Yes indeed, I (with the help of others) restored a 1919 built Plymouth Model BL-2 (~ 70 hp gasoline Buda 4 cylinder "prime mover", standard gauge).

Was equipped with Hyatt "roller bearings" on both axles.

Funny thing was the "rollers" where actually wound like springs from square steel bars (about 3/8" square). Were hardened and apparently ground to a round cylindrical profile after heat treating.

Awful lot of extra steps to create a cylinder that rotated between two cylindrical hardened races. Bearing boxes had enough play to "move" along with the axles when things went up/down along the track. Max speed was maybe 20 MPH on a downgrade before the operators kidneys exited the cab..

I think maybe the "spring wound rollers" where meant to be a "shock absorber" of sorts ??

Found more info online, these Hyatt roller bearings with "spring rollers" where apparently more accommodating to axle/bearing box misalignment, but more expensive to produce and fell "out of favor" by the 1920's/30's.

https://books.google.com/books?id=RWgrA ... ng&f=false

Rollers and races (inner hardened race pressed on axle and outer hardened race pressed into bearing box) where in pretty good shape after being abandoned to the elements for about 40 years.

Cheers, Kevin.

During WWII, the Rock Island retrofitted driver axles of quite a few engines with Timken roller bearings. 64 4-8-4's, 18 4-8-2's, 28 2-8-2's and one 2-10-2. All but 40 of the 4-8-4's had built up bar frames. Of course, these aren't small engines, but engines with bar frames can be retrofitted.

Tom Hamilton

The 'spring' rollers would have benefited from the longitudinal grain 'refinement' during drawing of the stock. The separation of the surface might enhance oiling between roller and race under load.

Hyatts are cylindrical, so there is no lateral stress that would involve transverse 'spring' action, and you'd be ill-advised to use the 'wound' construction on a tapered Timken-style roller.

True, but a simple spiral groove ground into the surface of a hardened cylinder would aid in lubrication and be easier to manufacture.



Well, seems to me that if you press against (from a shock load) the outer diameter of a precisely ground spring it has to "get longer" for a while until the shock load is removed. In these bearing there was no "end/axial/side-to-side restraint", so the rollers would "float" side-to-side inside the races (WRT end to end / Axial movement). There where separate bronze thrust bearings between the bearing boxes and the rear face of the solid steel wheels to align the frame to the flanges.

Of course, I did not design these bearings and can't know their reasoning for that method of manufacture, just speculation on my part.

Cheers, Kevin.

My chief problem with the 'spring' construction would be fretting damage near the point of contact between 'turns' of the spring right at the imposed pressure face. I would further be concerned that you'd get preferential stress raising across what is basically a kind of aleatory gauge corner that would induce cracking laterally into the "square bar" of the bearing steel. That's going to start running away as the cracks allow more and more deformation under load...

The 'normal' place you'd put lubrication grooves is where the Isothermos box puts them for plain bearings: in the metal of the race, where small dislocations don't proceed to deformation or spalling in the rolling members. See also how uncaged needle bearings do their lubrication; to my knowledge, there are none that have circumferential grooves or relieved areas in the needles; they have a continuous ground line contact their whole length.

In the early attempts at Lima to remedy the disaster of the American Arch articulated trailing truck, an interesting expedient was tried: in a long Delta-style two-wheel truck the Bissel geometry was calculated as if the truck were a large two-wheel trailer with its axle at the rear position, and the front axle was allowed to 'float' laterally without forced centering. That was nominally done with a pair of 'hardened steel rollers' transversely placed in the pedestal space, roughly where the Fabreeka pads were in the original centipede-tender construction. It might be interesting to see what would happen if the 'spring-wound' roller construction were tried in this application, where there is controlled (equalized) vertical load, and reasonably frequent displacement from centerline, but relatively slight overall displacement even on sharp curvature.

Yes, seems like this would be "stress riser city", but it is a series of "outside corners" along the length of the roller (about 5 or 6 "twists" along the ~5" length of each roller).

I was taught/learned that sharp inside corners are the big source of stress risers/cracking. Outside corners/edges are usually "rounded over/break all sharp edges" to; "make it look nice". "don't cut any human skin/ piping / cables during handling" and "eliminate contamination from broken off bits from edges (in clean room / space environments),

The "spring rollers" from 1919 did not show any signs of cracking, a few corrosion spots (maybe 2% of the external surface). Races looked almost like brand new with a "well pressed" finish, but no grooves, pitting, or cracks.

The "cage" was two round "washers" with a smaller diameter rod through each roller. Ends of the rods where "peened over" to complete the bearing cage. The rods and end washers where a softer steel and had some corrosion present.

The specimen locomotive was built September of 1919 (start of the roaring twenties) and was repurposed from the NYCRR Despatch Car building shops (East Rochester NY) in WWII to a landing craft / landing barge factory on the shore of Lake Ontario. It was rolled off the "end of track" onto an asphalt parking lot about 1965 and slowly sunk into the gravel until it was recovered about 1998.

Very interesting detail design. That is a highly interesting version of 'cage' implementation, as it keeps contact entirely away from the rolling-element surface (at the expsnse of limiting the effective width of the bearing races). If I understand the action, it's like Morse roller chain without webs in the 'links' of the chain... what was the clearance between the inner pin and the roller ID?

I assume a bearing constructed this way had separate hubliners and contact surfaces.

Thanks for the detail!

I'm going from memory here (I cleaned repacked these bearings over 10 years ago), I'm gonna say the "pins" between the roller cage side "washers" were about 1/4" diameter, and the bore inside the "spring wound" roller elements was about 7/16". So about 1/16" clearance between the roller ID and the cage pin OD.



Correct, this bearing design had no lateral/axial restraint of any kind inherent to the roller bearing. The axle had a hardened cylindrical interior race pressed into place and the bearing box also had a hardened cylindrical exterior race pressed into the bearing box.

On the outside faces of the bearing boxes was a bronze thrust washer between the outside face of the bearing box and the inside face of the steel wheel. The bearing boxes had flanges that pressed up against the side frame of the loco to control side to side motion of the axles.

This was a "low speed" switching/industrial locomotive, so these simple arrangements seemed to work.

Cheers, Kevin.