Aluminum framing square black

[addicted]

I have a question about using an aluminum framing square. Bought one a while back and was happy that it was truly square. A week ago I put a 24' 8x10 on the saw horses and place the canopy over it to give me a break from the sun. I begin checking for wind using a steel framing square and an aluminum one. Everything goes ok but I left the black aluminum one partially in the sun for about a half hour. Then proceeded to do layout. I rechecked one line with Big Al and it was off. Checked with the steel square, and the line was off. Checked the aluminum square for "square" against Big Al and the steel square and the aluminum one was obtuse. So I took a punch and hammer and pounded it square again. Next morning, it's acute.
Question is, is this common? Do aluminum squares go out of wack by temp/sun exposure if they're black or dark in color? Has anyone else run into square problems? I'd hate to have to continue peening  this thing every time the temp swings.
Thanks again
Rusty

[Brian_Weekley]

Rusty,

I don't have a black, aluminum framing square and don't know the answer to your question.  However, it reminds me of the old adage:  "a man with two watches doesn't know the real time".  Maybe you need three framing squares! :D

[Jim_Rogers]

I do all my layout with one tool, the Big Al.

Once you have decided on your arris for your reference edge using one of your correct framing squares you should be all done with that square and do all future layout with the Big Al.

I feel that if you layout everything with one tool and that tool is off a little then it doesn't matter that much as everything is off the same amount which usually is very little.

Mixing tools for layout has just shown you the problem with doing that.

It's like measuring the same distance with two different tape measures. You may get two different readings. That why we layout the entire frame using one tape measure, labeled "frame tape" and only use that tape for laying out the frame. I never use my "frame tape" for any other jobs or chores. It is strictly a dedicated "'layout frame tape".

Now that we have our new "timber framers ultimate layout tape" that is the only flat tape I use for all layout.

Jim Rogers

[addicted]

I couldn't agree more Jim, but this was my first time running chalk lines to make up for the excessive crown in this particular tie beam. I used the framing square to do the layout from the chalk reference line. Of course after running the chalk lines and finishing about half the layout, I finally understood some of the comments about where to run the line so you're not measuring for every line in every joint. What do most people use to run a line perpendicular to a chalk line?

Brian, very true. Instead of reserecting a third square I was contemplating putting a trail cam in the garage to catch the gremlins that were altering my tools.
Rusty

[Dave Shepard]

When I'm snap lining, I use a framing square to get my perpendiculars. I suppose I could erect the perps with dividers, but that would be a bit time consuming. But fun. ;D I'm surprised that your squares moved that much in the sun, I should probably check mine sometime. I read recently that the expansion of the railroad track between Darwin and Adelaide was 1.2 kilometers! They account for it at installation but that is a bit wild to think about as steel expands at .000006" per inch per degree F.

[addicted]

Dave
I guess the lesson here is either full sun or no sun with this particular square. I wonder if sunscreen would help :D.
   And now that I've gone back and started to double check everything with back up tools, I've noticed the difference in measurements using the big al. I can't say I'm proficient yet but it seems that some measurements the pencil line is on the inside of the cut and others are on the outside of the cut.
  Grandpa used to say " if you're not learning, you're not paying attention "
Rusty

[addicted]

Jim
As you said before, use one tool for layout, then it doesn't matter if the pencil line is in or outside of the cut, they're all the same.
Rusty

[Jim_Rogers]

Jim
As you said before, use one tool for layout, then it doesn't matter if the pencil line is in or outside of the cut, they're all the same.
Rusty

Pencil lines are just for visualization of the joint. After the entire joint is laid out with pencil I then knife the joint to cut the lines. But I cut by tape. What I mean is I put my utility knife blade point where the tape tells me it should go, not where the pencil line is. IF the pencil line and the knife line are in the same spot, that's great, but the knife line is absolute. It is the cut line.

I had one teacher say, when asked, "do I cut the left side of the pencil line? the right side of the pencil line? or what?" His reply was cut the pencil line down the middle.

Can you do that? I can't. I don't even try. I cut, by hand saw or by skil saw next to the knife line (on the waste side) and pare the remaining wood off with my chisel, to the knife line. Then my joint is perfect.

And as it is said "perfect is close enough"....

Jim Rogers