# Fraction Table



## Ratbob (Apr 6, 2015)

OK, I admit it . . . I'm lazy! One of the very few things that I hate about woodworking is having to convert between decimals and fractions. 

Maybe you'll find this spreadsheet handy. At a glance you can find the nearest acceptable fraction for a decimal number, or find the nearest 1/16" increment from a caliper reading in 124ths of an inch. I keep a screen shot on my phone, and a hard copy in a clear sheet protector on a nail near my work area.


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## Cherryville Chuck (Sep 28, 2010)

Save yourself a lot of time and effort and just buy an all metric tape. Lee Valley sells at least one. No fractions. Everything is base 10.


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## Ratbob (Apr 6, 2015)

But then I'd be spending my time converting back and forth between metric and US measurements . . . lol. Something about old dogs . . . :lazy2:


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## Stick486 (Jan 4, 2013)

so get a dual/tri measure caliper that will auto convert from unit of measure to another...


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## Ratbob (Apr 6, 2015)

I don't see where that would help me Stick, my calipers can read in decimal, fractions, or metric but that doesn't help when I get a reading like 73/128" or .573". With a quick glance at my table I can see that it's about 1/128" away from 9/16" which is something that I 'can' find on my marking scale and is close enough for most things.


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## Stick486 (Jan 4, 2013)

Ratbob said:


> I don't see where that would help me Stick, my calipers can read in decimal, fractions, or metric but that doesn't help when I get a reading like 73/128" or .573". With a quick glance at my table I can see that it's about 1/128" away from 9/16" which is something that I 'can' find on my marking scale and is close enough for most things.


you doing woodworking w/ those measurements???


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## Ratbob (Apr 6, 2015)

Did I say that I was new to this? :grin:

I'm not trying to work to the nearest 128th, but that is often the kind of number that I read on my caliper. I've tried opening and closing the jaws to try to find a more 'usable' number but that too is frustrating. This is why I created the table.


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## Stick486 (Jan 4, 2013)

Ratbob said:


> Did I say that I was new to this? :grin:
> 
> I'm not trying to work to the nearest 128th, but that is often the kind of number that I read on my caliper. I've tried opening and closing the jaws to try to find a more 'usable' number but that too is frustrating. This is why I created the table.


you need a new set of calipers or stop using them and go w/ rulers...
get a set that only show larger units of measure... dial instead of digital...
in a former life were you a machinist or engineer???

as your experience in WW matures you will more than likely find that working to a 32nd of an inch is very acceptable in woodworking...
too tight of tolerances will work against you more often than they will help...
natural wood movement or the thickness of pencil mark will defeat or lend to a lot of difficulties in attempts to work in finer tolerances...
the part I'm having difficulty with is why all the need for conversions down to such finite measures...
if you need to work in decimals get an engineer's rule...
use the measuring instruments for the units of measure you choose work in....
FWIW.. doing conversions lends to mistakes/measures and will show up in the final project ......
the plus side to that is you will learn a new skill level set working out of the mistakes...


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## Stick486 (Jan 4, 2013)

Ratbob said:


> Did I say that I was new to this? :grin:
> 
> I'm not trying to work to the nearest 128th, but that is often the kind of number that I read on my caliper. I've tried opening and closing the jaws to try to find a more 'usable' number but that too is frustrating. This is why I created the table.


you could lean a crude compensation math...
add or subtract a 1/128 and divide that number by two to get the nearest 64th...
add or subtract a 3/128 and divide that number by four to get the nearest 32nd...
add or subtract a 7/128 and divide that number by eight to get the nearest 16th..
you get the idea...


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## Ratbob (Apr 6, 2015)

Stick486 said:


> you need a new set of calipers or stop using them and go w/ rulers...
> get a set that only show larger units of measure... dial instead of digital...
> in a former life were you a machinist or engineer???
> 
> ...


