Both of these planes are first to be seen in the December 1934 Pocket Catalogue and both were withdrawn by April 1962.
The clip above is from the March 1936 Pocket Catalogue, as any previous mentions were by description only. Throughout the manufacture of both planes, only the M10 is pictured and the same cut was used throughout that period.
As can be seen the M10 was 13″ long and the M 10.1/2 was 9″ long, therefore about the same sizes as the M5 and M4 sizes. But the blade width was always 2.1/8″ wide which went from outside to outside of the plane. Although not mentioned anywhere these planes where manufactured from Malleable Iron, as were all other manufacturers’ equivalents. It is easy to see why this should be so, because any accidental drop of this design plane in Cast Iron would immediately fracture the side of the casting above the side aperture. These planes would have both followed the same changes in construction and colour as the general Bench planes, and this would apply to the appearance of the plane number behind the front knob around 1937 and the introduction of the Ogee frog around 1938. But, as with the other Bench planes, there is always the possibility that these planes would have been put together at the factory from parts available at that time and painted with the colours of the day and this would have been done when there was a new call for stock from stockists in the provinces and thus it is hard to pin down the manufacture date with any certainty. Because on those planes not commonly used there would be a backlog of stock available from a previous casting run and these older castings could be called into service at a date far later than when they were actually cast.
The above M10.1/2 is a perfect example. It is painted with a Red frog on a Red base, which generally did not occur until c.1944< But the frog is pre-Ogee, in other words before 1938! The solid brass depth adjusting nut is associated with the 1944 era as are the handles of dark Rosewood coloured varnished Beech.
The above M10.1/2 has a Black non-Ogee frog [ c.1937]. A Red base which, up till now, has been ascribed to 1944<. But, this base does NOT show the M 10.1/2 casting numbers each side of the knob [ie c.1937] . The handles are grain-painted Beech and the Brass Depth adjusting wheel is concaved with coarse parallel knurling [Post War]. So it looks as though they grabbed a c.1937 base and a pre-finished Black non-ogee frog and married them together with post war handles. Can you now see how very difficult it is to realistically ascribe a reasonable date to the manufacturing of MARPLES planes!!??
The M10 above ‘Red on Red’ shows a number behind the front knob and therefore c.1937<. It has a non-Ogee frog and what looks to be a Rosewood handle but a Beech knob. The Lever Cap looks too good to be nickel plated and may therefore be Chrome plated. Was this plane changed from the original to present in this condition? Who knows.
But I have noted that most of these Malleable Iron planes seem to present in a rough casting condition. This rough casting seems to have not been addressed by judicious grinding or sanding and therefore this may be a class effect.
The plane shown below is a Black non-ogee frog on a Black base with full Rosewwod handles, these are very rare to find today in this condition.