LumberJocks

All Replies on Is 89 degrees square

  • Advertise with us
View lizardhead's profile

Is 89 degrees square

by lizardhead
posted 03-23-2012 03:03 PM


48 replies so far

View dbray45's profile

dbray45

2536 posts in 1464 days


#1 posted 03-23-2012 03:20 PM

When dealing with a square, the first three angles will be 90 degrees, the fourth usually isn’t.

When working with one or two 90 degree angles if the straight edges are 1”, 89 degrees works, if the straight edges are a foot or longer, probably not.

-- David in Damascus, MD

View TrBlu's profile

TrBlu

361 posts in 1313 days


#2 posted 03-23-2012 03:33 PM

“When dealing with a square, the first three angles will be 90 degrees, the fourth usually isn’t.”

How is that possible? The sum of the angles of any quadrilateral must equal 360 degrees. If three angles are 90 degrees, the fourth must be 90 degrees. For one of the angles to be 89 degrees, the 1 degree must be made up in one or more of the remaining angles. Granted, 90 1/3 degrees is difficult to measure. You eyes may not recognize that a quadrilaterial with three 90 1/3 angles and one 89 degree angle is not square. But, it is not geometrically possible to have a quadrilateral with three 90 degree angles and one 89 degree angle.

Maybe I am reading this too literal.

-- The more I work with wood the more I recognize only God can make something as beautiful as a tree. I hope my humble attempts at this craft do justice by His masterpiece. -- Tim

View JoeyG's profile

JoeyG

1248 posts in 1313 days


#3 posted 03-23-2012 03:36 PM

IMHO we are working with wood here, not steel. I will be the first to say that the closer to 45 you are the better your corner, etc. I also know that no matter how perfect it is when I mark it or cut a piece of wood, it is going to move. That’s what wood does. Just my opinion, Some people like expensive tools, personally I like expensive wood. In my world I can’t have both.

-- JoeyG ~~~ http://www.facebook.com/JHGWoodWorks

View Manitario's profile

Manitario

2363 posts in 1571 days


#4 posted 03-23-2012 03:50 PM

I’m not too sure what the limit of error in a square that is detectable by the human eye, but I know that an error of 0.5 degrees results in a gap on my mitres or a gap between the rail and stile on a raised panel frame. On my jointer, if the fence is not set to 90o the edge joints don’t come together perfectly. I have a number of squares, some cheap, some not. Finding a perfectly 90o square from a big box store is hit and miss, or having said cheap square stay 90o is also hit and miss. When I pay more for eg. Starrett, it is because I know that it will be 90o out of the box and will likely stay 90o for many, many years.

-- Sometimes the creative process requires foul language. -- Charles Neil

View Loren's profile (online now)

Loren

7734 posts in 2336 days


#5 posted 03-23-2012 04:03 PM

I imagine new squares would tend to be more accurate at lower
cost than in the past due to computerized manufacturing and
quality control.

-- http://lawoodworking.com

View BobM001's profile

BobM001

388 posts in 1018 days


#6 posted 03-23-2012 04:06 PM

The funny thing about “small errors” when building anything. They tend to “compound” as you move forward. The truer you stay, the better the end results.

-- OK, who's the wise guy that shrunk the plywood?

View canadianchips's profile

canadianchips

1831 posts in 1685 days


#7 posted 03-23-2012 04:13 PM

I’m going out on a limb here:
Squares are over rated !
You can put finishing trim on a door without using a square. As long as the reveal is uniform, the naked eye will see a crooked reveal sooner than a miter that might be 44 1/2 ! (Old crooked homes are perfect examples of finishing tricks to make it LOOK good.
Building things “Square” is an easy way to continue any project without measuring to death every move !
The first NEW house I finished , the footings were 6” higher at one end than the other. The lower level concrete walls were 1 1/2” thicker at bottom than top _The rest of the house followed along (the person that started the mess was fired_). By the time I was called in…..........Yikes….....

-- "My mission in life - make everyone smile !"

