Measuring the Spring at 48mm

To measure the power of the 52mm spring I took an index card and bent it so that 48mm was positioned vertically.  This gave me a height to stop at  when measuring the spring strength at 48mm.

Take a reading here.

Measuring the Spring at Full Strength

 I then press the spring almost completely down to get a reading at full strength. If you press the spring until all the coils are completely collapsed you will not get a true reading because you are now pushing directly on  the scale itself.

Take a reading here

Ametek Force Gage

 A postage scale is a cheap way to go but the same job should be done with a Ametek Force Gage. These gages can reads either grams or pounds and the range should be between 0-1500 grams or 0-5 lbs. The device can also be used to measure the pull on the chain created by the mainspring. These can be found on eBay from $10 -$50

Tool For Measuring The Mainspring Strength

Here is a tool that is great for measuring the strength of a mainspring. The tool is call a Torque Watch and they come in many sizes. The best size to get is a 20 oz. in. , the product number is 651c-2. You can find these almost every day on eBay and they sell for around $15 - $50.

Measuring The Mainspring Strength

Attach the tool to the arbor of the mainspring. Hold the handle of the tool and turn the barrel around three turns and take a reading. Turn the barrel one more turn (4 turns) and take a reading, then turn the barrel once more (5 turns) and take your finial reading. I placed the barrel on a nonskid mat and roll it to get my reading.