WTB: Digital/Vernier Calipers

[robrenz]

robrenz,
That is impressive machining!

Thanks, its a labor of love for the last 49 years.

[robrenz]

I just finished building a complete assembly that uses the Mitutoyo caliper guts in the custom cases I make. This unit holds two motorized diamond dressing spindles on a threaded wheel gear grinder. The digitals measure pressure angle and spindle spacings. These cases are a newer style than the ones pictured earlier in this thread and use the older -20 caliper guts. 

[Kjelt]

wow that is one beautifull piece of work Robrenz. 
How does the Mitutoya measure, is it mechanical or optical, so can it be used with any metal rod or does it need some carvings/etchings, i can not see exactly how it works

[robrenz]

Thanks, the read head has a pcb pattern that slides on a pcb pattern that is under the graphic cover of the beam of the calipers. I think it is capacitively coupled.  As long as there is power to the read head you can actually remove the read head from the scale and put it back and it will not lose its position, It is truly absolute position technology.
I have a segment of the digital beam glued to the base pieces under the digital cases that the read head is working with. The fitting hole in the digital cases is for positive pressure air purge. These things get showered in grinding grit and that is the reason for the slanted top surface/window on the units so the coolant and grit naturally run off.

[Galaxyrise]

As a machinist I like the 8" better and the Micy's are first class. Over that I use Starrett Master verneer calipers, easy to read for verneers and exceptionally well made.

BillWojo

+1  I have a 6" and 24" of the Starrett master verniers and the 50 division vernier is much easier to read.

Thanks for the input, everyone!  I ended up trawling ebay for an 8" Mitutoyo.  It is very nice!

I also picked up a Starrett for when the battery dies in the Mitutoyo and to give me increased confidence in the readings if they agree (which they do.) They're cheaper on ebay than the Mitutoyos despite being more expensive new.  I really like the fine adjust on the Starrett, and that satin chrome finish is indeed quite pleasant on the eyes. Mine is much more difficult to move on the bar than the Mitutoyo is... is that normal, or is that just my 1977-era instance? 

[Kjelt]

Thanks, the read head has a pcb pattern that slides on a pcb pattern that is under the graphic cover of the beam of the calipers. I think it is capacitively coupled.

If you ever can make a picture would be appreciated.
I know these kind of systems which are cheaper but probably less accurate, sorry only dutch but the pictures and price give a good idea:
https://www.hbm-machines.com/producten/metaalbewerking/metaalfreesmachines/digitale-uitleessystemen/hbm-horizontale-digitale-linialen
and you can add extra readouts for them
https://www.hbm-machines.com/producten/metaalbewerking/metaalfreesmachines/digitale-uitleessystemen/hbm-1-assige-digitale-uitleeskast

[robrenz]

Pics

Under the scale graphic


Read head bottom


Read head top and LCD

[Kjelt]

Thanks, looks capacitive indeed but I still wonder how they can read it that accurately.

[tjb1]

Pics

Under the scale graphic


Read head bottom


Read head top and LCD

Are those 5 pads for the serial interface and did you purchase one with a serial interface?  Might take mine apart to see if those are present.

[robrenz]

The serial interface is always there, the access port on the case is the only difference. That module was purchased in a no interface case.

[Galaxyrise]

I just finished building a complete assembly that uses the Mitutoyo caliper guts in the custom cases I make.

It really warms my heart that there is still a place for craftsmanship like this, thank you for sharing!

[HighVoltage]

I just finished building a complete assembly that uses the Mitutoyo caliper guts in the custom cases I make. This unit holds two motorized diamond dressing spindles on a threaded wheel gear grinder.

I am deeply impressed by the quality of your work.
Having done some machine work myself, I know a little bit about your work of art.
What material is this made out of?
Thanks for sharing these amazing pictures.

[robrenz]

Thanks all for the kind comments.  The base is made from grey cast Iron. Digital cases are 6061 Aluminum. The digital buttons and the battery cover screw are Torlon.  I used to use sapphire windows on the digitals but now I just grind them up from microscope slides.

Here is the top dresser that goes on top of one of the spindles that mount to the main unit.

[quarks]

@robrenz, that is beautiful work!!!

Mitutoyos are great, but I decided to go with TESA because of the CR3032 Li battery and the larger display size.

[robrenz]

Thanks quarks,  Tesa makes excellent products. I have several Brown & Sharp Best Test mechanical indicators made by Tesa. IMO they are the finest mechanical lever style indicators in the world.

[HighVoltage]

robrenz and quarks,

based on your experience, I need some advise...
I am looking for a new caliper with data output to Excel and came across the MAHR MarCal 16EWRi as my first choice so far.
It has a wireless connection to the PC.
And the trigger point for data transfer is right on top of the caliper.

I know Mitutoyo also has a dataport but it seems not so easy to use it, since it has an external trigger box.

And I am not sure if the TESA caliper even comes with a dataport?

Any suggestions?
Thanks

[quarks]

TESA TWIN-CAL always is with Tesa-Link for data connection and wireless is available, but you need a receiver and software to use it (probably high priced)

http://www.tesagroup.de/en-gb/products/connectivity-f20.htm