Just personal opinions here Lew; I'd try to avoid doing that if only for the sake of preserving the integrity of the keris .
When I unmounted my anak alang blade I found that someone had started to try this; fortunately for me and the keris the hacksaw cuts were very shallow .
On the esoteric side I believe this would be detrimental to the powers of the blade; I've often heard that the base of power in a keris resides in the pesi .
Can the jejeran be drilled deeper instead ?
Rick