On Wed, 21 Dec 2016 10:14:36 -0600, dpb advised:
I guess the first question is *WHY* we can't patch next to the sidewall.
Is it that the patch won't hold? Why?
Is it that the patch will flex too much?
Or is it that the belts are damaged and they will break?

All of the above in greater/lesser degree depending on just where and
how bad the damage is...

Thank you for the information as some were on the last tread groove (see
below how we patched it with a home-made plug patch.

None of those are even close to the sidewall; they're all well out in
tread area.

Thank you for that advice because I wasn't sure at all how close you can
get to the sidewall for it to fail the patch test.

We patched this alloy-wheel 55-series tire where a flat-on-both-sides tiny
bolt (with no sharp edges whatsoever) had wedged itself into the last
groove, and eventually punctured the tire.
http://i.cubeupload.com/09PwHs.jpg

Here you see the tiny (now headless) bolt next to the puncture hole:
http://i.cubeupload.com/6F0CnI.jpg

To properly patch that hole, we reamed the hole with this hand tool:
http://i.cubeupload.com/sZ6qxo.jpg

Using that hand tool, we probed the hole slant (it went in straight):
http://i.cubeupload.com/UxYLNx.jpg

Then we grabbed this second hand tool & slobbered glue on the plug:
http://i.cubeupload.com/EMU9zy.jpg

This is the plug sticking up on the outside of the 55-series ti
http://i.cubeupload.com/V1dCGA.jpg

To cut off the protruding plug, we failed trying the diagonal cutter:
http://i.cubeupload.com/ra3Prp.jpg

We also failed with the flush dikes because the plug was too rubbery:
http://i.cubeupload.com/M2BHaA.jpg

We ended up slicing it off with a utility knife but we learned how to slice
the plug off more neatly when we cut off the plug protruding on the inside:
http://i.cubeupload.com/r0n5WI.jpg

The dremel tool metal blade cut off the plug flush with the inside wall:
http://i.cubeupload.com/QSBXAK.jpg

Then we buffed with a wire wheel, where we learned that it would be much
nicer to have a "ball" shaped wire wheel because of the angles involved in
buffing away the outside rubber to expose the virgin rubber to the
vulcanizing glue:
http://i.cubeupload.com/QNrRco.jpg

Here is the buffed result before applying the patch over the plug:
http://i.cubeupload.com/otho8w.jpg

After applying vulcanizing glue, we stitched down the patch:
http://i.cubeupload.com/BrkYl3.jpg

Where this is what the final patch looked like:
http://i.cubeupload.com/UBOmyw.jpg

Any advice you can provide will be helpful as the whole point was to learn
by doing, where already I'd do it differently the next time (e.g., I'd use
the dremel tool on both the inside and outside and I would get a roundish
wire brush that fit the inside of a tire better.