Re: Scale Digital Caliper


Tim O'Connor
 

Right. It's easier to remember that with 87.1 scale, and a digital
caliper that breaks an inch into 1000 parts, that each part is a scale
.0871 inches (and .048 in P:48 and .064 in S scale)

So to convert the digital readout of 5.580 into HO scale, just multiply
5580 x .0871 = 486.02" . In other words, ignore the decimal point, and do
the multiplication. This is why it would be so easy to change the readout
to HO scale - Assuming you can handle HO dimensions in decimal. :-)

Tim O'Connor

The problem arises when people internalize the incorrect scale factor, then apply it to large dimensions. Example:

A nominal 40'-6" freightcar is 486" long. Properly scaled, that's 486/87.1 = 5.580 actual inches.

Do the same calculation using 1" = .012", and you get 486 x .012 = 5.832 actual inches.

5.832 - 5.580 = .252
.252 x 87.1 = 21.95"

You've just built a model that's almost two HO scale feet too long. And people had a fit about the Branchline 41'-6" boxcar.

All these estimations have a use, and a place where they are appropriate, but we need to realize what we are doing. Some of the recent messages here are telling me that some people might not.

Dennis

Join main@RealSTMFC.groups.io to automatically receive all group messages.