Ok now comes the biggy the bearing block or trunion and bearings, on these vintage style keys it is one of the hardest parts to make, and seeing as I don't have any large milling or even foundry facilities I will have to make it up from a number of parts and fit them together, Also the bearings on any Morse key are in my opinion the very heart of the key, everything literally hangs on the bearings, average bearings means average action in my view, AND this is where I depart from copying the original (oh no) my previous key 140 was a bit taller and more "Sit up and beg" than the original as I wanted it to look even more vintage than the original which I like to think I did, however on this one I want it to be lower slung shorter and stockier and a bit meaner :() and this will be reflected in the bearing block more squarer and lower, but anyone following this could easily stick to the original design the principles are the same. below is the original key being measured and under that the piece of scrap brass (all my keys are made from off cuts and scrap brass) that will form the base and I shall clean it up and cut it to size with the slot saw.
I think now is a good time to mention Brass, not all brass is the same, it comes in various grades and mixes, I tend to use if I can CZ121 or 108 it is a general purpose brass that cuts easily, the one to avoid at all costs is CZ120 or Compo brass which is mainly used for engraving, it is difficult to work and clogs up the tools, but it is expensive so you don't come across it that much. below is the brass mounting base trimmed to size
Next comes the end plates, I usually make both of these at the same time, below you can see the piece of brass that I will make them from, I am about to drill out the centre and then cut it in half, here you can see it being centre punched as it is important that the hole is in the exact centre. again it has been cut to size from an odd piece using the slot saw.
Below you can see it being drilled out, a smaller hole first
Then the big one, this is the time honoured way of drilling a large hole in a small workshop, the hole will stay central and round
Now comes the time to cut the block in half, it has to be exact and the easies way of lining it up is to keep the jaws slack on the vice and then take the work up to the side of the saw and then tighten the vice jaws
Then simply wind the work back and move it in front of the cutter, below you can see the two halves
And here are the two halves below where they will be fitted as end plates, I have made them slightly oversize for reasons you will see later
Now below I'm making the rounded tops that will fit on the plates, I have "Trued" up the bar to size and cleaned up the ends
Now below I am putting a centre hole using a centre drill prior to drilling a 5mm hole through what will become the two top pieces that will hold the ball race bearings, the reason for the 5mm hole will become clear further down.
Now we are getting somewhere, below are the various pieces loosely assembled, and you can see that there is a piece of 5mm bright steel bar running through both holders, this bar will do two jobs when it comes to sweating the whole assembly into one piece, firstly the holes in the two end pieces must be in EXACT alignment with each other because if they are not then the ball races won't run freely and the bar through the holes during assembly ensures that they will be, also it temporary holds everything in place up top as well
And that is it for this page, on the next page I will show how the whole assembly is made into one piece.