Assembling Cannonball cast archbar trucks

This forum is dedicated to Riding Scale Railroading with propulsion using other than steam (Hydraulics, diesel engines, gas engines, electric motors, hybrid etc.)

Moderator: Harold_V

Post Reply
rkepler
Posts: 53
Joined: Sat Jan 04, 2003 10:50 am

Assembling Cannonball cast archbar trucks

Post by rkepler »

I'm assembling some Cannonball cast aluminum archbar trucks and am having some real trouble putting in the bolsters. If I machine the side frames to plan as well as the axle/wheels the side frames are about 1/8" too wide (each) for the bolster to fit in the slot. There's only one place for the slot for the side frame in the bolster unless I want it to rattle around with no inside support so it seems to me that the side to side distance for the side frames is set by that. If I use that I need to take about 1/8" off the inside of the side frame journal box, and that doesn't seem right.

If there's someone out there with a set of these please let me know the outside distance between side frames where the bolster rides. That'd give me a check on a basic dimension and maybe restart this assembly process.
rkepler
Posts: 53
Joined: Sat Jan 04, 2003 10:50 am

Re: Assembling Cannonball cast archbar trucks

Post by rkepler »

I'm more a 'paint by the numbers' sort of guy and not (usually) a 'file to fit' guy - I like plans with numbers. The instructions start with the sideframes and really the bolster really needs to be machined first. The bosses that the sideframe rides in is already over the 3/4" sideframe thickness on the underside due to pattern draft, so there's really only one place to put the cuts for the sideframe. For me this gave me an 11" distance between the sideframe outsides (and this with a little 'cheating' making the outside cut longer than the inside).

I followed that by adjusteing the sideframe bearing pockets to run on the axles as specified. Part of my problem was that I'd machined the wheels to about .875 instead of .812, if I'd gone with the narrow tire I might have gotten the sideframes to fit buy increasing the bearing pocket depth - instead I took .065 from the pocket face and increased the pocket depth by the same.

They rolled nicely on a friend's track this afternoon. They're going to be cleaned in the morning and painted, then I'm starting on the hopper car above the trucks.
User avatar
Benjamin Maggi
Posts: 1409
Joined: Wed Apr 25, 2007 10:38 pm
Location: Albany, NY

Re: Assembling Cannonball cast archbar trucks

Post by Benjamin Maggi »

Any pictures? The only pair of arch bar trucks I have built were Allen models. I never bothered to make a fixture to ensure all the bars came out the same. I had to rebend some of the bars multiple times, but the trucks were nice in the end.
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
rkepler
Posts: 53
Joined: Sat Jan 04, 2003 10:50 am

Re: Assembling Cannonball cast archbar trucks

Post by rkepler »

I hope the image link works (Really? Images limited to 800 pixels wide? *and* it gives a small preview?):

Image

We'll see how these work with the hopper car soon.
User avatar
Benjamin Maggi
Posts: 1409
Joined: Wed Apr 25, 2007 10:38 pm
Location: Albany, NY

Re: Assembling Cannonball cast archbar trucks

Post by Benjamin Maggi »

They look nice.
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
ccvstmr
Posts: 2230
Joined: Sat Jan 04, 2003 10:37 am
Location: New Lenox, IL

Re: Assembling Cannonball cast archbar trucks

Post by ccvstmr »

Russ, your finished truck looks nice. Congrats! Did you check for truck "flexibility"? Place the truck on some rails and try to roll (1) wheel up on a 1/4-20 nut. If the other 3 wheels stay on the rail...your truck should provide good (and hopefully) trouble-free service.

One thing missing was a bolster center. Without a center, you'll need to shim the car body to get the couplers at the proper height. My solution... spun a piece of alum for the center. Made that as thick as the height of the side sway posts. With all three points in the same plane, placed a 1/32" Teflon fender washer between the disk and the car body bolster (can easily use a zinc plated washer). This provides a minimum clearance for truck movement under the car.

Here's a few pix of several different C-ball bolsters. Some needed repair because the outer tabs on the end of the bolster broke off. The broken piece was TIG welded to the bolster and then machined/filed to shape. The button head screws were installed to provide some spring "pre-load" and provide a better means for the side frame to rock 'n roll over track deviations.

IMG_1686.JPG

Next photo, bottom bolster, had some alum blocks TIG welded to the top of the bolster and machined to the desired height for the side sway pads.

IMG_2302.JPG

Hope this helps you with your car building project. Good luck. Carl B.
Life is like a sewer...what you get out of it depends on what you put into it!
I don't walk on water...I just learned where some of the stepping stones are!
I love mankind...it's some of the people I can't stand!
rkepler
Posts: 53
Joined: Sat Jan 04, 2003 10:50 am

Re: Assembling Cannonball cast archbar trucks

Post by rkepler »

Trucks seem OK on rails, but the proof will be when I have them under the hopper car and the car full of ballast.

I have the bolster centers as well as what seems to be a UHMW washer to go between the center and the top of the bolster. I thought about machining the sway pads but I think that'll wait for some real world use to determine clearances, etc. Right now they're just a hair proud of the bolster center.
Post Reply