What's going on here?

[steamer]

Marv,

What is "dry"....what is "wet"....what is "lubricated".....What was the surface finish of the two pieces in the test....how flat were they?.........if you answer those questions....you will have your answer.

You and I know that finish and flatness don't have any mathmatical impact on the calculation,,,,but we both also know it does in real life......wish I could be more specific...but I think that's as close as we're ever going to get to it.....unless you want to open up a lab?

Dave,

I'm not an engineer but if I measured something for a table to be placed in a professional reference and got two values that differed by a factor of 0.8/0.15 = 5.3, I would do one of the following...

Repeat the measurement until I got repeatable values

Enter the values into the table as a range rather than a single value

Indicate in the table error bounds for whatever value I chose to use

Instead we have tables with no indication of error bounds or surface finish.  If these tables are as useless as they seem, why do folks go to the trouble of constructing them?

Only the shadow knows!....

All I know is ....if it matters.....I measure it myself...under the conditions that it will be used....

Dave

[mklotz]

Me too, Dave.

Trouble is, I'm starting to wonder now about what else in MH I shouldn't trust.

I've already found imperfect solutions in their compound dividing tables and now this. 

[John S]

Marv,
I have found MH invaluable, without it my workshop door would have banged shut ages ago.

[Bezalel]

Snip>  [Perhaps they didn't have static friction back then.] >Snip
 

That would explain how they built the pyramids