According to Bob Jackson site, 753 is 0.5mm tube wall. Reducing the inner diameter of the tube by 0.2mm would effectively reduce the material by 20%. Then theres the chance that the drill doesnt go in evenly.
Given that 753 frames are rare and sought after objects, only made by Reynolds certified builders, it would be unwise to machine it.
According to Bob Jackson site, 753 is 0.5mm tube wall. Reducing the inner diameter of the tube by 0.2mm would effectively reduce the material by 20%. Then theres the chance that the drill doesnt go in evenly.
Given that 753 frames are rare and sought after objects, only made by Reynolds certified builders, it would be unwise to machine it.