From an email to Repeater-Builder.....

"pop" @ Lee Hardware has been cutting keys for 60 yrs, so consider him a master.

The blank is an industry standard "SL1", he used an ILCO. The convex groove is thinner. The concave groove is wider. This allows the key to fit. Anyone telling you this is the wrong blank shouldn't be cutting keys!

He does not have a coding machine so all measurements are made with calipers.

The cut side of the key is the "top" side.

All measurements are in thousandths of an inch and "pin" cuts are measured from tip (insertion end) to head.

Move Top stop (nearest head, cutting side) back 0.250 towards head.

Move bottom stop (uncut side) back 0.105 towards head.

First pin cut (from tip) 0.238 back x 0.032 deep.

Second pin cut (from tip) 0.242 back x 0.015 deep.

Third pin cut (from tip) 0.536 back x 0.018 deep.

So if you are an amateur key cutter and have a small needle file and some calipers, you're in business. A vice would help too.