The last three keys were great fun to make and were quite different from each other demonstrating different aspects of Morse key design, this next key is somewhat of a composite of the last three, completely original, to be honest I love making keys to my own original design, I was very impressed with the performance of key 163, however the frustrating part is after "tuning" the key to my own requirements I have to admit they are MY requirements and almost certainly won't suit all future owners of it, so I thought in this next key I might try to make the performance adjustable by placing three contacts along the contact spring with matching threaded holes in the contact block so the key could have three levels of "Feel" to it soft medium and hard, the key shape would be low slung and heavy similar to the old Marconi spark key 161 a fairly long lever with a 1 to 1 leverage similar to key 162 but with a pivot block based on key 163, the overall impression would be chunky and vintage looking but with an excellent adjustable performance, well that's the plan but things do have a habit of getting changed as things progress :() below are the basic parts that I cut out this afternoon I shall leave the contact block until later as I still haven't got that finalised in my mind yet and it will be all important
Below is the first Mock up, the various parts are pushed and placed together propped up with bits of scrap so I can get a rough idea how it will look further on in the construction, it looks a bit like a one legged man at the moment, and the Mahogany base doesn't seem to be working with this key, I may try a piece of Acetal plate and see how that looks on that, it's having a difficult birth so far :()
Below you can see I've abandoned the mahogany base and gone over to an Acetal one upper left is the basic idea and it is basic the contact block having four places of contact along the contact spring where the contact can go, below right is the basic action, the ballraces yet to be fitted already the key is starting to develop a personality, a low slung greyhound of a key, I'm really looking forward to a test run soon to try the idea out :()
Well, above is the key finished enough to test out AND there is a problem, the idea works extremely well, being able to change the position of the contact point along the contact spring is fascinating as it changes the entire personality of the key, HOWEVER the balance and leverage is not quite right,  it is a very fine key as it stands, but I'm sure it could be much better, so I'm stuck with two options, it is very close to completion so I could simply finish it then sell it to recover my costs and start anew, or face a major rebuild, the rebuild would consist of shortening the nose of the key this would mean the removing the tensioner block and repositioning and drilling it out and filling the old hole, cutting off the nose and re-slotting it and re-fitting the contact spring then repositioning the pivot so it all aligns up again, the real problem is taking it all to pieces as it was a multiple soldering job when I assembled it, with very close fitting joints, it won't take kindly to coming apart again. Decisions like this are part of key making when the performance is being pushed to the level I'm expecting, it's always a trade off, the key has to be almost complete before it can be tested and then of course it is usually to late for major changes, if I start early I may get it done in a day, so looks like it's a rebuild :(  Below
Above you can see the rebuild, to the untrained eye you may say "what rebuild" but if you compare the pictures carefully you can see the tension point is now much closer to the pivot point and of course the pivot is closer to the contacts, this has had the effect of increasing the leverage on both tension spring and contacts, it is very slightly tail heavy but this is because there is no heavy tension adjuster knob fitted yet, also you can see a spare hole behind the pivot plate this is the old position of the pivot which has now been moved forward about 1cm, all this may sound trivial but it has transformed the key action from good to excellent, in position 1 where the contacts are closest to the tensioner the key is very firm mimicking the action of hard keys such as Marconi 635 and GHD types, in position 2 the key is superb just that perfect mixture of firmness with a hint of bounce, such as my Amplidan copies that used ball race bearings, Position 3 is very similar to the original Amplidan, in fact I have run the keys side by side and they are virtually identical, position 4 is not to good, far to much bounce so much so that I may cut the end hole off to reduce the size of the top contact plate and contact spring and just leave the three options , time now to fit the fiddly bits, knobs and terminals to replace the temporary nuts and bolts.. This is turning out to be some key
 

Another thing I have just found out as I have been experimenting with this design is the importance of the rest post or resting contact position, in relation to contact adjuster, in most keys they are in alignment and provided they stay within 5mm nothing happens BUT move them further apart and the performance degrades drastically, this was the reason for position 4 being useless, by putting a stop directly under it it becomes quite pleasant, a little slow and bouncy but a nice relaxing action, SO another mod is due, I shall slot the fixing holes in the resting post so that it can adjusted to slide back and forth about 10mm for a reasonable alignment with the contact position, more designing on the hoof so to speak :()
Below you can see the modified resting post where it is slotted, it can't quite get exactly under the appropriate contact but close enough.


And finally it is finished, I have put a reasonable shiny finish, not every scratch and blemish but it does look very nice, and handles like a dream, it is the best performing key I made so far, not so much in ease of setting up, or maybe looks, but in performance it excels, the weighting and balance is spot on and the subjectivity has been removed with the four settings, it is hard for me to chose between the central settings as they are both how I think an excellent keys should be, the inner hard setting would suit any operator who prefers that staccato feel reminiscent of the Marconi 365 design, and the outer setting would suit a slow methodical way of sending with lots of spring in the action suitable for long slow ragchews.    great fun