Decimal Inch versus Decimal Foot

[rgsparber]

I was looking at various steel rulers and came across an odd thing.

Decimal Foot:

I have always preferred my decimal inch ruler which is 6 inches long. But I noticed I can buy decimal tape measures that are 25 feet long.

http://www.amazon.com/Stanley-33-272...h+tape+measure

Sounds like a nice addition to my shop. But now it appears these rules are decimal FEET, not INCHES. That means there are 10 decimal inches in a foot. Wow! So on that rule a tenth of a decimal inch is not the same as a tenth of a (common) inch. Anyone else see this or am I just confused?

Rick

[mklotz]

Yet another confusion of the inferial measurement system. A new opportunity to make mistakes. Whenever is this country going to start using the metric system?

It reminds me a bit of the surveyor's 'chain' which is a puzzling* 66 feet long but, in what I suppose was a half-hearted attempt to make computation easier, was divided into 100 'links'. Thus the 'link' becomes a so-simple-to-work-with 66*12/100 = 7.92 inches.

----
* It may be another mish-mash of units. The mile is divided into eight furlongs, an example of Americans preoccupation with powers of two. But they divided the furlong into ten chains so each chain is 660/10 = 66 feet because, deep down, they knew that powers of ten made computation easier.

[PJs]

Hi Rick, I have had the "contractors grade" 33-272 (yellow, better case) and it is graduated fractions on one side and decimal on the other. The fractional side is in 32's up to 6" and 16'ths there after. On the decimal side it is in .020 up to 6" and .1" there after. Mine does Not have "Foot" marks. I love this thing and had it for years because I think in decimals and is great for shop eyeball use...otherwise I use a 16R scale. To me the 20thou scale is what I grew up on in board drafting back in the early 80's and easy to use.



If you read the review at the bottom of the the Amazon link the guy named "woodworker" from 4/1/07 states the above but seems confused about the first foot?

Here are a couple of links for the one I have. Prices are all over the board, but could not find it on Stanley's site. Think I got mine at McMaster at least 12 years ago¿

From BisonOffice

From Overstock.

Not sure of the relevance of the video. Even with the foot markings it is still in 10ths and think the foot marks just confuse the issue. If I have to measure anything over 144" I break out the big guns and really don't want to know decimal inches. LOL

~PJ

[Paul Jones]

Marv,

The Imperial measurement system can be pretty strange at times and thanks for mentioning the surveyor's chain.

and

PJs,

I think I will stay with conventional fractions for my wood working measurements because the cabinetmaking blueprints I have seen use this convention. Some of the blueprints are very old.

Good comment about the 16R scales. Almost all of my 6" to 24" machinist steel rules are marked with 16R scales because I like designing and working in decimal inches but can accommodate blueprints specified with fractions. I also have a few rules with 1/10 and 1/50 decimal inches on one side and 0.5 mm and 1 mm scales for use when reading articles, tool catalogs and blueprints specified in millimeters.

I would be interested in what types of steel rules (rulers) are preferred and why. I do like satin chrome finishes on the rules but this adds to the cost. I don't like seeing the steel rules used to sweep chips out of the way but I will save that for another time.

Sorry Rick, I didn't mean to hijack your thread but you started with an interesting discussion.

Regards, Paul

[rgsparber]

PJs,

That Stanley 33-272 seems to be exactly what I want. Will order it tomorrow! Too bad they come with a metalized plastic case now but the rule looks great.

Thanks,

Rick