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Socket headed capscrews -when first used?


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#1 Garsted

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Posted 04 August 2022 - 19:59

A friend is re-commissioning the E type ERA known as GP2, and there is some debate in the workshop about whether the large number of cap screws (Allen screws) on the engine are correct for the period or later additions. It was designed just before WW2 and finished just afterwards.
Does anybody know:
When they were first invented
When first used in motorsport or, more to the point,
Whether they were ever used by ERA?

Thanks, Steve

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#2 D-Type

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Posted 05 August 2022 - 13:53

According to Wikipedia (usual health warning applies) the Allen screw was patented in 1910.  So they could have been original.

As the E-Type engine was similar to the early ERAs so it would be worth taking a look at them.  But after over 80 years of almost continuous racing, they are all far from original.



#3 GregThomas

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Posted 05 August 2022 - 19:15

There are a few engine bay pics of an E - type on line. There appears to be a lot of studs with nuts used which I would think would have been usual practise postwar.

I'd do some comparing car to pics.



#4 Bikr7549

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Posted 08 August 2022 - 03:14

A look at drawings and photos in Pomeroy's The Grand Prix Car volume 1 shows external hex head fasteners holding the cam/valve covers in place for cars of roughly this vintage-ERA cars are not discussed here; tho general practices might be assumed if you want to do that. The 1927 Delage 1.5, Bentley 4.5, Auto Union and the Mercedes. Some of these may be nuts rather than bolts, and some of the German cars may be using acorn type nuts (rounded and closed over type nuts) rather than plain hex. Plates 36 and 37 in the Quick Silver book (Cameron Ear) clearly show the acorn type being used on Auto Unions.