Squares Are Not Square, and Levels Are Not Level

[Nissim Avrahami]

Hi Bob

You are so correct. Some 10 years ago I bought "Machinist squares" (4 of them) just to find out that non of them was square...since then, I don't buy any square...I make them myself.

I found that the plastic drawing triangles are very square and accurate even in 45° or 30° so, I "copied" them to a plywood and, on few of them I added a strip to the base so I can use it for both checking and marking.

Regards
niki

[Chuck Burns]

Having been a machinist in a past life all I have to say is to drop the dollars once for Starret. It's extremely expensive but there is a reason; they're not just charging for their name. Use the Starrett when things are really critical, like for machine set-up and checking and to check your "users".

[Lance Norris]

Im not trying to start a fight, but I would recommend checking every square you buy with one you know is true, even a Starrett. I recently had trouble with a 6" Starrett combination square. I got the problem resolved, but the new Starrett square was clearly defective.

http://www.sawmillcreek.org/showthre...tarrett+square

[Dan Barr]

Hey Lance,

glad to see you here. i remember your post.

I check my starretts occasionally also. it's not that im not pleased with their quality, but, im a little paranoid. they always check out though.

v/r

dan

[Al Willits]

Lance hit it right on, I was always taught to check any set up tool or measuring device before starting, only takes a minute and can save ya grief.

Al

[Thom Sturgill]

I think the both should be used in tandem.

If you measure and do the 3-4-5 and it still comes out wrong according to the flip-over/straight line method, then you know your tape or rule is off as well.

thats the thing about checking accuracy. sometimes you find out more than you want to know. then you have to deal with it.

v/r

dan

For the 3/4/5 method you just need CONSISTENT units for the method to be accurate. It does not matter whether you use 3/4/5 inches, feet, meters, cubits, or miles.

If the tape varies unit to unit, (for example, the distance from 1' to 2' is not the same as the distance between the 2' and 3' marks) then it is truly worthless.

[Chris Padilla]

For the 3/4/5 method you just need CONSISTENT units for the method to be accurate. It does not matter whether you use 3/4/5 inches, feet, meters, cubits, or miles.

If the tape varies unit to unit, (for example, the distance from 1' to 2' is not the same as the distance between the 2' and 3' marks) then it is truly worthless.

Keerrrrect!! In a pinch, I've just used scrap wood...could've cared less what it's length was...just marked three of 'em one way, 4 of 'em up, and then measure for 5 of 'em across.

[Gary Keedwell]

Hi Bob

You are so correct. Some 10 years ago I bought "Machinist squares" (4 of them) just to find out that non of them was square...since then, I don't buy any square...I make them myself.

I found that the plastic drawing triangles are very square and accurate even in 45° or 30° so, I "copied" them to a plywood and, on few of them I added a strip to the base so I can use it for both checking and marking.

Regards
niki

Plastic squares are not all made the same. I have heard my share of horror stories about people who ASSUMED plastic squares were some kind of "standard". To to fair I would also check metal squares,too. As a machinist in a prior life I can tell you that standards are not like they were 20 years ago. In today's market, where profits rule, there is no guarantee where it was made or who, or if, it was inspected properly. (quality control).

[Dan Barr]

What is the world coming too. people dont even sell square squares anymore.

seriously though, its very irritating and stirs up a little anger that these kinds of practices are the norm.

What can we do? i know i only buy starrett when i want something thats worth a &%$@. i wont buy anything else. But i guess that me being selective does not add up to a drop in the bucket huh?

I guess that the public is generally ignorant and there are plenty of them buying this crap. so... i guess im not really affecting their market segment.

