Description
Find the thread pitch on everyday nuts and bolts, inch or metric, with two clear cards and an SAE size chart. Made for the garage, the shop and the driveway.
A metal thread gauge with swing-out leaves needs room to sit in the threads. On a bolt tucked behind a bracket, a stud on a small engine, or the threads inside a nut, it often won't fit. A clear card doesn't have to. Hold it against the threads and look through it, or take a pencil rubbing and read that instead.
What's in the package
- Clear Card Thread Checker, Imperial SAE (threads per inch), in a vinyl sleeve
- Clear Card Thread Checker, Metric SAE (thread pitch in mm), in a vinyl sleeve
- SAE & Common Sizes chart, inch and metric
- Instruction card
Two ways to read the pitch
First, peel off the protective film. Each card ships with a thin plastic film on it. Take it off and the threads show through clearly.
1. Hold the card against the threads. Slide it along until one row of arrows lines up with every thread crest. The number at the end of that row is the pitch.
2. Take a pencil rubbing. Lay a piece of paper over the threads and rub lightly with a pencil. Put the card over the rubbing and match it to a row of arrows. If you can get a pencil and a scrap of paper on the threads, you can get the pitch.
The inch card reads 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 20, 24, 28 and 32 threads per inch. The metric card reads 2.5, 2.0, 1.75, 1.5, 1.25, 1.0, 0.8, 0.7 and 0.5 mm.
The chart ties it together
Once you have the pitch, the chart lines it up with the bolt size and the wrench size. The inch side runs from #0 machine screws up to 1-1/8" bolts, with the wrench size and the coarse (UNC) and fine (UNF) threads per inch for each. Know the pitch, find the bolt, grab the right wrench.
Who uses these
Technicians, DIYers and shophands matching a bolt for a car, a lawnmower, an engine or a bicycle. Bring the card to the hardware store and you won't come home with the wrong thread.
Want the nut gauge too?
The Metal HexSizer and Clear Card Thread Checker Set adds a metal gauge that sizes the nut and bolt, with thread profiles engraved on the back. Pick SAE Inch or SAE Metric. Working on big studs and flanges instead? See the Heavy Hex Clear Cards.
Frequently asked questions
Why can't I see the threads through the card?
The protective film is still on. Peel it off.
Does it work on threads inside a nut?
Yes. Take a pencil rubbing if you can reach the threads, or hold the card against them and look through it.
Inch or metric?
You get both cards, so you don't have to know before you start. If one card doesn't match, try the other.
