How square is your square

[Bodgers]

I have Axminster engineers square which is still out by a small margin.

What margin?

Show us a picture

Hi
I have taken some pictures and measurements from my Axminster PRECISION grade II which I will share. As it has been mentioned earlier in this forum there is almost 0.5 mm inaccuracy at 250 mm.
The shank is not straight at all.
There is a 0.1 mm difference between two ends of shank height.
I am struggling to attach photo as they are apparently too big for the website.

Best regards

It is not within tolerance.

I have the same Precision series 250mm square and it is perfect. Send it back for replacement.

 

[Inspector]

Well if you really want to check a square you’ll want to get a surface plate/table, usually granite and a cylindrical square. With the cylindrical square on the table you offer the square and if there is a gap you can measure it to see if it is in spec or mark the square and then dress the square until it is. The surface plate is also handy for checking straightness of your rules.

Over the top for most every woodworker but if you also have a metal working hobby you may already have the surface plate. So getting a cylindrical square isn’t a big leap but they are spendy once over 6” long.

Pete

 

[Trevanion]

I've always been an advocate for the cheapie Bahco squares. As a rule, I've never bought one that wasn't square straight out of the box and the build quality is very good. Only minor note about them is that the blade is rather sharp on the corners but a quick swipe with an oil stone remedies this.

But as a humble brag I recently picked up one of these:

It's an old ex-MOD 18" Forged Steel Starrett Combination square in pretty good nick, it was absolutely covered with micrometer blue when I bought it but that cleaned off easy enough with meths. I happened to see it listed on eBay as "Set of levels" with a rather small starting bid (I won't say exactly how much because it will make people jealous ) I recognized the shapes of the attachments as Starrett ones so I just put in a little bid and I ended up winning it. I've never really used an expensive combo square too much except when playing around with other people ones but I can definitely see why some people think paying more for one is worth it, It's buttery smooth in its action and just feels right in the hand which is weird. The ministry of supply box is also quite a nice thing.

Although I probably still wouldn't pay top whack for a new one, and I probably won't use this one as much as I use the Bahcos as it's just too nice for the rougher style of work I do with it. Special occasion square :lol:

 

[rafezetter]

At the risk of being even more unpopular after my brexit posts (I'm certain several members put me on ignore for) I'm going to have to add my opinion because this makes little sense, and giving out advice that a person MUST shell out more money then necessary "coz reasons" is not good advice.

Sorry Shed9 but this post:

An £8 tool is going to be the absolute bare minimum in quality of materials and build, if you buy it expecting it to be true for any long duration, that's a tad wishful. As for a Moore & Wright surviving a drop of around 1m or less, no I wouldn't think it reasonable to expect it to be square after that myself, I'd put it down to experience, suck it up and get another.

and this quote:

........ an £8 square is not going to stay square for long whereas a precision tool will.........

Just don't add up. If you think it's perfectly OK for a moore and wright or other expensive square to be out of square just as easily as a cheap one after a drop - then what other parameters are you basing this "a cheap one will be out of square compared to a precision one over time " statement?

Temperature? Metal quality? - what?

Because if I'm honest, suggesting the more expensive one is less prone to these affects to ANY NOTICEABLE DEGREE, is stretching credulity beyond beleiveability. Yes I KNOW that aluminium behaves differently to steel in temperature variations but can YOU see that? Could it be discerned by anyone outside of a testing lab?

Or do you think, assuming that BOTH squares are only used very carefully, no dropping, brought inside every night to stay out of the cold and other such pampering, that the cheaper square is somehow going to magically behave differently to the more expensive one, given all other influences on them are the same?

I am of course talking about an all metal square vs same, with a build quality sufficient that there is no slop in the fitting of the metal from the outset. Squares with a wood stock are not part of this equation as that's an understood difference of materials.

Oh and your comment

When you buy a precision tool you are paying for precision, not the better chance of it actually being precise in an open skeet shoot. They are built to tolerance and checked before being sent out the door, that's what you are paying for.

Just made me laugh - sorry, at what price point is this supposed to happen? The 2 squares you mention (Incra & Bridge city) are both north of £40 for ONE square, so a person buying the set of FOUR by Axminster for £39 including a carry case, should automatically assume they are not accurate?

Can you provide any empirical evidence of ANY of this ?

I'll leave it there.

 

[Jacob]

At the risk of being even more unpopular after my brexit posts (I'm certain several members put me on ignore for) ....

I doubt it.
I thought your posts were interesting even though completely , er, shall we say, eccentric!

 

[Rorschach]

He's talking rubbish, I wouldn't waste your time.

 

[Inspector]

The only difference between a cheap tool and expensive tool when dropped is the gut wrenching doh (homer) you feel when you realize what you just did. Either could be just fine or both rendered junk.

Pete

 

[shed9]

At the risk of being even more unpopular............................................................................I'll leave it there.

What is this, a rally round for MikeG?

At what point did I say anyone MUST? I said;

The short answer is if you want precision, put more money down IMO.

And at what point did I compare the Moore & Wright being dropped comparative to the elusive £8 tool being dropped? I simply said I personally didn't think it was reasonable to drop a Moore & Wright from 1m and it still be expected to be in tolerance, that was it. You added the comparison.

As for a tool keeping its tolerance, it’s a tool and it’s going to get used, it’s going to take some day-to-day abuse (not dropped from 1m but used). A cheap tool is just that, it’s built for a particular market and its manufacture, materials (yes different metals with different treatments), construction method, fastening, adhesives, rivets, screws, etc, etc are not designed to the same tolerance of a more expensive product. No magic, no pampering, just the reality of products at that price point.

