Need to buy force gauge

[Ed Law]

I need to buy a force gauge, or sometimes called a push/pull scale. I checked online and some costs over $500. I need something for FIRST robot use that I can measure force but I do not need display up to two decimal points. Any recommendation of an inexpensive model that will do the job for most FIRST applications? I searched on CD but can not find anything.

[NickE]

For something not super-accurate, I've seen scales intended for weighing airplane luggage. They typically have a handle with a digital display in it and a hook to attach to the luggage. This would probably work fine, depending on the application, and would be fairly affordable.

EDIT: Here's some for under $20.

[dtengineering]

What range of forces are you planning to measure?

Can you purchase a spring at the hardware store and calculate its spring constant using a known mass?

What if you fix the head of a torque wrench so it doesn't turn, then tie a string to the wrench a known distance from the head?

Jason

[James Tonthat]

A digital fish scale might do what you need.

[MrForbes]

a few years ago I saw a picture or video of some of the 842 folks showing how they measure the pushing power of their robot...they use an old analog bathroom scale, leaned against a wall, and have the robot push against it.

Without knowing what you're trying to measure, and how accurately (why you need the numbers), it's kind of hard to answer your question.

[Collin Fultz]

Originally Posted by jtkellertx

A digital fish scale might do what you need.

I'll second this if all you need to do is measure force in a pulling direction. They key is mounting it in a situation that allows the robot to keep full contact with the floor (i.e. don't have the scale "pulling" the robot "up").

[Dick Linn]

For pulling up to 75 pounds, a $10 luggage scale might work:

http://www.amazon.com/Travelon-Stop-...ref=pd_sbs_a_1

Otherwise make something with a spring.

[Ed Law]

Originally Posted by NickE

For something not super-accurate, I've seen scales intended for weighing airplane luggage. They typically have a handle with a digital display in it and a hook to attach to the luggage. This would probably work fine, depending on the application, and would be fairly affordable.

EDIT: Here's some for under $20.

Originally Posted by Dick Linn

For pulling up to 75 pounds, a $10 luggage scale might work:

http://www.amazon.com/Travelon-Stop-...ref=pd_sbs_a_1

Otherwise make something with a spring.

Originally Posted by jtkellertx

A digital fish scale might do what you need.

Originally Posted by Collin Fultz

I'll second this if all you need to do is measure force in a pulling direction. They key is mounting it in a situation that allows the robot to keep full contact with the floor (i.e. don't have the scale "pulling" the robot "up").

Thank you to all for the ideas. I really like the fish scale and luggage scale idea, and I don't have to spend a fortune. I will look at amazon.com and other places.

[Lowfategg]

Harbor Freight (Every FRC teams fav tool store ) has a few,

http://www.harborfreight.com/cpi/cta...emnumber=65613
http://www.harborfreight.com/cpi/cta...emnumber=97227

We used the second one last year with good results. A lot more accurate than a cheaper fishscale we bought.