Description by the restorator Mr. Danny Ritson
1. The lock has been fully stripped down, all damages removed where possible (90-95%). The internal mechanism had major issues as you were aware of some of it. Cotterill keys look nothing like the key that somebody made for the lock. In order to get an "ordinary" key to work this most of the internals need to be removed. This was the case out of 7 sliders all were missing (2 were present but badly damaged had to be replaced making 7 in total required by bespoke manufacture) All 7 springs were missing/rusted away as well which again required special manufacture. Some damage to the lock case required weld repair and machining back to factory standard look by use of a special tool made for the purpose in order to hold safely in the lathe. Knurling on lock front edge and other detailing had to be re-done. Shackle lath that was broken has been successfully weld repaired. This was riveted into the lock when it should be secured in with 2 small countersunk screws. Had to drill the rivets out to remove the shackle and make 2 small screws to assemble it back as original cutting the threads in to suit. Key is a genuine Cotterill design, un-stamped (as I don't have stamps for this brand unfortunately). Lock will be riveted back up when finished to original spec.
2. Sliders fitted to lock can be seen through keyhole. Has 8 in total specially made. 7 spring loaded, 1 static.
Escutcheon/keyhole cover requires new Brass screw had to be drilled out to remove part for machining case. Key blank shown here will be bright Steel on completion, this is the color after rust removal as it is from new old stock. May need to make a bigger diameter stem for this key blank, will see on key cutting, shouldn't wobble around in these locks or cause problems.
3. The lock works well with its new key and will be riveted back together and receive its final surface finish and lacquer. Nobody will know this lock has a complete new mechanism and many will think the key is original as it is an authentic Cotterill blank minus the stampings.
4. The internal lock has several screws some Steel some Brass. The state of the lock previously required replacement of 2 screws immediately, which I had in stock but had to re-cut the threads in the lock due to damage. To avoid any possible issues of reliability once the lock has been permanently riveted back up I will replace the other screws inside the lock which hold but are not tightening up fully. Would benefit from new screws of a slightly larger thread size that can tighten up fully once new threads are cut in the lock parts. This will ensure you won't experience any issues with parts working loose or jamming up.
The key fits and works the lock perfectly. It is unusual to find one of these that works this well but it is due to the mechanism being newly made needless to say. Usually they are very notchy in feel when turning the key and some even require a jiggle around with the key to work. They are a nightmare to make keys for when badly worn or damaged.
5. Welding up of the old holes in all internal components that were stripped as mentioned. Those screws are fitted now basically all screws internally are new and tight having welded up the stripped holes and re-taped out to suit the new screws. This will ensure no failure of any parts. Note photos do not illustrate polished key but does show what the key looks like it is to cotterill design and works perfectly.
6. Welding materials like this is not easy as they are all made from cast metal, brass and Steel which is naturally dirty and porous especially metals of this era. The production of metals was not as superior and consistently pure as it is in this day and age. I was pleased with the results and was able to drill and cut in the new threads in all parts concerned successfully.
This amazing restoration work has been done and described by Mr. Danny Ritson.
Feb - March 2019