Zeiss STD 18 Nosepiece Problem

[rs6000]

Recently acquired this Zeiss Standard 18 and we have to remove this spanner bolt as the nosepiece dovetail is bent. Does anyone know what can be used to loosen it? I know that those scopes which use a hex cap bolt here ( eg. Standard 14) are very hard to loosen. We are trying to salvage two damaged Standard 18s to make one working unit.
Thanks.

[Hobbyst46]

I am not an expert on this but I tried it once. I modified a pointed tip pliers since I could not get the suitable spanner. I managed to loosen it on one stand, with plenty of WD-40 pre-treatment, but failed with the other stand.
I strongly recommend NOT to try it with an inappropriate tool. The nosepiece is precision aligned on the arm. Even the slightest bending or deformation can set either of the parts or both unusable.
Perhaps, if the dovetail is only slightly bent or deformed, it could be fixed by filing with a needle file or a Dremel-type fine grinder? instead of trying to remove the nosepiece?

P.S. check out this post
viewtopic.php?f=18&t=6030&p=54627&hilit=spanner#p54627

[MichaelG.]

Recently acquired this Zeiss Standard 18 and we have to remove this spanner bolt as the nosepiece dovetail is bent. Does anyone know what can be used to loosen it? I know that those scopes which use a hex cap bolt here ( eg. Standard 14) are very hard to loosen.

You will almost certainly need a strong, and well-fitting, 'two peg' spanner:
I would probably drill two holes in the end of a hexagon bar ... or modify a square-drive socket.

But first ... Measure the diameter, depth, & spacing of those two holes; and also check what diameter of bar would have straight-line access.

MichaelG.

[MicroBob]

I haven't tried this myself but have read that some people with enough experience have not been able to loosen the bolt.
My first try would be to restore the dovetail in place. It is long enough to work with short stretch removed.
If it is not avoidable to remove the bolt: Make a pin spanner from steel or brass bar and the ends of HSS drills as pins so you can power it with an impact driver. They hit fast and hard and it is often the gentelest method of all. Just hold the stand in hand, tho knocks from the impact driver and screw is loose, if it can be loosened at all.

With a damaged noosepiece I would also check wether nosepiece and table are still coplanar to each other with a water balance.
The Zeiss microscopes looked alike over longer periods but there have been internal changes, so look closely wheter parts really match.

[75RR]

The fact that the nose piece holder has locating pins is a definite help re realignment - some don't.
I would however suggest that you try to correct the original problem: "nosepiece dovetail is bent" first.
If you do have to attempt it get or machine a close fitting tool. Using anything else is just asking for trouble.

Can you post a photo of the "nosepiece dovetail is bent" Someone might be able to suggest a sensible fix.

[rs6000]

here are some update pictures there is a definite high spot on the top as you can't even begin to slide the turret on it jams at the first engagement
almost like the nosepiece/dovetail is squashed in sideways seems impossible as heavy duty and thick it is?
BTW where can I locate the retention spring loaded set screw for the Binoc/tube its missing as well.

Cheers

[MicroBob]

Ok, a repair of the part won't be possible here, the part is warped completely. The positive thing is that is probably has taken up much of the shock so the other parts may have survived. Do the fine and coarse adjustments move without hard spots? Is the table parallel to the base in both directions?
These Zeiss Standards are really robust microscopes so there is still a good chance that it will work again.

Are you able to make a impact driver adapter for the job? It would do to visit a car mechanic to use the impact driver for a minute.

[rs6000]

HOW could This part be warped is doesn't seem possible as its A very Beefy metal section? By the Way look at this Condenser adjustment screw its bent in 2 directions and its a 5MM+ thick shaft

[75RR]

It is a heavy stand. If dropped on the screw it will bend it.
You could try and unbend it. (Nothing to lose) Mind you do not ruin the threads though.

[Hobbyst46]

almost like the nosepiece/dovetail is squashed in sideways seems impossible as heavy duty and thick it is?

The nosepiece is made of brass. Brass is not nearly as hard as steel. An impact blow or mechanical pressure could deform it. And that bent condenser centering screw or nosepiece set screw, shown in the photo above, can be bent relatively easily - I think that it is not made of hard steel. maybe it is even brass as well.

[PeteM]

In addition to using a proper fitting pin spanner, I'd suggest judicious application of heat and something like "Kroil." Removal will make it easier to work on. If a thread locker was used, heat will help free it. If it's just a bit of corrosion, the combination should help free it.

Once removed, I believe your nose can be salvaged. Somewhere between tapping out and filing out the dent should allow you to begin to slide a nosepiece. By using bluing you can determine, bit by bit where you might need to file to allow it slide further in. Whole thing might go fairly quickly.