Woodworker Chronicles #1: Don't be such a ☐

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Blog entry by PurpLev posted 11-13-2011 06:15 AM 7704 reads 1 time favorited 11 comments Add to Favorites Watch
no previous part Part 1 of Woodworker Chronicles series Part 2: emBRACE the BOREdom »

I’ve always wondered why are there sets of squares out there. Isn’t a square a square? aren’t they all the same? Can’t you just have 1 and be done with it since if something is square…well – it’s square, right?

A recent check made me realize I probably have more squares than any other tool in my toolbox (excluding chisels and drill bits of course). How did that happen?!?

When I first started woodworking, I got myself a 12” square from the BORG. it’s an Empire Pro 12” combination square. It was always square and did it’s job well. In fact, I still have it and use it on a regular basis to this day and have nothing bad to say about it. it simply works and is very affordable It’s just that at some point, I stopped at an estate sale and found a 12” Starrett equivalent which I reviewed here (as compared to the Empire Pro square). In fact, It started to grow on me after writing the review. It’s not that the Starrett was any squarer, it’s just that it’s operation was smoother, and it’s finish more refined, easier to read, and at a higher (64th) graduation, not that I read 64th much, but when you need to it’s nice to have it, and so I repurposed the Empire square to household jobs (it has a level in it, so it does come in very handy around the house) and kept the Starrett at the toolbox.

A 12” combination square is a very handy and versatile tool. It can check for square, it can check for 45s, it can be used as a straightedge in certain situations and it can transfer square and parallel lines 12” deep into parts:

...But, since it IS this long and it does have this reach, it also means that it’s more cumbersome and less friendly to use when working with smaller parts, or for checking parts for square, not to mention good luck trying to keep this in your front pocket all day long (yes I can think of a joke or 2 and I know you can too). Enter the eBay found 6” smaller version:

Same functionality in a smaller footprint and much easier to handle as the head is smaller and can fits nicely in your palm for quick work. Also since the head is smaller it can reach into 45 corners deeper than the 12” square (good when you are setting your TS at 45 and want to verify the angle when the blade is lowered for example). Great all around square bar none with the smoothest action I’ve seen in this size.

But even that one doesn’t fit too well in a front pocket… Decided to try Rocklers 4” double square:

This one has been my all around square for the longest time. it’s small, fits in the pocket, fits in your hand for quick work, with the only down side compared to a combination square is that it doesn’t do 45 angles which is fine since the majority of my work around machines and workbench involves square and flat and for those times I do miters I can grab one of the combination squares. the 4” double square is probably the tool that gets the most use as I use it to check for square, measure small parts, and mark parts for joinery and transfer lines. Unless I need longer layout lines this one does it all.

But what I really wanted was a square that is small and can not only fit in the front pocket, but also in an apron pocket. something that just won’t take space, and be light and unnoticeable until I need to use it. For that I use a 2 1/2” precision square. Mine is a Brown&Sharpe, but other makers make a similar square (Starrett, Lufkin to name a few). I kinda like the B&S because the top of the head is beveled in where it meets the rule allowing a very clear view of the markings at the edge of the rule:

I must say of all the squares this is my favorite one. Although the all metal body and oily/sweaty fingers do call for extra care to be taken with it (wiping after use) not extreme, but something to keep in mind.

Last but not least, there is also the die maker square:

This one also has a 2 1/2” rule as well as other rules (thin, offset, 45/30 angles), but it’s unique feature is that the rule can be set to anywhere between 0-10 degrees off square which is really meant to check the offset of dies, but in woodworking can be used to layout dovetails or similar geometry:

And so looking back, from just needing a square, this collection has grown quite a bit:

You can kinda see which one gets the most use right there, but the funny thing about it is that they all see use on a regular basis.

Checking for Square
So what good is it having a square if it isn’t a square? or wait a minute… how would you even know if your square is a square? use another square? what is that square isn’t square either? use a 3rd square? oh boy…

There are several ways to check a square for squareness. Some requires more measuring tools then others, some providing quicker results then others, some providing more accurate results then others. For sake of woodworking, the following are 2 ways to check your square for squareness. One requiring an additional device that I believe is available for purchase or can be made and provides with a faster and more accurate result, while the other doesn’t really take much to achieve and can be done in any shop at any time and like I said for the purpose of woodworking is just as good as any other method.

The Round Square
What you say? round square? how is that even possible? and how would you check a square with a round object?

The answer is explained in the method of making the measuring device, the Cylindrical-square. A cylindrical square is a cylinder that is made on the lathe to very high tolerances. The idea is that if the cylinder is turned to be of consistent diameter across it’s body than that means that the sides are totally flat and parallel to the axis of it’s rotation (on the lathe). If then the base is faced totally perpendicular to the axis of rotation then that results in the base and the side of the cylinder being square. In fact the base doesn’t even need to be highly machined as long as the circumference of the base is faced properly and there are more details about it, but that probably won’t make this any clearer so I’ll stop here.

Using a flat reference surface (granite for example) and a cylindrical square is a fast and accurate way to check a square for squareness if it’s rule makes full contact throughout it’s length with the cylinder when placed next to it:

The Straight Edge Method
If you don’t have a flat reference surface and don’t have a cylindrical square (like most of us don’t) then an alternative to checking a square for squareness and in my opinion what should be named ‘the official woodworker way to check a square’ is to use a surface with a known straight edge (jointed on the jointer, or another known surface/part that has a straight edge – yes even using a straight edge).

