I have a Coventry die head but this doesn’t work well on short threaded studs or bolts, due to the fact it needs to pull its self forward out of its main body by 3/4mm to disengage.
To aid threading under power I decided to machine a die stock which fitted in to an Archer friction tapping head as can be seen in the first photo.
With the clutch set correctly on the tapping head, it is possible to machine right up to a shoulder or the chuck jaws under power without fear of snapping of the screw or pulling the job out the chuck or damaging anything for that matter. Having a positive stop/datum aids length tolerance repeatability, of the thread being cut. I have added a link to some bolts I made for my 1” scale Minnie traction engine in bronze using the tapping head setup.
This is a link also to my split die setup which saves a lot of time and effort http://www.homemadetools.net/forum/s...ie-setup-65783
Link to minnie traction engine cylinder block bolts Practical Engineering
Again thank you for taking the time to view my post
The Home Engineer