I am an electrical engineer, have been for a long time. As I'm trying to become proficient in WW I want to be able to produce joints that 'fit'. To this end I replaced my dial caliper (.01" res) with a cheap digital caliper (.001" res) thinking that the fractional readout would be useful. 

I do most of my measuring and marking with tape, rule, and combo square, but sometimes a caliper is the right tool. Now I can easily relate the ridiculously precise readings to something a little more practical.

As another example, I was just working to a plan that spec'd a 3/8" hole centered 0.360" from the edge and 0.312" from the end. How would you mark that for the drill? With a glance at the chart I marked half way between 11/32 and 12/32 from the edge, and 5/16 from the end. Took all of 5 seconds to figure out.


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## Stick486 (Jan 4, 2013)

Ratbob said:


> I am an electrical engineer, have been for a long time. As I'm trying to become proficient in WW I want to be able to produce joints that 'fit'. To this end I replaced my dial caliper (.01" res) with a cheap digital caliper (.001" res) thinking that the fractional readout would be useful.
> 
> I do most of my measuring and marking with tape, rule, and combo square, but sometimes a caliper is the right tool. Now I can easily relate the ridiculously precise readings to something a little more practical.
> 
> As another example, I was just working to a plan that spec'd a 3/8" hole centered 0.360" from the edge and 0.312" from the end. How would you mark that for the drill? With a glance at the chart I marked half way between 11/32 and 12/32 from the edge, and 5/16 from the end. Took all of 5 seconds to figure out.


this may sound like a rhetorical question but will/could you define ''joints that fit'' as you see or know it...
it's unusual to see plans in decimal and fraction... was this a WW plan??? 
and go have words w/ who ever drew them up...

screw the conversions...
I'd set the measures on the caliper...
locked the caliper...
and used the caliper as a marking gage...

get a dual measure caliper... there are lot of them out there.. wide range of prices too...
Amazon.com: Shop Fox D3208 Fractional Dial Caliper: Home Improvement

Plan ''B'' through ''Z''....
Marking - Lee Valley Tools - Woodworking Tools, Gardening Tools, Hardware Supplies

to get these finite measures you seem to be after you'll need a 0.3mm mechanical pencil which in a very very short order you'll soon trade it in for a 0.5 or a 0.7mm...
I mostly use a 0.7mm 90% of the time and the 0.9 for rough work w/ rough materials...
this pencil is cheap, available everywhere and lasts way longer than any other I've ever used... add a grip barrel to it and you'll really have something...
Search results for: 'p205/7/9' - Pentel


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## COBOB (Apr 2, 2015)

Thank you very much for the chart. I will find it very useful.



Ratbob said:


> OK, I admit it . . . I'm lazy! One of the very few things that I hate about woodworking is having to convert between decimals and fractions.
> 
> Maybe you'll find this spreadsheet handy. At a glance you can find the nearest acceptable fraction for a decimal number, or find the nearest 1/16" increment from a caliper reading in 124ths of an inch. I keep a screen shot on my phone, and a hard copy in a clear sheet protector on a nail near my work area.


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## neville9999 (Jul 22, 2010)

For years I worked with both, I did not convert between the two I just used the one I was working with, these days I just use metric, all my tools and tapes these days are metric so I don't use the imperial sizes. N


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## Bricknhank (Dec 28, 2013)

Stick486 said:


> you doing woodworking w/ those measurements???


:laugh2::laugh2::laugh2:


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## Shop guy (Nov 22, 2012)

It is to bad that the USA didn't convert to the metric system when they were working toward it about 50 years ago. It would have made things a lot easier today. I'm 75 years of age and I can see the many advantages the metric systems has over the imperial system. Once you get to using it it is just easier.


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## Cherryville Chuck (Sep 28, 2010)

Ratbob said:


> But then I'd be spending my time converting back and forth between metric and US measurements . . . lol. Something about old dogs . . . :lazy2:


You don't convert. You just measure in metric. The imperial equivalent is immaterial and you ignore it. Do you think all the metric countries convert from imperial before they start working in metric?


