Mixed Metric Designs

[tdculbert]

Our electronics company has long designed our products in metric and the mating tooling & fixturing in imperial to continue making use of the in-house machine shop for tooling fabs.

I've recently began designing and submitting tools designed in metric, much to the shop's anger. The company continues to be split about which dimensioning scheme to use. The main argument being the cost of re-tooling the shop to metric "unnecessarily" - "just because the product is in metric doesn't mean the tooling needs to be" they argue.

Their pushbacks have produced several compromise proposals:
1) Don't convert - it's always worked; don't rock the boat.
2) Dual dimension prints; Since the shop (and our auxillary machining vendors) will be converting back to english anyway.
3) Design dimensions in metric, but use english fastening components - english dowel pins & fasteners/tapping.


My responses -
1 & 2 - there's inherent conversion error introduced in switching from one to the other; additionally, since our english unit precision is governed by decimal places, this complicates conversion of tolerances
3 - I don't have a good response to this; just feels wrong to go half-way.

I'd be curious about advice on this battle and input on these objects from those who've gone this road before?

 

[ajack1]

Would that be a US Bushel 2,150.42 cubic inches or a British Bushel 2,219.36 cubic inches?

Pah, who needs metric when the other option is so great?

 

[dgallup]

Shoot, anybody can use a simple base 10 system. Training our students to use PSI, inch-pounds, cubic yards, teaspoons, drams, pecks & BTUs gives them much better mathematical training.

My favorite unit is the miners inch, which varies by local statute:

* 1/60 ft³/s (472 mL/s) New Zealand
* 1/50 ft³/s (566 mL/s) southern California, Idaho, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, Utah, Washington
* 1/40 ft³/s (708 mL/s) Arizona, northern California, Montana, Nevada, Oregon
* 1/38 ft³/s (745 mL/s) Colorado
* 1/36 ft³/s (787 mL/s) British Columbia