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If the ram is through-drilled, just heat the end of the ram with the stuck arbour in it close to red heat, and bash the arbour out with a hammer and a suitable sized punch. Hold the ram in a sturdy vise with soft jaws in it for the bash fest.Is the ram from a Sherline or is it a Chinese import? If Sherline or Taig or other make of lathe made in USA you may be able to get a replacement ram. With Chinese ones you might be able to get a new ram from the importer but it may or may not fit. Seems parts interchangeability is not a given with the China machines, although purchase price is low.
Commiserations on the mishap. Part of the territory, but a real pain when these things happen.Some nice parts you have made already though...
Chris Rueby (code name crueby in this forum) is an expert with his Sherline tools and he could probably comment whether 3/8" drilling in brass is advisable / possible or not in your Sherline lathe.Any twist drill as it comes from the factory will tend to snatch in brass. You can grind flats on the cutting lips of the drill parallel to the drill's axis for drills you plan to use only on brass, which will reduce the snatching tendency. However such drills will no longer cut steels well, if at all. A better way in your machine may be to drill a smaller hole to start with and progressively bore it out in small steps to whatever diameter you need in any material. Much less risky for your machine and a lot less drama. The holes will be rounder as well. Glad to hear your replacement parts are on the way. Good luck with the engine!
Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque. Never had it gall the parts together though. For the larger drills, I usually either start at 1/4" and step through the larger sizes, or drill 1/4 and use a boring bar to take the hole out the rest of the way. The boring bar usually gives better results, the larger drills tend to wobble slightly and give odd shape holes.Chris