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## chessnut2 (Sep 15, 2011)

Thanks, Jeff. I'll use this. My reason isn't laziness, it's that I still come up with 2 + 2 = 5. thanks.


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## MEBCWD (Jan 14, 2012)

I land/construction surveyed for 15 years so when I do any large project in the yard like fencing I use a surveyor's chain or tape (100ths of a foot).
I also built one of a kind aircraft cabinetry so I use an engineers tape and scales (100ths of an inch) for woodworking. (but I do not nit-pick measurements)
I use an imperial tape measure for carpentry.
I very seldom work in metric and usually convert everything before starting a project, but if it is a simple project I will use the metric side of a combination tape measure to save time.

I think the most important thing to learn from this post is that it is best to use the measuring technique that you are most comfortable with using.


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## Ghidrah (Oct 21, 2008)

Being a framer for ever, remembering and converting from decimal to fraction comes hand in hand, but the accuracy never goes finer than 1/16th. Since I've been messing around with trinkets, boxes and furniture I rarely ever felt the need to go below 1/64th. Depending on the species, 1/32nd usually provides me with a more than satisfactory joint.


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## jschaben (Jun 21, 2009)

I have a Harbor Freight caliper that resolves to 128th which is way more information than I want to deal with. I just open or close the caliper until it gives a fraction that I can deal with.


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## DaninVan (Jan 1, 2012)

I _hate_ counting off the metricized markings. Give me the staggered height indications on an Imperial ruler any day!
Scale Rules. Printable Imperial Scale Rulers - Imperial


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## Ratbob (Apr 6, 2015)

Ghidrah said:


> Being a framer for ever, remembering and converting from decimal to fraction comes hand in hand, but the accuracy never goes finer than 1/16th. Since I've been messing around with trinkets, boxes and furniture I rarely ever felt the need to go below 1/64th. Depending on the species, 1/32nd usually provides me with a more than satisfactory joint.


I absolutely agree Ronald, it would be ridiculous to do WW to the nearest hundredth. I don't walk into the shop thinking "Let's go reduce some fractions!" and I find the mental gymnastics tedious. I get enough of that at work bouncing between binary, hexadecimal, and decimal. So, I created a tool that lets me take any fractional number and come up with a number that I can find on my rule that makes practical sense.


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## Ratbob (Apr 6, 2015)

DaninVan said:


> I _hate_ counting off the metricized markings. Give me the staggered height indications on an Imperial ruler any day!
> Scale Rules. Printable Imperial Scale Rulers - Imperial


Cool link Dan!


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## DaninVan (Jan 1, 2012)

Jeff; a drill index table does that and more.
Drill Size Conversion Table


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## Herb Stoops (Aug 28, 2012)

A lot of my cutting is mark and cut. Get perfect fits that way.

I like those tables Dan, got to fool around with those.

Jeff, thanks for posting this thread, sure smoked out some good conversation. Might also try a Harbor Freight caliper with a dial graduated in inches instead of a digital, that way at a glance you can see the nearest fraction. Kind of like looking at a watch as opposed to a digital watch.
Your table kind of reminds me of the rafter cutting scales on the old Stanley framing squares. 

MEBCWD I too did that for years and got quite used to the .01 of a FT. but I never could get the hang of metric.

My advice to all is do it the way it is comfortable to you.

Herb


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## Ratbob (Apr 6, 2015)

Stick486 said:


> this may sound like a rhetorical question but will/could you define ''joints that fit'' as you see or know it...


Let's take for example the double rabbet I used on my router fence. After the initial cuts, a dry fit showed a gap between two of the edges. Instead of creeping up on the cut (which may have been the better way to go) my engineering background leads me to measure the exact amount needed to be taken, make one adjustment to the fence, and take a final cut.


> it's unusual to see plans in decimal and fraction... was this a WW plan???
> and go have words w/ who ever drew them up...


The plans were for creating a drill template for adding a sacrificial fence to my Osborne EB-3. 


