This MF chain and chisel mortiser was listed on eBay recently.

MF-3.jpg MF-2.jpg

A closer look at the serial number on the tag just causes confusion.

MF 692117:D.jpg "MF 692117/D" ?
And no test number .

A bit of scratching the grey matter followed. The stamped digits have something "Bursgreen" about them. Could this be a product of 1969 ("69" being the first two digits)? But the tag is definitely a Green Lane works tag.

I have seen this before when the production of a model was moved from Green Lane to one of the former Bursgreen factories, and components of a pending batch were transferred - including the tags .

So assume for a moment that the "D" stands for Durham (Fence Houses) works.

The earliest MF I can find is MF 207 of 1937, and the last pre-1969 MF I can find is MF 1889 of 1964. But wait! There's more! the next is MF 2233 of 1972. And the very last I've found is MF 2493 of 1978. All with Green Lane tags.

So could a batch have been made a Durham?

If we look again at that serial number MF 682117/D we see that 2117 fits nicely between MF 1889 of 1964 and MF 2233 of 1972.

I believe the mystery is solved. A batch was transferred to Durham for completion, for some reason - but total production was not transferred, with later batches again being built at Green Lane, Leicester.

Cheers, Vann.