Converting journal boxes

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Gra2472
Posts: 274
Joined: Sat Jan 25, 2020 8:02 pm
Location: Monte Rio California

Converting journal boxes

Post by Gra2472 »

I have a set of Allen arch bar trucks that have flat back bearings in them. I was wondering if any of you machine shop wizards have a good method for converting them to roller bearings.

Thanks

Garrett
7.5" Allen Mogul
3 x 7.5" West Valley Baldwin Westinghouse Electrics
The railroad is almost done.
G. Augustus
Monte Rio, Ca.
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SZuiderveen
Posts: 530
Joined: Sun Jan 05, 2003 12:03 am
Location: Baltimore

Re: Converting journal boxes

Post by SZuiderveen »

1. Purchase 8 new journal boxes and lids from Allen. Purchase 8 R6-2RS roller bearings.
1a. (Optional) weld up and grind smooth outside journal box holes in archbars
2. Spot new outside hole at 1.1875” from inner hole
3. Machine new journal box. 1 5/8 inches tall to fit between archbars. Face rear side .8125 from centerline of bolts. Bore for bearing .875” x .966” deep centered .8125” above bottom archbar seating. Elongate bore .005” toward the top and .005” toward the bottom to permit flexing of truck.
4. Shorten axles to 10.5625” long. Find and spot centers.
5. Machine axle ends to 376”(light press fit to R6 bearing) x .280” long. Press or loctite R6 bearings to axles.
6. Reassemble truck.

Regards,

Steve
Attachments
Truck before final trimming and application of journal lid.
Truck before final trimming and application of journal lid.
Mounting of R6 rollerbearing
Mounting of R6 rollerbearing
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NP317
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Location: Northern Oregon, USA

Re: Converting journal boxes

Post by NP317 »

I did what Steve Z did:
Purchased the new design axle boxes from Allen Models and rebuilt the trucks with sealed ball bearings.
https://allenmodels.com/locomotives/ten ... on-13.html
You should also request the print for the new box design. The required dimensions are all there.
The new boxes are wider than the old design so I had to drill one new hole in the bars for each axle box. (Nobody has noticed the old holes...)

I know you specified roller bearings, but the ball bearings are working just fine hauling my Butt around.
No need for rollers, and it is easier to modify the trucks using Steve Z's method described above.
RussN
Gra2472
Posts: 274
Joined: Sat Jan 25, 2020 8:02 pm
Location: Monte Rio California

Re: Converting journal boxes

Post by Gra2472 »

Thanks guys! Thats really awesome. I think I used the term roller bearings as more of a type than specific design. Ball bearings should be perfect. Most excellent.
7.5" Allen Mogul
3 x 7.5" West Valley Baldwin Westinghouse Electrics
The railroad is almost done.
G. Augustus
Monte Rio, Ca.
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Dick_Morris
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Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: Converting journal boxes

Post by Dick_Morris »

It's been a very long time ago. Using old style aluminum boxes, my recollection is that I made steel sleeves with around a 1/16 inch wall (maybe thinner), bored the boxes to fit the sleeves, and Loctited the sleeves in place. I think I followed up with some JB Weld or may have used JB Weld before boring for the sleeves. There isn't a lot of meat left at the sides of the bore. I went to the shop to verify but the covers are glued in place. Otherwise, I did them similar to Steve's description and used the same bearings. I believe the diameter through the wheel with mine is larger with only the end for the bearing stepped down to 3/8" to reduce the chance of bending the end of the axle.

I also changed the size of the bolts. I used #5 at the journal boxes and #8 in the center. The bolts on the print were too oversized for my tastes. I also used cold roll steel for the bars instead of the pre-formed hot roll that was supplied. I have castings for several more. I machined the 32 wheels but I still need to finish the machining and assembly of the other parts. For them, Gene was able to supply uncored journal boxes. I plan on trying 3/32 bar for the center arch bar on this batch. A smaller bar was often used there in the prototype.
Rwilliams
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Joined: Thu Dec 22, 2005 2:45 pm
Location: Central California

Re: Converting journal boxes

Post by Rwilliams »

Some arch bar trucks were constructed with the top bar in a U shape or short leg channel. Same overall width as the other bars, but featured both sides on the top with ridges about 5/8 wide and 3/8 tall. Scaled down this is not much in 1.5 scale, but can add some interesting detail to a truck seldom seen in model building.
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