View Peter Oxley's profile

Peter Oxley

1426 posts in 2562 days


#8 posted 03-23-2012 04:38 PM

I guess the thing to consider is that any error will compound with multiple joints. If you rip a piece for a shelf with an 89 degree edge, no one will notice. But if you rip 180 strips with an 89 degree edge on each side, you can make a cylinder.

As for Starret vs. anything else … well, Starret’s probably the best. But you can correct a square if it’s not true. And one drop on the floor and it probably won’t be true, regardless of the name stamped on it. That’s why the couple of Starret tools I own almost never see the light of day … I drop things.

-- http://www.peteroxley.com -- http://north40studios.etsy.com --

View Doss's profile

Doss

779 posts in 952 days


#9 posted 03-23-2012 04:53 PM

We have rules in engineering about tolerances… how accurate can you afford?

Yes tolerances due stack, but not if you make adjustments as you go along.

To put it in perspective, let’s build a square frame (like a picture frame) using 10’ long by 1/16” wide strips of wood (just helping with a visualization of lines).

First piece of wood down. Measure 90°. Put second piece down. Measure 90° again. Put third piece down.

This time though, we get sloppy and lay the piece at 89.75° relative to inside angles. The result? Instead of closing your perfect square, you are now roughly 1/2” (0.5235971141695884”) from perpendicular to the inside of the square. At 89° the gap grows to a little over 2” from perpendicular.

The question is, is 89.75 or 89° close enough for you and can you make the adjustment?

Yes, this is not a compounding problem where the slightly off angle will definitely bite you when building a square, but it helps in visualizing an error in measurement and how significant it can be. I’d say if you build things with long straight runs, long sides that need to appear square to each other, or need really tight miters, then I’d try to get as accurate a measuring device as possible.

This does not stop you from making a mistake when cutting or attaching though or even as the wood moves due to changing conditions.

-- "Well, at least we can still use it as firewood... maybe." - Doss

View Sawkerf's profile

Sawkerf

1730 posts in 1756 days


#10 posted 03-23-2012 06:37 PM

A big +1 to Canadianchips!! I can’t remember ever casing out a door or window with a level or square. I eyeball it and nail it. Nobody has ever mentioned a problem.

I once used a laser level to install a chair rail and it looked terrible. It was dead level, but the 2” difference in the wall made it look goofy. I put the laser away and just made it look right.

-- Adversity doesn't build character...................it reveals it.

View lieutenantdan's profile

lieutenantdan

176 posts in 994 days


#11 posted 03-23-2012 08:35 PM

Well, then there is the other extreme. A square that reads 91 degrees instead of 89 degrees. Life can suck if you let it. I used to be a perfectionist. My doctor says I am getting better every day.

-- "Of all the things I have lost in life, I miss my mind the most."

View Sawkerf's profile

Sawkerf

1730 posts in 1756 days


#12 posted 03-23-2012 09:25 PM

A square that is 1* off introduces a 1.1% error in your measurement. Is that ok? Probably not a biggie in rough framing, but bothersome for a nice cabinet. – ol

-- Adversity doesn't build character...................it reveals it.

View MrRon's profile

MrRon

2860 posts in 1931 days


#13 posted 03-23-2012 09:57 PM

A Starrett square is a precision tool intended for machinist accuracy. It wasn’t intended for woodworking or framing a house, although it could be used for such. The garden variety square that you can buy at your home building supply store or Ace Hardware will not be as precise as the Starrett, nor does it need to be. For one thing, doing layouts with a pencil, no matter how sharp, will never get you a precise line. Even marking of metals with layout dye and needle pointed scribers are never 100% precise. Wood changes with temperature, humidity and internal stress and there isn’t much you can do to compensate for it. The goal is to use whatever tools you have and be as precise with what you have. Using a Starrett square to draw a line will still not be precise due to the pencil point which has thickness to it, so there’s no good reason not to use the generic brand square, as long as it is “reasonably” square. I have a Starrett square that I use only to check the squareness of generic squares and for metalworking. When not in use, it stays hidden away. It’s never used for general woodworking. The square I use for woodworking is a Stanley. It checks out pretty good by the Starrett; good enough for woodworking.
Just think about this for a moment; layout for a 45° miter,(2 possible errors); set the miter gauge on the saw to 45°, (1 possible error); the miter gauge has a sloppy fit in the slot, (1 possible error); make the cut with the saw, (1 possible error) due to blade or arbor runout. Add up the errors, (5) and your 45° miter is no more. I may go out on a limb and say “it is impossible to cut a perfect 45° miter”. If you do, it’s an accident and not intentional. So don’t beat yourself up trying to get perfection. We should always strive for it even if we know it can never be achieved. I’m certain if I was to lay out a 45° miter, one with the Starrett, and another with the Stanley, the final result would be the same. Just my 2¢ worth.

