Dial Indicator Part 2

The first version of the mount (https://solidoodletips.wordpress.com/2012/08/01/dial-indicator-project/) didn’t quite work out.  The magnets are strong enough to hold it, but they can still slide back and forth on the bolts.  As the indicator’s plunger drags across the bed, the mount can wiggle and throw off the measurement.

Version 2-

I ‘m using 4 bolts as attachment points so there is less chance of pivoting, and made holes sized for the bolts so the mount can fit over them and sit flush with the face of the extruder.  The hot end sticks out a little from the acrylic, so I left a notch for that.

I added holes in the back to push the magnets in so they would hold on to the bolts once the mount is set onto them.  I would rather print this lying down so the holes would be drawn horizontally rather than vertically to give them a better chance of coming out round.  I also want to have the hole for the gauge done horizontally, so I split the mount into two pieces.

The tab glues onto the face of the mount, and the lip at the bottom tucks under the bottom edge to make it easier to put it on straight.  It also holds the gauge lower, closer to the print bed.

The holes need to be in exactly the right spot, and the right size to make a solid fit.  Since interior holes don’t print at the size designed, the surest approach is to print a few tests.

There are some strings running through the bolt holes from plastic oozing while the extruder moved past them. I’ll need to check on the retraction settings to see if I can minimize that.  In the meantime, a bit of work with the exacto takes care of that.

One problem with printing multiple parts at once is that when the extruder moves from one part to the other, it can drag a little plastic with it, leaving blobs at the exit points.  Retraction can help with this too, but printing one thing at a time will leave a smoother surface.

I glued the pieces together with acetone.  Just a little bit brushed onto both surfaces melts the plastic enough to bond them together when the acetone dries.

Now that I have the mounting plate worked out, I can use it as a base to put a fan on the extruder with a duct to blow air on the plastic just around the extruder.  This would help cool small parts and PLA.  It would look something like this one, from http://www.thingiverse.com/thing:16955.

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6 thoughts on “Dial Indicator Part 2

  1. I hope im not being rude by asking this but do you plan on making your little mount available to us? thingiverse?? Its a great idea. Being a toolmaker, id much rather use an indicator to level my bed etc. Keep up the good work!
    Dale

    • I was just excited about getting the blog post up, I haven’t had time to make the Thingiverse page.

      When moving the carriage around, the plunger doesn’t always ride smoothly over the kapton. I don’t want it to put any sideways pressure on the gauge and shift it. I’ve been trying to think of a way to reduce the friction between the plunger and the kapton without using anything that would stay on the bed and cause a print to not stick. The only thing I can think of is putting a drop of lubricant on the plunger, and then laying down a fresh layer of kapton when the leveling is done. Any ideas?

      • spray the bed with glass cleaner, run the indicator over the bed. Then wipe the cleaner off? Little bit crude but it should work. Keep the downward pressure of the plunger minimal to, doesnt need to be right down to measure. .2-.3 should be fine…unless the bed is right out of level.

      • You mentioned the issue with the end of the dial not sliding smoothly across the print bed. What if you were to print a rounded foot, that slides over the end of the plunger? Say the size of a fingertip, rounded off with a low sloping angle?

  2. Once you have the measurement device set up what adjustments are made to level the bed? Does the printer have adjustments for print position or do you have to make something?

    • There are 3 spring loaded screws on the bed which you adjust to raise those points up or down for level. There is another screw on the back of the case which is positioned over a limit switch on the bed. The limit switch bumps the screw as the bed rises toward the nozzle, and you raise or lower the screw to control the height of the first layer of the print.

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