Tadco Autogard 250

I have recently aquired a Tadco Autogard 250 tapping device with a No2 Morse Taper shank. Before I bust any taps can anybody tell me how they work. Does this device slip when a suitable torque is reached for a particular tap. The end of the thing rotates and screws in and there is a scale which has numbers that do not relate to any thing obvious. Sadly there was no instruction book.

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IIRC the setting figures were on the box lid.Doesn`t matter anyway,these things were never exact and depend on hole size,tap type,speed,depth of thread etc etc. We machine tap 100`s to 10,000`s of holes a week and never use tapping attatchments and very rarely break taps either,as a percentage of holes tapped. If you must use your Autogard,wind the setting collar back a bit until it slips when you tap a hole which is the correct size for the NEW tap you will be using,wind it on slightly and you are there.If this does not sound to technical,tough cos it`s as good as these things ever get. Remember these things are from an age long gone.Forty-fifty years ago anyway.

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Yes but does it slip if the tap bottoms out?

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Engineers set the machine so it does not bottom out and you will spend a lot of time tapping holes if you think otherwise.