Floating Tap Head - Advice Please

[UKRobotics]

Would somone care to explain to me exactly what a floating tap head is and how they work ?

I have heard them mentioned several times but solid information on the subject seems hard to come by on google.

I would be very greatfull if somone could describe how these things work, where I could get one from, what sort of price they retail for and the difference between standard and reversing types ?

[Al_The_Man]

I don't know all the aspects of these, but I use one on an excello mill I have, they are essentially used where the Z axis is not geared or synched to the spindle by encoder.
You do have to have good control of the spindle, however.
Although the chuck drives the tap rotation as normal, the tap is allowed to move back and forth under spring return pressure, so although you have to program the Z feed and spindle speed in order to approximate the tap thread lead, the floating aspect allows for discrepances between feed and speed, I have a canned command for floating tap the does not allow spindle or feed over ride when the Cycle is in use.
The spindle has to be able to fast reverse in order to keep in sync with the Z reverse for back out.
I am sure there are other users out there that can embellish on the use of these .
Al.

[UKRobotics]

Thanks Al, though I was under the impression that you could get 'auto reversing' which somehow change direction without reversing the spindle?

Certainly if such a thing exists for a realistic price I'd be very interested.

If someone could shed some more light on this topic that would be great.

[Geof]

Your first post is referring to two things; a floating tap holder and a tapping head. They are different.

As Al describes a Floating Tap Holder allows the tap to move axially between springs so when it is entering the hole it does not matter if the feed does not exactly match the thread pitch for the rpm that the spindle is running. This is provided the error is not greater than the spring travel. The floating tap holder can be the rotating part when used in a mill or the stationary part when used in a lathe. For the tap to retract the rotation has to be reversed.

A Tapping Head is quite different; this is nearly always used in a mill or drill press, both manual or CNC, and is always rotating. Inside the body of the tapping head is a sun and planet gearing with two clutches and attached to the body is a torque arm. The tap is held in a floating holder on the output shaft of the gearing. A spring holds the tap holder up into the body and this engages the forward clutch so everything rotates as a unit and the tap can be driven into the hole. When the tap is deep enough the body is retracted which pulls the tap holder out disengaging the forward clutch and engaging a reverse clutch so the tap reverses out of the hole. The torque arm provides the reactive torque for this. It is not necessary to reverse the spindle with a tapping head.