LocostUSA.com

I'm building a 442e frame and in the plans it calls for measurements like 36.4 inches, now I have an engineers measuring tape but the tape doesn't have the same measurements as a everyday measuring tape. Can someone explain this to me?

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it's all fun & games until you add weight to the car....

Don't use an engineers tape as they are in feet and 100ths of a foot. You could print out a conversion table for decimal inches to fractions.

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John - Slow and Steady. . . Well slow anyway
Build Loghttp://www.locostusa.com/forums/viewtopic.php?f=35&t=6245

Haynes doesn't appear to like fractions. Maybe they think they don't print out clearly. It seems if the writer sumbits a manuscript with a measurement of 34-3/8", Haynes editors will change it to 34.4.

That's because the Haynes Roadster, and probably even the Ron Champion Locost 7 before it, were probably built in metric. Ron Champion taught shop in Brit schools when metric instruction was the norm, but I'll give odds that the bracketed metric measures in the Champion book are the originals and the British units (in that case, inches and tenths) were the conversions.

When I attended university in the UK in the early 70s (OK, I'm old) we carried out our engineering studies in both British and metric units, but when I then worked for Vickers Shipbuilding (in the UK) every ship drawing I saw was fully metric, although there were oddities. A lot of legacy equipment was still British units (Unified threads, not Whitworth: those died with the MG TF!), so if you wandered through a ship you might find little labels on equipment like "This equipment uses British fasteners."

At the risk of being flamed (again), buy a metric tape measure!

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

I have an assortment of tape measures I have collected over the years and even my surveying tape measure has the metric measure on the bottom when reading it left to right. All 13 of my tapes had the metric on them. The only measures that didn't were the 100' and 200' reels. I checked at Home Depot and theirs all had the metric measure on the bottom also. So I guess you can say that all tape measures are metric and English.

Tom

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Sometimes, I'm as confused as a baby in a topless bar.

My short term memory is absolutely horrible and so is my short term memory.

https://www.youtube.com/watch?v=sG16m2e4O6I

Yup,

And to add to what I said earlier ... it's not entirely the Brit's fault. The +442 dwgs are of course US, but done with AutoCAD or something like it. You get your choice of units, but I bet inches and fractions isn't one of the standard options.

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

I find metric sooooo much easier to work with when it's something of this scale and degree of required precision. Sure, if I'm making a compost bin or something crude out of 2 x 4's I'll use inches. Otherwise being able to note (and easily remember) a relatively long dimension down to a mm is far easier than trying to deal with inches and fractions...or even decimal inches. I've been using it while working in steel for 25 years but where it REALLY proved itself was when I went to do the wood floor and trim in our house a few years ago!

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-Keith

You should definitely use the system you're most familiar with. Lower likelihood of mistakes that way.

As for the original Locost, it was designed in inches, as evidenced by the lengths of the primary tubes. And the original fractional units weren't 10ths. If you look at something like the plans for the rear axle brackets, you can see they were originally 6-1/4" tall, and 3-1/8" from the center of the axle to either end. In the book these were converted to 6.3" and 3.1".

Similarly the bushing tubes, which should be 1-3/8" long to match the length of the Triumph-sized bushings, are shown in the book as 1.4". It's a small difference, but enough to cause problems when you bolt the bushing into a bracket.

Hey thanks for making me understand this so much better and stick to a everyday measuring tape.

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it's all fun & games until you add weight to the car....

1, learn decimal fractions.

2, learn the common fractions as a decimal.

3, learn the common fractions in millimeters

4, the dimentions in Rons book the have been rounded up or down, this is common and shows the level of acuracy that is "not" required to build one of these cars, if the decimal is over .050 it would be rounded up, if its below .050 then its rounded down.

a dimention of 3-3/8" for example is to three places 3.375", this would be rounded up to 3.4", or as a metric version, 85.8 mm, this would then be rounded up to 86mm.

i was taught this at primary school, and that was almost 60 years ago, did they teach you anything or were you just not listening but looking up the teachers skirt instead?

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this story shall the good man teach his son,
and chrispin chrispian shall ne'er go by,
from this day to the end of the world.
but we in it shall be remembered.

Sure it is

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Peace, Ron

John, they don't call it "primary school" anymore. And who knows what they teach nowadays. Probably not math. You're right that building a Locost doesn't require much more precision than 0.1", but I'm sure you did better than that. If you can, you should.

RTz, guess I should have kept quiet!

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

One of my favorite measuring tapes that I've had for years is a 10' Stanley Powerlock showing both decimal inches and metric. Model number 33-223 I think. Not sure if its still available.

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Cheers, Tom

My Car9 build: viewtopic.php?f=35&t=14613
"It's the construction of the car-the sheer lunacy and joy of making diverse parts come together and work as one-that counts."
Ultima Spyder, Northstar 4.0, Porsche G50/52

Why not do both? "More is More", I always say.

I use a Stanley tape with inches on one side and cm/mm on the other. When laying out new things, I often use inches because I think in those terms having used feet/inches daily all my life. When actually doing things, I often switch to mm because it's easier to use in many circumstances. For example, if I've built something that is an aggregate of steel pieces, but now I want to mount something in the middle of that collection, it's typically much easier to divide 186 mm in half than something like 11-9/16 inches.

There are lots of other times I use metric too. The only frustration with the dual tape is that there are times you can only "hook" the tape in one direction (trying to push a 3m tape doesn't work well!) on a piece and there are times when that gives you the inches scale when you want mm or vice versa.

By the way, I learned the metric system three times in my life: 1954 (Eisenhower's metric conversion mandate); 1967 (SI units); and in 2010 again (yes, I'm really old), all right here in the USA. The only problem is that we live in one of the 4 or 5 countries of the world that in practice still uses the Imperial system, so in ordinary life I never use metric and I'm afraid it's become a case of "use it or lose it." However, it may surprise all of you to learn that the USA has officially been (as in Congressionally mandated) a metric country since 1866 and was one of the first countries to do so after France.

Even now, I'm willing to convert to metric, but it's not as easy as you think. By coincidence, I happened to be in Vancouver, British Columbia on the very first day of their official, provincial conversion to metric weights and measures (1990?) and watched the older store clerks melted down as they had to to everything in kilograms, liters and so on. Lots of people aren't technical like we are here and it can be very threatening to ordinary folks.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886