Tapping cast iron backplate question

Second will be fine. If I have to buy specials I only buy the second as they will usually do most jobs

-- Regards,

John Stevenson Nottingham, England.

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In article , mangled snipped-for-privacy@yahoo.com writes

I do this on a Fobco 1/2" - having removed the belt I hand-turn the pulley at the top of the quill and, once the tap starts to 'bite', I let it feed itself in at its own rate.

A word of warning though: check the pulley for sharp edges before taking too firm a grip - guess how I know :-(

He may find that the drill chuck will not hold the tap firmly enough to drive it all the way through. It doesn't matter that much, since you only need to get the tap started straight.

Mark Rand RTFM

Hve a look here

Peter

Me too, but I find that when backing off (mild steel), particulary on M10 and M12 taps I can't get enough grip (tap turns in chuck, pulley slips on shaft, hand slips on pulley...) and end up with a pair of mole grips locked onto the shank of the tap to "help".

Holes end up tapped square though.

Steve

Thanks to all for the answers, an HSS second tap from Chronos did the job fine. I found CI is nicer to tap than ms and the idea of turning the drill chuck via the pully works great. No cut hands either :-).

Thanks again,

David