Let me know what you guys think.
I've been working on a new method (new?) for checking the squareness of a square
using a dial indicator. The method works in theory. I've tried it and it seems
to work in practice. A caveat is that the square needs a thick edge to support
I am going to work on a video demonstrating the process.
On Thursday, January 3, 2013 6:24:52 PM UTC-5, Dave Balderstone wrote:
read the article.
A minor caveat to this method is that it can be difficult to discern small gaps between the two pencil lines (especially with a thick pencil lead). The most you might be able to detect is a 0.010" difference which equates to a minimum detection of 0.036 degrees with an 8" square.
Another caveat is that the edge you place your square against must be perfectly flat, otherwise you will not get an accurate calculation of your square's angle error.
The dial indicator method is 10X more accurate.
On 1/3/2013 6:21 PM, firstname.lastname@example.org wrote:
What difference does it make what the numeric value is?
If it's enough to detect that way, it's enough that for really precise
layouts it's off.
So, what you gonna' do at that point, anyway even if you do know
_precisely_ how much that is? Eggs-ackly the same thing as if you only
know it's off---either ignore it and go on, go get a new Starrett, or
adjust it until it does pass (the peen method works a charm for that).
If it passes the pencil test, it's plenty close enough for woodworking;
even fine woodworking. The wood itself moves more than that.
On Thursday, January 3, 2013 8:41:23 PM UTC-5, Larry W wrote:
Scenario: You make it out to the woodshop after a hard night of drinking. As the acetaldehyde takes it's effect on you, you drop your Starrett square on the concrete floor. What do you do? Continue to use it and hope for the best or check to see if it's still of 'Starrett Quality'? How do you check?
I'm by no means a teetotaler, but I haven't had a "hard night of drinking"
in over 20 years. And if or when I did, I sure wouldn't head to the wood
shop afterwards. And if I did, I probably wouldn't use one of my Starret
squares. And if I did use the Starret, probaly wouldn't drop it. And if
I did happen to drop it, after a hard night of drinking, I probably
wouldn't care enough to check it.
What was the question again?
Make it as simple as possible, but not simpler. (Albert Einstein)
Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
Doesn't happen in my shop. That's a hard and fast safety rule here: if I drink,
I stay out of the
shop until after a full night's sleep.
That doesn't mean I can't or won't ever drop the square, of course -- just means
that if I do, it
will be the result of my own innate clumsiness, not of inebriation.
Your imagination is lacking, Brian <g>. I can think of at least half a dozen
things I could
check it against:
-- angle between the jointer fence and bed (previously set using the same
-- angle between the fence of the Incra 3000 miter gauge, and the miter bar
-- angle between the Incra 3000 and the table saw blade (ditto)
-- one of my Jevons 3D squares <http://www.jevonstoolco.com/ -- I have no
with the company, except as a *totally* satisfied customer -- these are great
as close to dead-on-perfect as a woodworking tool needs to be (within 0.002" in
according to the manufacturer)
-- my crosscut sled
-- any corner of at least seven pieces of furniture in my home that I've made
using some or
all of the above
I check it periodically, using both the Starrett and the Jevons
squares. Don't you?
Why would you think that?
Just for giggles and grins, I just checked a corner of an end
table that I made about 12 years ago -- put the head of the
Starrett square against a corner of the tabletop, and tried to
slip a 0.002" feeler gauge between the blade and the tabletop. It
won't fit, anywhere within 7 1/2 inches of the corner.
I'm satisfied with 99.97%.
On Thursday, January 3, 2013 10:43:22 PM UTC-5, Doug Miller wrote:
I periodically check my jointer fence with a dial indicator (Powermatic) and
it's always off by +/- 0.003". I shim the pos stop w/ paper when needed.
I wouldn't square anything against it as a reference.
Same goes for my Osborne EB3 that hangs on a wall. It needs periodic adjusting.
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