You are reading a single comment by @CamPhil and its replies.
Click here to read the full conversation.
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
@CamPhil
No problem checking the calibration of a torque wrench as long as you have a known weight and a ruler.
Just fit the wrench (maybe via an adapter) to a socket extension placed horizontally in a vice.
Turn against the ratchet until the handle is horizontal.
Hang the known weight from the handle near the head of the wrench, then slide it along until the wrench clicks.
Measure the inches and multiply by the pounds.
Don't forget to add half the weight of the wrench at half it's length to the measured value.
If you do a little pre-calculation you can select a weight that will check the mid-point of the calibration range at about halfway along the handle - then you can use a singe weight to check most of the range, simply by how far along the handle you need to slide it, measured from the centre of the ratchet head.
e.g. The Norbar 11037 has a maximum capacity of 180 in/lb and an handle length of about 8.5".
180/8.5=21.2 so a 20lb weight will allow you to check the calibration almost to the top of the range - while when hanging at the ratchet end of the handle it will only be about 0.5" from the pivot, or about 10 in/lb. For more accuracy at lower values just use a smaller weight.
Add about 3.5 in/lb for the torque applied by the weight of the wrench (0.88lb x 4").