Novice Ponderance....

[IBBugsy]

I've been reading about home-made jigs, templates, fences, etc. and notice they all seem to have fractional dimensions (3 3/16", 1 7/8", etc.) for length and width? Even project designs (tables, shelves, etc.) seem to do the same??

Just wondering why nobody seems to use whole inches (except for the thickness) wherever they can?

I've only made a handfull of simple things so far and always start with overall dimensions in whole inches, then cut pieces accordingly to achieve that intent in the end.

[cabinetman]

We do that purposely to create wonderment. Nothing wrong with fractions. Get used to them. They are a part of life like taxes. Actually to answer your question it may be just how things worked out, or necessary for something else to work out. For example, it may be due to the diameter of a bit, or a sawcut. As you get into making them you'll see how very little things work out to be even.



"I'M NEVER WRONG - BUT I'M NOT ALWAYS RIGHT"

[bigsteel15]

When jigs are made of BB ply you need to adjust for the actual thickness (3/4" = 18mm = ~ 11/16".
Also you want nice straight, even material so even if you're using finished store bought stock you will likely plane it down to the next 16th.

[LarryG]

Well, in MY shop, it's because I start out with a nice, even, 2" dimension, mess something up, and semi-recover by skinnying it down to 1-7/8" ...

[ssmith1627]

What will it take to get us all to switch over to metric ? I stare at that side of the ruler on occasion. It really does sound like life would be easier after you got through the trauma.

The English gave us this system and now even they don't use it.....that says a lot.

But we'd need some new router bits as well as a hundred other things I guess....

Steve

[Stytooner]

One reason is because this is how I learned it. Another reason is because my tape measure has fractional increments. I do sometimes have to convert fractions to decimals and that's generally easy enough to do. The more I do it, the more I can simply figure it out in my head or from memory.
In woodworking, fractions seem to be a very precise way to measure.
In metal working, decimals are the only way to go.

[jackellis]

What will it take to get us all to switch over to metric ? I stare at that side of the ruler on occasion. It really does sound like life would be easier after you got through the trauma.

The English gave us this system and now even they don't use it.....that says a lot.

But we'd need some new router bits as well as a hundred other things I guess....

Steve

The English have switched reluctantly. I lived in England for 18 months earlier in this century (sounds better that way) and have visited several other countries in the Commonwealth. Much to my surprise, many folks in still use Farenheit for temperature and English units to measure things.

It would make a lot of sense for the US to go metric in spite of the obvious costs, but most people really dislike change so that's why we're not changing. Besides, saying 28 grams of prevention is worth 0.454 kilograms of cure just doesn't sound the same, does it?

[JR]

I'm not sure, but I heard it's because the West was won by the inch, the yard, and the mile. I could be wrong, though.

JR

[LCHIEN]

if we were to work in whole inches then all those marking on the ruler would be wasted. An inch is treally too coarse to use to make things and furniture based on inch-thick slabs would be heavy and expensive.

[RodKirby]

I think most of you know, we (in Oz) only work in mm - I always convert to inches in the interests of international cooperation

See my signature...

[cwsmith]

In the early 70's I was on a task team to push SI Metrics into our work place. At our company we made everything from small garage air-compressors to massive pipeline and refinary gas-process compressors. After more than 30 years, with production, service, and sales internationally, about the closest they've gotten to metrics is providing the metric equivalent in parenthesis after the American dimension in publications. The equipment itself, at least the few things left that are made in the U.S. are still in U.S. dimensions.

On the other hand, could this be a reason why everything is getting moved over seas??

In the wood shop, I can't imagine limiting yourself to whole inches. Fractions or decimals really isn't all that hard.

CWS

[bmyers]

I was a grade school boy in the late (late) 70's and early 80's. It was a time when the US thought they would switch to metric when Canada did. The schools stop teaching SAE and started teaching mostly metric. We all got pretty good at it. We had little centipede meter sticks, cool rulers. Oh the fun we had...

Then the US basically said screw it, never mind, just kidding Canada! I prolly know metric better than quarts or pints or cups or yards or miles.

Decimal SAE: Oh wait, I know what'll help. Let's take some fat guys thumb, divide it up into 1000 pieces! Brilliant! Oh the problems it will solve.. So smart..



Bill

[cbrown]

A ruler marked in 1/32 inch gives finer (but still usable) resolution than a ruler marked in mm.

Dividing a measurement in half is easier in fractions than in decimals.

Apart from the UK, Europe uses the metric system because it was conquered by Napoleon. We Americans never were.

Who cares about powers of 10 unless you're counting on your fingers? Powers of 2 are the way of the future!



--------
Christopher

[RodKirby]

Dividing a measurement in half is easier in fractions than in decimals.
Christopher

Oh, really

[LinuxRandal]

They confused people talking about the conversion, when they were talking to them in the language we were supposed to go to, Esperanza.


Things change, only when the consumer accepts it, think new Coke!