Friend of mine has an old pillar drill that takes these,his goes up to at least an inch.Hi , I was sorting through a box of old drill bits, I was given and found these two. I have never seen drills with this type of shank before. I presume they are fairly old, going by the way ,the 7/16th one is marked. Does any one have any info on these?
Here is the type of thing although the one in this pic doesn't have the clamp as part of it.
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