Decimal versus fractions

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Forum topic by richgreer posted 09-02-2011 03:54 PM 4878 views 1 time favorited 40 replies Add to Favorites Watch
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4541 posts in 3074 days

09-02-2011 03:54 PM

I have a ruler that has a scale that divides an inch into 10 parts (and in the first 3 inches in 20 parts). With this I can determine that a measurement should be x.y inches instead of the fractional equivalent.

As a coincidence, the scale on my jointer also measures in inches on a decimal basis.

I’ve decided I like to measure and think this way. It’s just easier than always dealing with fractions.

Of course, we cannot buy lumber that has been measured this way, but most of us mill our lumber to the size we want anyway.

I don’t think metric measurements will ever feel natural to me, but I am very comfortable dealing with inches on a decimal basis.

This transition in mind reminds me that at one time we bought and sold stock (on the stock market) in fractions of a dollar. Eventually, we transitioned to dollars and cents and that made a lot of sense (cents).

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

40 replies so far

View Cosmicsniper's profile


2202 posts in 3158 days

#1 posted 09-02-2011 04:02 PM

Good point, Rich. I try to think this way too, especially since my Wixey digital stuff (on router and planer) uses decimal inches. Same with the digital calipers. I wish my Incra positioner did the same…ooh…just thought of it…why wouldn’t Incra actually HAVE a sliding template that does that? Do they? Oh gosh, I need to check this!

I’ve been trying to find a good 12’ to 16’ tape measure that also measures in decimal inches, but such has eluded me.

-- jay,

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4541 posts in 3074 days

#2 posted 09-02-2011 04:13 PM

I also have been looking for a decimal based tape measure. Maybe some manufacture will read this and get the idea.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View Woodwrecker's profile


4149 posts in 3575 days

#3 posted 09-02-2011 04:18 PM

Funny you should mention this rich.
I bought a OneWay multi gauge a while back and have been using it more and more to set bit and blade heights and stuff.
The wood whisperer did a nice video showing it’s benefits as well.
It seems once I started remembering the decimal equivalents of frequently used measurements, I think that way more and more.
I’m with you on metric. I see the benefits of a 10 based system but I was brought up on the American system and I’m too old to change now! lol
(I also cheated and bought a very nice laminated decimal equivalent chart from McMaster Carr for cheap and have it taped to my band saw cabinet).
My dad was in tool and die and I’m fortunate to have a few gauges he used for decimals as well.
Good post Rich.

-- Eric, central Florida / Utor praemia operibus duris

View Bluepine38's profile


3379 posts in 3084 days

#4 posted 09-02-2011 05:00 PM

All of the small 6” rulers I have spread around my shop are metric one side and inch the other, and I am using
the metric for a lot of measuring. My bolt assortment is mixed with a strong proportion of metric, since the
automotive industry started going metric in 1980 and is now almost entirely metric. I figure that if I am too
old to learn, I must be dead, and I am not ready for that yet..

-- As ever, Gus-the 79 yr young apprentice carpenter

View crank49's profile


4030 posts in 2970 days

#5 posted 09-02-2011 05:15 PM

McMaster Carr, Stanley Tape.
Sku # 6802A77

View Woodwrecker's profile


4149 posts in 3575 days

#6 posted 09-02-2011 05:16 PM

then i must be dead and forgot to lay down…lol

-- Eric, central Florida / Utor praemia operibus duris

View Elizabeth's profile


817 posts in 3143 days

#7 posted 09-02-2011 05:18 PM

View helluvawreck's profile


31092 posts in 2866 days

#8 posted 09-02-2011 05:20 PM

Rich, on all of our drawings for our molding plant we use decimals. Once someone has done this for a while they learn the decimal numbers for all of the key English measurements anyways (1/32, 1/16/, 1/8, ect.). You get to where when you are looking at a drawing in decimals you can mentally convert from one to the other.

We also use the decimal system because for some things it just makes good sense. If you just remember one thing in metric conversion, 25.4 mm = 1 in., you can easily jump back and forth from metric to decimal.

-- helluvawreck aka Charles,

View Loren's profile (online now)


10396 posts in 3647 days

#9 posted 09-02-2011 05:53 PM

10ths are easier to work with, agreed. My Robland planer had a scale
in 10ths. Luthiers work with 10ths, 100ths. The dial caliper is such
a useful tool. Of course you learn the numbers that make the
8ths fractions too: they go in .125 increments so it’s not too hard.

