Vintage Unbranded Barrel Key

Skate

Clock

Typewriter

For Square Stock

Used a digital calipers to measure inside dimension at:

3.81-3.82 mm

0.153-0.155 inches

I had previously and erroneously sold this as a key for an antique Hammond typewriter but it did not fit so I refunded the purchaser.  So, please make sure you measure for your application.

Thanks for looking!