Using calipers to measure the thickness of the bottom of a "bowl"

[evansd2]

I was talking about engraving IKEA cork coasters, and how to detemine the thickness of the bottom. There are lots of ways to do this, but for my money, using your digital calipers is the fastest and most accurate way to get there. This technique would work with anything with a “lip”, so you can adapt it to your specific needs. Here’s how:

Get a small item that is thick and will fit inside the coaster. A nice big 6-sided die will work fine.

Be sure it’s taller than the lip.

Cool, measure the die.

Zero the caliper.

Put the die in the coaster and measure the whole thing. Voila, height of the bottom.

Simple right?

Now do you want the “height” of the lip?

Close the calipers and zero them again.

Open them to your base thickness, my measurement was 0.2635".

Rezero them here.

Now measure the thickness of your coaster, this will be your lip height.

Great, it’s less than 0.5", you’re good to go, now you just need to go engrave it.

Be sure you know how to remove the tray and engrave thicker items here, as the entire height of the coaster is more than 0.5".

[HATCHideas]

Many Calipers have a little bar on the back at the end of the scale that acts as a depth gauge. You’re version certainly looks sturdy enough to have that feature. I use a stainless steel scale and calipers to measure depth specific to various points so I can see if there is a high or low point or grade of some kind.

[cynd11]

Neat trick! Thanks for sharing.

[evansd2]

@HATCHideas

Many Calipers have a little bar on the back

Yup. This one is tricky though, because the inside edges are sloped. I also find that it’s hard to maintain a 90 degree angle when using the depth probe on oddly shaped items, so enter the die trick

For lots more caliper goodness, I posted this a week or so ago:

Caliper tutorial

This is great for anyone who is new to calipers: https://makezine.com/2015/11/13/how-to-use-your-digital-calipers-7-tips/

[randy.cohen]

Other handy tools available for cheap money at Harbor Freight:

Micrometer - can often be used to reach over a lip to read an “inside” dimension.

Disc Brake Caliper - These have a very deep “reach” of 4 or 5 inches. I have a set of metal tabs I can screw on to the tips of the jaws to increase how deep I can measure on a “reach over”.

[wesleyjames]

Use the die to create the 90* edge you need to measure straight down.

[evansd2]

@wesleyjames

Use the die

There are lots of ways to do it, that’s for sure. Not sure that would be much easier in this case, since the inside walls of the “bowl” are sloped. Anyway, go forth and measure! )

[raymondking32]

Funny how as soon as I read this, my brain is like, “duh”. Probably something I could have figured out if there was a need, but I appreciate you sharing so I don’t have to rack my brain only to have an ah-ha moment under stress. Thanks, again!

[ptodd]

Nice of you to post clear photos on the process. Many people are new to calipers … and I’m sure this will be a BIG help!

[timjedwards]

Okay, those are some great tricks of the “wish I’d thought of that many moons ago” variety.