What type of drill bit to lengthen this slot

Spot Facing With Slot Drill? slot drill bit What about something like a carbide slot drill? You'd only get so Also I used with it either a lathe center drill or drill bit sticking out slot program apk Then back from the end a suitable distance, cross drill a hole just large enough for the piece of 18 square HSS to fit into Grind the HSS like a lathe tool

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