Butt you square against the straight edge of the part on one side of the square, and mark a line down it’s rule:

I like using a mechanical pencil as the lines produced are always fine, and always consistent in width and sharpness (I use softer graphite so it does not gouge the wood) and it should look like this:

Pretty isn’t it?

Now flip your square and butt it against the same straight edge now with the square facing the other way, align the rule with the previously made line and mark another line (yes I can use both hands):

If your square is out-of-square you will probably see something like this:

But if your square is indeed square, the 2 lines should merge into one, and what you will hopefully see (what you WANT to see) which verifies your square is indeed what its named after is this:

Just make sure the rule in your square (if you have an adjustable square) is properly positioned and locked in the head and that there are no debris or dents on the head of the square that otherwise WILL introduce and error and throw your readings way off.

Now you can feel good knowing your square is up for the challenge you present it with everyday you use it. Hope this was useful and if not at least entertaining and if not then there isn’t much I can say since I will not be reimbursing anyone for lost time ;)

Thanks for reading,

-- ㊍ When in doubt - There is no doubt - Go the safer route.

11 comments so far

View Karson's profile


35128 posts in 4457 days

#1 posted 11-13-2011 06:47 AM

Sharon: I think you are “Square”

In a good way.

Great trivia, In a good way.

I’ve done the opposites match when cutting wood and checking the table for square, but never thought about using it to check a square. Nice job there.

I’ve also never heard of a cylinder square, but them I haven’t done much lathe work.

What do you do when the outside of a square is square, but the inside is off, or vise-versa.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia †

View Dennisgrosen's profile


10880 posts in 3172 days

#2 posted 11-13-2011 11:26 AM

it seems to me I need a smaller one than the framing square I have ….. :-)
I´m with Karson …. what do you do if one of the sides ain´t paralel with the other

great blog :-)


View ellen35's profile


2738 posts in 3489 days

#3 posted 11-13-2011 12:04 PM

You can never have too many squares or clamps!
Nice job on the blog, Sharon.

-- "Don't let the perfect be the enemy of the good." Voltaire

View Lee A. Jesberger's profile

Lee A. Jesberger

6860 posts in 4036 days

#4 posted 11-13-2011 02:07 PM

Are we square on this now?

I think so.

Nice write up, Sharon.


-- by Lee A. Jesberger

View woodpeckerbill's profile


205 posts in 3330 days

#5 posted 11-13-2011 03:38 PM

Glad you are all squared away! Great write-up.

View Dale J Struhar Sr's profile

Dale J Struhar Sr

495 posts in 3187 days

#6 posted 11-13-2011 07:22 PM

Great article, very interesting.

-- Dale, Ohio

View willie's profile


534 posts in 2511 days

#7 posted 11-13-2011 08:42 PM

I find myself using my 4” Starrett comb. square more than most of the others, but on the other extreme, I picked up a couple 24” rulers for my larger combination heads. They don’t see a lot of use but they are great when needed. I have one 24” ruler that takes a bigger head that I have not been able to find. It is 1 1/2” wide and makes a great straight edge but I would like to find the other head. They are all Starrett or Lufkin and do interchange.

-- Every day above ground is a good day!!!

View PurpLev's profile


8539 posts in 3705 days

#8 posted 11-14-2011 03:54 AM

cjwillie- yes, I noticed that starrett/lufkin/b&s rules share similar sizings and can be interchanged between heads.

Karson – If the inside is square but the outside is not or vise versa than either the head or the rule is malformed. if this is a carpenter square you can pin it with a hammer to expand the metal and fix it (much like fixing it’s out of square) but for combination squares with hardened rules I am not really sure what can be done about it other than resurfacing it or – if you check it on time – replacing it under warranty. the majority if times I noticed a square gets out of square is usually from a nick or scratch on the head/rule which can be sanded/filed off carefully (As long as you don’t file and reshape the rest of the surfaces)

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View mafe's profile


11739 posts in 3146 days

#9 posted 11-14-2011 12:39 PM

Hi Sharon,
I also ended up with a good bunch of squares, and use about the same as yours even I also use a big carpenters square often, these also comes in Japanese versions and that is my favorite.
Interesting reading, thank you.
Ready for some square dance now…
Best thoughts,

-- MAD F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

View PurpLev's profile


8539 posts in 3705 days

#10 posted 11-14-2011 05:54 PM

ah, yes Mads – the good’ole carpenters square. I actually have one of those but use it so rarely that I completely forgot about it when I wrote the above :) It’s just so large and bulky that unless I really need to scribe a square line on a large surface I’ll probably opt for something lighter and easier to manage. I did notice the japanese version on leevalley website which looks very nice, but haven’t found a need that would justify purchasing it as of yet. what do usually use it for?

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View mafe's profile


11739 posts in 3146 days

#11 posted 11-14-2011 10:21 PM

I use it for all bigger marking, this summer when I made the shavinghorse in was in use all the time, and the Japanese one have been my pal while working on Japanese work lately. You will see when I get to post.
My Japanese is this version (the bigger) I bought it because I wanted to use Japanese marking tools with ink.
The standard Danish looks like this:
So the use is for marking wider boards than our standard square can handle.
Best thoughts,

-- MAD F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

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