Underhead

wiser discretions, that have the thread of reason to conduct them, offend without a pardon; whereas underheads may stumble without dishonour.

Well, booby, what's that to you, underhead?

Data in the column headed "Underhead" are demerit ratings related to the degree of darkening of the underhead. A rating of 0 indicates a completely black underhead, while a rating of 10 indicates a completely clean underhead.

The valves were removed from the engine at 25 hour intervals and zyglo inspected for cracks in the underhead and stem.

Other important tasks accomplished were the removal of the neutron shield tanks, decontamination of the reactor building air coolers, closed-circuit television inspection of the 282 ft. elevation, raising and parking of all eight axial-power-shaping rod leadscrews, and first steps toward a complete characterization of radiological conditions of the reactor-vessel underhead.

The shape of the underhead is very important: it determines the tightness of the reversed bucktail and the shape of the finished head.

However, if the bolt or screw is the flat-top design (where the top is flat and the underhead is chamfered for a countersunk fit) , length always denotes overall length, from top of the head to the tip of the threads.

So far as absolute strength for carying the load is concerned, this reduction of area need cause no alarm, but the effect of the indentation of the underhead or base of the rail is a different and I fear a serious matter, because it is well known, that it indent a piece of steel and subject it to a blow produces immediate fracture […],