Converting Allen Archbar trucks to sealed ball-bearings

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NP317
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Location: Northern Oregon

Converting Allen Archbar trucks to sealed ball-bearings

Post by NP317 » Sat Mar 04, 2017 12:16 pm

I recently finished converting a pair of 14-year-old Allen archbar trucks from the old half-bearing design to new sealed ball bearings. I also converted them to leaf springs, from the old coil springs.
This is in preparation for placing them under the tender of my 90-ton 2-8-2 logging Mike.
Polson #90.jpg
To do this work I machined new wheel sets and axles, new axle boxes (all castings from Allen Models of Nevada), and used twin-leaf spring sets I got long ago, from a forgotten source! (sorry, in advance.)
Here are the parts I replaced:
NewBB ABTrucks-3 small.jpg
Replaced parts
The finished trucks came out just fine:
NewBB ABTrucks-2 small.jpg
The new Allen axle boxes are narrower than the original half-bearing boxes, and much more scale. This required drilling new mount holes for the inner bolts in the bar frames. The challenge was the less-than-one-diameter hole spacing change. So I used an end-cutting 4-flute mill in the milling machine to make the new holes.

For the leaf springs, I required stronger springing than they provided. Solution was to cut rubber blocks that I force-slipped inside the installed leaf springs. A small amount of grease lubed the blocks sufficiently for his operation. Vertical holes in the blocks fit over the central rivets holding the leaves together, securing the blocks in place. I also drilled some holes in the blocks to "adjust" the compression forces. This was done by making several test blocks to determine the desired compression forces. The rubber block was a "Jeweler's block" found on Amazon.
Search Amazon for: Jeweler's Solid Rubber Bench Block - 4" x 4". Cost was about $8.

Finally, I R&R'd the old MCC vacuum brakes by adding actual brake liner material to the shoe surfaces. The bulk liner material came from McMaster-Carr. I got the thinnest available, at approx. 3/16" thick.
I drilled three 3/16 inch "divots" into each pad and into each cleaned, roughed-up shoe surface, to provide anchors for the Quick-Set JB Weld used to bond them together. These modified shoes will work FAR better than the old bronze-shoes-on-cast-iron-wheels, which are normally referred to as "bearings..."

Anyway, Steve at Allen Models of Nevada was very helpful, selling me the castings and bearings I required for this conversion.
Thank You, Steve.
And my Polson #90 logging Mikado will have correct-appearing trucks under the tender, that will be essentially maintenance free, to haul my arse around the tracks! I'm looking forward to that in a year or two, depending on how productive I can be in my new shop.
~RN

Steve Alley
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Re: Converting Allen Archbar trucks to sealed ball-bearings

Post by Steve Alley » Sun Mar 05, 2017 5:02 pm

Thank You for the comment about me and Allen Models. I would like to add that you said the new Journal boxes are narrower. They are wider for the bearing to fit the casting. But I did not do this Steve Szuiderdvee did this. He was a partner with Marty Knox at one point of Allen Models history. Need to honer who was the person that made the change. I have been working on a pattern for the future, that just makes the boxes. This will be for the kit basher to make his own truck design. We are working on a brake kit also, This kit will fit all of the Allen Trucks. I am Look at the brake cylinder to be mounted in the center of the tender frame to work both trucks as proto type. Steve Alley

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NP317
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Re: Converting Allen Archbar trucks to sealed ball-bearings

Post by NP317 » Mon Mar 06, 2017 11:14 am

Steve:
Perhaps the new axle boxes are wider (I cannot verify measurements, because new snow is keeping me from the Shop at the moment!), but their mounting holes are closer together than the older design boxes.
If you expand the photo of the completed trucks, you can just see the old mounting holes visible sticking out from under the nut/washer of the vertical bolt.
Regardless, the new axle box castings are excellent!
~RN

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Gary Armitstead
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Location: Burbank, CA

