# Help with identifying a circa 1940s Blood Brothers u-joint, PTO series?



## gibson_registry (Jul 20, 2016)

I am working on a circa 1940s Blood Brothers u-joint and was wondering want series or model it is. It is part of a driveline from a small rail track car built by the Kalamazoo Manufacturing in 1945 using a WW2 Jeep powertrain. But the 1-3/8" x 6 spline on the one end and the primitive design of the cross (see pictures) make me think it it is likely an agricultural series (PTO) rather than a automotive series. I know it is _NOT_ what is used on the Willys/Kaiser/Jeep of the fifties. I have bits of those around.

The cross has a curious (to me) construction of one straight pin passing loosely through the other stepped pin to trap it into the center square block. A 1/4" diameter pin then passes though the stepped pin and the straight pin to in turn trap it. You can see this small pin partially pulled out in the attached picture.

I did find a image online of a the cover of a Blood Brothers publication that seems to show this type of u-joint, but whether it is a BW, N, or D series I do not know. The purpose of posting is the hope that someone might be able to provide a copy of this or similar publication or identify the series. it would fill in some of the background information about where they sourced the parts from.























Amazingly for its 75 year age the condition is very good, in most respects. The pins have about 0.0002" wear in the direction of thrust and the hardened steel bushes likewise. The intended design clearance seems to be 0.004" for the grease lubrication, so wear I would consider negligible for a railcar and 'mint' for a PTO shaft! But something must have happened where the hardened sleeve(s) fell out of one yoke and the journal of the shouldered pin started to wear a groove in the yoke eye (indicated by a red arrow in the one picture.) The repair at some unknown distant time was to install two bronze bushings and lacking the threads to screw on the Blood Brothers dust caps, plumbing pipe caps were welded in their place. Ugh! That lovely repair recently failed. The step pin of that repaired joint is corrugated on the journals where it ran in the bronze bushings. So will be making a new step pin, some hardened steel bushes, a few replacement dust caps, and repair to the damaged yoke eyes. I did some searching, but not unexpectedly replacement parts are not to be found; what a shocker!

-Doug


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## gibson_registry (Jul 20, 2016)

Well the Blood Brothers u-joint is fixed up. Still no idea as to what series it is, nor have I found any literature on it. Did find one Kunn's automotive repair book that showed a line drawing of what looks to be the same style, though no details. If the same, then the design dated back to at least 1922. One yoke eye needed welding up and machining. New hardened bushes all around; made oversized, two as replacements and the rest so I could run a hone through the eyes and true them up. One new step pin, though in hindsight I wish I had just made all new pins. And new caps, just because the originals had been gnawed on by a pipe wrench.
-Doug


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## Bob Driver (Nov 1, 2017)

Man that's some impressive machining skills, but way to time consuming for me....

I've heard that set up called a "double cardan joint", or a "double Hooke's joint". You could have gotten a couple of new $10 Spicer SPL series u-joints and the $45 Neapco "center coupler" shown below from NAPA, or the complete set up for $80 from Agrisupply. They are made for several different u-joint sizes and come in different eye-to-eye lengths. Off road guys run them on 4-WD "rock crawlers". Max suggested operating angle on a standard u-joint is 3 degrees, a double cardon can run up to 37 degrees, which allows for the massive suspension travel you see in You Tube videos of rock crawlers. Check out the Neapco, or Spicer, u-joint catalogs for the various dimensions they offered. 










https://www.agrisupply.com/double-j...MIzbe8lL657QIVZxitBh02xwi7EAQYBCABEgLph_D_BwE


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## gibson_registry (Jul 20, 2016)

The one yoke was problematic in that I could not find an easy match in the Spicer catalog, but with some machining and modification I am sure I could have used modern components for certainly less time than used to repair the original. I did look. But the point was to keep a historic railcar as original as practical. Which means keeping as many components as can be salvaged and where replacement is unavoidable to stay ‘in period’. Part of the experience of operating vintage equipment is what it takes to both operate and maintain them. Which usually means more frequent oiling and greasing! In any event, it did not take that long to do. My reason for posting was capture some interest on the chance someone might recognize what series Blood Brothers u-joint this is, and if anyone had a copy of the publication depicted? -Doug


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## Bob Driver (Nov 1, 2017)

I take it you're not billing some one by time & material.... Just out of curiosity, where do you plan to take that railcar for a shake down run, or is it just for show?


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## gibson_registry (Jul 20, 2016)

The railcar belongs to Railways to Yesterday, a trolley museum in Rockhill Furnace, PA. They have about 1.5 mile of track to operate on. So it was a volunteer job. The shaft is already re-installed and it is back in service. In the off-season (which much of this year has been!) it makes more sense to use a small gas-motor car to run up and down the line for right of way maintenance then spin the electric meter and run a full size streetcar.


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## Bob Driver (Nov 1, 2017)

That's awesome.... Could you post a picture of it? I worked on the Section Gang of the Pikes Peak Cog Railroad one summer when I was in college. Most people have no clue what I'm talking about when I tell them I once worked as a "Gandy Dancer"

The fascinating part about the job was the chance to spend hours talking to a couple of old timers that were still around in the maintenance shop and actually ran the steam rack engines to the top of Pikes Peak.


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## gibson_registry (Jul 20, 2016)

I would, but it might be pushing the moderators' tolerance if I start posting pics of trains on a tractor forum. I figure the possible link between the u-joint and vintage PTO applications was probably the limit of straying off topic. I don't want to start a non-tractor trend. But museum's website is easy enough to find and they have a pictorial roster. Look for M-100. Be prepared to be underwhelmed, it is nothing much more than a shed on wheels. Abound as mundane and plain a piece of equipment as you can possibly get!


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