Drawing Terminology -Bare

[Runner]

Hi all,

what does the term "bare" mean when applied to a dimension? I sensed that I was asking a stupid question, so before posting I did a search for "bare" on this website to see if it had been asked before, it hadn't. Is it a Martin Evans' euphemism for a dimension being not under the value specified?

Regards,

Brian

 

[tel]

'Bare' is usually found only on drawings done with fractional dimensioning. eg 1/8" bare refers to erring on the short side of 1/8", you will also come across the term 'full' which, of course, means exactly the opposite. More usually found on carpentry or cabinet making plans.

 

[Runner]

Thanks Tel,

yes the term bare is used on fractional dimension drawings for, inter alia, the boiler. Without exception, no tolerances are specified on any drawings for the locomotive, so I suppose it was Martin Evans method of communicating a dimension that needs to be a shade under. But by how much is left to the individual. I assume that it was a term was coined in the days when it was expected that the reader was an experienced craftsman who intuitively knew what are bare dimension should be. For the record I made these dimensions as close to the decimal equivalent that could be read on my dial caliper gauge and made no obvious difference.

Regards,

Brian

 

[tel]

That will well and truly get you out of trouble. 'Bare' and 'Full' are usually associated with marking out with a rule and scriber.

 

[Mainer]

I've heard it as "scant" and "full."

 

[dgjessing]

I used to do it as + or - in cabinet work detailing. For instance, 3/4"+ meant something like "a fuzz more than 3/4"" :. But this was generally done not so much to convey a hard dimension, but to alert everyone that some hand fitting was required because the actual dimension was unknown.

 

[Cedge]

Here in the southern states its often heard as "almost" and "just a skosh over". Military term was simpler.... plus or minus a RCH (red C*** Hair)...LOL.

Steve

 

[wheeltapper]

I've heard it referred to as "a gnats c**k, also three eighths and a puff.

Roy

 

[Tin Falcon]

fractional drawings imho always have to be interpenetrated with wisdom.
I had a spudivisor while working at the boat yard that insisted I make a particular dimension exact.I respectfully explained there is no such thing. and asked what tolerance he wanted. He replied it has to be exact! then i told him I had measuring tools at home I could give him plus or minus a couple thousands of an inch accuracy. his response it does not need to be that exact!!. HMM Ok how about plus or minus 1/32 of an inch ,the reasonable limits of a tape measure. that is what he really wanted. but was not smart enough to express.
Before that I worked on a pole barn crew for a while when I expressed dimension in sixteenths of an inch I was told this is rough carpentry , you aint a cabinet maker we only work in eights. Ok fair enough . then they tell you to cut a 2 x 4 and "take the line" or "leave the line" what the Hey is that.
The old school Rudy K and Elmer V drawings are often fractional and you are given dimension fro the bore then piston dimension is " to fit cylinder bore" and the 1/4 inch shaft and the 1/4 inch hole in the bushings and the 1/4 press fit in the fly wheel .
You are expected to know a running fit hole is a few tenths bigger than nominal and a press fit hole is a few tenths small. Or use undersized and oversized reamer as appropriate.
Tin

 

[Lew Hartswick]

There is a WORLD of difference in whether the "drawing" is for you own use or someone
else.
...lew...