View TopamaxSurvivor's profile

TopamaxSurvivor

14864 posts in 2364 days


#14 posted 03-23-2012 10:02 PM

I think for our purposes in wood working, if it is pleasing to the eye, it is square. For moon shots, you’d better be prefectly square with the earth when you launch or you’ll miss ;-)

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View mtenterprises's profile

mtenterprises

830 posts in 1381 days


#15 posted 03-23-2012 10:29 PM

Just my 2cents here, one day at HF they had orange plastic speed squares on sale for like $2.99. I said to myself, how good can a $2.99, PLASTIC, Made in China be? So on a lark I bought one. I’ve wasted more money on other items that I never used or that didn’t work. I took it home and took out my machinist dial protractor and to my suprise it measures dead on nuts 90 deg. and 45 deg.. I proceeded to put a screw in my table saw frame, hung it thare and use it all the time. I guess it just comes down to trust. So, lizardhear after your testing do you trust your tools and your skills? Some people think they must have the very very best or the most most expensive.
Sign in my shop – It is not what your shop looks like nor the age or quality of its tools. It is the quality of work that you can produce there with them that is important. -
MIKE

-- See pictures on Flickr - http://www.flickr.com/photos/44216106@N07/ And visit my Facebook page - facebook.com/MTEnterprises

View lizardhead's profile

lizardhead

518 posts in 1529 days


#16 posted 03-24-2012 01:18 AM

I used to beat myself up every time I made a 12 segment ring for my segmented bowls, because they quite often did not have tight joints. A 12 segment ring has 24 miter cuts. 24 X’s anything can be a lot, I’m talking about smidgeons here guys, maybe even half a smidgeon. Then I would have to go to the fix it stage. Now I just glue up 2 halves, then disk sand till flush the glue up the 2 halves. Ah perfection

-- Lizardhead---Yeah but it's a dry heat--Tempe, Az

View Mainiac Matt 's profile

Mainiac Matt

4160 posts in 1016 days


#17 posted 03-24-2012 01:19 AM

My squarest square is an old Stanly…

I have a $75 Starrett combo square and it’s been slightly off since day one. I recently got a set of small thin Swiss files and found that one of them will fit in the slot of the combo. square.

They (intentionally I think) cut a profile in the bottom of the slot, somewhat like an upside down “U” and just a swipe or two with that very fine file will make a noticeable adjustment over 12”.

All that said. The guy who taught me the little bit I know about finish carpentry didn’t carry a square in his tool belt. He carried a block plane.

Square or not, his joints are tight and look good.

:^)

-- Pine is fine, but Oak's no joke!

View Mainiac Matt 's profile

Mainiac Matt

4160 posts in 1016 days


#18 posted 03-24-2012 01:38 AM

OBTW, the only place a ‘truely’ square square exists is in your head.

If you think you square is perfectly square, you just need to get a reference with finer increments…. or in the OPs example, a sharper pencil.

It always comes down to what’s “good enough”

-- Pine is fine, but Oak's no joke!

View RandyM68's profile

RandyM68

693 posts in 1006 days


#19 posted 03-24-2012 02:45 AM

The only time it has to be perfect, is when you have an anally-retentive Q.C. inspector trying to check your work. They focus on crap like that and miss the important things like, does it work? and does it look like it fits right? If you are making bunches of interchangeable parts they have to be perfect. If you’re building one cabinet, it just has to look good. The pieces don’t have to match the blue-print, just each other. If you get caught up in perfection, you’ll throw away a lot wood that is .015” too short. It just doesn’t matter that much when laying out cuts. On the other hand, I bought two clamp-its from Rockler. I tried to use them to square up a face frame when I glued it up. The joints wouldn’t close. I checked everything with speed,framing, combination, and machinist squares. Neither one of the clamp-its is square on the inside angle. That does matter. Good thing they were on sale.