Re: Converting Allen Archbar trucks to sealed ball-bearings

Post by Gary Armitstead » Mon Mar 06, 2017 3:04 pm

Image

RN,

Thanks for the tip on using Steve's new journals with the bearings. My 36 year old caboose (recently restored by to its "glory days") still has the half-bearing brass in the trucks. I have been wanting to change-over to ball-bearings and now you have shown the way. I have a new print from Steve showing the new drilled holes in the bars is now 1.188. I don't have my old prints anymore from the build of my ten-wheeler to check the old dimension. I really don't want to change the bars if I can get away with it. Are the bars on your trucks made to the old prints that Gene had?
Gary Armitstead
Burbank, CA
Member LALS since 1980
Member Goleta Valley Railroad Club 1980-1993

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SZuiderveen
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Location: Baltimore

Re: Converting Allen Archbar trucks to sealed ball-bearings

Post by SZuiderveen » Mon Mar 06, 2017 9:54 pm

Steve A., thank you for the kind words.

I had to make compromises when redesigning the arch bar truck to cast iron. I wanted a genuine MCB journal box, from the 1918 proceeding book. I also wanted to use Steve Pontarelli's excellent journal box covers. Frankly, the original Harpur journal boxes are a caricature of a real journal box, from the original Thornburgh Model Railroader series in 1959. The new drilled holes are the scale distance of an MCB 5 1/2 x 10 journal box. I figured anyone doing a retrofit could get the old holes wire welded up, ground, and respotted. The casting is 1/8" taller than MCB, to accommodate the existing bend of the arch bars. If you want to make a scale truck (and these boxes could be used for a custom truck, or even an Andrews truck) simply mill them down an extra 1/16 top and bottom, the rest of the box is directly from the MCB drawing. The core is designed to be cleaned out with a 7/8 end mill (if you are doing large batches, like I have been) or they can be bored out if you are only doing 8. The roller bearing is a very common size that can be sourced far into the future for maintenance.

BTW, the box covers can be pinned with a #17 wire nail, but I have had the same experiences with losing covers on my CliShay, so I epoxy them on, using sealed bearings I do not need the access to lube.
IMG_1231.jpg
Present batch of Allen journals being machined.
Regards,
Steve Zuiderveen

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NP317
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Re: Converting Allen Archbar trucks to sealed ball-bearings

Post by NP317 » Tue Mar 07, 2017 10:45 am

Gary Armitstead wrote:Image

RN,

Thanks for the tip on using Steve's new journals with the bearings. My 36 year old caboose (recently restored by to its "glory days") still has the half-bearing brass in the trucks. I have been wanting to change-over to ball-bearings and now you have shown the way. I have a new print from Steve showing the new drilled holes in the bars is now 1.188. I don't have my old prints anymore from the build of my ten-wheeler to check the old dimension. I really don't want to change the bars if I can get away with it. Are the bars on your trucks made to the old prints that Gene had?
Gary:
Nice caboose! It has survived the years in good shape.

I used the original frame bars and simply made one new mount hole - as described - for the inner bolt on each box. I did not even weld in the old hole, because the new axle box design has a "captured" bolt through upper and lower ears. In fact, I never even unbolted the bar frames from the center casting! I milled the new holes with all assembled.
I did mill shallow grooves in each new box (< 1/16" deep top and bottom) for the bar frames. This made assembly and alignment much easier.

My goal was to make the conversion replacing as few parts as possible. I could have used the original wheels with new axles, but I like the new spiral-backed wheels now offered by Allen of Nevada, so made those too.
And now I have wheel and axle box sets for another pair of trucks, if desired.
Anyone want the old parts? Let's make a deal...
~RN

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NP317
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Joined: Tue Jun 24, 2014 2:57 pm
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Re: Converting Allen Archbar trucks to sealed ball-bearings

Post by NP317 » Sun Apr 02, 2017 9:03 pm

The used arch bar truck parts detailed above have been sold and delivered.
May they roll on.
~RN

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