MARPLES Hand Drills were not really introduced into the line-up until 1984 and then they were only a ‘RECORD Tools‘ extension of their #423 and  labelled M423.  This drill had a  Jacobs 5/16″ chuck and key,  Black enamelled wooden handles and a Blue Malleable iron frame and parts.

Around July 1989 I find that there are now 3 drills offered, M423; M422 and M421.  The M423 has a keyed chuck whereas the M422 was like the M423 but had a keyless chuck.   The lightweight for DIY M421 had a 3/16″ hand tightened chuck, was constructed of an Alloy and had plastic handles. The handles were highlighted with different colours [Blue and Green have so far been identified] and the handle had a screw fitted round end cap and could house drill bits in the hollow centre. It was nevertheless still double pinioned  and these were enclosed [see photos] The only identification that this was a MARPLES was the transfer name on the side of the gear wheel. The M421 also was not furnished with a side handle. It really was ‘cheap and nasty‘.

By January 1994 only the M423 and M422 are offered for sale. and by 1996 even these are not to be found listed anymore.

Below is the entry for Feb 1984 along with a catalogue photo.

Below is shown the 1988 entry showing just an M423 for sale:

The entry below is from July 1989 showing the introduction of M422 and M421:

Here is a breakdown diagram from 1991:

Gallery:

M422:

M423:

And then the M421 showing the enclosed gears and no side handle provision:

These hand operated large boring drills were very short lived.
I can only find them listed in the 1897 and 1909 Catalogues, outside of that I see no listings.
I think it safe to estimate that these now rare drills were offered for sale from c.1895 to c.1912.
If you can find them they will be in poor shape and probably with missing parts. [Especially the ‘level’ on those drills that were provided with such.]   The Rosewood turning handle is particularly prone to having a rusted out centre steel rod which has expanded and therefore cracked the Rosewood handle. Expert restoration is needed in this case.

Here are the 1897 Listings:

And below here are the last entries of 1909:
The only drills that survived from the 1897 listings are shown here with their re-listed numbers:
Breast Drill No.1191 became #6045
Breast Drill No.1191A became #6046
All the other 1897 Breast Drills became obsolete and were discontinued in favour of new drills as shown in the 1909 Catalogue. [below]

Here is what I think is a #6407 Breast Drill:

And below is a #1191B:

The next example has a MARPLES chuck and therefore British [BSF or BSW] chuck thread [which would not fit on an American Breast Drill frame] but I cannot locate this example in the catalogues that I have. It may be a later or earlier #6407 or even a #6506, the latter of which we have no pictures.