What should we expect from clamping squares ?

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Forum topic by OldBull posted 07-08-2020 08:06 PM 1546 views 0 times favorited 21 replies Add to Favorites Watch
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458 posts in 454 days

07-08-2020 08:06 PM

Happy Wednesday to everyone,

My hope was to have a square reference that could be clamped to but not have to treat it like a beating heart. My engineers squares are hidden away and I have some 123 blocks but I am not quite care free with them. I bought these clamping squares with the hope of throwing them around and grabbing them as needed. But they were not square, and they flexed, and yes they were BORG purchased and reasonbly cheap, $12. They were manufactured in halves and seamed together which was also off, I put them on my mitre station tops I built before these arrived and used them as a reference to how square I build things and they were off and flexed to easily. My 3 square references I have all agreed to the same thing, they were off on the inside, off from side to side (different half) and off a little worse on the outside (appx 3/64 in 8”).

But maybe I was expecting to much, what should we expect from clamping squares, flex no flex, you get what you pay for and there are better, or, for clamping squares that is the norm? Or just maybe you might say use a square rule and forget clamping squares. The idea of being able to clamp to something square would be a great help aligning things, that was my hope. Some will say make your own, probably out of wood, but I have to ask does moisture effect wooden tools created for accuracy?

Thanks for any help.


21 replies so far

View HokieKen's profile


18417 posts in 2297 days

#1 posted 07-08-2020 08:34 PM

I have some small clamping squares that are machined steel and I made some large ones from 3/4” plywood. They both do what I expect which is act as clamping aids. Plywood is stable enough that I trust them to stay square. All that said though, they are just clamping aids. Whatever I’m clamping needs to be square during dry-fit or fixed prior to glue up.

To your point, if they flex too easily, they aren’t much good. There are some good metal versions available and there are plans available to make your own. They are handy things to have around for sure.

-- I collect hobbies. There is no sense in limiting yourself (Don W) - - - - - - - - Kenny in SW VA

View tomsteve's profile


1175 posts in 2377 days

#2 posted 07-08-2020 09:47 PM

for using on interior clamping, i made 8 of these. they work great

View CaptainKlutz's profile


4667 posts in 2652 days

#3 posted 07-08-2020 11:55 PM

+1 make your own.

IMHO – the legs of a square should be square.

Bought some Rockler clamping squares when they came out. Same problem.
Took them back to store, along my trusty engineering square and was only able to find 2 out of ~12 that were square. Store ordered some more, the next lot was ~50% square. The ‘bad’ ones were more like 89° with measurable 0.010-0.020” gap near corner on one leg.

They also flex to much IMHO. Using them for large boxes is dangerous. Can easily bend a leg and make case out of square.

My review on Rockler site showing they were not square and how easy the bend was removed. My complaint to corporate folks got me a dear klutz letter with the advice that if not happy with purchase, can return to store for refund.


-- If it wasn't for bad luck, I wouldn't have no luck at all, Doom, despair, agony on me… - Albert King - Born Under a Bad Sign released 1967

View AlaskaGuy's profile


6698 posts in 3467 days

#4 posted 07-09-2020 12:30 AM

I have a small set of 4 metal one that work OK but I find I always in need of different sizes so I just make my own.

How to make your own

Edit: I now see someone else posted the same video so here’s a bunch of others to pick from.

-- Alaskan's for Global warming!

View Redoak49's profile


5320 posts in 3147 days

#5 posted 07-09-2020 12:42 AM

I made clamping squares like the video in four sizes. They were made from a double layer of 3/4” Baltic birch and they work great. Boxes I make with them check square with my engineering squares. Cheap, rugged and square!

View mtnwalton's profile


104 posts in 2184 days

#6 posted 07-09-2020 04:19 AM

I’ve got four of the Woodpecker clamping squares (6” i think ), they are square but I always check during glue ups. I would avoid the plastic ones

View therealSteveN's profile (online now)


8215 posts in 1732 days

#7 posted 07-09-2020 07:09 AM

Those gaps would be depressing if you spent a lot of cash on them Pretty easy to make from plywood, or you can buy some.

Simple Cove shows how to use plywood to make them. Actuially a lot of video is available doing this same thing, and I imagine a lot of posts here as well.

