I don't know what you call a square that is not square, but unless it is, it is useless under any name!
The Combination square is one of the first square you should get and it MUST be precise. That means forget about all these El Cheapo imitations at the Big Box store or hardware store and get yourself a real one.
Starrett is a brand that get mentions a lot everywhere and for good reasons.
Starrett tools were never cheap but you are paying for precise machining and a tool that will outlast us all. Other machinist precision brands are Sharpe & Brown, Mitutoyo and etc. Forget Stanley, Johnson and Empire etc.
A good 12 in Combination Square will cost you about $100 but it is worth every pennies.
My 50+ years old Starrett, still perfectly square since the day it was made.
Ruler is a bit dark, but I rarely used the markings if ever.
Cast iron head, not poly carbonate, or glass filled or aluminum and etc.
Low sheen finish on the ruler, etched markings, precise machining of the slot and pawl so that the ruler slide easily and lock square every times.
Why 12 in? Because it also double as a straight edge, a precision ruler etc.
Forget these nice looking rosewood handled square, they are often only "square" on the inside of the square and not on the outside, it will bite you eventually....
Here is your first clue, the brass edge is **Only** on the inside
Get yourselves some Machinist metal square. Often called Engineers square.
Look for BS939 Grade B. That means British Standard 939 and Grade B is not as precise as true machinist squares (grade A) but plenty good for our woodworking. The specs are less than 0.001 in deviation per inch over the full length of the blade. And since a small 3 or 4 in is the one used often we are well within tolerances for working wood... we are not machinist but woodworkers.
These are Groz. Made in India, BS 939 B inexpensive and plenty good,
But regardless of which brands or how old, always check them regularly.
DOVETAIL MARKERS, SADDLE SQUARE
Not a must, but sure makes your layout faster and easier
There are various styles, you can easily makes one with a piece of scrap wood, but I really like these saddle squares from Veritas. Makes transferring your line across two faces so much easier. I also used the saddle square and the mitre saddle which I also used as guide to pare my 45 degrees with a chisel on small stock.
They make a whole series of these in various angles
Myself I used 14 degrees for most everything
Another type of dovetail marker.
Woodpecker has been making a series of "red" tool which are pretty good, Ralph swear by them.
Another tool which is very handy in the square dept is the Veritas Cabinet maker square, very handy. Just ask Ralph...
These simple looking tool are very handy but can be frustrating in use... because of the blade locking mechanism.
Ideally once locked you should be able to lay it flat on both sides, most don't.
Those that lock with a lever, even with the area recessed,
don't lay flat on this side
Forget about laying flat with a big knob sticking out
The only ones that can lay flat on both sides are the ones that use a locking mechanism at the butt end, providing the nut is not bigger than the stock.
This Millers-Falls "Buck Rogers" lays flat
So does this Disston, except that the wing nut is a smidge bigger and depending on the locking position it sticks up a bit. I can easily work around that.
Sliding T Bevel are very handy and you should have a "few" on hands. That way you can leave one set at a given setting throughout a project or check your drilling angles from two directions etc. Here is a new and inexpensive T-Bevel that lock on the butt.
A must when flattening stock with planes, but regardless of how you are trying to flatten your stock with machines or by hands, you need these to check for twist.
Veritas winding sticks
You could make you own out of wood, or buy commercial ones such as from Veritas, but you could easily save yourselves a few bucks by buying a piece of extruded angle anodized aluminum at your local hardware store for a few bucks, cut it in half and voila! a rugged pair of winding sticks.. Perhaps use a black marker to make the top of one of your stick stand out more and you are good to go and would not cry if (when) you will knock it off your bench :-)
In addition by using them inverted (resting on the two edges) they are very stable.
You cannot have too many, just like Sliding T-Bevel and dividers.
At a minimum you need two types, which are sometimes incorporate into one tool. A marking gauge and a Mortise gauge.
The marking gauge has a single pin, whereas the mortise gauge has a fixed pin and a movable one.
The traditional British mortise gauge often comes with a fixed pin on one side of the beam (the marking gauge) and two pins on the other side (the mortise gauge)
They also often feature a recessed screw to lock the beam, requiring the use of a screwdriver whereas the American ones used a wing nut type of screw.
Stanley No 76 mortise gauge
Featuring a special plate to be able to trace around curves
Typical screw recessed locking screw on British gauges
A modern Veritas wheel gauge, first generation.
To cutter does not recess into the head, nor is there a flat on the head to prevent it from rolling around. Both problems are fixed on the new ones.
I get around that by dropping it in one of my bench dog holes when in use.
Pin or Wheel gauges? I have and used both, the wheel types are able to scratch a good line cross grain, easier than a pin, but have more of a tendency to follow the grain when used along the grain. Proper holding techniques can easily overcome that tendency. Wheel types are also easy to sharpen, just rub on the flat side.
Micro adjust one such as the Tite-Mark and the redesigned Veritas are very nice (insert drool here)
DIVIDERS, CALIPERS AND COMPASS
A must in the shop. They come is various sizes, usually in 4, 6, 8 inches and bigger. You need a least one and preferably a few, again to leave them set throughout a project. This is one tool where buying as a set can save you some money.
This is a 8 in set
Stay away from cheap kindergarden type compass and buy yourself a good solid one. at least in the 6 to 8 in range or bigger. For bigger circle you are better off with a set of trammel points.
This is what I meant by Kindergarden set :-)
And yes, that was my first kit as a kid, which somehow survived me...