-- I can explain it to you, but I can't understand it for you. I'm sorry,thanks.

View lizardhead's profile

lizardhead

518 posts in 1529 days


#20 posted 03-24-2012 05:05 AM

In my particular case 99% of the time that I use a square is to check what I have already cut. The “square” is in my jigs or in my sliding miter guage. and if you want to do a little check on that get yourself 3 pieces of scrape pine about 10-12” long & cut 1 piece at both ends at 45 degrees, and the other 2 pieces at one end then friction glue the joints or otherwise attach them then measure the joints end to end. and then measure across the open end if they measure the same it is square if not—well you are not square

-- Lizardhead---Yeah but it's a dry heat--Tempe, Az

View ChuckV's profile

ChuckV

2438 posts in 2215 days


#21 posted 03-24-2012 11:44 AM

Don’t forget to keep in mind the curvature of the earth, if not the curvature of space itself:

-- “While the world with closed eyes sleeps, The sky knows and weeps - steel rain. ” ― Nathan Bell

View mtenterprises's profile

mtenterprises

830 posts in 1381 days


#22 posted 03-24-2012 01:13 PM

Chuck yes!
Now is it possiable to have a triangle with 3 – 90 deg. corners? Yes it is! If you cannot figure this trick out I’ll tell you later.
ALL IN FUN!!!!
MIKE

-- See pictures on Flickr - http://www.flickr.com/photos/44216106@N07/ And visit my Facebook page - facebook.com/MTEnterprises

View ChuckV's profile

ChuckV

2438 posts in 2215 days


#23 posted 03-24-2012 01:24 PM

Imagine a triangle with vertices at the North Pole, 0 deg longitude at the equator and 90 deg W longitude at the equator.

-- “While the world with closed eyes sleeps, The sky knows and weeps - steel rain. ” ― Nathan Bell

View mtenterprises's profile

mtenterprises

830 posts in 1381 days


#24 posted 03-24-2012 01:27 PM

DAMN MAN YOU GOT IT ALREADY!!! Congrats! Look at that a 13 minute WINNER!
MIKE

-- See pictures on Flickr - http://www.flickr.com/photos/44216106@N07/ And visit my Facebook page - facebook.com/MTEnterprises

View miles125's profile

miles125

2179 posts in 2693 days


#25 posted 03-24-2012 01:29 PM

A 200 dollar trisquare for wood is like using diamond tooling to carve a bar of soap. It works, but what’s the point?

-- "The way to make a small fortune in woodworking- start with a large one"

View bondogaposis's profile

bondogaposis

2594 posts in 1039 days


#26 posted 03-24-2012 02:21 PM

First, I would say that 89° is not square. That is too far off. Second it hardly matters what my square is because the cuts are made at the table saw. So what really matters is if the table saw is tuned to being square. Of course it helps if the square you use to tune the saw is accurate. I feel that if I can make a cut a and flip and mate them if they are visibly square then that is good enough for my work.

-- Bondo Gaposis

View Jorge G.'s profile

Jorge G.

1526 posts in 1163 days


#27 posted 03-24-2012 04:17 PM

Sorry but I can’t help it. Isn’t this dumbing down the craft? Sorry, but 1º off over 8 feet is a lot when you are making doors or windows. If you think, “ah well that is carpentry not wood working” how about 1º off when making an 8 foot table?

