I know Cleveland Form Forged Irons are on the “Do Not Bend” list, but is it safe to use a .370 spiral fluted reamer and a drill press to change a set of irons from current .335 to .370 to accept graphite shafts?
As long as the heads are set up correctly and the bore is precise, you should be able to drill them out from .355 to .370. Form Forging is nothing more than investment casting of carbon steel, followed by one hit in a forging press. I don’t know which particular model you have, but the CG1, CG2, and CG4 models were a material that was not just a carbon steel. It was infused with another material that made these models brittle. The later models of CG10 and CG11 wedges were also difficult, if not impossible to bend. The other models of Cleveland irons we list on the non bendable list (TA2, TA7) had the micro cavities in the top of the iron cavity that would collapse when you locked them in a bending machine and then tried to bend.
Britt Lindsey
Correction….current Clevelands are .355 not .335 as incorrectly identified….but I still want to ream them to .370 if it is safe to do so with a form forged head