# Those screw size measuring devices in hardware stores **URL:** \ **Category:** Factual Questions\ **Created:** [September 10, 2003, 10:03pm UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851 "2003-09-10T22:03:25Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![pestie](https://avatars.discourse-cdn.com/v4/letter/p/e5b9ba/32.png) [@pestie](https://boards.straightdope.com/u/pestie)\ **Post date:** [September 10, 2003, 10:03pm UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851/1 "2003-09-10T22:03:25Z")
Hardware stores all have these nifty retangular pieces of plastic with different sized holes in them used for measuring the diameter of a screw so you can select a replacement. Some have other features, like molded “threads” to compare with the threads on your screws. My question is this: what are these things called, and where can I buy one? Every hardware store I’ve checked has them, but none actually sell them to the public. Sometimes I want to know the size of a screw without taking it to the hardware store. Sometimes I _can’t_ take it (like the screws that stick out of the side of my house for mounting sheets of plywood in case of a hurricane). Google searches for terms like “thread gauge” or “thread gage” have turned up nothing useful, but I’m sure someone here must know. ---
**Author:** ![Julius\_Henry](https://avatars.discourse-cdn.com/v4/letter/j/8797f3/32.png) [@Julius\_Henry](https://boards.straightdope.com/u/Julius_Henry)\ **Post date:** [September 10, 2003, 10:51pm UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851/2 "2003-09-10T22:51:05Z")
It’s called a screw gauge. Now that I think about it, I’ve never seen one in a hardware store either. (I’ve got one I inherited from my father, no telling where he got it.) Try some of the specialty hardware stores like Rockler, Woodcraft, Lee Valley, etc. If none of these are in your area (look under “woodworking” in the yellow pages), you can find these companies online and order from there. Most of the gauges I’ve seen also include gauges for drill bits and bolts. They’re usually plastic and cost $5.00 US or so. ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [September 10, 2003, 10:56pm UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851/3 "2003-09-10T22:56:36Z")
I got one from Snap-On™ years ago. Check places that sell machinists tools and measuring devices like micrometers. ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [September 10, 2003, 11:12pm UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851/4 "2003-09-10T23:12:21Z")
[Free guage](http://www.boltdepot.com/?s=ot) [More guages](http://www.threadtools.com/) Couldn’t find one in the current Snap-On catalogue. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [September 10, 2003, 11:31pm UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851/5 "2003-09-10T23:31:17Z")
You could also ask the store where they got theirs, and if they could special-order one for you. ---
**Author:** ![BlackNGold](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@BlackNGold](https://boards.straightdope.com/u/BlackNGold)\ **Post date:** [September 11, 2003, 1:24am UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851/6 "2003-09-11T01:24:53Z")
> [@](#): > > \*Originally posted by pestie \* > **My question is this: what are these things called, and where can I buy one? Every hardware store I’ve checked has them, but none actually sell them to the public.** I work in the fastener biz, around my place we call them “screw checkers”. They usually come in three flavors, machine screw sizes, bolt sizes, and metric. I also used to work at Sears, and they were sold there (8 years ago). I checked their website, and they are still at least showing the machine screw gauge. In the hardware department, look for the “precision tools”. They are sold under the “SkillTech” brand. IIRC look for blue cardboard packaging. Should be in with calipers, small screwdrivers, etc (that are not Craftsman). If that fails, look in your local hardware store either with the measuring tools or perhaps with the taps & dies. ---
**Author:** ![Zenster](https://avatars.discourse-cdn.com/v4/letter/z/cdc98d/32.png) [@Zenster](https://boards.straightdope.com/u/Zenster)\ **Post date:** [September 11, 2003, 6:15am UTC](https://boards.straightdope.com/t/those-screw-size-measuring-devices-in-hardware-stores/200851/7 "2003-09-11T06:15:15Z")
[Olander](http://www.olander.com/contacts.htm). Ask them about their Screw Chek’r and Metric Screw Identifier plates. They usually give them away for free, these guys are the pros.