Tom Silva of 'This Old House' explains why the rivets on a tape measure are so important

Editor's note: This article was originally published on December 17, 2020. It has since been updated.

Have you ever wondered why the metal tip at the end of a tape measure wiggles around a little bit between those rivets? Don't worry, your tape measures aren't faulty. As it turns out that little wiggle space is actually there by design and we all need to be a bit gentler when letting the tape slide back into its case. Tom Silva — the beloved general contractor who's been a part of the iconic home improvement show, "This Old House," for over three decades — demonstrated this little-known function in an incredibly helpful video and we could watch him talk about tape measures forever.

"See this little movement right here?" Silva asks in the video, wiggling the metal tip up and down. "Is that because my tape measure isn't working right? No... If I just take my tape measure and every time I use it, I drop it in, I bang it. Every time I do that, I'm putting more tension on this little part right here," he continued, pointing to the rivets. "And maybe that would slide a little more than I want it to. Because I want it to slide. [Do] you know why I want it to slide?"

Silva then proceeded to demonstrate how the sliding helps account for the thickness of the metal tip when measuring the inside or outside edge of a surface. The U.S. Tape website explains it as such: "The metal tip at the end of your tape measure is a little bit loose for a reason. The first inch of the tape is short by 1/16 of an inch. This isn’t an error: it's meant to provide you with accurate readings whether you're measuring the inside or outside edge of a surface. This feature is known as 'true zero.'"

"The metal tip is exactly 1/16 of an inch thick. If you’re measuring the outside of a surface and hook your metal end on the edge, that metal piece will shift out and create a gap, so that you aren’t counting it in your measurement," it continues. "And if you need to measure the inside of a surface – like in a window frame, you want to count the thickness of the metal piece in your calculations. Thus, the metal piece will shift back to fill the gap. Always take care to pull or push your tape so that it’s taut to take advantage of the true zero feature."

Silva ends the video by highlighting the importance of exercising caution when letting the tape slide drop back into its case. "That's why it's important when you're done with your tape measure to let it slam on your finger and then let it go in," he explained. The expert contractor's tip was a big hit on social media where many netizens admitted that they'd never known the purpose of the rivets. "I literally *just* had a discussion with my child last night about the metal end of the tape measure. But I didn't know the purpose of the wiggle was for inside measurements! We did talk about the purpose of the hole being for hooking on a nail," wrote Facebook user Liz Anne.

"Watched this last week. The next day I carefully closed my old, beat-up tape measure the first few times. The fifth time, my old bad habits kicked in and the metal piece just broke off in protest of my erroneous ways. The next one will be better, Tommy, I promise," commented Deb Vb. "I ask lots of people why a tape measure does that, 99 times out of 100 they don’t know. Neat how something so simple has such a huge purpose," wrote Will Bauska.