How to square a piece of stock metal

I bought a couple of pieces of steel 1/8" thick, about 3"x30" that will form the main frame of a Simplex. But the pieces metal I got are not straight. The main problem is that the edges are not perpendicular to the two larges faces. What is the best way to square these up without a mill? (I've been working at it on my grinder, but I'm not sure I going about this right)

Here's an image: I need to make the piece square to the dotted line:

There are two ways for you to get a job like that square, I suggest.

You can file or grind the duff edge, testing as you go with straight-edge and square, until it is straight and at right angles. This takes time and skill. The more skill you have the less time it takes, and the bigger the workpiece at the end.

Or, you can set it up in a mill or similar machine which has faces made at right angles, and then the machinery will produce what you need fairly quickly and without much waste.

So, if you have insufficient skill and no capable machine it would be worth joining a model engineering club. They may have a member or two who wants to pass on his skill to the next generation. Alternatively, there may well be a firm near you which can help using their machinery. By the time you have needed their help for three or four jobs it may occur to you that you would be better off spending some money on a mill (etc) rather than paying someone else to use theirs. That's what I did, anyway.

Regards, Tim

As you have made it clear you do not have a mill available....which would obviously be one of the easiest solutions

You could try and sandwich the metal between two thicker pieces preferably straight and that could help to minimise error when grinding, make sure your rest is square with your grinding wheel...take your time...best of luck

Gary

At an 1/8 thick why not just draw file the edges. Using a combination of files it should not take too long and good filing excercise.

If you have a lathe you could bolt it down to the cross slide and put a mill or flycutter in the chuck, then run the stock past the cutter in stages to do your frame.

Or there's always the grinder, square, straightedge, and file.

Do the edges really need to be square? In theory you could drill some datum holes and lay everything out on the frames to those, only making edges square where something sits on the edge at a dimensioned distance. I mention this as I've done it often for fixture work in industry to lower costs. Often everything in the fixture can be designed to be controlled by fits to accurate machined holes and cutouts, not to the edges. The plate is placed in a mill or jig borer, holes laid out and accurate openings made, then the outside can just be sawcut roughly to shape and the edges deburred. This saves a lot of money and time vs prepping all edges of the plate square and flat.

Just food for thought. Your mileage may vary.

Jared,

Similar to Jeffs description (mounting the plates on the lathe cross slide), it might be worth taking a look at this superb description of a modified William build here **LINK**

The frames for William are a similar length to Simplex and the builder was faced with almost exactly the same problem.

If this is not a realistic option, then carefully clamp both strips of steel together (using say 5 off strategically positioned 3/32" or 1/8" rivets), switch the radio on, clamp the plates in the vice soft jaws and start filing with your longest flat file.

I have recently cut a set of Rob Roy frames using a hacksaw and a set of files. I appreciate that Simplex is about 10" longer but I think it is the thought of filing the strips that is so off putting i.e., provided that your marking out and hacksawing are done very carefully, once you get going, you really will get there quicker than you think.

Phil H

Hi Jared,

A long straight edge, vice, set square, and files and some decent light.

I have never milled any loco frames, though some have been of quite complicated shapes plus all the cut outs in the frames and lightening holes/openings, plus of course the openings for the horncheeks which must be done very accurately.

I rivet the 2 frames together before commencing any of this .

When I use the long straight edge (for many years a long builders level owned by my Dad), chalk marks were put on the frames that needed attention.

Cheers,

Julian

As previous posters have said filing is not to difficult. As you do not have a great amount of material to remove the filing will not be too much hard work but will be an exercise in precision. You may be pleasantly surprised at how accurate filing can be. You will need a good square and straight edge as a reference but you should finish up with a straight and square edge to your frames. Patience will help as well.

Mike

More accurate than milling in many cases.

If using a hand file on brass start with a new file. Use it only on brass. Files used on steel do not do so well on brass.

Set it up with a piece of angle iron clamped on the side and use the top surface of the angle iron like a filing rest .