Hints & Tips № 8 — Straightening Meccano Angle Girders

“Impossible”, I hear you mutter, “What’s he on about now?” Well, it’s difficult, but in many cases it can be done. In fact it’s probably harder to describe how it’s done than to actually do it. But here goes (if I totally confuse you, ask me for a demonstration).

Angle girders, of various lengths, are fairly sturdy parts, but the longer they are, the more susceptible they are to damage. A careless foot, or dropping a model, can easily kink a girder, which is particularly galling if it happens to be one of those expensive 24½” ones, or has perfect paintwork.

Removing the kink is relatively easy, if you have a vice, though this is only the first step. Wrap the girder in paper to protect the paintwork, and squeeze each ‘leg’ of the girder in the vice to take out the kink, several times if necessary. With the kink removed, the girder will still, in all probability, not be straight. This is because when anything is bent, even a metal Meccano part, part of the material is stretched. If the object does not spring back to its original shape when let go, then that part of the material is ‘permanently’ stretched.

Most ‘de-kinked’ girders will be curved, because the outside part of the leg has been stretched, and is longer than the inside part (where it joins to the other leg, to form a right angle). If the outer part of the leg has been stretched it should, theoretically, be possible to ‘compress’ it again to its original length and thus straighten the girder. This is the tricky part. Just trying to bend the leg back straight, over your knee, for example, will simply kink the girder again.

Put the girder back into the vice, so that the leg you are trying to straighten is vertical and gripped in the jaws — tight. The spot where it was kinked (you did make a note of where that was, didn’t you?) should be about 1” (25mm) in from the right hand side of the jaws, leaving, say, several inches projecting to the right of the vice. The other (horizontal) leg should be in contact with the top of the vice jaw.

Straightening a bent angle girder
Straightening a bent angle girder

Now bang down gently with your fist on the projecting part of the girder, about 3” (75mm) to the right of the vice, three or four times. Move the girder about ¼" (6mm) to the right, in the vice, and repeat the operation. Move it another seven or eight times, banging in each position, remembering to keep the vice tight. Now take the girder out and inspect the results, by eyeing along it. If the girder is kinked again, you’ve banged too hard. If it’s not yet quite straight, repeat the exercise, perhaps over a longer length of the girder, either side of the old kink.

Of course, you’ll probably have to repeat the process with the other leg and, by now, may be wondering whether it’s worth the effort. If you’re left handed, you may have to do it all the other way round.

I have had some success using this technique, and providing you are willing to experiment and gradually get the ‘feel’ of the metal (and this is quite variable, remember) I hope you do too. If the kink is near the end of the girder, this method may not be possible — so get the hacksaw out and make yourself some short angle girders!

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