Thread: Budget friendly straightedge

Despite Britain leading the Industrial Revolution and inventing standardised threadforms it was the Americans who really got behind establishing proper standards for manufacturing and construction; and the rest of the world ended up pretty much following them. As per ASME and ANSI unless it states “dry” then threads and contact faces should be lubed with SAE 40 weight oil. So for a bolt that’s the threads and under the bolt head, for a stud then again it’s the threads plus the face of the nut. Also the threads have to be manufactured to specific tolerances and clean.

Originally Posted by Chief Tiff

Despite Britain leading the Industrial Revolution and inventing standardised threadforms it was the Americans who really got behind establishing proper standards for manufacturing and construction; and the rest of the world ended up pretty much following them. As per ASME and ANSI unless it states “dry” then threads and contact faces should be lubed with SAE 40 weight oil. So for a bolt that’s the threads and under the bolt head, for a stud then again it’s the threads plus the face of the nut. Also the threads have to be manufactured to specific tolerances and clean.

AH HA!

That explains why there are strong opinions on both sides, but until your post I haven't seen such a clear and simple explanation of the differences as opinions I've seen seem to approach the issue on the basis that it's a universal dry or lube. Thanks.

I've probably very carefully torqued countless bolts dry when they should be lubed, and vice versa, because I don't recall seeing any advice to the contrary in workshop manuals etc. No doubt that's because the writers / manufacturers of technical manuals directed to qualified tradespeople reasonably assume that readers understand what you've just said.

I feel a little better knowing that some of the confident opinions I've seen in the past on make specific and more general car and outboard forums by qualified mechanics weren't any clearer on the issue than I was until a few minutes ago.

Thanks again.

Originally Posted by Chief Tiff

Despite Britain leading the Industrial Revolution and inventing standardised threadforms it was the Americans who really got behind establishing proper standards for manufacturing and construction; and the rest of the world ended up pretty much following them.

Off topic, but building on this.

I have an interest in military history.

When the US started supplying Britain with motor vehicles, aeroplanes and other materiel in WWII, British mechanics were often astonished by the accuracy and simplicity of replacement parts for American machines due to the consistency of production control (which isn't the same as quality control). Pull the old one out, slip the new one in. No reaming, filing, peening or other on site modification to make the item fit as often required by British products.

Meanwhile the Germans, despite their supposedly brilliant engineering and improved production under Speer, were actually producing things like main battle tanks in a sort of cottage industry with various makers supposedly making the same components in diversified factories with problems about production control, further complicated in some instances by using unqualified and hostile slave labour.

America's immense and hugely efficient production line processes and manufacturing capacity ensured that it would win the war so far as those aspects went.

Post-war, W Edwards Deming, an American statistician who developed management, production and quality control methods which were ignored in America was instrumental in applying them to industrial production in Japan, which saw the higher and consistent quality of Japanese consumer and other goods start to overtake American ones by the mid-1960s.

If only the Americans had taken notice of Deming and his quality control principles like the Japanese did, they could have maintained their dominance in mass production. Instead they produced the unstable Chevy Corvair and fire prone Ford Pinto and gave birth to Ralph Nader and other consumer advocates, without whom the consumer protection movement and protections might have taken very much longer to emerge. Quite a step down from American manufacturing dominance a bare two decades earlier, and entirely an American 'own goal'.

That problem of production control was avoided here when we chose US manufacturing equipment and methods to produce the Lee Enfield rifles at Lithgow. A major hiccup was the ‘Enfield Inch’ But the yanks were up to it.
I understand Henry Ford didn’t produce the Merlin for RR because of the tolerances specified meant hand fitting which doesn’t work for mass production with whatever labour the drafts have left.
The German cottage industry was a major problem for the allied bombing effort so I guess that’s where the idea of wiping out whole citys by firebombing happened.
H.

Maybe this article helps to clear up the requirements when torqueing bolts, but it doesn't help the problem where this thread all started. The important thing when tightening down a head is that it is flat and all bolts are done to the same correct torque.

Originally Posted by Treecycle

The important thing when tightening down a head is that it is flat and all bolts are done to the same correct torque.

Except when different torque specs are specified for some of the bolts!
https://arpinstructions.com/instructions/134-3610.pdf

Originally Posted by droog

Except when different torque specs are specified for some of the bolts!
StackPath

Can't say I've done heaps of head work and it's a long time ago, but IIRC the same torque applied to all bolts or studs. Those torque limits sound weird, almost as if the compression ratio is 2/3 lower on bolts 11 to 15 than the rest, which obviously it can't be. Any idea why such a big difference on one side of the same head?

Originally Posted by 419

Can't say I've done heaps of head work and it's a long time ago, but IIRC the same torque applied to all bolts or studs. Those torque limits sound weird, almost as if the compression ratio is 2/3 lower on bolts 11 to 15 than the rest, which obviously it can't be. Any idea why such a big difference on one side of the same head?

Because they are short bolts into limited amount of block material, they are also smaller thread size.