Making a Z-Axis DRO on the cheap

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Making a Z-Axis DRO on the cheap

This topic has 7 replies, 4 voices, and was last updated 6 January 2010 at 14:45 by mgj.

Viewing 8 posts - 1 through 8 (of 8 total)

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5 January 2010 at 23:56 #4908
Alvin Schlitter
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@alvinschlitter80339
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5 January 2010 at 23:56 #47069
Alvin Schlitter
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@alvinschlitter80339
Hello All;

Has anyone modified a standard digital 150mm (6&#8221 caliper to fit on the front of a milling machine.

Looking at this process one could cut off the jaws and removing the sliding tail

(depth indicator) of the caliper, then remove the slide wheel and lock pin. Then epoxy three pieces of aluminum or steel to the back of caliper and digital display, then screw the assembly to the face of the mill to provide a digital display for the Z- axis.

Yes, one can buy a unit for mounting with a vertical display but this sounds like a cheap solution.

Just throwing this out for thoughts!
6 January 2010 at 10:35 #47077
Les Jones 1
Participant
@lesjones1
Hi Alvin,

This is how I mounted a modified 150 mm caliper to show the quill position on my Sieg X3 mill.

The top mounting is to the end of the depth gauge to give some flexibility in the mounting.This is to allow for the fact that the quill rotates a small amount due to play in the locating key. Other in the album show the other scale mountings.

Les.
6 January 2010 at 12:14 #47079
Alvin Schlitter
Participant
@alvinschlitter80339
Hello Les;

Very nice set up of the DRO’s on your machine. The caliper on the Z axes however looks longer than a 150mm length?

I intend in the future on going the full route like you have done with the 3-axes plus the display unit. However still need other items for my new ZAY7045FG-1 Milling machine. Once this is complete, I will then set aside five hundred dollars or so for the upgrade.

However for now, a cheap and easy solution should work!

Thank you for the posting!
6 January 2010 at 12:24 #47080
KWIL
Participant
@kwil
These setups are fine if you remember the accuracy [ or lack of] such devices leave much to be desired. See the parallel discussions elsewhere on that matter, better than nothing at all of course.
6 January 2010 at 12:47 #47082
mgj
Participant
@mgj
Alvin – why bother.

If you are going to fit a proper DRO, then just wait.

Having said that I did fit one of the 6″ digital reading units from Chronos, rather than bodging a caliper. Came with all the brackets ready. That is very accurate and holds up well against the micrometer, so, although I have a proper DRO on Xand Y, I am not about to change or get rid of the cheapie.

It reads to 1/2 thou, and is repeatable at that, so its staying.
6 January 2010 at 13:25 #47086
Les Jones 1
Participant
@lesjones1
Hi Alvin,

The comments by Kwil and Meyrick are correct about the lack of accuracy. I find them good enough for most of the work I do and are better than not having any kind of DRO. The scales on the main Z axis and X axis are from Machine DRO or Chronos and work on the same principle to the calipers. (With the same potential for inaccuracy.) An even cheaper solution I used before buying the scales was to use rotary encoders on the leadscrews initially connected to a home made display (Using a PIC16F628A and 2 * 16 line LCD display.) and later to a Schumatech DRO350. The DRO350 is a design you can build yourself from a kit or just buy the PCB an and buy the components elsewhere.

The rotary encoders here on motors removed from DEC LA36 or LA180 printers.(1980’s vintage.)

Les.
6 January 2010 at 14:45 #47089
mgj
Participant
@mgj
I suspect that you get what you pay for.

I came by a set of cheap 6″ calipers somewhere – I think they came free with something. Compare them with a set of good Mitutoyos and its chalk and cheese. Well actually you cannot compare them, because the freebies are where they belong – in the trash can.

I’m not sure that butchering a set of £70 Mitutoyos for a temporary solution is such a grand idea!. Using cheapies and ending up with some screwed up castings is even less of grand idea….

So, sorry Alvin – just save and stump up for decent kit. As they say – the statisfaction of using quality remains long after the pain has gone.

Or – there is the cheap solution, and the expensive solution. The expensive solution involves buying cheap and replacing it. The cheap solution is to just buy decent stuff in the first place. One doesn’t have to buy the best – good is OK, but it wants to be good.
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