Help with No32 Mk3 scope setting focus

[vintage hunter]

My machinist pal would'nt be able to turn out more than a couple at the time anyway on account of where he is employed and will have to produce them under the radar as time permits so the individual fit requirement would be an advantage. I'll see if I can get hold of a lead screw on this side of the pond so he can get an idea on what will be involved in making them.

[Merlin266]

I have a similar issue with my Mk3, graticule is slightly out of focus. I understand what Peter is saying at the start of this thread about how to adjust the focus, however trying to shift the locking segment is proving to be a right dog. Rather than nadge it, I have put it back together. If the little hole in it was threaded, I could of popped a screw in it and pulled the swine out

[Peter Laidler]

Threaded........... The bloody hole IS threaded! That's how those that know get them out......... They ain't got threads in them now because cack handed clowns try to pull the segments out with bits of drill shaft, snipe nosed pliers, oversize instrument screwdrivers, Leatherman/Gerber tools, old allen keys, broken stud extractors and anything else suitable - or UNsuitably sized that you can think of - to get the simple but stuck locking segment out. All it needs is a bit of heat and a splash of chemical

Sorry to sound negative V-H, but I'll sound off a bit more later too, but the lead screws might look identical and act identical but THEY AIN'T IDENTICAL. Each lead screw is matched and lapped to the little lead screw nut. Listen to me PLEASE.......... Most often, they're not even interchangeable between the lead screw nuts on the same bloody telescope. I have a box of new, factory made Ordnance issue lead screws that I have to use to replace those butchered by over enthusiastic amateurs and tinkerers who've used their snipe nosed pliers or leatherwood tool to fiddle and faff about with before they get someone to fix it.

Now I'm of the older generation of Armourers and Grad. Engineer and teacher types who prefer to see and encourage folks to 'do it ye'rself first.....', but you've got to know when to ask for a bit of advice first and then ask the pro's. What this thread has taught me is the total reluctance to call it a day, keep flogging the dead horse until it, well....., dies!

And guess who has to fix it?

[gsimmons]

I see a lot of that in watch and clock repair.

[Merlin266]

Threaded........... The bloody hole IS threaded! That's how those that know get them out......... They ain't got threads in them now because cack handed clowns try to pull the segments out with bits of drill shaft, snipe nosed pliers, oversize instrument screwdrivers, Leatherman/Gerber tools, old allen keys, broken stud extractors and anything else suitable - or UNsuitably sized that you can think of - to get the simple but stuck locking segment out. All it needs is a bit of heat and a splash of chemical

Sorry to sound negative V-H, but I'll sound off a bit more later too, but the lead screws might look identical and act identical but THEY AIN'T IDENTICAL. Each lead screw is matched and lapped to the little lead screw nut. Listen to me PLEASE.......... Most often, they're not even interchangeable between the lead screw nuts on the same bloody telescope. I have a box of new, factory made Ordnance issue lead screws that I have to use to replace those butchered by over enthusiastic amateurs and tinkerers who've used their snipe nosed pliers or leatherwood tool to fiddle and faff about with before they get someone to fix it.

Now I'm of the older generation of Armourers and Grad. Engineer and teacher types who prefer to see and encourage folks to 'do it ye'rself first.....', but you've got to know when to ask for a bit of advice first and then ask the pro's. What this thread has taught me is the total reluctance to call it a day, keep flogging the dead horse until it, well....., dies!

And guess who has to fix it?

Obviously not being in the know, I'll get me coat.

[Peter Laidler]

Just put the tip of a hot soldering iron on the top of the BRASS segment for 5+ minutes. That'll soften the concrete like mastic. That SHOULD do it. If not, it's chemicals - but then it's a total strip down as it gets inside!

But if you have a sintered alloy segment (from the grey alloy colour) then don't use a screw to lift it of a soldering iron to ease it as those methods will/may disintegrate it. Just chemicals

[Merlin266]

Just put the tip of a hot soldering iron on the top of the BRASS segment for 5+ minutes. That'll soften the concrete like mastic. That SHOULD do it. If not, it's chemicals - but then it's a total strip down as it gets inside!

But if you have a sintered alloy segment (from the grey alloy colour) then don't use a screw to lift it of a soldering iron to ease it as those methods will/may disintegrate it. Just chemicals

I shall try the soldering iron, on my scope I notice that the 4 screws holding the plate/cover on has one screw larger than the other 3 which fits into the brass segment. Clever.

[Peter Laidler]

Definately something wrong there.......... THere should be 4x screws (2x longitudinally* on later telescopes) and threaded 8BA. If one of them fits into the 6 (or is it 5?)BA segment then it's been stripped and threaded oversize.

* There was an early 50's modification (mod 6 or 7 I think, will look later) that in the event of stripped segment cover threads on the 4 screw Mk2. 2/1 and 3 telescopes the telescope will be modified by the filling and soft soldering of the holes and fitting the latest two hole index plate cover. You have to mill (you wouldn't....., you'd just carefully file it clear) the recess in the segment locating collar, mark out, drill and tap new corresponding holes. Never saw this relate to an L1A1 or 2 but if they came through modified a) who'd know and b) if it was good enough for the Mk3, then it's good enough for the L1's

[vintage hunter]

Sorry to sound negative V-H, but I'll sound off a bit more later too, but the lead screws might look identical and act identical but THEY AIN'T IDENTICAL. Each lead screw is matched and lapped to the little lead screw nut. Listen to me PLEASE.......... Most often, they're not even interchangeable between the lead screw nuts on the same bloody telescope.

I'm listening Pete, as always when you say something, but this is one of those rare cases where you're not telling me anything I didn't already know. I learned this most 30 years ago whilst serving my millwright apprenticeship. The only differences are I was working with industrial machinery and the screws were 100+ times larger but the principle is the same.

[Merlin266]

I'm listening Pete, as always when you say something, but this is one of those rare cases where you're not telling me anything I didn't already know. I learned this most 30 years ago whilst serving my millwright apprenticeship. The only differences are I was working with industrial machinery and the screws were 100+ times larger but the principle is the same.

There's me thinking what a good idea, using one of the cover screws to fit. When all along, some ballsack has stripped the threads on one of the 4 cover plate holes and had it opened up.