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Daily Archives: March 22, 2022

Some old drawing tools for clothoids

I took some photos of old (vintage if you prefer) drawing tools that I have at our laboratory at the university. We found this in the storage many years ago and people seem to have forgotten about them. Instead of heading for storage or being forgotten or worse, thrown away, we decided to keep them at our laboratory mainly to show our students how certain highway or street curves were drawn in the ‘old days’. I am currently the custodian of this and another set that I have kept at my other office at the civil engineering building.

The wooden box is at my office at UP Diliman

The sign basically translates to clothoid drawing tools made by a company based in Setagaya in Tokyo. There are 14 instruments in the box for clothoid parameter values of A = 20m to 350m.

Opening the box shows slots holding instruments for drawing clothoids or spiral curves

Some of the instruments from the case – the large one on top is for A = 300m and 350m (scale 1:1000)

Comparison of size of instruments for (top) A = 60m and 65m, and (bottom) A = 30m and 35m (scale 1:1000)

Instrument for A = 30m and 35m (Scale 1:1000)

A protractor came along with the set but I assume other instruments such as a compass were used in drawing/drafting the curves.

I shall take photos of the other set when I get to visit the other office. These will be for records purposes as well as for posterity. These are practically museum pieces that are now perhaps rarely if even used.