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Give me good old imperial. I can't think or visualize in metric. I know in my head that 7/16 is .437 and I looked it up in metric and its 11.1125. How is that any easier? If you tell me to take 5 or 10 thousanths off of something, I understand how much that is and can do it. Tell me to make it 3 millimeters, or go about half a kilometer and take a left, or the temperature is 40 degrees centigrade, or something weighs 5 kilograms, and I just stand there and scratch my head!
Contributor
I spent my life in the construction industry so I think in fractions though I have no problem toggling between fractions, decimals and metric. I have a couple conversion charts tacked on the wall and my Construction Master calculator for larger conversions if needs be. In the shop it's just me. I jot down numbers in 16ths w/o the denominator, i.e., 7 = 7/16", 8 = 1/2", etc. I also use + and - signs to get me to the 64th w/o having to do the math though if things get this critical I usually use a story stick or some other direct reference.
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Decimal inches, for everything. Decimal is much easier to do math on than fractions. Inches makes for easy conversation with customers.
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Mostly I use Imperial inches and traditional fractions --- sometimes I'll grab a DTP Pica/PostScript points ruler from my desk if I need it for a measurement to come out even. Using metric for handwork annoys me with all the odd numbers and the frequency of dividing stuff by thirds and it not coming out to a nice even dimension (72 points per inch ensures that such a division will come out to some even number, or at worst, a half-way mark --- I never feel confident of marking off a third or two-thirds of a millimeter).
Using metric for CNC, except that I can't find all the information there as metric --- if someone has a source for:
- chiploads
- metric formulas
- typical metric units used
I'd be grateful.
Contributor
I agree Glenn, we went metric in the seventies when I was in high school. Science was taught in the SI system, and I was too young to really have developed a fondness for the Imperial system.Originally Posted by glenn bradley
I've never had a drivers license when we weren't metric for road signs, when I drive in the US I simply keep the GPS in metric units so I have a feel for the road speed.
That said 3 of my motorcycles are in Imperial units. My oldest daughter was loathe to ride her Honda CB350, she always wanted to borrow "our" R90/6 BMW. One day she remarked how everyone drove so slow through the school areas. I said that it was odd, her response was that the speed signs were 40 and everyone was doing just over 20.
I remarked that the BMW was in miles per hour and she said "it's in what"?.................Too funny...............
As for other measurements, if you gave me one pound of meat and asked me how heavy it was, I wouldn't know. I also wouldn't know what it was in the metric system. I just know that at the deli, I ask for 300 or 400 grams of meat. Now, if you really want some fun, ask someone how much they weight in metric units, guaranteed they come up with a number of kilograms...............Rod.
Contributor
Tony, it's the Imperial system that's difficult.
I take a nice piece of wood, planed to 20mm thickness and it turns out to be 0.787". How am I going to measure or add that?
As you've just seen, the issue is that you shouldn't be converting, you should either make your piece of wood 3/4" thick or 20mm thick.
The problem is that you have no familiarity with the metric system, you didn't have any familiarity with the Imperial system until you learned it.
To this day I have no idea what the unit for mass is in the imperial system, and I have to use a conversion factor from power to obtain horse power for a motor.
It's all what you're familiar with, however working in the metric system can be easier than the Imperial system, however it's application dependent.......regards, Rod.
Member
Base 12 FTW
Contributor
Usually 'round dis long, so high and yay thick gets me there.
Contributor
That's so true about a lot of the things we make isn't it?Usually 'round dis long, so high and yay thick gets me there.
Member
I have trouble visualizing medium-sized metric measurements. I have zero issue visualizing 15mm, or a kilometer. But when I hear 783mm, I have to really think, while 30" would be an instant visual. I don't know why that is.
All of my tools have fractional SAE markings, and some but not all have metric markings. I have SAE drill bits mostly, very few metric. When measuring differences, it is obviously so much easer to say "cut this 1mm shorter" or "make it 29mm instead of 30mm." Overall I'm OK with either but since everything has inch fraction markings, that's my predominant working measurement. Oh, and I often have various helpers who are firmly stuck in inch fractions, so telling them anything else would just create confusion.
Member
Same here, weird how that works.
For projects, I usually do the conceptual stages in imperial just because I can visualize the normal sizes of things I build better in inches and feet. I can get by in metric at this point, but it requires more conscious thought to visualize the sizes. But when it comes to time to take precise measurements and start building I usually switch to metric. I just find it so much easier for dealing with offsets and overlays with cabinetry, or really anything where you're adding or subtracting a bunch of numbers. And even with my relative inability to quickly visualize some metric sizes, I find using it has reduced errors and sped up my work.
And like Rod mentions, I size the stock to suit metric. So what might be 3/4" or 13/16" thick and 3.25" wide rails and stiles in imperial would be 20mm thick and 80mm or 85mm instead (unless I'm matching something existing of course).
Member
One thing people get hung up on is the idea that stock needs to be 3/4" or whatever. No, it just needs to be consistent. While working in metric once someone asked me how I was going to get my 20mm boards to be 3/4" to "finish" the project. Er, what? Come to think of it, the digital readout on my drum sander is currently set to metric.
Contributor
I work in imperial decimal most of the time, though I will use metric when necessary (Cup Hinge Locations). Of course, I work in a machine shop, so decimals come easily to me and I know most fractional/decimal equivalents.
Contributor
I have to be comfortable switching between them all. But at the end of the day I still visualize in fractional inches. I can strike a mark within an inch of 48 inches without measuring but I wouldn't recognize 400 mm if it slapped me in the face.
Member
My eyecrometer is calibrated in SAE fractions also. I can usually hit closer than 1/8 by eyeball only.
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