Centering the No.32 scope

[ToineS]

Hi all,

Today I centered my No.32 (replica) scope.
I used the ‘vee jig’ method which worked quite well.
At 800 yards there is still a very slight wobble, but I can’t get that out.
I decided that that ‘wobble’ was most likely me rotating the scope through 360 degrees.

Tonight I read of another method: the mirror method.
When I check the centering with a mirror, the deflection setting is dead center, but the mirror image is too high.

Is that normal for a No.32 scope?
In other words, is the optical center not quite the same as the mechanical center with these scopes?

If it is, should I rely on the ‘vee’ method or the mirror method?

Thanks!!!

Information

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[Atticus Thraxx]

I tried the vee jig haven't tried the mirror. My T throws low and left at 100 yds from a bore sighting. Mine matches and everything is tight and pinned. I'm debating sending my 32 in for service per Brian Dick's recommendation back they quoted a 3-6 month backlog. I'll wait to make sure the world doesn't burn this summer and check with them again in the fall. What's a bore sight show?

[ToineS]

I tried the vee jig haven't tried the mirror. My T throws low and left at 100 yds from a bore sighting. Mine matches and everything is tight and pinned. I'm debating sending my 32 in for service per Brian Dick's recommendation back they quoted a 3-6 month backlog. I'll wait to make sure the world doesn't burn this summer and check with them again in the fall. What's a bore sight show?

The right Lee hasn’t presented itself yet.
I figured I’d start with the sight and go from there.
If you’ve vee’d the scope, then according to PL’s articles, you’ll have to further zero it on the rifle. The centering is done to allow equal movement to both sides when zeroing, as I read the articles.
Am I interpreting it in the wrong way?

[Roger Payne]

No, I think you have it pretty clear (if you'll forgive the pun). Also the centre of the lens will have the least effect of spherical aberration.

[ToineS]

No, I think you have it pretty clear (if you'll forgive the pun). Also the centre of the lens will have the least effect of spherical aberration.

😁 Thanks!
Do you know if the mechanical centre of the No.32 scope differs from the optical centre?
If so, that would explain the difference in graticules when doing the mirror check...

[Roger Payne]

EMERS L1A1 Telescope, 1971, para 38: The optical axis of the telescope should be aligned to the mechanical axis of the telescope tube to within a tolerance of 0.3 mils when the range & deflection heads (drums) are reading zero. There should be an equal amount of overrun at each end of the range scale (approximately 14 clicks) & the deflection scale (approximately 9 clicks).

Hope this helps.

[Surpmil]

[Warren]

Something to check...
Check the turret assembly and see if it is TIGHT on the tube.
I've repaired about a dozen where people have squeezed the tube onto the mount with the cap screws.
The cap screws will exert tremendous torque and IF the aligning pin on the scope is too large for the slot on the mount (many are) it will force the scope onto the mount but break the turret loose.
As I said, I have repaired about a dozen so buggered up this way and it is not a nice job.
Check the turret assembly and make sure they are tight on the tube,,
If not, drop me a PM
cheers,
Warren

[ToineS]

EMERS L1A1 Telescope, 1971, para 38: The optical axis of the telescope should be aligned to the mechanical axis of the telescope tube to within a tolerance of 0.3 mils when the range & deflection heads (drums) are reading zero. There should be an equal amount of overrun at each end of the range scale (approximately 14 clicks) & the deflection scale
Hope this helps.

Yes Roger, thanks. That does help understand the situation with the mechanical and optical centre of the scope.
The Vee jig method shows a near spot on centre (as near as I can get it), but the mirror method shows a vertical difference.
I think I’ll trust the Vee jig method as that is what Peter Laidler suggested to center the scope.
Thanks for the help!

---------- Post added at 08:33 AM ---------- Previous post was at 08:25 AM ----------

Something to check...
Check the turret assembly and see if it is TIGHT on the tube.
I've repaired about a dozen where people have squeezed the tube onto the mount with the cap screws.
The cap screws will exert tremendous torque and IF the aligning pin on the scope is too large for the slot on the mount (many are) it will force the scope onto the mount but break the turret loose.
As I said, I have repaired about a dozen so buggered up this way and it is not a nice job.
Check the turret assembly and make sure they are tight on the tube,,
If not, drop me a PM
cheers,
Warren

The turret assemblies do not move at all. The range turret itself has the teensiest bit of movement, but that was there before mounting the scope. It also turns just that little bit easier than the deflection turret.
The scope seated perfectly, even without the caps on, so I guess I’m fine there?

[Roger Payne]

I can't remember the specific limits, but there is some tolerance, more so in the vertical plane, when centering the vertical pointer. And don't forget, that with this type of scope the grat block moves downwards (user's field of view - upwards in reality) as you adjust the range settings from 1 to 10.