I understand not wanting to work to machinist precision, but really, ranting about being accurate? My experience has been that those time I thought “to hell with it, it is close enough” I have spent more time fixing errors or even actually re doing the offending piece than if I had been more patient and done the thing as accurate as I could to begin with. The difference between a mediocre craftman and an excellent one is patience and that one would say “it looks straight enough” the other one will grab the shooting board and make sure it is… :-)

If the argument is against expensive tools, this too is silly in my opinion. One, you should have at least one reference tool, one that you know is certified as square. Two, you are willing to spend countless hours and many hundreds of dollars on wood but you don’t want to spend a $100 or $150 on a tool that might make your work fit better and go faster? Seems you are being penny wise and pound foolish. There is a middle ground between working to 1/10000 of an inch and being sloppy, that is the one I am taking… :-)

-- To surrender a dream leaves life as it is — and not as it could be.

View Doss's profile

Doss

779 posts in 952 days


#28 posted 03-24-2012 04:45 PM

I think the point most people are trying to make is that you have to know how to adjust for your tools and have a reasonable degree of know-how that you understand when something is off. It’s great to have a good reference that you trust, but if your tools (like a tablesaw) are off, a good square won’t help you much (unless you use it to square your TS :-) ).

When I make measurements on long cuts, I normally draw a line out on the wood to make sure that when my tools are cutting, they aren’t wandering too much. I have to trust the straightedge for that.

Like I said above, 1° on a 10’ run means about 2” out. 1/4° off and that means about 1/2” out. That’s a big deal to a lot of different pieces and carpentry. But, if I had a square that far off, I would probably trash it and buy a new one.

As an engineer, I know the cost of having ultra-accurate tools. The question is always how accurate do we need to be to keep our costs competitive and turn out a quality product.

Even the cheap squares are pretty accurate nowadays and you can check them pretty easily with other tools like a good ruler. Sure, you’re not going to build an F22 Raptor with one of them, but there’s more chance of operator error than the square being off in my opinion.

-- "Well, at least we can still use it as firewood... maybe." - Doss

View lieutenantdan's profile

lieutenantdan

176 posts in 994 days


#29 posted 03-24-2012 04:45 PM

“I have a $75 Starrett combo square and it’s been slightly off since day one.” ssnvet

Me too (me not the square). LOL

-- "Of all the things I have lost in life, I miss my mind the most."

View Lee Barker's profile

Lee Barker

2169 posts in 1538 days


#30 posted 03-24-2012 05:12 PM

Interesting discussion with lots of good thoughts and points of view and I value them all. I have only two things to add, and they may have already been covered.

1. You can adjust a framing square by peening it flat at the angle, toward the outside or inside, as needed.

2. Some of the apparent affection for machinist-precision tools such as Starrett squares is generated by our friends in the woodworking magazine industry who fail to incorporate the notion of experience into the arc of progressing skill.

Their recipe is:
1. Buy these plans, or use these published ones.

2. You’ll need a(insert portable power tool name here). And a zero clearance insert (ok, that’s one of my favorite objects of ridicule, I admit it).

3. Buy exactly this much wood and cut these parts out of the boards in this pattern.

4. Use this new foolproof, whizbang finish (hmmm, that’s the same brand in the ad on page 36) that takes only one coat.

5. You will complete this project in one weekend and your family will beam with pride.

I am not knocking the magazine industry. Good for them. They help sell tools and materials, and those companies profit, and can innovate and so on. I just think it is important that we have this sort of discussion about precision (and coping with the results of the lack of it) so that beginning and even intermediate woodworkers can understand and appreciate that this craft is not one you can buy your way into. The dues are measured in hours in the shop, doing.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View Eric_Somerville's profile

Eric_Somerville

20 posts in 1579 days


#31 posted 03-24-2012 08:01 PM

I’m my previous life in the machining industry, Starrett was considered mid-level certainly not high end.

-- EDS

View Jorge G.'s profile

Jorge G.

1526 posts in 1163 days


#32 posted 03-25-2012 01:59 AM

but if your tools (like a tablesaw) are off, a good square won’t help you much (unless you use it to square your TS :-) ).

Isn’t that the idea, to have one reliable tool that will help you tune the rest of them. I am anal about 90º cuts in all my machines. This way I know if something goes wrong it was my mistake, not the machine. There is nothing worse than to fight with a joint because it is not square only to find out it was not you but your miter/table/band saw…

-- To surrender a dream leaves life as it is — and not as it could be.

