Low speed drill press bores big holes! Vintage DIY project

machine shop vintage diy big bore drill press plans

THERE’S a secret to boring up to 1-in. dia.
holes through steel with a ½-in. capacity drill
press. You reduce the speed of the drill bit
and increase the torque with a speed-reducer.
The speed-reducer is simply a jack-shaft consisting
of a mandrel with a 4-step cone pulley on
one end and a 12-in. pulley on the the other end. This reduces the drill press chuck
speed to a low of about 125 rpm and a high of
about 600 rpm, depending on how the cone pulleys
are belted.

CLICK HERE to download and print these plans(pdf format)

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