Lowell Component Downbearing Gauge

[Ron Nossaman]

Farrell wrote:
> Breaking news item: Lowell Component Downbearing Gauges are now 
> available from Pianotek.
>  
> I have a question regarding the instructions for measuring downbearing:
>  
> "Multiply the number of divisions the bubble crossed by three and 
> one has the front or rear bearing, in thousandths."
>  
> My high school chemistry teacher would string the author of this 
> gibberish up by his/her thumbs. I can hear him now: "Where are your 
> units? Without units this means nothing!"
>  
> Thousandths of what? Inches I suppose. But what does that mean? So I 
> have a couple thousandths of an inch of downbearing - what does that 
> tell me? I don't have a backscale length. The only thing that means 
> anything is an angle. Angles are not measured in thousandths of an inch 
> - it is not a linear measurement. Are they trying to suggest a slope 
> maybe - as in so-many thousandths of an inch of vertical length per inch 
> of horizontal length?
>  
> The author should get a job at NASA and send another rocket crashing 
> into Mars.....  ;-)
>  
> Terry Farrell

It's 0.003 vertical units per linear unit, or 0.003" per inch 
rise/drop per bubble graduation. The graduations are 10 
minutes of a degree each, so there are six graduations per 
degree. That's 0.018" rise/drop per inch per degree. Three 
grads=30'=0.5°.

Not that cumbersome once deciphered.
Ron N