Manufacture of Compression Springs Part Two

19th January 2021

Finishing a Compression Spring (by hand)

Part 2 of 2

You have to continue counting until you achieve the active target coils in the completed compression spring. Then let it wind a couple of more coils. Keep counting and unfasten the lead screw. The wire lays on itself and starts forming closed coils.

  • Turn off the lathe machine after allowing about two closed coils to wind on the arbour. Don’t allow the end of the pin past your wire guide. Note down the number of final coils done for your reference.
  • Slowly rewind the chuck a little to loosen the spring on the arbour. Don’t allow your pickup pin or chuck jaw to catch the wire front because the spring will loosen on the arbour.

If you have additional wire left, cut it. Afterwards, you have to put the compression spring in the oven to reduce any stress. In this trial process, you have to leave it inside for about thirty minutes. Remember that this process of relieving stress will make the music wire springs contract a little. In the case of stainless steel springs, it expands a little.

After completing the process, allow the compression spring to cool down at room temperature, i.e. by air-cooling. You can measure the spring to find out how near you are to the target. You should check the diameter initially. If the diameter is not correct, you need not bother to do any more measurements. You will require a different arbour which changes all the remaining dimensions of the compression spring.

However, if the diameter is perfect, count the active coils of the compression spring. If would be nice if you ended up quite close to your target. It is fair to be one-fourth of it off on either way for a smaller figure of springs. If it has more than 25% variation, you have to calculate how much additional or lesser you require and try achieving the target coil count next time.

Winding While Not Using a Lead Screw

You may also coil compression spring on your lathe without using the lead screw. But here the problem is that you may not make the same springs. Let us learn how to do it without a lead screw.

  •  Find the required value of spring pitch. Take the wire length and subtract 5.5 times of dia and divide the resulting figure by the figure of active target coils.
  •  As earlier, bring the chalk at your tool post. Move it closer until the arbour puts a couple of marks on the chuck.
  •  Switch on your lathe and allow the chalk to mark a full circle on the arbour.
  •  Bring your tool post slowly towards right using the handwheel by still allowing the chalk touching the arbour. The chalk keeps on marking almost the same place where you want the spring to be made.
  •  You can count the coil marks made by chalk as per your target and halt the rightward movement.
  •  The lathe should run till the chalk marks are there all over the arbour.
  •  Make a winding of trial spring by following the chalk marks as close as possible.
  • If the spring dimensions are incorrect, clean the chalk marks from the arbour and attempt again by recalculating the target pitch.