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Discussion Starter · #1 ·
New to this site First post.
To some degree or other I have been woodworking to some extent for most of my life. Well since High school woodshop classes. Graduated back in '71 so it has been a few years and many projects.

I am in a early phase of building a torsion box workbench.

I have built more workbenches than I care to count, including on built on square steel tubing.

I needed to rip 4 strips each from 3 plywood sheets. I bought a 8 foot level to use as a guide for my circular saw. Made a new base plate for it that was square to to the blade.

I checked the edge of a sheet of ply with the level and it appeared to be bowed in. Checked the other 2 sheets of ply and opposite sides same thing. What the heck?

So I pulled a line from 1 end of the level to the other. Saw about a 3/32' bow inwards at the middle of the level.

So did I get a bad level or are the made that for a reason?

Ken
 

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Ross
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Welcome to the forum Ken.
 

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I can see a possible reason;
If there is even a tiny speck of grit along the 8ft surface youre measuring, then the level would show out of true very quickly. So the vertical bow would help that as long as the two surface ends were flat with the bubble.
But; as far as I'm concerned thats a dud. take it back.
 

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Welcome,

The surface of the level needs to be straight. Otherwise, it would rock if you put the convex side down, and read inaccurately concave side down when used on shorter than full length surface. Somebody used yours as a pry bar, or it was damaged in shipment.

You can get an 8 foot straightedge made for your purpose a lot cheaper than an 8 foot level. It's thin enough to let the saw motor clear it.
https://www.amazon.com/Johnson-Leve...TF8&qid=1522039852&sr=8-18&keywords=saw+guide
 

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welcome ken... glad ya made it...
string line your level to see if it's straight..
it may have flexed as you sawed... did you center clamp the level before you cut???

can you return the level and go w/ one of these..
if you decide to, leave the Bora brand alone...
the clamp on them isn't the best and it slips...
https://www.ptreeusa.com/clamp_progrip.htm
 

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Mine are all cast Aluminum and there's no deviation; take yours back for exactly the reason Andy stated.
All mine have machined ends...no plastic end pieces. To my view those style ends were introduced to cut manufacturing costs, not to make life better for the trades/craftsmen/women who use them.
Oh yeh; mine all have double vials per station. The single vial reduces accuracy IMHO (the double vial type has a very slight curve to the tube).
Levels 101: Spirit Level Vial Quiz | Levels | Johnson Level & Tool Mfg Company
 

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Hey, Ken; I forgot to say "Welcome!"

I went looking for levels meeting my criteria...man, am I disillusioned!
It would seem they've all gone to gimmicky and cheaper construction. :(
They'll have to grave rob; I'm taking mine with me.
 

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How often are you going to use one? Just once? or every day?

We used to make them out of 3/4" plywood and use them for years.

of course that was before "Designer" straight edges.
Herb
 

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David
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Welcome to the forum, Ken! When you get a minute go ahead and complete your profile with first name and location. We like first names and often the location helps us to help you.

I graduated in '71 also and have built only a couple of workbenches. But I have built a few torsion boxes. I went the low dollar route on a 4' level from HF. But they had about a dozen there so I checked each one against the others until I found one that seemed to be as straight as one could be. When I got home I checked it against my 24" Starrett straight edge and the HF level actually turned out to be straight within a couple of thousandths end to end, near as I could measure. You might have the same luck with the 8' HF (I think they make one that long...).

David
 

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the HF level actually turned out to be straight within a couple of thousandths end to end, near as I could measure. You might have the same luck with the 8' HF (I think they make one that long...).

David
Go Harbor Freight................................................Yeah!


Herb
 

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A bunch of us use a saw guide like the one built in this video:
The advantage of using this guide, besides the fact it's cheap to make, is that it eliminates measuring the offset of the edge of the sole plate to the blade. You just mark where you want the cut and lay the edge of the guide on the marks and cut. All you have to watch is that you are cutting on the correct side of your marks. I like to use 1/4 to 3/8" ply for the base and 1/2 to 3/4" ply for the fence.
 

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Welcome, looks like you got your answer. Return it. Herb's post is a very good suggestion for breaking down sheet goods. To get a truly straight, use the factory edge of 3/4 ply to use for the guide rail. Some folks use ply, others use Masonite for the base. Make the base a little wider than the distance from fence to blade. Your first cut will be cutting off the edge of the base and will give you a very good straight edge. You can use the string trick to check the straightness of the ply edge. Many circular saws come with an edge guide so you can cut the narrow edge guide piece fairly straight, barring any little glitches during the cut, which is why you take the trouble to make sure the edge is nice and straight with no dings or warping. There was a very long discussion of this issue not long ago, centered on track saws. Lots of details and opinions in that string. At any rate, I think you'll like it here.
 

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I believe there was a company - don't know the name - that produced 8' levels that were bowed in (concave) on both sides; ie not concave on one side and convex on the other. The reason was so the level would tell whether the wall was plumb by comparing the top to the bottom or at least to a place 8' away so as to avoid an inaccurate reading cause by a bow in the middle of the wall. If yours is concave on both sides, it may have been designed that way. Never owned one or saw one, but read about it somewhere long ago.
 

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Welcome to the forum, Ken. Make a guide out of plywood and save a little money and have a quick reliable way to use your circular saw.
 

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Discussion Starter · #20 ·
Well thanks for the warm welcome guys.
I picked up a 8' straight edge before my first just before my post. It is at least straight.
Just made my brain hurt that a level would not be true straight. I suppose I can see a reason. But for me I would just use shims at the ends if I needed to ignore a middle bow in a wall.

Now to tell on myself I should just have rotated the level 90° and used the side surface.
I used a spring board in the middle to force true and to make sure I did spring it out while cutting. Although I applied only modest pressure against the level.

I had already made a new baseplate that was dead on square with the blade. Some real easy cutting when the saw is not fighting you.

I used my table saw to make trueing cuts on the strips I had cut off. First real job for it. Just bought it last month. A Delta 5000 series. Not the one in the big box stores that has split rails for the fence.

And now off to a few jobs around the house before I can get back to my bench.

Again thanks for the warm welcome.

Ken

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