Well, like I have said many times before the best laid plans of men n mice sometimes go belly up, well it happened again this morning
nice n clear weather wise ideal for using the Mig, job set up welded in no time, allow to cool, put in 3 jaw chuck, machine it down
it looks the part
it is a very neat fit into the hollow spindle, so I get a tad cautious here, not wanting to get something jammed in the spindle I tried it
out in the old spindle (read bent about 15<>20 thou) it fits down dragging the 1/2"Whit thread on the sides, then comes to an abrupt halt
the 1/2" Whit will not fit through the hole to engage the 3MT, damn bugger n blast it , so I do the same using the spindle in the mill, and
it's the same.
The spindle will take 12mm threaded bar, but the 1/2"Whit is a just a tad thicker, so now I will have to find another 1/2" Whit bolt so I
can cut off the threaded end, set it up in the lathe, drill n tap it M8 1.25, then using a M8 bolt with locknuts on it, apply some 'Loctite'
and screw it into the end of the 3MT arbor, then make up another draw bar, I still need to revisit that job.
Moving right along, I have since found a few issues with the drawings, just a couple of minor things that I have modified to suit my locomotive, one issue was self made, the main leaf on one of the springs was a approx 3/64" too long, I think it happened when I clamped it up to silver solder the spring eyes
so I used the jig to line it all up before clamping/silver soldering
I was also concerned about the bottom leaf sitting inside the horn cheeks, so I modified the center bolts
and assembled with redesigned spring keeps as well
all loosely fitted to the frame
still a few things to do/check before final assembly.
It has been many years since I've made a compression spring, I had to make some tools to do the job, first was the Mandrel
with a 1/16" dia hole in it
then I needed a guide, a suitable piece of steel selected, using a 0.020" slitting saw to cut a 0.010" groove along it
then check the wire fits so that it stands proud of the surface
just as well I have 2 metal turning lathes as I can't work out how to cut an Imperial thread on my new one LOL
so set it up on the older machine, run in back gear, with the leadscrew in reverse, first allow it to run on 3 coils, then engage leadscrew
to put on 7 turns of coil, before stopping and apply 3 coils, these would be ground off, but I'm not using this spring as the
wire diameter is too small it' 24SWG I need 20SWG, anyway I'm happy with the job, just shows I haven't lost he plot yet
it's big isn't it anyway cheers Dennis