3/4"Arch Bar Trucks

[jbodenmann]

Then to the lathe.

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[jbodenmann]

Here is how it fits over the main body of the fulcrum.

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[jbodenmann]

And here are all the bits.

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[jbodenmann]

Silver soldered.

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[jbodenmann]

And here is the fulcrum pivot silver soldered to the main body. Laying on the steel rule is a tiny piece of silver solder, the same size as the piece that was used here. Both parts were fluxed and fitted together, then the tiny piece of solder was set in place where they meet. Nice even heating with the torch and the solder slurped right into the joint, easy peasy!

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[jbodenmann]

Now the fulcrum can be held with a square collet in the spindex to drill the hole for the lever pivot pin.

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[jbodenmann]

Now the spindex has been rotated ninety degrees so the slot for the lever can be milled with a brand spanking new 1/16" end mill. The spindex is a very handy little trinket, and can be bought here in the states sometimes for as low as $39.00. Buy the collets as you need them.

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[jbodenmann]

Now the ends can be soft soldered on. Remember now this is just to be used as a master, soft solder would not be strong enough for an actual fulcrum. Once again a tiny piece of solder has been put between the parts. The solder was hammered thin on the steel table and then a wee bit nipped off. You can see the piece of solder between the parts.

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[jbodenmann]

Here a length of 1/8" square brass has been used to align and weight the square end for soft soldering. The little vise will act as a heat sink and prevent the solder on the other end from melting.

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[jbodenmann]

Now here we go! The brake beam sort of mocked up. 1/8" brass for the actual brake beam, .071" round brass for the truss rod with a #1-72 nut. And in the middle is the fulcrum with a lever stuffed through.

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[jbodenmann]

Last one for now. Still to be made are the brake hangers and safety hangers, safety hanger brackets, column guides, I beams for the bolster, and side bearings. Now I know why the railroads were happy to do away with arch bar trucks! But they sure are fun to model.
See you in the funny pages
Jack

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[jbodenmann]

Hello My Friends
Here are a few more photos of what I have been up to. The wheel will have a finished diameter of 2-3/16".

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[jbodenmann]

Here the fluting for the backside of the wheel is being carved out using the milling machine and rotary table.

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[jbodenmann]

Here you can see how the fluting will be let into the back of the wheel.

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[jbodenmann]

Set in place

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[jbodenmann]

And well slurped up with soft solder

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[jbodenmann]

And all the little bits ready for reproduction.
Too much fun
Jack

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[jbodenmann]

Hello my friends
Here are a few shots of the arch bar trucks. Went to the Spring Meet at Los Angeles Live Steamers and picked up the castings. Here is a wheel and axle assembly. These wheels are just brass to see how things work out. The final castings will be steel.

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[jbodenmann]

Here are the arch bars and axle boxes. The backs of the axle boxes are held in place by #00-90 flat head brass screws. The top two arch bars are 1/16" x 1/4". The bottom arch bar is .040" x 1/4".

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[jbodenmann]

Here you can see the half brass in the axle box. These axle boxes and half brasses are designed so that once the axle is stuffed in, the brasses can not become misplaced.

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