Stanley produced two steel block planes: the No.118, and the No.S18. (Technically, Stanley also produced the “Stanley-Handyman”, H101 trimming plane, and H102 block plane, in the 1960s, but I think these planes are junk).
The No.118 was advertised as the “School block plane“, it seemed to be geared towards manual training classes. The entire plane is made of steel, with the blade sitting at 12º. Depth adjustment is by means of screw adjustment, and like many planes of this genera there is no throat adjustment. The “Hand-y” grip, like that of the Sargent was a [bevelled] hole on the side of the plane body. It was produced from 1933-1973.
The No.118 was unique in that it used a thin metal plate, held in place by the front knob, to mark the plane as a No.118. The stud used to maintain the position of the lever cap was fixed in place (i.e. welded to the frog before it is spot welded (see CONSTRUCTION section at the end of this post).
Name plate and fixed pin
The nickel-plated lever cap is held in place by a machine screw with a large pancake shaped knurled knob. The blade depth adjustment mechanism is of the sled-type, manipulated by a machine screw, typical of low-angle block planes. What is interesting about this is that even the sled is constructed using a piece of folded steel.
Lever cap and depth adjustment mechanism showing folded steel sled
The Stanley No.S18 is the indestructible version of the No.18, built between 1925 and 1941. It had a 20º blade angle. This may have been the most expensive pressed-steel block plane to manufacture, because it was likely the most complex, owing to throat, blade depth, and lateral adjustment mechanisms. It really is just an indestructible version of the No.18. Its demise may have been precipitated by the onset of WW2.
This is one of the few all-steel block planes hat has both a throat adjustment mechanism, and a lateral adjustment lever. Due to the fact that the body is so thin, the plane’s throat piece doesn’t fit into the sole, but rather sits atop the body of the plane. The problem with this is that the throat piece is curved, and as the mouth closes, a gap forms behind the throat plate (which can clog with waste).
The throat adjustment mechanism uses an eccentric cam that’s unique to this plane. The cam pivots directly below the knob with the arc-shaped slot swinging over a small, projecting pin that’s peened onto the sliding section, moving the throat piece. The No.S18 had a unique lever cap, which added to the complexity of this “low-cost” plane.
Stanley opted for two different methods of constructing their pressed steel block planes. The No. S18 used one stamped piece to hold the lever cap machine screw, and another to hold the depth adjustment mechanism. Both are riveted in place, using at least 10 rivets. The No.118 alternatively uses a one-piece frog, and appears to be spot-welded to the plane body.
Plane sub-structure: S18 vs. 118
On the S18, the fore finger-rest and rear thumb-screw thread are attached to the plane body by spot-welding (look closely under the plane and you can see the tell-tale rings).
CHEAPER? NOT SO MUCH
One would think that these planes were cheaper, but this was not always the case. In Stanley’s catalog from 1934, (Catalog No.34), the No.18 was being sold for $2.85, whereas the No.S18 was being sold for $3.45, a 20% premium for being indestructible (and likely somewhat less usable). It might be that it actually cost more to construct the No.S18.