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SIP coax indicator

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BillTodd:
Getting there...

managed to trip over by band saw and punched something to stop me falling base over apex , took a chuck out of my little finger :-(

awemawson:
Ouch  :bugeye:

Next thing you know Ade will be asking for pictures  :clap:

PekkaNF:
This looks really interesting. Hardly can wait out how this turns out.

How do you put the pivots on the same axis? Just extreme manufacuring accuracy ot there was a cunning plan? I can get drilling, boring (and maybe reaming) the central hole and then plugging them with very carefully machined "divots"....but is it ever that simple?

BillTodd:

--- Quote from: PekkaNF on May 25, 2020, 03:14:08 AM ---This looks really interesting. Hardly can wait out how this turns out.

How do you put the pivots on the same axis? Just extreme manufacuring accuracy ot there was a cunning plan? I can get drilling, boring (and maybe reaming) the central hole and then plugging them with very carefully machined "divots"....but is it ever that simple?

--- End quote ---

The pivot alignment is not actually that important. The only position that puts the lever 's top-flat perpendicular to the spindle axis ( and hence the same reading on the indicator 180 degrees apart ) is when the two pivots are directly inline with each other along the spindle axis. 

So , even if the two pivots are wonky , as long as the lever/indicator can accommodate the necessary offset, there is a position where the lever and indicator will give a consistent reading.

BillTodd:
After my completely legal and necessary trip over the band-saw - Yes I know i used the lathe while bleeding but I had to check I would be able to make it back to the kitchen for the first aid, before I set out... (does filling in the comments on the tax return form, make me a government advisor??) - I have finished sort of..

Upper centre , Arm and pin made  (I will remake the arm as i ballsed it up while trying to give it some shape)

Setting up was not too difficult , I clamped a parallel in the vice and dropped a spare ball in its countersunk hole. Lowering the centre towards the ball , I found I could centre fairly well using only the reflection on the centre.

To set the position(up/down) of the arm  (to set the position of the lever) I used my 5mm mitutoyu DTI   and centred the travel of the lever while adjusting the arm clamp. Then I centred the XY of the table to get minimum deflection on the dti .

Once roughly centred I could swap to the +/-200um compac DTI and tweak it to zero the XY and then tweak the DTI position to zero it  at 12:00.

Observations:

Once set up it is easy to use and repeatable

It is very sensitive  - seems to have a gain of about 2:1 100um in the dial is less than 50um in the DRO

Jury's out on the sprung bottom cone: it certainly helps setting up but makes the thing sensitive to knocks. I found the whole thing was more stable if I just lightly preloaded the indicator with the quill feed until the spring was squashed.


 

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