Guys,

does anyone own a cheap Machinist's Square set from Harbor Freight?
Price is great I just want to make sure it's not a piece of junk.

Thanks

On Sun, 25 Sep 2005 17:37:24 +0000, Alex wrote:

Guys,

does anyone own a cheap Machinist's Square set from Harbor Freight?
Price is great I just want to make sure it's not a piece of junk.

Thanks

Harbor Freight stuff is kind of a crap shoot. If you do buy them, compare
hem to a known good square.t

Alex wrote:
Guys,

does anyone own a cheap Machinist's Square set from Harbor Freight?
Price is great I just want to make sure it's not a piece of junk.

Thanks

If you do compare them to a known right angle and find them a little
off, a traditional "strongarm" method for improving them is to peen the
blade leg near where it joins the thick leg. Peen it at a spot off the
centerline of the blade on the side where "swelling" the metal makes the
blade warp in the correct direction.

You may have to check and take a little off the edge of the blade if the
peening makes it bulge out a little.

HTH,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

The bodies in Chinese machinist and combination squares are all too thin
IMO. Even though they are within tolerance limits, the castings are
weak, the blades are thin, the hardware is cheap, and they just don't
hold up to normal use. You are better off spending a few $$ more and
getting a quality set from Starrett or Mitutoyo.

Alex wrote:
Guys,

does anyone own a cheap Machinist's Square set from Harbor Freight?
Price is great I just want to make sure it's not a piece of junk.

Thanks

I have a three piece set from Harbor Freight that are made in India.
If you set them on a flat surface (mill table) and check them against
each other, you can not see any error. Checking all against each other
ensures the angle is actually 90 degrees.

Dan

Not sure what Dan means here. If they were all. say, 89.5 deg. and you
nested them all together, they would be in agreement - but they would not be
90 deg.

Bob Swinney
wrote in message
oups.com...
I have a three piece set from Harbor Freight that are made in India.
If you set them on a flat surface (mill table) and check them against
each other, you can not see any error. Checking all against each other
ensures the angle is actually 90 degrees.

Dan

Robert Swinney wrote:

Not sure what Dan means here. If they were all. say, 89.5 deg. and you
nested them all together, they would be in agreement - but they would not be
90 deg.


You place them "back to back" on a (good) surface plate. If there were
only two, and they were both off the same amount in opposite directions,
say at 89 and 91 degrees, they'd mate ok and you wouldn't know, but if
there's 3 or more and they "black out" in all permutations, then they
all must be damn close to 90 degrees.

Same principle as scraping and checking three surface plates against
each other.

snipped

Jeff





--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

"Jeff Wisnia" wrote in message
...
Robert Swinney wrote:

Not sure what Dan means here. If they were all. say, 89.5 deg. and
you nested them all together, they would be in agreement - but they
would not be 90 deg.


You place them "back to back" on a (good) surface plate. If there were
only two, and they were both off the same amount in opposite
directions, say at 89 and 91 degrees, they'd mate ok and you wouldn't
know, but if there's 3 or more and they "black out" in all
permutations, then they all must be damn close to 90 degrees.

Same principle as scraping and checking three surface plates against
each other.

snipped

Jeff





--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

There is no need to compare squares.

The simple method is to draw a line across a smooth clean piece of
stock, metal or timber, then turn the square over and draw another line
across the stock on top of the first.
If the square is any good the lines will be as one but any error will
show them diverging at twice the error.
--
John G

Wot's Your Real Problem?
..

Flipping squares on a white sheet of paper his is not nearly accurate
enougth for precision metalworking tolorances... the thickness of hte
pencil/pen/marking device/ line is not fine enough to see minute angle
differences... particularly as most of hte HF squares are in the 4-6'
range... 8-12 if the OP buys the larger ones. Not nearly long enough to
see an angle difference .... unless the square is horribly out of square.

The accepted way to measure is to place the reference square (assumed
to be a perfect 90 degrees) and the test square on a flat surface plate
(plate glass will do) with a soft light placed behind the two squares.
Gently push the two squares together... if they are perfect 90's, you
will see a thin sliver of light getting smaller and smaller until it
literally blacks out.

The eye is extrodinarily sensitive to light and you can see differences
literally to ten thousands of an inch -- if not finer. Minute
differences are simply lapped until perfect.

This is how most manufacturers test precision squares.... but they use a
darkened room as well. And as one poster mentioned, 3 squares are
required to truly test 3 unknown squares.... if you do have a reference
square, then the above method works fast and easy.

Steve


John G wrote:

"Jeff Wisnia" wrote in message
...

Robert Swinney wrote:


Not sure what Dan means here. If they were all. say, 89.5 deg. and
you nested them all together, they would be in agreement - but they
would not be 90 deg.


You place them "back to back" on a (good) surface plate. If there were
only two, and they were both off the same amount in opposite
directions, say at 89 and 91 degrees, they'd mate ok and you wouldn't
know, but if there's 3 or more and they "black out" in all
permutations, then they all must be damn close to 90 degrees.

Same principle as scraping and checking three surface plates against
each other.

snipped

Jeff





--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."


There is no need to compare squares.

The simple method is to draw a line across a smooth clean piece of
stock, metal or timber, then turn the square over and draw another line
across the stock on top of the first.
If the square is any good the lines will be as one but any error will
show them diverging at twice the error.

I got a 3" import square from my supplier that seems excellent. Heavy....
If HF is similar, no problem. May want to check w/ your local supplier,
might be competitive.

I got 6" carpenter's squares from my local 99c store for... 99c.
About 87 degrees....
----------------------------
Mr. P.V.'d
formerly Droll Troll
"Alex" wrote in message
news
Guys,

does anyone own a cheap Machinist's Square set from Harbor Freight?
Price is great I just want to make sure it's not a piece of junk.

Thanks

John G wrote:
There is no need to compare squares.

The simple method is to draw a line across a smooth clean piece of
stock, metal or timber, then turn the square over and draw another line
across the stock on top of the first.
If the square is any good the lines will be as one but any error will
show them diverging at twice the error.

Thats good enough for woodworking but not hardly for machinists.
...lew...