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3d indicator design

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DaveH:
Damn clever Bill  :bow: :bow: :bow:
 :beer:
DaveH

BillTodd:
 :thumbup:

To save making two of the thrust washers, I've redesigned the slide so that the slide-tube and nut do the job (they're very lightly loaded so don't really need to be hardened). I've also found some SS mudguard washers in suitable sizes (16x50)  which will avoid having to make any more bloody washers!.

 

BillTodd:
I found the time this afternoon to fix my cock-up and make the two new ball cages, so now it is almost finished.

However, I've discovered a snag with the cir-clip idea; The large thrust washer has to be held against the step in the main body if the zero reference it to be stable. The cir-clip does not hold the washer tight enough (there's no room for a spring) .

To solve that I've redesign the body to have a screwed in locking ring at the bottom. As a simpler alternative, it would be also possible to screw the washer in place with a half-a-dozen small screws.

The next problem is because everything is tight with minimal clearances, I keep getting random jams - one minute it'll slide nicely, next it'll snag and jam  - a major PITA  :bang:

Brass_Machine:
Fast work Bill.

How do you plan on dealing with the random jams? Will you use any type of lubricant or keep it dry? I was thinking maybe one of the NanoLubes that are always up on ebay? Dry? maybe time for some uberpolishing or will that lose too much tolerance?

Eric

BillTodd:
Hi Eric,

Well, your polishing idea has helped a lot :)  (it also showed me I had a slight eccentricity in the upper taper part ) Although, I think the main problem is a poor choice of materials (aluminium is too reactive to make a good sliding material).


It is now basically working (apart from the loose main thrust washer). I'm getting about 3.5mm movement in all directions.

However, I have spotted a fundamental flaw in the design; Most of the play in the sliding parts can be removed or ignored (i.e. the ball-slide can be tight and it really does not matter if the upper taper is a bit sloppy because it is biased one direction by the forces on it). 

But, the bottom taper has to slide perfectly in the vertical direction without side play or the centre 'zero' position will be inaccurate  :bang:

Back to the drawing board...

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