> screw the conversions...
> I'd set the measures on the caliper...
> locked the caliper...
> and used the caliper as a marking gage...


I like that idea, thanks for the tip.


> get a dual measure caliper... there are lot of them out there.. wide range of prices too...
> Amazon.com: Shop Fox D3208 Fractional Dial Caliper: Home Improvement


Already have one, and I find it has the same problem, though to a lesser degree being that it's graduated in 64ths. I took a math class once and know how to reduce a fraction. I'd simply prefer to quickly find the nearest 'practical' fraction instead of doing the calculation in my head.


> ...
> to get these finite measures you seem to be after you'll need a 0.3mm mechanical pencil which in a very very short order you'll soon trade it in for a 0.5 or a 0.7mm...
> I mostly use a 0.7mm 90% of the time and the 0.9 for rough work w/ rough materials...
> this pencil is cheap, available everywhere and lasts way longer than any other I've ever used... add a grip barrel to it and you'll really have something...
> Search results for: 'p205/7/9' - Pentel


Not sure why you are so fixated on the fact that I'm trying to over engineer my WW. That was never the point! I know that I can't expect to cut to the nearest 128th or even 64th of an inch.
As far as pencils go, I prefer this one.


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## Ratbob (Apr 6, 2015)

Herb Stoops said:


> A lot of my cutting is mark and cut. Get perfect fits that way.


Thanks Herb. As I'm pretty new to WW I'm not sure what you mean by 'mark and cut'. Could you give an example?


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## Herb Stoops (Aug 28, 2012)

Ratbob said:


> Thanks Herb. As I'm pretty new to WW I'm not sure what you mean by 'mark and cut'. Could you give an example?


I cut a piece to length ,then use it for a pattern and mark it on another and cut that one. I just take the pencil mark off when I cut it.
Herb


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## DesertRatTom (Jul 3, 2012)

Thanks for the table. I also have problems reading the fine tick marks on rules. I also generally mark the piece, often with a blade if I want to be fairly exacting.


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## DaninVan (Jan 1, 2012)

.5mm automatic pencil for me, in the shop. I like the relatively inexpensive ones...but they have to have a metal ferrule to feed the lead. The ones with plastic ferrules are crap.
You also can buy replacement leads in various hardnesses. I generally use HB but F might be better in some cases(?).

Re that 1st picture of the Imperial scale; those smallest markings are 32nds...if you can accurately split those into 64ths you're a better man/woman than me. 128ths ?! That's quartering those fine marks!! 
Even my utility blade would leave overlapping marks.


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## Ratbob (Apr 6, 2015)

Herb Stoops said:


> I cut a piece to length ,then use it for a pattern and mark it on another and cut that one. I just take the pencil mark off when I cut it.
> Herb


Got it, thanks Herb. I do about the same, though sometimes I leave out the mark. Just lay the reference piece over the piece to cut, square it to the miter fence, and line up the reference board to the cut in my sacrificial fence, remove the reference board, and make the cut.

I don't need the table for every cut, but it sure comes in handy when I need it. As a matter of fact, I just built two flower boxes from some old distressed fence board for my better half and I didn't make a single measurement! As you say, just mark and cut.


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## Stick486 (Jan 4, 2013)

Let's take for example the double rabbet I used on my router fence. After the initial cuts, a dry fit showed a gap between two of the edges. Instead of creeping up on the cut (which may have been the better way to go) my engineering background leads me to measure the exact amount needed to be taken, make one adjustment to the fence, and take a final cut.
*creeping/sneaking up on a cut is a wonderful thing....
w/ rabbets, rebates and dadoes a shoulder plane would be a strong ally... just saying...
if you decide on one I strongly suggest you leave the Stanley 
sweetheart plane at the store..
also, there are a bazillion aides to help accurately set up your cutting operations which have been covered to death here....
test cuts on scrap are about as mandatory as you can get...*

