In article ,
Ignoramus26879 wrote:

On 2010-05-02, Larry Jaques wrote:
On Sat, 01 May 2010 10:06:38 -0500, the infamous Ignoramus26879
scrawled the following:

On 2010-05-01, Joseph Gwinn wrote:
In article ,
Ignoramus9191 wrote:

http://igor.chudov.com/projects/Weld...ble-Grab-Hook/

I welded this double hook from two Harbor Freight grab hooks and a
1/4" steel plate. The purpose of it is to let me use arbitrary lengths
of chain, single and two ends, when lifting stuff, as well as grab to
access lifting eyes with just a piece of chain (see last
picture). Welding was done with 1/8" E7018 electrodes.

While you will no doubt get lots of advice on welding and redoing the
heat
treatment of the hooks (if HF hooks are in fact heat treated), don't
forget to
proof test this to four times the intended max load.

I just proof tested it in a 12 ton arbor press. See my another
post. This was actually a good idea Joe.

You _pulled_ on it in a _press_? Bar through the eye over the jack
backstop, chain under the ram fastened through the two hooks, I'm
guessing?

I'd think the eye would be by far the weakest link. Weld some 1/4" rod
around the top, eh? I'm sure you already know enough to not get
-under- anything lifted with it.


Something will always be the weakest link. This eye has a 1/4 of a
square inch in the smallest cross section. At 50000 PSI, it works out
to 10,000 lbs. I am not losing my sleep over it.

If the eye loop is 1/4" by 1/4" square, that's (0.25)(0.25)= 0.0625 square
inches, or 1/16 of a square inch. At 50,000 psi, that would be 50000/16= 3,125
pounds, which is a bit too close for comfort, for lots of reasons. Not least of
which the steel in hot rolled plate may not always be that good. And the eye
loop geometry may not be perfect. And so on.

Joe Gwinn