Here's a HF
FAIL. The Pittsburgh 6" Long Reach Digital Caliper.
I was in HF tonight to buy some wire brushes. I was looking at the 12" Digital caliper and was far from impressed with the quality. The grinding was rough, etc. Nonetheless, given the success I had with the digital micrometer (
http://www.harborfreight.com/digital-micrometer-68305.html), I figured I give the 6" Long Reach calipers a try (
http://www.harborfreight.com/6-long-reach-digital-calipers-60248.html)
First things first. Powered it on. The display immediately started flashing which indicates a low battery. OK. No problem. They include a spare. Installed the spare and within minutes the display started flashing again. Multimeter confirms it: two dead batteries. I have spare LR44 batteries in my toolbox (Energizer brand). After installing one of those the flashing stopped.
Next step, check it out against some gauge blocks...
With the long reach these things have, gib adjustment will be critical or else they'll be very sensitive to closing pressure. I noticed the measurement head had a bit of play with respect to the beam. Oddly enough, only one of the two gib screws is accessible externally. So, apart it came. While pretty outside, the ground surfaces exposed by removing the cover looked like someone did it with an angle grinder - and I'm not exaggerating. There was tons of swarf inside too.
After cleaning it all out, I put it back together. I found that I could not get the gibs adjusted properly without causing it to bind at about an inch from fully closed. OK. Not the first import measurement tool that needed some judicious lapping.
Just to get a rough idea how much (and where) I needed to lap, I took a few measurments of the beam. 0.6235 at the left end and 0.6170 at the right side.
Yep 6.5 thou of taper. No wonder it was binding.
Also noted was the overheated steel on the tapered measurement tip. It was blue-brown.
This thing is going back to HF tomorrow... My new battery has been replaces into the toolbox and HF will get their two dead ones back.
By the way, both the box and the website says it "Reads in SAE and metric". Does SAE have their own version of the INCH???
John