That ring can be a right pain to undo if its gotten tight or gummed up over the years.

Best to make a clamp ring thing bored to sit neatly on the round casing behind the slotted ring with two sheet steel fins to engage in the slots. With the ring sitting securely the fins don't cam out of the slots so it's much easier to get things undone. You seriously don't want to damage the slots.

Naturally if you do go to the trouble of making tool it will come undone really easily.

The proper tool for such things is pretty much a simple friction opening divider with flat bent over ends so those rings are clearly not supposed to be vey tight.

The quick and dirty tool is simple sheet steel U with the ends bent up to fit the slot. I find that style, and the proper divider like adjustable one, hard to hold in proper alignment so one or both tips jumps out when I try to turn things. YMMD.

The jaws are simple triangle shapes held apart to fit the closing cone by springs. Tipped jaw usually means a damaged spring. A spring from retractable ball point pen (Parker knock off perhaps) cut down nicely to fix things when I had that problem many years ago.

Clive

Edited By Clive Foster on 22/04/2023 21:44:18

I'm glad this post came up. I have just taken possession of a Archer No.2 Tapping head and have just stripped all the tap clamping mechanism to clean it up. The knurled knob did wind off with the spring in place, but will certainly not reassemble with it in place. It is a delicate operation with scriber and small screwdriver. To my mind it is a gentle reminder not to turn the knurled knob too far, rather than being a preventative measure to stop removal.

I have had to make the arm and the complete depth stop parts. I just now need to find out how to use it. If anyone has access to the manual in a .pdf form I would appreciate having a look.

Thanks,

Colin

Boiler Bri,

Google manual for Archer no.2 tap head. Multiple answers and ref to YouTube vids

John