If you see these sold solo, and they don’t cost too much, get one, and try a known good square against it. A 10 pack of them is 43 bux at Amazon. You can get smaller, less expensive angles for construction that come square, most you can bend, but if you don’t they work. Again it’s fun to bring in a small engineers square that you know is a good 90*, and just check them, most are dead on.

-- Think safe, be safe

View becikeja's profile


1175 posts in 3971 days

#8 posted 07-09-2020 10:20 AM

Agree 100% that if you pay for square, it should be square. Discussion over. No excuses.

With that said, I am curious about what you’re working on. I think I do a good job in my craft but have never found the need to be dead-on square in woodworking. I have a simple metal square I picked up somewhere along the way. I use that with a couple corner clamps, and have never had an issue. I will say I have wrestled with some larger table frames in the past, but always seems to work out. Just curious as to why this accuracy is needed.

-- Don't outsmart your common sense

View OldBull's profile


458 posts in 454 days

#9 posted 07-09-2020 12:17 PM

@becikeja ”” Just curious as to why this accuracy is needed.””

I am new to woodworking and once you learn how something is supposed to be, you look back on the way you did things and see how bad they were. I can’t draw a stick figure very well and I can’t draw a straight line. Now I am trying to go the other way. Without much experience, I thought that errors would multiply, so I am trying to teach myself to be accurate, how much ? I have no idea !!

Thanks everyone, I will build some and keep an eye out for others as I need them.

P.S. There is a lot of finite “accuracy” (.0001) used (talked about) for tuning blades and saws, so I guess in my learning I thought it was supposed to be “that” accurate maybe. Also, I kind of like getting that accurate, it is unusually satisfying.

View HokieKen's profile


18417 posts in 2297 days

#10 posted 07-09-2020 12:35 PM

I don’t know what size of work you’re doing but in addition to clamping squares, you might consider some 1-2-3 blocks. They’re precise and rock solid and pretty affordable. You could use them for clamping glue ups but there are infinite ways they can be used in the shop.

-- I collect hobbies. There is no sense in limiting yourself (Don W) - - - - - - - - Kenny in SW VA

View OldBull's profile


458 posts in 454 days

#11 posted 07-09-2020 12:40 PM

I have them, but admit I have been kind of protective like my engineers squares. As I was just thinking how to screw two 123 blocks together and get them tight without any head exposed ? They also don’t seem to reach out far enough. Maybe I should try 246 blocks !!

View controlfreak's profile


2487 posts in 760 days

#12 posted 07-09-2020 12:44 PM

I got some rockler ones that attach to some clamps. I didn’t expect much as the reviews were littered with “out of square” but hey they are plastic. I think of them as more of an extra set of hands for building plywood boxes and such. Anything I build that is needing to be dead on will likely have some joinery that a well placed clamp can pull square.

View HokieKen's profile


18417 posts in 2297 days

#13 posted 07-09-2020 12:45 PM

2-4-6 blocks would be even better. For that matter, look at some angle plates. I imagine you can get some Chinesium ones for not a whole lot.

-- I collect hobbies. There is no sense in limiting yourself (Don W) - - - - - - - - Kenny in SW VA

View bondogaposis's profile


6000 posts in 3509 days

#14 posted 07-09-2020 01:01 PM

Just make your own, they are easy to make and will be as accurate as your table saw.

-- Bondo Gaposis

View Madmark2's profile


2958 posts in 1746 days

#15 posted 07-09-2020 01:34 PM

Generally you don’t need precision from the inside of a square. Did you measure the outside?

I have those same Rockler clamping squares and although not perfect, they’re good enough. I can flex a 1/2” plywood panel more than the amount of error you’re showing. Many ply panels will have a bit of warpage. What matters isn’t if the temp clamp fixture is perfect, but is the final result ok.

The square and fence make an assembly corner.

I use them as a 3rd hand to keep things from falling over during assembly. I check my stuff for square using the diagonals test. I don’t use four clamping aids and call it good enough. These are NOT “layout” squares.

Are your woodworking skills so fragile that the error you’re showing impacts your cabinets?

NONE of our tools are perfect. Part of the art of wood working is being able to do precision and quality with less than perfect tools/materials.

Use them for what they are, cheap, injection molded, clamping “mostly squares” and don’t demand perfection from low cost plastic.

-- The hump with the stump and the pump!

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