View single post by Salada
 Posted: Fri May 1st, 2015 06:33 pm
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Joined: Mon Nov 4th, 2013
Posts: 1169
A versatile, quick & easy to make crossing V (frog) assembly jig.

1) Glue a straight thin piece of wood to a wood base.
2) Using a short bit of rail as a spacing guide, glue a 2nd strip of wood tight alongside.
3) Screw a 3rd strip of wood so it can be swivelled to the correct frog angle then locked.

The photos will make this rather more understandable.

The assembled jig:

The burnt area is where the two rail V point is soldered together onto a thin scrap of brass that fits into a slight depression cut into the jig base plate. To fit into the jig one of the crossing rails (either the point rail or the splice rail) obviously must be straight. The curved crossing V was made in the jig & then bent afterwards.

The second screw hole, to the right of the screw, allows the swinging strip to be re-positioned to cope with very obtuse angles such as K crossings (diamonds).

The faint pencil lines give automatic alignment for commonly used crossing angles.

The two glued wood strips are bevelled on their lower edge to fit the foot of the rail & hold the rail exactly vertical. See vertical elevation drawing below :

The two glued strips must be held tight against the rail profile whilst glueing to ensure a tight, vertical fit to the rail.

To use the jig, first prepare the rail ends by filing etc. Slide one rail into the guide slot, swing & lock the swivelling strip to the correct angle and hold the 2nd rail in place by thumb & something heat resistant. See photo below :

Flux the job up & apply heat + solder, job done.

Total cost nil, jig assembly time about 10-15 minutes. Simple. like it's designer.


This jig was about the only fancy tool used to build the following switch-work :  

The wheel-set is my one & only track gauge !

I believe the Herb-O-Frog (TM) switch building manual suggests starting with the curved stock rail but then he is also a member of the "drive on the wrong side of the road" Club. My preference is usually to start from the straight stock rail, if there is one.

As I had to fit FIVE V's into only a few inches I freehanded the working drawing by drawing along a thin flexible lath that automatically makes a flowing curve. The frog units were then positioned as in the next photo :

I had to include the beer mat as a rare example of a steam loco illustration. You can also hear the BNSF's rolling through from the bar and, if you step outside**, you can see them. **( this being the U.S. you have to leave your beer inside, how weird). I can thoroughly recommend the Beaver Street real ale (craft ale) brewery.

The photo above shows a thin wood lath held to the closure rail by a bulldog clip so as to establish the correct, flowed, position for the frog prior to final soldering down. Each frog had to be correctly located not to a stock rail but to the next frog !.

Finally, two photos of the finished job :

The very short switch "toes" and severe departure angles are typical of UK colliery track, as is the dirty ash, muck etc. "ballast".
Only 0-4-0 locos & SWB wagons allowed !!

You may notice that there are 5 V's but only 3 polarity change wires (yellow/green). This is because 4 of the frogs are built & wired as electrical pairs to simplify route switching.

My preference is to build complex trackwork 'on the bench' rather than in situ on the baseboard - I ain't that brave.

All photos by Salada.

Regards,                  Michael 


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