View gfadvm's profile

gfadvm

11234 posts in 1378 days


#33 posted 03-25-2012 03:53 AM

“This craft is not one you can buy your way into” Thanks Lee, I think you just explained why woodworking has become such a passion for me.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View canadianchips's profile

canadianchips

1831 posts in 1685 days


#34 posted 03-25-2012 12:07 PM

I rarely copy paste another persons line.

This craft is not one you can buy your way into”

That line is the BEST one I have read in 2 years.

-- "My mission in life - make everyone smile !"

View miles125's profile

miles125

2179 posts in 2693 days


#35 posted 03-25-2012 02:50 PM

“This craft is not one you can buy your way into”

That needs to be a blog all by itself. I’d just note my observation that those that do attempt buying their way into it miss the whole point of adversity and forced ingenuity making a better craftsman.

-- "The way to make a small fortune in woodworking- start with a large one"

View JoeyG's profile

JoeyG

1248 posts in 1313 days


#36 posted 03-25-2012 02:52 PM

I’ve done so much, for so long, with so little, I am now qualified to do everything with nothing.

-- JoeyG ~~~ http://www.facebook.com/JHGWoodWorks

View mtenterprises's profile

mtenterprises

830 posts in 1381 days


#37 posted 03-25-2012 03:24 PM

Miles and Joey – YUP.
MIKE

-- See pictures on Flickr - http://www.flickr.com/photos/44216106@N07/ And visit my Facebook page - facebook.com/MTEnterprises

View MrRon's profile

MrRon

2860 posts in 1931 days


#38 posted 03-25-2012 07:22 PM

JGM0658 “The difference between a mediocre craftman and an excellent one is patience”. Not so; The difference between a mediocre craftsman and an excellent one is; the excellent one knows how to cover his mistakes better.

View gfadvm's profile

gfadvm

11234 posts in 1378 days


#39 posted 03-26-2012 12:59 AM

Me too Joey. But that is the fun/ rewarding part for me.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View William's profile

William

9149 posts in 1530 days


#40 posted 03-26-2012 01:45 AM

I used to worry myself to death about “square”.
You know what I have learned over time though?
I can make something PERFECTLY square today.
That doesn’t mean it will be prefect on a different day under different weather conditions. Not if I build it out of wood anyway.

-- http://wddsrfinewoodworks.blogspot.com/

View Jorge G.'s profile

Jorge G.

1526 posts in 1163 days


#41 posted 03-26-2012 01:50 AM

The difference between a mediocre craftsman and an excellent one is; the excellent one knows how to cover his mistakes better.

Not so, you will be surprised how little mistakes are made when you have well tuned machines. Human error is another matter.

-- To surrender a dream leaves life as it is — and not as it could be.

View Grandpa's profile

Grandpa

3182 posts in 1363 days


#42 posted 03-26-2012 02:23 AM

My go to square for general work is an old steel square that I got from my Grannie’s stuff when she passed at age 88. Why she even had a square beats me. I used it for years and only checked it a time or two. I also used it as a straight edge for scoring plastic laminate with a carbide tool. That has to be bead for the edge. It has to scrape the metal. I was getting ready to start a chest of drawers for each grandchild. My son is the Manager of Quality at his company’s mfg plant. he got to talking about how accurate that old square was or wasn’t. It had been thrown in a pickup tool box and carried miles to jobs etc. He to it to the optical comparator and checked it out. It was off .003” in 2 feet. That is close enough for me. You can get closer but you can’t cut any closer on a woodworking saw or with a woodworking saw blade. Blades wobble far more than that. I try to set everything up the best I can and then I go to work. I only check parts if something doesn’t work.
As for a lunar shot those are not measured with a square but with math and then adjustments have to be made when you get close so we can not achieve square.