I find centimeters a little small for most woodworking stuff. I know
my metric stuff okay too, but a tenth of an inch is such a more useful
measure than a tenth of a centimeter in general hand woodworking.

For machines and stuff like that of course the way to go is with story
sticks and things like that so you’re not even looking at measurements
that much.

View Jim Bertelson's profile

Jim Bertelson

4174 posts in 3164 days

#10 posted 09-02-2011 06:05 PM

Here in La Conner, Washington for a week.

Well, I got into this issue quite awhile back. It got exacerbated with my digital Wixey calipers and table saw digital readout. Now I keep a calculator handy for those times when I am doing a bunch of sequential calculations. I have one scale that reads in decimals. I need more I think and then I could do the whole conversion to fractions of an inch.

I made this a couple of years back or more:

I keep a couple of copies of this around, covered in plastic stuff, and with a hole punched in the top so that I can hang them up. Feel free to do the same.

-- Jim, Anchorage Alaska

View richgreer's profile


4541 posts in 3074 days

#11 posted 09-02-2011 06:20 PM

Jim, this is very helpful. Thank you for sharing.

I’ve already printed it off. FYI – I found that if I enlarged it to 123% it will fill (top to bottom) a single 8.5×11 sheet of paper. I wanted it as big as possible for my tired old eyes, but I also wanted it on a single sheet of paper.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View Jim Bertelson's profile

Jim Bertelson

4174 posts in 3164 days

#12 posted 09-02-2011 07:12 PM

I don’t have this printed out here in La Conner, so I have just printed it myself, and I am putting it on a piece of scrap pegboard. I only have a black and white printer here. In Anchorage I printed it in color, and glued a copy of it front and back on a heavier piece of paper, and then covered it with some clear plastic shelf cover stuff. That way it never has to be turned over. Here in La Conner I just have to make do with what I have for now.

Should be a pretty day today here, sun is out, nearly 60 deg, and it will undoubtedly get into the 70’s.

-- Jim, Anchorage Alaska

View docholladay's profile


1287 posts in 3058 days

#13 posted 09-02-2011 07:20 PM


Nice point. Personally, I have seriously thought about using metric in my work. In metrics, you generally don’t have any sort of fractions to deal with. Decimals are still a fraction of some sort. With metrics, you don’t even have to worry about that. Only whole numbers. I know, back when I worked as an auto mechanic, I much preferred metric wrenches over SAE. This was especially true when teaching new folks from time to time. It is easy to tell that a 15 mm is bigger than a 14 mm. However, not so clear when you think that a 3/16” is bigger than a 5/32” for example or maybe 1/2” is bigger than 7/16”. For educationally challenged folks (as many mechanics seem to be) they often have a little trouble figuring this out.


-- Hey, woodworking ain't brain surgery. Just do something and keep trying till you get it. Doc

View Sawkerf's profile


1730 posts in 3068 days

#14 posted 09-02-2011 08:12 PM

In my nuke engineering career, I got comfortable with metric units and have often thought of going metric in my cabinet/woodworking business. Since my customers probably would have trouble with cabinet drawings in mm or cm, I may start working in tenths. It would definitely simplify a lot of things. The biggest issue would probably be getting all of my measuring tools in tenths. – lol

-- Adversity doesn't build reveals it.

View HorizontalMike's profile


7757 posts in 2913 days

#15 posted 09-02-2011 08:37 PM

I am stuck in both worlds. I have been driving and working on Toyota Trucks since 1980 (Metric) and on my 1997 Harley since new (Standard). In my astronomy hobby metrics rule and like Helluvawreck that 25.4mm=1in ration is tattooed on my brain.

In WW, I find myself converting digital/decimals to fractions more often than not because of particular WW plans being drawn/published in inches and fractions. I do find decimals an advantage while using my lunchbox planer to sneak up on an exact desired thickness.

Jim, thanks for the conversion table. I have printed it, but hope to NOT have to use it. So far I am mentally converting these measurements in order not hang out with that pig farmer, Al Swiners, too often. ;-)

-- HorizontalMike -- "Woodpeckers understand..."

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