Tuesday, April 27, 2010

A sows ear out of a silk purse

Today we head out into the dark lands, to the realms of the arcane arts and black magic. Yes folks, its how to make a point frog with out any fancy tools* in 10 minutes, and theres no secret rituals or handshakes involved (well, unless you have your own goat, but we dropped that bit years ago).

(*Well, I guess what your definition of fancy tools is. A week ago I would have said a fret saw is a fancy tool but since I've now had one donated to the cause, it no longer is. If anyone has a spare lathe going free, just drop me a line)


First up, cut a piece of rail (code 55) to length (about 30mm in this case).
Now, take your fret saw and cut through the rail until you have cut far enough through the top and the foot (the top bit and the bottom bit) that you can see a line on the other side of the web (the middle bit). you don't have to go through, as the line indicates you are deforming the metal so its very thin. If you cut too far, just start again.

The next step is to establish the angle of the frog. For this part unfortunately you need to know where your track center lines are. Transfer these onto a piece of tracing paper. In this example I have marked out the straight and curved lines directly from the point, and then transposed the curved line onto the straight line so that a 'X' is formed


CAREFULLY bend the rail to fit this X. Break it, and you will be set back a whole 2 minutes.

Then move the bent rail to the vice, and position it so that you can merrily file until you get to the point where you are down to the same level as your initial saw cut.

Taking it out of the vice you can see how we have filed out the inside.

Then carefully bend the rail back on itself using the first cut that you made as the center point of the fold
And the end result.


Normally you would do the finally soldering in situ to get the correct angle , but in this case I've just done it as a demonstration to show that its actually fairly easy, and you don't need a fully equipped workshop or a stack of skills.

5 comments:

lalover said...

Goat!!! you had a goat!!!! you lucky bastard...

Amateur Fettler said...

Well, we called it a goat....it was more of a big hairy dog...we couldnt afford a goat.

Motorised Dandruff said...

And by a big hairy dg, we sort of mean a medium sized or small dog, or possibly a cat...

Anonymous said...

Now this is an interesting approach, I have never seen it done this way before and have been lucky enough to observe many master caftsman working in "HO". Did you learn this appraoch from one of those lost souls that model S scale?

Cheers

Pete C

Motorised Dandruff said...

Indeed. I've never seen this method mentioned before either, but it certainly works.