View JPZ's profile

JPZ

17 posts in 1164 days


#43 posted 03-26-2012 03:58 AM

I am fortunate to still have all my precision measuring instruments from my prior life in high precision sheet metal. I am used to working with tolerances of +/- .0004 and angles that needed to be +/- 1/2 degree over an eight foot length. But I have found my hardware store Stanley 8” square is super accurate for all my needs. It comes out to 89 degrees, 25 minutes….. more than enough for woodwork.
However, where I can truly appreciate my precision tools is when I am either doing a setup on a machine or when tuning up my machines. I also spot check my cut pieces with a caliper for dimensional precision just to see how far out things are and that tells me when it’s time to do a tuneup.
I guess the true test is how your finished work looks. If I was using a lot of wood filler to conceal bad fitting joints then I would look to my methods and tools of taking measurements.

View dbray45's profile

dbray45

2536 posts in 1464 days


#44 posted 03-26-2012 12:04 PM

One of the points I was trying to make earlier and didn’t do well is this – your cut may be prefectly square or 45 degrees, or 22 1/2 – but wood hold moisture. It is dried to, hopefully “X” MC. Once you cut this material, what you had changes. Even if the length or width and even thickness changes ever so little, your cut is not square to the work.

This is why you don’t glue breadboard edges. We (where I work) had tables that had breadboard edges in the cafeteria. These tables had a 2” mitered strip around the edges, glued tight. Every one of these tables were split with up to 1/8” gaps for a 30” x30” table and the main panels were plywood. Wood moves – even with air conditioning and heating.

If you allow for this movement on the 4th corner, your other three corners are good. Doors are a good example, the bottom corner away from the hinge is the corner that doesn’t have to be exactly square because your eye doesn’t see it.

-- David in Damascus, MD

View Jorge G.'s profile

Jorge G.

1526 posts in 1163 days


#45 posted 03-26-2012 02:27 PM

This craft is not one you can buy your way into

Yes and no, the purpose of a tool is to disappear in your hands so that you can concentrate with the task at hand. Generally, the better more expensive tools are able to do that more often than the cheap ones. Sure there are some gems out there, I hear the third generation woodriver planes are a very good value. And certainly you don’t need a $10,000 plane. A good example are the 98 and 99 planes. When you need to fit a dado these are invaluable.

-- To surrender a dream leaves life as it is — and not as it could be.

View lieutenantdan's profile

lieutenantdan

176 posts in 994 days


#46 posted 03-26-2012 04:58 PM

If perfectly square mattered, GOD would not have made the earth round.

-- "Of all the things I have lost in life, I miss my mind the most."

View DS's profile

DS

2131 posts in 1108 days


#47 posted 03-26-2012 05:15 PM

It just so happens I had a conversation with a friend this weekend on this very subject. He was complaining that he had a difficult time getting good results with his tools. He thought he needed more expensive tools to fix his problem.

I told him that it didn’t matter how cheap or expensive his tools are. Take the time to set them up properly and your results will significantly improve.

When I get a new piece of machinery, I always break it down and re-assemble it to as tight of tolerances as I can reasonably manage. It is worth taking this extra time to have confidence in your equipment. Even my tape measure is calibrated so I can be confident in its accuracy.

JGM said there is a middle ground bewtween 1/10000 of an inch and sloppy. Everyone knows that tolerances in woodworking better than 5/10000 of an inch is overkill ;-)

(BTW 5/10000”, or +/- 0.0005”, is an accepted tolerance standard for CNC woodworking machines)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View Jim Jakosh's profile

Jim Jakosh

11732 posts in 1793 days


#48 posted 03-26-2012 08:01 PM

Hi Dave. Being a tool maker and now a wood worker, I do like to work with Lufkin or Starrett squares because I can trust their accuracy. There are plenty of squares that are mass produced and some are right on and some are close. What I do , like you said, to check them is to draw a line with the square against a straight edge and then flip the square and draw another line over it to see if they track perfectly. If you can notice the variation, it is not making a true 90 degree angle and that can affect your work. What I have done is to take a Lufkin square to check a cheap square( like from harbor Freight) and then file the edge of that cheap square until it matches. I have done that several times and it works out okay. I start with the high point and work it out so it is straight and square

One important feature when checking for square corners on a project is to make sure the boards are straight. If you check a frame and three corners are square, and only one is out, there must be a curve in one of the boards that affects the corner

............Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase