Here's this morning's first job, fit the gland to the valve block complete with 7BA studs.... Nowt to it eh? Soon knock this off. Dream on Kids! One thing I realised was that I was mistaken yesterday when I complained about the casting not having a face big enough to accept the gland, I was looking at the wrong end! It always pays to check the drawings.
First job was mark the gland up and drill the 7BA clearance holes. Then transfer them to the valve block. In order to make sure I had it lined up properly I had to have the piece of stainless rod in place to make sure I had it lined up correctly. Hence the sophisticated set up, I needed a third hand to stop the valve rod falling out. By the way, I have put witness marks on the gland, the valve block, the cylinder top and the lid so that I can always preserve the correct relationship.
Then under the drill press, make sure it was upright and then drill the tapping holes for the 7BA studs. I drilled both holes, not enough feel to tap using the drill chuck. I hate small taps! By the way, I am cheating, I am drilling these holes 2.1mm instead of the correct size, 2.05mm, there's no strain on the studs and I want to make tapping as easy as possible. The increase will be OK.
The first hole was OK but just as I was getting to depth on the second..... Even though I was being ultra careful I sheared the drill off. Luckily I had been clearing the chips after each peck in the hole and before I went into a decline I gave the block a couple of smart taps on the surface plate and out popped the broken end. I'm not trying to avoid responsibility but usually when this happens it is chips jamming in the flutes and this is evidently not the case here which leaves the jury out on why the drill broke. But that's academic, I resharpened the drill and put back in the box.
With the broken drill in mind I was very careful as I tapped the holes. If you remember, the last time I hit trouble with these 7BA taps I bought a set of new ones.... No dramas and no forcing.
We've jumped forward here and left out a lot of finishing, filing and adjusting to get the gland to fit, get it bolted down and fitted with valve rod in place. Not surprisingly, I was a thou out with my alignment, the vale is a very close fit in the block, and had to recourse to files and other destructive tools to get it tightened down with a valve rod that slides freely.
Knocking off time, all this has been slow and painstaking. I think you can see the witness marks on the lid and the cylinder. Slow I know but it's OK, we can move on....