I thought this little tapping machine might be of interest and was curious to hear if anyone has ever seen one like it?
I've been doing a lot of tapping (#2-56 = 8BA) lately which reminded me of tapping machine I saw on a visit to England some years ago.
Visiting a friend's workshop in Essex, I was shown this which he rescued from a skip. I wouldn't have recognized right off what its purpose was,
but he recognized it immediately and quickly gave it a home. It's a simple but ingenious machine.
The powered horizontal shaft drives single friction-faced cone which sits between the two opposing cones on the spindle.
The spindle can move vertically but is limited to the range allowed by contact with the driving cone.
After adjusting its position, the table is raised and lowered by a rack lever.
So with the work piece fixed on the table, raising the table also raises the spindle where its lower cone contacts the driving cone.
This turns the spindle in the CW direction, advancing the tap, with the table following along.
When the required tap depth is reached the table feed is slacked, ending spindle contact with the drive cone, which stops the spindle.
Lowering the table then engages the upper side of the drive cone thus reversing the spindle to CCW and the tap is withdrawn.
It's really quite brilliant and works beautifully and quickly. At that time my friend was engaged in small batch building of Gauge-1 live steam locomotives
and he told me it never breaks even a tiny tap. Unfortunately I didn't take note of the Mfg or country of origin, and neither of us had ever seen one like it.