GH Thomas Headstock Divider

[Allen Smithee]

Don,

Many thanks - when I get home I'll look at it again with the book and lathe in front of me, and hopefully the penny will take the lemmings leap!

Chaps - a thousand thanks for suffering my stupidity with such good grace. I know I'm an idiot, but your willingness to overlook it is what makes this such a great place.

AS

[zeeprogrammer]

I know I'm an idiot

I don't see any here. 

I can point you to a couple of threads where they seem to thrive.

[Allen Smithee]

OK chaps, I think I now understand!

I'm assuming the diagram Don was talking about was this one (on page 228 of my book, because of course there's more than one book about this!):



And I think the cause of my confusion is that for no really good reason he chose to draw the template on its side; the edge "x" is drawn horizontal but when the template is used it's vertical - is that right? And I assume that in use this edge is aligned with the joint between the countershaft casting and the headstock casting, with the upper edge 1/8" above the flat(ish) face of the countershaft casting - please tell me if I have it wrong, because I just don't trust my little grey cells at the moment!

So (by shamelessly stealing Rod's photos and graffitting over them) the template position on the left (gear end) of the headstock would look roughly like this:



That looks simple enough. But on the right (chuck end) of the headstock it would look like this:



Which, due to the position of the flanged edge of the countershaft casting, means I have to either put a spacer behind the template or use the template in the inside of the casting and somehow try to drill a pilot hole through from the inside. I think the spacer approach sounds best!

So do I have it right? Sorry to labour this, but I don't want to drill more holes than strictly necessary in my Myford - it's previous owner would get very upset and she'd probably slap me or something...

AS

[Don1966]

I think you have it Allen and now you see what the notch is for on your last photo it's for the bolt head.

Don

[Allen Smithee]

Right, that clattering and slapping noise is the combination of the dropped penny disappearing under the bench and my forehead receiving multiple slappings while I shout "DOH!!!" If GHT has said "BTW that nice template on the drawing is shown turned on its side" then I'd have gotten it straight away (that's my excuse and I'm sticking to it). Once I grasped that the words in the text miraculously transformed into English from the colloquial Swahili that was there before...

Don's id definitely fitted lower than Rod's one, because GHT suggests the hole centres should be 1/8" above the flat bit of the countershaft case casting. But this is visually exaggerated by the way the spindle speed labels are clearly in different places on the two machines - Rod's one is screwed on very close to the bottom of the casting, where Don's is riveted an inch or so further up the face of the casting. I'll have a look at mine and probably move it - I've always though it was a stupid place to put it anyway, because it's very difficult to read where it is.

But I am now ready to proceed - I'll make the fixings (which even for me should only be an hour's swarf-time) and then get it fitted. Thanks again for all you help, chaps.

The game's afoot!

AS

[Allen Smithee]

Well it *was* afoot until the drill bit of fate met the old iron casting of destiny...

So on Saturday I managed to get an hour or so, and I carefully marked the required position for the hole on the left (gear end) of the countershaft casing.

Then I checked it, and checked it again.

Then I centre-popped it and checked it again. All was well. So I got a new, sharp 3mm drill bit to pilot the hole with, and starting slowly got the hole started, with a bit of lube on the drill. All was well, so I added some more lube and increased the speed. The drill got about halfway through and then suddenly hit a hard spot in the casting, moved sideways and broke through in a position about 5mm down and forward of where I needed it.

Damn and botheration!!! Call myself an engineer and can't even put a single hole in the same postcode as the marked position! 

So I checked and the unit will work fine in this position, but I now have to make a template to find the ACTUAL position of this hole so I can transfer it to the other side to drill the matching hole.

I was just starting to do this when I heard my Better Third's voice calling. Apparently the gutters needed demagnetising and the bedroom needed moving 3" to the south, or something. So the time window snapped shut and the job will have to wait for another day.

It won't be next weekend, because there's no way I'll get away with the 1st GP of the season AND swarf-making time in the same weekend...

AS