Metric dimensioning convention
Metric dimensioning convention
(OP)
Not having been metrified early on I have recently ran across a little something in the use of the metric system that I have found no answer for.
We have a process with sevral very large tubular reactors where all the dimensions are in mm, over 1000 dimensions on
one print. Every equipment piece is dimensioned in mm nothing Else. We have other equipment that all dimensions are also all in mm.
The question come from some prints that crossed the table this week that originated in Europe that carry dimensions in meters and cm's, no mm's. The prints have locations that are referenced to 115.16 cm while that the larger dimensions are 10.25 meters.
What is the convention when calling out metric dimensions of equipment?
We have a process with sevral very large tubular reactors where all the dimensions are in mm, over 1000 dimensions on
one print. Every equipment piece is dimensioned in mm nothing Else. We have other equipment that all dimensions are also all in mm.
The question come from some prints that crossed the table this week that originated in Europe that carry dimensions in meters and cm's, no mm's. The prints have locations that are referenced to 115.16 cm while that the larger dimensions are 10.25 meters.
What is the convention when calling out metric dimensions of equipment?





RE: Metric dimensioning convention
Chris
SolidWorks 06 5.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 10-27-06)
RE: Metric dimensioning convention
The other reference is also some large equipment with the mixed dimensions sans mm's.
RE: Metric dimensioning convention
i.e. XX mm/[XX cm]
Chris
SolidWorks 06 5.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 10-27-06)
RE: Metric dimensioning convention
Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca
RE: Metric dimensioning convention
RE: Metric dimensioning convention
Chris
SolidWorks 06 5.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 10-27-06)
RE: Metric dimensioning convention
Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca
RE: Metric dimensioning convention
RE: Metric dimensioning convention
XX mm (XX cm/M) either one is acceptible in any machine shop. The one I work for prefers mm, why, I don't know. My personal belief is all the metric system is base 10. Nothing more, I have engineers that have 4-5 different scales, I myself only have 1. This is the easiest dimensioning one can do. The rest of the world is doing very well with it. Why don't we use it regularly? Because we have the lasiest people in the world that can't throw that foot and inch tape measure away. We have lobbiest in washington dictating the way we should do things. We here were converting to metric, spent three years developing procedures...blocks...etc. Then the lobbiest convinced congress. Guess what happened we still have to design and build in english. What a waste...
Regards,
Namdac
P.S. Had to vent sorry.
RE: Metric dimensioning convention
RE: Metric dimensioning convention
The continental Europeans (and if I recall correctly Japanese) seem to have a fondness for all the other metric units & derived units. I'm pretty sure I've seen French technical info in cm. I've even seen continental European stuff in dm, that's decimeters for our imperial friends
IMO meter is by far the best metric unit to use for calculations etc as it removes any factors. When doing calcs a lot at uni I was so used to 10^x etc that I didn't think twice, so could have happily used it on drawings now my brain takes a while to figure it out so I wouldn't think of straying from mm (plus of course it's in the standards)!
As long as it's clear which dims are in cm and which are m or even mm I don’t' see it as a major problem. I'd much prefer it to be consistent, at least on each drawing, but I'd hope anyone using engineering prints can multiply and divide by 10, 100 or 1000 easily enough.
At school in UK up to about 13-14 it was almost always cm, with m just for 'big things'. Once science got more technical it was all m with 10^x as required, this continued to university. Once I got into the work place it was all mm. Plus at home it was mainly yards, feet and inches.
To this day when measuring stuff at home I use whichever scale on the rule corresponds most closely with the point I want to measure to!
When it comes to drawings it's all just marks on a scale, inches, feet, yards, meters, cubits.... As long as I know which I'm using I'm fine, I don't get all the fuss.
Like I said though when it comes to calcs give me meters any day.