<VV> Dwell Tach

[Smitty Smith]

Smitty Says: The post on trouble with a digital Dwell tach brings to mind a problem I have had for years with the analog ones.  I have had a good half dozen different ones and must have three around here now.  They all read different.  I have one that I use consistantly because I know it will not lead me too far astray but that is not what we use instruments for.  They are supposed to give us the facts Mam.  So how does one find a standard to calibrate them with.