Already have one, and I find it has the same problem, though to a lesser degree being that it's graduated in 64ths. I took a math class once and know how to reduce a fraction. I'd simply prefer to quickly find the nearest 'practical' fraction instead of doing the calculation in my head.
*merely suggested a dial style caliper that simultaneously reads in decimals and fractions...
you can find them graduated in 32nd's...
it'll give you the nearest practical fraction at a quick glance...
no conversion required...
also, there is no issue as to you knowing how to do conversions.... 
I'm making the suggestion that you avoid doing conversion whenever possible because on the best of days errors/mistakes happen and easily compound... *

Not sure why you are so fixated on the fact that I'm trying to over engineer my WW. That was never the point! I know that I can't expect to cut to the nearest 128th or even 64th of an inch....
*I'm not fixated.. at least I did think of myself being that way... sorry...
you will find that better WW machines have micro adjusting capabilities and w/ a little experience 64th's and 128's are doable...*


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## Stick486 (Jan 4, 2013)

DaninVan said:


> .5mm automatic pencil for me, in the shop. I like the relatively inexpensive ones...but they have to have a metal ferrule to feed the lead. The ones with plastic ferrules are crap.
> You also can buy replacement leads in various hardnesses. I generally use HB but F might be better in some cases(?).


those Pental P205/7/9's have metal ferrules and cost around a buck seventy five each and a 10 pack drops the cost to pretty close to a buck..
as far as leads go I use the synthetic poly blends.. (HB/F in the .5 and a 2H in the .9)
Picking the Perfect Pencil Lead Hardness Grade - JetPens.com
Category - Faqs - Pentel of America - Pens, Pencils, Refills, and Markers

now for the eraser...
I use vinyl in stick form gotten at the art shop.....


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## DaninVan (Jan 1, 2012)

Thanks for the eraser tip, Stick, those useless *&^$# things that come with the pencils, I know exactly where they belong!


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## Ratbob (Apr 6, 2015)

Thanks for the heads-up on the 'Sweathart', I'll make sure to keep that one off of the shopping list Stick. I have a small rebate plane, but I haven't looked into shoulder planes yet. My adventure is just beginning here, and I appreciate the input.

Micro adjusting the fence is not a problem on my setup. If I need to, I can set a dial gauge against the fence and make adjustments to the nearest thousandth. I haven't found the need for that, and wouldn't be surprised if I never did, but at least I know how and have what I need to make it happen. So far I'm really liking the fence that came on my R4512. It locks repeatedly straight, as verified with a dial gauge referenced to the miter slot. While I don't trust the tape on the guide rail for absolute measurements, making relative changes to the nearest 32nd is really easy.


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## Stick486 (Jan 4, 2013)

about that saw....

1st...
blade parallel to miter slot... this matters a bunch...
2nd...
fence parallel to the slot and to the blade...
3rd...
miter gage set to the blade...


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## Ghidrah (Oct 21, 2008)

My1st horror show with metric came while roofing a house; I'd vaguely heard of IKO shingles and never used them prior and didn't know they were metric. Bird was the brand everyone used unless using textured shings. The contractor ordered them and didn't tell us, we prepped the roof and snapped lines for standard American shingles. When you have 4 guys on the same side, roofing like something's wrong up stairs, (auto pilot). We nearly got 2 sq. on before somebody said what's wrong with these shingles and took out a tape.


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## Ratbob (Apr 6, 2015)

Stick486 said:


> about that saw....
> 
> 1st...
> blade parallel to miter slot... this matters a bunch...
> ...


Absolutely true with any saw, and I'm aware of the shortcomings of my table mounted trunnion. The earlier R4512s had some serious alignment issues, but I seem to have escaped those (for now )
My fence is set square to the miter slot with a .002" toe-out at the out-feed. So far this has been very repeatable, but thanks for the reminder, I'll check it again.
The blade is currently less than .001" across 5 or 6 inches when measured with a dial gauge referenced to the miter slot off of the same tooth rotated front to back. Again, probably a good time to re-check.
As for the miter, I recently picked up an EB-3, and haven't yet taken the time to true it yet, but soon.


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