My next set as a teenager, also survived me and is still in use.
My regular shop one, notice the perfect use for
those small pencil at the Lee-Valley store to write in your order...
Oups you are supposed to leave the pencil at the stores :-)
Trammel points set. you are only limited by the length of the bar
which you can make any size you need
Another essential tool for making precise marks AND setting the stage for the chisel or saw to follow. A true marking knife has only one beveled face, the flat face is riding against the ruler, square or whatever.
Paul Beebe marking knife. Good all purpose knife but the blade
is too thick for some uses such as small dovetails
Czeck Kerf Kadet knife. Pricey but I love it. Good balance,
nice thin and long blade sneaks in everywhere
Crown small awl. Some prefer to use an awl to strike marks,
but I prefer the cut edge left by the knife
Recently Lee Valley came out with a great marking knife, nice thin, long blade in a glass reinforced plastic handle, inexpensive and great buy. If you are starting, and don't have any, buy one!
Beside the marking knife, I like to use a shop knife to deepened the marks left by the marking knife to help register the chisel or saw plate. You could also used a chisel to do that, but a good shop knife quickly becomes indispensable.
My all time favourite is the German chip knife No 8.
Technically it is a carving knife, but I just love the way
the handle fit my hand and the balance
There are many such punch and variations, but I like a good automatic punch. Put it where you need it, depress the top and it fire a spring loaded tip to leave a mark. So handy, to me it is indispensable and do belong into any minimalist tool list. Perfect to ensure you are drilling right on the money...
I prefer a rigid ruler to a tape measure any day, but a small tape comes in handy, especially when measuring your stock and getting the rough cuts set up.
When I says small I mean around 10-12 ft should be plenty long. Larger ones such as 25 ft are more for carpentry than woodworking, beside why carry around the extra bulk and weight!
Or for the ultimate in compactness carry one of those in your pocket.
That is a 6 ft tape... Yes it is a replica of an antique.
I used both metallic and wood rulers. Metal ones should have their markings etched then ink filled for durability and legibility. You want a low sheen or the glare will get you :-)
I just love folding rules, vintage ones are a crap shot at times, but they now have started to make them again, yeah!
Traditionally woodworkers would carry a 2ft, 2 fold rule and a long Zig-Zag type for longer distances up to 8 ft. My Zig-Zag rule has a brass slider on one ends which is very handy.
Rabone No 1167 2 ft, 2 fold rule.
That one has "Blind man" markings, big ass numbers for old guys like me :-)
Lufkin X48 Red ends, 8 ft rule with a brass slider
Other handy rules to have around would be a good pocket clip 6 in metal ruler
And a center finder rule. I don't know how I got along without one all these years before, soooooooo handy to have.
In many instances you don't need to know the exact measurement, you just need to know if an opening, or assembly is square or a set reference length. A simple pinch sticks will act as a Go-Nogo gauge and is a lot simpler to use than trying to measure the diagonals of an assembly at glue time. You can buy the hardware at Lee Valley or buy a complete unit at Woodpecker or Rockler or you can simply make your own (watch Pinch rods and Squeezy blocks). Very simple, but sooooooo handy. What size? Sized to whatever your needs are.
A pair of these in two different size should handle the vast majority of your needs.
The Veritas hardware for making a pair. I already have one made, this is for another sizes as a one day project, someday...
Finally since the world is not flat, you need to be able to find level and plumb, and sometimes you need to determine what are all the angles you see :-)
For woodworking a torpedo level, about 9 in long is all you need. The 2 ft and 4 ft etc are more suited to carpentry and house renovations.
You have the choice of a glass vial or electronic version. Heck you can even download one of the various Apps for Smart phones that will turn your phone into a handy level.
Good old fashioned and reliable glass or poly vials
Electronic. You don't even have to look at it, it beeps when level is reached.
Have this one for over 20 years now, and my wife is constantly stealing it for leveling pictures :-)
A pint of beer makes a very handy level...until it is empty of course :-)
There are numerous tools out there that would fit the bill, from the simple plastic angle protractor found in any drafting kit to the various digital gizmos available.
Whatever you get, get one that you can read easily and adapted to your job.
For example you would be hard pressed to check the angle of a blade in a tablesaw armed only with your drafting set Angle protractor!!
Inexpensive plastic angle finder. Pretty good but maddening at times trying to remember how to read that darn thingy...Save the instructions :-)
Heck of a lot easier to read, no instructions required :-)
Love this little digital gauge, I find new uses every day for it.
While you could easily make such a board with an angle protractor, you can buy an Bevel setting board. It is very handy to have.
Next I would add a set of setup's blocks. They are not only handy they make setting up tools and cuts so easily and precisely without trying to decipher small strange markings (you know those pesky metric thingy)
I had to exert great control not to include such a set into this minimalist list. That how much I rely on them all the time. The thing about measurement accuracy and transfers of those numbers on various devices is: Every time you measure or read a distance, you introduce errors. By not trying to measure anything by using Go-Nogo gauges and known dimensions blocks, the actual "measure" is very accurate and easy to duplicate over and over without errors.
This is the basic (starter set). It is the one I used all the times
I like it so much, when they came out with expansion sets, I bought them too.
This is the 1/16 expansion kit and the 1/32 set with the starter kit.
That in effect spread the measurements out for easier reading.
So by now you may get the idea that I don't like to take actual measure, and if so, you would be right...
Bob, who doesn't like to be restricted by imperial or metric measurements. I am a Free Range wooodworker you hooo