Here is a tachometer from 1883 that was used on steam engines that was on ebay and has since sold. I have been looking for a period tachometer for my T and considered bidding on it, but could not figure a way to hook it up, so I did not bid. Can any of you see a way in which it could have been made to work on a T? Scroll down for more pictures. Jim Patrick
http://www.ebay.com/itm/Antique-Very-Rare-Tachometer-from-1883-RPM-Meter-for-Mac hinery-Steam-Engines-/252778840188?_trksid=p2047675.l2557&ssPageName=STRK%3AMEBI DX%3AIT&nma=true&si=xeb6t4HuAQy6eeZnuljgX%252BLxHRg%253D&orig_cvip=true&rt=nc
look at these for some ideas..(Not the steam one, but a tach just the same)...