Archive for April, 2009

This week’s tip: Cleaning your micrometer

Posted in Tool Tips on April 28, 2009 by Peter

Micrometers are probably the simplest tool you’ll use, but also the most accurate and therefore the most affected by damage or their environment.  The slightest bit of dust on the anvils, or even the oil from a finger, can change a reading. 

So the first thing is:  Make sure the anvils are clean.  The handiest way is with a normal piece of clean paper, or even a business card (as shown), so long as it’s not a glossy finish.  Tighten the mic on the paper so that you feel some resistance as you slide the paper back and forth.  This will remove any dirt or grime without scratching the anvils themselves.  Make it a habit to clean the anvils prior to every use.  You’ll get consistent, accurate readings.

MPTS Mic

If you have a lot of buildup on the anvils, try wiping them down with isopropyl alcohol first; then use the paper.  For the rest of the mic, just use the toothbrush and alcohol as you’ve been doing with your calipers.  However, pay careful attention to the spindle, since that’s how most contaminants are going to get inside the mic.  Keep it clean at all times.

Next week:  Do brands matter?

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This week’s tip: Cleaning fluids

Posted in Tool Tips on April 17, 2009 by Peter

The best cleaner is isopropyl alcohol.  It dissolves coolant residue, and it won’t hurt electronics or most plastics.  If you’re cautious and sparing in your use, a squeeze bottle — or even a water pistol — can be used to spray the alcohol on a tool’s moving parts.  Then work the tool back and forth through its range, and wipe it down.

WARNINGS:  1) Don’t use any other kind of alcohol.  2) DO NOT use acetone (nail polish remover); it degrades and weakens plastic.  3) Be careful not to get too much alcohol on your tool’s crystal or readout screen.  It can fog them up.  4) You may get an error reading from an electronic tool after using isopropyl because it hasn’t fully dried off the circuit board.  Let it sit for a few minutes, then try it again.

Lastly, isopropyl alcohol doesn’t work well on adhesive residue.  You can use a solvent (lighter fluid is excellent), but it takes only a little bit.  Solvent leaves its own residue, but luckily it’s soluble in the alcohol, so make that your final cleaning step.

Next week:  Micrometers

This Week’s Tip: Electronic Calipers

Posted in Tool Tips on April 10, 2009 by Peter

Electronic calipers are probably the best option overall for shop work.  They have fewer moving parts than dials, and are easier to read than verniers.  But they can be more expensive too, both to buy and repair.

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Cleaning is similar to dial calipers:  Use last week’s toothbrush to clean the groove in the beam where the depth rod sits.   Many electronics have wipers on either side of the reading unit where it rides on the beam strip.  These can get buildup on them, so brush them off as well.  As always, check the beam for nicks or burrs.

Check for smooth movement of the jaw up and down the beam.  You most likely won’t feel chips, of course; but if the movement is uneven, or drags in some spots, some more advanced cleaning techniques may be necessary.  We’ll profile those in upcoming posts.

Next week:  Cleaning fluids.

This Week’s Tip: Dial calipers

Posted in Tool Tips on April 4, 2009 by Peter

The main thing to remember about a dial calipers is, it has an exposed geartrain.  Anything that can get into the gears will do it via the rack.  So you have to take special care to (1) keep stuff out of the rack — ie, keep it covered when not in use –, and (2) get stuff out of the rack if it gets in.  The best tool for this is a simple toothbrush (click the thumbnail).  Open the calipers all the way and brush any dirt or chips down and away from the moveable jaw.  For a more thorough cleaning, use brushstrokes parallel to the rack teeth and work your way down and away again.

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Once you’ve brushed the rack, run the moveable jaw back and forth a few times to check for smooth movement.  If you feel an occasional little bump or catch, you still have a chip in the rack somewhere.  Use a ten-power lupe to check those spots, and brush them again.   However, if you feel or hear a regular ticking or catch, a chip has become embedded in the gears themselves.  That’s when you’ll need to call us, because the geartrain will need to be dissassembled and cleaned or repaired.

Next week:  Electronic calipers.