As I said to MikeG, I get it, you don’t agree with me but no need for the attitude; the suggestions of unbelievable credulity, suggestions I have magic powers to see temperatures no one else can see and the mocking attitude to the perfectly reasonable statement that precision tools from the likes of Moore & Wright, Starrett, Bridge City and Incra are going to be marginally better than a cheaper tool (including a set of four from your local Axi).

As I keep saying, repeatedly - This is just my opinion, take it or leave it. If you have an issue with me at least say what it is then maybe we can move on. I've said nothing contentious, good tools cost more in my opinion, that's it.

 

[SMALMALEKI]

Thank you all for the replies. What I am still trying to understand is what tolerance would you accept?
It has been mentioned several times that although it is not acceptable for engineering job but acceptable for woodworking.
What is the critical point when you would say the square is not true enough for hand woodworking?

Thank you again

 

[Bodgers]

Thank you all for the replies. What I am still trying to understand is what tolerance would you accept?
It has been mentioned several times that although it is not acceptable for engineering job but acceptable for woodworking.
What is the critical point when you would say the square is not true enough for hand woodworking?

Thank you again

In the end it is down to you as you are the one using it. It looks like you aren't happy with this one, so I'd get a replacement. If the results of using it are bad, then it isn't good for you.



Sent from my P027 using Tapatalk

 

[lurker]

Engineering is usually metals.
They don't "move" any where near as much as wood hence the reason they are used for the jobs wood isn't.
Most of us can't cut wood anywhere near to the tolerances engineering work to.

Others might disagree but half a millimetre and I am happy I have got it as good as I can, usually it's nearer 1 mm.
I might be able to make two bits of wood sit together tighter but it's by fettling final fit rather than first mark and cut.
And even then a gap might show up later.

In engineering a hundredth of a millimetre is fairly mundane accuracy.

 

[Doug B]

Thank you all for the replies. What I am still trying to understand is what tolerance would you accept?
It has been mentioned several times that although it is not acceptable for engineering job but acceptable for woodworking.
What is the critical point when you would say the square is not true enough for hand woodworking?

Thank you again

This is totally personal choice there is no fixed answer, I wouldn’t accept any inaccuracies in a square but that’s just me, In my eyes an out of true square is as useful as a blunt saw or plane, no use whatsoever.

 

[shed9]

What is the critical point when you would say the square is not true enough for hand woodworking?

As others have said, that's up to you and your needs. If you are not happy with the tolerance then that's the critical point. There are multiple levels of acceptability to most people as noted on the thread. As mentioned previously, combination squares can be reset and there are standard resettable squares available which allow you to adjust accordingly throughout the life of the tool. Of course these options require a reference point but that's a different subject and to be honest, given the vitriol I've received myself on this thread I'll leave it there lest it derails again.
In terms of industry acceptable tolerance and an agreed level of it, BS939 and DIN875 are the typical standards (as others have pointed to) with DIN being more prevalent in my experience. Both of these standards have variations within them dependent on other factors (length, intended use, etc). Plenty of online resources to explain these differences at leisure. You mention an Axi Precision grade II with a discrepancy of 0.5mm over 250mm (if I'm reading that right). I assume the blade is 250mm but you can use https://toolsmach.com/en/content/29-tab ... tolerances to check against your own equipment and individual lengths.

Despite the inference from many that a cheap square will suffice, this is possibly true for most people but if you believe your square is not square and you yourself said you had given up with big box stores then my original advice stands, invest in a better square. Not all tools are built the same with the same components to the same degree of manufacture and quality control.

Edit: Just found the BS standard specifically applicable to carpenters squares; BS3322 which states 0.01mm in every 10. So a 10"/250mm blade is allowed up to 0.25mm error along the full length of the blade.

 

[Gerry]

Tolerances on squareness of blade edges to working faces of
stock
BS 969:2007

You wouldn't need anything better than grade B for woodwork (um = micron)

Size of square Tolerance measured at tip of blade
Size Grade AA Grade A Grade B
mm um um um
50, 75 4 8 16
100, 150 4 8 16
200 4 8 16
300 6 12 24
450 8 16 32
600 12 24 48
800 16 32 64
1 000 20 40 80

Gerry

 

[Benchwayze]

Saeid.
If my squares pass the straight edge test and two drawn lines are parallel then I am happy. If not l find a better square or correct with judicious filing . With long combination squares check at two or three places along the blade..
A new square should be much better than the example you showed me.

John

 

[Racers]

I thought the only way to check a square was with a cylindrical square and a surface plate.

Pete

 

[shed9]

I thought the only way to check a square was with a cylindrical square and a surface plate.

Pete

It's not the only way to do it but for engineering / machining, it is the best option if you have it. When you get to that level however you end up having to confirm the tolerance of the tools you use to check the tolerance in the first place - but then that's engineering not woodworking.

 

[Gerry]

In my calibration laboratory we have to have the calibration equipment verified/calibrated to national standards by a UKAS laboratory.

Gerry

 

[Trevanion]

In my calibration laboratory we have to have the calibration equipment verified/calibrated to national standards by a UKAS laboratory.

Gerry

But who calibrates UKAS's calibration equipment? :shock:

 

[AndyT]

But who calibrates UKAS's calibration equipment? :shock:

A quick search reveals the existence of a collaborative approach by all the EU national accreditation authorities - https://european-accreditation.org/mutu ... /#benefits

Now, you may be thinking that such collaboration will be threatened by Brexit, and you'd be right. If Britain ceases to be a member of the EU it will no longer be eligible to be a member of the EA. However, this statement - https://european-accreditation.org/ea-a ... of-brexit/ - suggests that if the UK does leave, there will be a two year transition period to work out how to keep the good work going and not mess it all up.

Maybe the Engineers are doing a better job than the Politicians! :wink: