Author Topic: Precision indicator stand  (Read 869 times)

Offline PekkaNF

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Precision indicator stand
« on: December 16, 2018, 07:10:50 AM »
Robin Renzetti - Stefan Gotteswinter -style

interweb:
http://gtwr.de/projects/pro_rore/index.html

tube:




materials on first parts:

* Indicator clamp S.G. "1.2767 toolsteel and will later be hardened to about 45..50HRC:"

I used 15 mm OD silver steel, Böhler K510 SILVER STEEL - 1.2210

Main driver being that I don't have Keats/prism chuck and it needs a turned feature to start with. 15 mm round has over 10 mm square hiding inside and screaming to be released.


*10 mm ball

S.G. used hardened balls and grilled them with HM-drill. I don't have drill that eats hardened steel for lunch, ordered 10 mm relaively soft balls:

https://simplybearings.co.uk/shop/p221140/10mm-Diameter-Grade-100-AISI-316-Stainless-Steel-Ball-Bearings/product_info.html

10mm Diameter Grade 100 AISI 316 Stainless Steel Ball Bearings
AISI 316 Stainless Steel with a hardness of 25 - 39 Rockwell Scale equivalent to 140 - 160 HB (Brinnel Scale).
..
Unhardened austenitic stainless steel with good corrosion resistance to sea water, dilute nitric, sulphuric and acetic acids, photo chemicals, inks, bleaches, dyes etc.

Can be machined / drilled

Offline PekkaNF

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Re: Precision indicator stand
« Reply #1 on: December 16, 2018, 07:19:41 AM »
Drilled the hole on ball on lathe, no problem there.

Then I turned the 15 mm OD silver steel spigot to 4 mm and fitted that to ball.

Next step was to mount it to square ER32 block. Only consideration was how much to stick it out. Obiviously I don't want square block ER nut and mill ER25 chuck nut to collide way before adequate length is milled.

Squaring the round went pretty well

Offline PekkaNF

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Re: Precision indicator stand
« Reply #2 on: December 16, 2018, 07:30:11 AM »
Because I don't need to use round 8 mm mount, I could modify measuremets a little out of 10x10mm, to 9,5x11 mm, which gives me a little more margin on next step.

I much anticipaed milling the 3 mm oval ....I had ONE 3 mm carbide mill and that has 8 mm cut length. See the problem there when it has to pierce nearly 10 mm.

I drilled the 3 mm hole with carbide drill and expanded the hole 2 mm c-c. I set right table hard stop before drilling and left table stop with 2 mm feeler gauge stack. I advanced mill down in 0,5mm steps and slot in X-axis.

Drilling and tapping went without problems. I tapped both holes trough....I needed to try knobs before comitting to which directions to make clearance holes.

Offline PekkaNF

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Re: Precision indicator stand
« Reply #3 on: December 16, 2018, 07:37:52 AM »
Dovetail is pretty small,



I made it to these measures, but in the end it came out slightly oversize....I milled it to dimenssion and tried the DTI, it would not fit, enlarged the slot for 0,25 and it was still sticky, removed all the burr and it was loose....Compared it chinese holder and Swiss and then it did not feel that bad any more.

I shoudl have used pins to measure the dovetail...tired it after it was finished and it showed that when right pin size is sellected it gives pretty good indication of the dove tail dimension.

Nice vid here:
=1031

Frigging frig doest not accept time, ok intention is at 17:20 - dovetail measurement with pins. In tis size thread measurement wires.
« Last Edit: December 16, 2018, 08:10:56 AM by PekkaNF »

Offline PekkaNF

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Re: Precision indicator stand
« Reply #4 on: December 16, 2018, 07:42:16 AM »
Sawing was a balancing act. 80 mm OD 0,8mm saw arbor has 3 mm portrusion at the bottom. I.E. blade will clear the vise bit over 3 mm - that is the blade offset from the vise jaw and leaves little to mount.


Offline PekkaNF

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Re: Precision indicator stand
« Reply #5 on: December 16, 2018, 07:53:25 AM »
Now I need to figure out where to put the knows and size. I have a bag of small M4 thumb screws to try...they are too small for this one.