... for a filing aid which might help. For "B" blades, print a straight template for a strange-size turnout having a 12ft straight switch and 1:32 crossing angle. The turnout road will then be straight. You need to print only this part of it. Make it up on some scrap copper-clad with the stock rails only (blue rails). Make sure the set bend is accurate and correctly positioned by measuring the stock gauge at 2 in the diagram. There are no curved sections: 2_090803_310000000.png The yellow rail is the blade being worked on. Mark it all over with waterproof felt-tip marker, so that you can see where you are filing. Make sure you have it the right way up (thick edge at the top). File the back of it, just going down to the web at the tip, and running out in a length of 29mm (29.33mm to be precise) at the end of the planing. Don't go far into the web, otherwise the blade will be too flexible ...