces of lignum vitae around the house that he had brought home. It was tremendously hard stuff. I remember him saying that they used it on the driveshafts of subs. It had the quality of being hard, would swell a little when wet so that it would hug the propeller shaft, and that it was an oily wood. I don't think that they relied on it being self lubricating. It was the water that helped to lubricate. I don't think they used it in any dry situations.
When the babbit bearings in my 36" Crescent bandsaw had a meltdown years ago I had a local machinist make me some Lignum Vitae ones to replace them. As I remember we greased them on installation and then they were on their own. I owned the bandsaw for another twelve years and then sold it to a friend who still uses it. The bearings are still going strong. They've been in use since about 1979.
Thats interesting to hear. I figure that they are not the right material to work on a wood lathe considering the speed that they would need to run.
Since they are still working on your bandsaw though, they might be worth considering. I imagine for a 36" bandsaw, the RPM would be relatively low though.
Motorized lathes tend to run at fairly high rpms so I'm skeptical of wood bearings. I have an old lathe that uses bronze bushings that require frequent oiling but it gets warm and noisy if I run it fast. It might take it just fine but I don't like doing it as it was originally designed as a treadle lathe. LV is harder than bronze, should be quieter, and self lubricating. As the wood bearing heats up, oil weeps out and lubricates the shaft. There is a company that makes self lubricating maple bearings, the wood is hyper-saturated with lubricant in a vacuum chamber and then works on the same principle as LV. What are you planning?
I am planning on building a lathe. Its a ways off from actually being built and I am still making the plans for it. I figured that lignum vitae would be a stretch and really not ideal for what I want but I thought I would see what others thought too.
I have several decent ball bearings that I will probably end up using.
The very modern top of the range V B 36 uses bronze bearings which heat up and it is a very expensive beautifully made lathe designed by Nigel Voisey .He swears by them as being the best and is very knowledgable on woodturning and lathes .Before then lignum vitae was widely used for bearings very hard dense wood which if I remember correctly does not float.I could be wrong maybe I am mixing this up with iron wood for the floating argument but for bearings it is a fantastic medium but of course not really used any more.It is famous for making Grass bowling balls now superceded by modern plastic.If you come accross older ones they are probably lignum, so snap them up, they could be worth a few bucks as it is expensive wood even for little bits. So as always Have safe fun .Alistair
Bronze are probably not bearings but bushings. The same with the Lignum Vitae. If it doesn't move, it's a bushing, if it moves it's a bearing. If it moves and shouldn't, > Duct Tape. If it doesn't move and should, > WD40.
In the old days, there were babbet bearings, you either shimmed them or poured lead to tighten them. The name was a misnomer, Rod and main bearings in and engine are actually bushings.
Or so an old German machinist fellow explained to me many years ago. He was old enough that he worked on the Graf Zeppelin, if that means anything to you.
He was also the one who helped me rebuild an engine from the ground up that powered a 1935 ACF-Brill passenger bus, including forging and machining pistons, rings, rods and a cam shaft.
He was a pretty Fart Smeller!, oops.
I think the folks at Clevite might disagree with you about the bearing definition and futher more be able to explain to you why what they make are in fact bearings.
Forgot to mention, LV is limited to a certain surface speed, heat is generated exponentially as that speed is increased up to the maximum the bearing can handle. This is far from a cut and dry situation as there are far too many variables to simply state a maximum speed. The load would be the single largest consideration, followed by lubrication, tolerances, cooling and being a wood product there will be at least slight inconsistencies as with many natural things.
I can back Alistair up on the sinking thing.
Years ago I was drying some LV deadeyes (dipped in BLO) on the float beside my boat when the wake of a passing boat caused the float to rock. They tumbled, two of them into the water and they floated like a couple of wrenches.
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