I made myself one a couple of years ago with the advice of a guy on another forum....here's what he recommended:
1. Get a 7-8-or 9 iron, preferably one with an undercut sole (or at least a cavity back)
2. Cut the shaft down to the length of a wedge or putter (about 35 inches is pretty standard).
3. Bend the lie more upright to about the lie of a putter (most wedges are about 64, putters are about 70-71
4. Add weight with either lead tape or stick on lead weights to weigh what a putter or wedge weighs.
Presto! You have your own custom made chipper! I built one like this with an old Wilson Staff 7 iron that
worked like a charm, but eventually, I learned to chip the "right way" using the normal clubs. If you like
to tinker with clubs like a lot of guys here, this would be an easy project.
If not, this Square Strike wedge seems to make sense to me.....they've made a lot of the adjustments I
described above.....shorter, heavier, more upright, etc.