I still wont buy that crap though.

aaarrrggggghhhhhhh,

dan

[Gary Keedwell]

I worked for a company that manufactured their own product. This company ( I worked there 15 1/2 years) did not need to tighten their purse strings because they have a monopoly on the market and they make huge profits.
So some suit decides to cut back on production costs. The first thing they did was to eliminate the floor inspector. This is the guy who inspects the first piece before it goes into production and makes random inspections during production.
So now these uninspected parts are brought to final inspection that usually only inspects a few out of the whole lot. Well, needless to say, this messes up assembly because there are now tons of parts that went through that are out of tolerance. Now alot of the parts will still go together but they are not right so there's where the trouble will be after the customer has this device over a period of time.
What I'm getting at is...they mat have some quality control....but that doesn't mean anything if it isn't implemented correctly. Most of the ISO quality control is strickly paperwork and not actual inspection.
Gary

[Howard Acheson]

No matter how much you spend for a device, you still don't know if it is square. I ran a large tool and die shop and we purchased a number of Brown & Sharp and Starrett devices and some of them were not "square". We had "standards" that our quality department periodically had validated by an outside service that we then used to verify the worker's tools.

One day, one of our designers brought in two plastic drawing triangles he had purchased at a local art supply store. He had them compared to our standards and they were as accurate as the tools could measure. The triangle cost a couple of dollars each. They would certainly serve very well as the "standard" in any woodworking shop to validate and/or adjust other devices.

An excellent way to validate the accuracy of the plastic squares is to use two squares on a flat surface. Get a $10-12 plastic 30-60-90 drafting square. To prove it's exactly 90°, take two to a glass counter, put the shorter legs on the counter and face the longer legs away from each other and butt them together (like a teepee). If the legs exactly butt, you can assume you have two perfect 90° angles. Using one of the plastic squares, do the same thing using your other tools. Any that mismatch, means that the tool is not square. You can also take the plastic square with you whenever you go to purchase another tool. Keep your "standard" somewhere where it doesn't get banged up.

Finally, remember that the wood you are using will expand and contract a couple of thousands from one day to the other. Does't pay to get too uptight.

While we are at it, I also only purchase the cheapest of adjustable squares. I square them with a drafting triangle and an auger file until they are square across 10". And I own a Bridge City square that isn't that accurate. Stainless steel machinist's squares are only square until you drop them. I have had several over the years and each has found a away to drop to the floor.

The key is to NEVER use your best square on for day to day measuring. Use it only as a reference tool to verify your other day to day tools.

In a comparison test reported in Fine Woodworking Magazine a couple of years ago, the Stanley 46-123 square was awarded the best value. It's much less expensive than a Starrett and just as accurate.

[Jay Kilpatrick]

Hummmm.... We're paranoid about being square, what about the parallel edges of your blades (on squares and straight edges) actually being parallel? I've returned quite a few that weren't parallel, so subsequently either the inner or outer edge could never be square simultaneously.

Just my .02 canadian (my advice is more valuable that way, right?)

[Dan Barr]

Were these Starrett's that you returned?

I have a Starrett straight edge and its the most parrallel thing i own. Dead on as far as i can measure with a digital caliper. my blades on my starrett squares are also dead on. but i check those before i buy them. the guys at the store always look at me funny when i check their squares for accuracy.

i put two of the woodcraft straight edges together and there was light shining between the two edges, so i handed the guy at the counter the two straight edges and told him about it. he put them behind the counter. I came in a week or two later and they were back on the shelf. LOL

v/r

dan

[Mike Marcade]

Were these Starrett's that you returned?

I have a Starrett straight edge and its the most parrallel thing i own. Dead on as far as i can measure with a digital caliper. my blades on my starrett squares are also dead on. but i check those before i buy them. the guys at the store always look at me funny when i check their squares for accuracy.

i put two of the woodcraft straight edges together and there was light shining between the two edges, so i handed the guy at the counter the two straight edges and told him about it. he put them behind the counter. I came in a week or two later and they were back on the shelf. LOL

v/r

dan

I was at my local Woodcraft telling the guy my story about Incra guaranteed squares not being square. He said well ... I would trust the incra before I would trust brand x. Sooooo ... we took an Incra he had out of the box and sure enough it wasn't square either. I'm pretty sure he put it right back on the shelf too.

[Chris Padilla]

One thing to keep in mind is that NOTHING is dead square and dead parallel. Everything has tolerances associated with it. Heck, even the temperature can worsen or improve a square's accuracy. Just like moisture can impact wood.

Can ya tolerate that?!