Summary

Yet another tool for levelling the building plate of Your Replicator (I)

Instructions

"The Calibrator" - Levelling Aid for the Replicator

When using a Replicator 3D printer, correct levelling of its base is essential for good results.
There have been some suggestions for tools on Thingiverse like
Replicator Bed Level Jig - http://www.thingiverse.com/thing:23257.
Since I just have a sliding caliper and no digital indicator as used in the above project I couldn't
use this of course.
For a while I did use the sliding caliper to level the plate, simply holding it upright to measure.
There's also another project on thingiverse that uses the complete calliper to do exactly that:
Vernier calliper bed leveller - http://www.thingiverse.com/thing:30300

I have to admit, I found this project after I had finished mine ;)

But anyway, I wanted more :)

I got another one of those (rather cheap) digital sliding calipers at Amazon and dissected it.

http://www.amazon.de/Br%C3%BCder-Mannesmann-M-823-160-Elektronische-Digital-Schieblehre/dp/B000K2LKUM/ref=sr_1_1?ie=UTF8&qid=1363453020&sr=8-1

This is an address on Amazon Germany, but as it looks there exist lots of different brands of this specific vernier caliper that are obviously all based on the same model.

What we need for the Calibrator is the display of course and the ruler which is glued and
screwed to the metal and is actually a pcb with some copper lines that are needed to detect
the position in relation to the display part. Just look at it, You'll see what I mean.

Remove the glue completely as the ruler must later be able to slide freely.

By now, it's obvious that my project means the destruction of the caliper, yes?

Next, print out my "contraption" on a (hopefully already levelled) 3d printer.
On my Replicator I used standard settings and "raft with external support" with good results.
The slot for the ruler might have to be enlarged a little bit (scalpel, file), as I mentioned:
It's essential that the ruler can slide easily, otherwise the measurements will be less precise.
On the other hand, contact between ruler and display must not be too loose, either.

Although there is a hole for screwing the display to the holder it will probably not be necessary
to do so as it all "fitteth snugly" :)

The whole thing is held in place by two magnets that are inserted into the appropriate slots at
the feet. I am using round magnetic discs measuring 10 x 2 mm. If You are using different
magnets You will have to change the slots of course. If You happen to know where to get
magnets like mine: I'd like to know.

Since the pcb, the ruler is made of, would eventually wear out (especially if You are levelling
Your building plate while it's hot) it would probably be wise to attach a more robust tip
to the ruler. Something with smooth edges like a steel ball, in order not to scratch Your
Capton surface ... I haven't had a good idea yet.

Also, using a rubber band to keep the ruler under tension might be a good idea (the point is to have optimum contact between tip and surface for maximum precision).

Well, this is work in project, okay?

Now, for levelling all You have to do is move the tip of Your calibrator over each of the four
screws that level Your building plate. Turn the screws to have the exact same height in each of
the four positions and You're done.
You don't necessarily have to level Your plate at the exact height You're going to use later.
All You are doing here is to make sure You have the same height for all four points.