NIF (UK) / PETER SAVAGE / CHARLTON IRONWORKS / THOMAS DUDLEY / STANTON PLC /
BRICKHOUSE DUDLEY / DUDLEY & DOWELL / CLARKS / BLAKES FOUNDRY / INTER-AX
Continuation of research from the gridders post.
A collection of the manhole covers and drain covers across the area (see route below). The colours mark out manufacturers that could be identified on the covers. Manhole covers and drain covers have been colour coded accordingly to show which have been ‘named’ and which share manufacturers. Blake Foundry can be found the most, claiming 6 drain covers. Peter Savage comes second, claiming a mix of manhole covers and drain covers. However, the 3 manhole covers outlined in yellow were made by Clarks, which have a very unique raised pattern which can actually be found on 6 additional manhole covers. This could bring their total to 9 claimed manhole covers, which would make them the most popular.
“Why are manhole covers round?” Even though I did not find a round manhole cover, this question has been made famous by Microsoft as an interview question and people’s answers on the shapes of manhole covers I have found interesting. Some are playful and some are more logical.
Circular ones cannot fall into the whole (same for equilateral triangle), can be locked by a quarter turn and use less material when made. In Nashua, New Hampshire triangular manhole covers are used to show the direction of flow. (http://www.nashuatelegraph.com/news/929971-196/historic-and-unique-nashuas-triangular-manhole-covers.html).