Hi Richard, I don't think you will find the recess threaded, below is a photo of my No. 2 one, this is the hide end and I've only just bought a new hide insert for it. The recess itself is tapered outwards and the idea is that once the new insert is fitted and you start using it, the copper swells into the taper. All the new copper inserts I've seen have a turned down plain end.
![Thor Hammer Thor Hammer](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
Regards Nick.
P.S. I've just looked on the Thor website http://www.thorhammer.com/Hammers/Rawhide/ and found a guide for replacing the soft faces. It's a download PDF at the bottom of the page. The copper end have grooves formed in them for the copper to swell into. There is also a drawing for making a combination tool for fitting the hide inserts.
Edited By Nicholas Farr on 25/10/2015 07:50:08