Baader Zero Tolerance T-Ring Mod

[richyrich_one]

Hi

I thought I'd share my mod for the Baader Zero Tolerance T-Ring which enables adjustable spacing at 48mm.

I purchased one without an integral filter and then realised that it is thicker than a standard t-ring to allow for the filter. This meant that the MPCC was overspaced by approx 1mm by default.

First you need to loosen the grub screws holding the S52/M48 adapter ring and remove it and the delrin ring inside. I'm not site why but at the very back of the t-ring is an internal M48 thread which will accept(with some persuasion) one of these:

https://www.telescopehouse.com/revelation-m48-2-locking-rings-including-ff359.html

The locking ring is not needed. The M48 thread needed to be shortened buy about 2.5mm to allow for it to be screwed far enough into the rear thread of the t-ring. Although the threads are M48 I suspect the pitch is slightly different as you can only screw it in so far before it gets tight. With it shortened it's easily adjustable and then can be locked in place by very carefully tightening the grub screws.

Assembled to give the correct spacing and locked in place.

With the MPCC fitted. It's also quite tight but goes on ok. Fully in it leaves a 0.5mm gap before the shoulder which is where the 57.5mm measurement needs to be taken from so you need to allow for this in the adjustment. Basically make the total thickness of the above assembly 13mm to give the overall 57.5mm spacing. Now to stop the whole lot tilting when I tighten it in the drawtube