Grip Strength Meter (Dynometer)




About: I am an American teaching English at Shangluo University, Shaanxi. I like making machines that do interesting but fairly useless things - I call them Quixotic Machines.

This simple and inexpensive device (a commercial one will cost you $97) will measure your hand gripping strength. It is made from 4 components: a fuel pump pressure gauge, a rubber tube, a tubing connector and a plastic water bottle.

To use just squeeze the water bottle and note the psi reading on the gauge. Then in my case I multiply the reading times 20 (about the square inches of my hand) to get pounds.

Grip squeeze pressure is a good indicator of physical health and you can compare your strength with others and yourself over time.

The great news is that you can buy everything you need to make one of these at Harbor Freight for 15 bucks: their cheapest fuel pressure gauge kit has the gauge, the tube, and the connector - all you need is a bottle and a hot glue gun.

By the way, my grip is about 7 psi (20 * 7 = 140 pounds).

Step 1: Insert Tubing Connector Into Bottle Cap

Drill a quarter inch hole in the bottle cap. Insert the quarter inch tubing connector (you can buy one at Home Depot for 99 cents) into the hole and glue using glue gun on both sides.

Step 2: Connect All the Parts

Attach the quarter inch hose to the pump and the bottle top tubing connector with clamps.

Screw on water bottle and squeeze.



    • Remix Contest

      Remix Contest
    • Sweet Treats Challenge

      Sweet Treats Challenge
    • Faux-Real Contest

      Faux-Real Contest

    5 Discussions


    Remember that the air will compress a little bit so it wouldn't be your proper strength, to fix this you should try filling it with water because the water can't be compressed as easily.

    Anyway nice Instructable.

    4 replies
    iSchwarzJacoby Yarrow

    Reply 3 years ago on Introduction

    How about a pressure gauge (manometer), then you could also fill the whole bottle with water for a constant pressure.


    Reply 3 years ago on Introduction

    I had to look up manometer. Yes it probably would be more accurate but cumbersome from the ones I saw on the internet and hard to calibrate.

    I like the term "manometer" though - seems fitting.

    JimRDJacoby Yarrow

    Reply 3 years ago on Introduction

    Thanks I'll try that. I wonder if water will hurt the pressure gauge? I do see commercial testers that use the pneumatic principle - I wonder if their gauges compensate for air compression. Makes me wonder how much pressure differential there is. Guess I will fill it with water and see how much difference I get in the readings.


    Reply 3 years ago on Introduction

    Replying to my reply: I did add water to the bottle but not to the tube so it still compresses air a bit - I get about 15 more psi this way. Also even adding half a bottle of water makes the bottle easier to compress with your hand as it does not allow you to crush the bottle so much. So as to absolute measurement, a pneumatic only bottle probably understates true psi readings a bit but still useful as readings are still accurate in relation to each other over time - in other words you can still use it to compare your use of it with your friends use of it. And it will still tell you if you are getting stronger or weaker over time. I'm sure the psi gauge is not that accurate even when using it for it's intended purpose of fuel pressure as there will always be a certain amount of air in the line.