today I had a go at making some small compression springs as I wasn't prepared to pay the minimum order quantities for half a dozen so thought I'd have a go at making my own. I need stainless steel springs so got some hard drawn stainless steel. this is available from the far east via ebay etc if you're prepared to wait for it, but can also be bought from K C Smith Ortho Ltd.
https://www.kcsmith.co.uk/
I'd been putting off the spring making for a while even though there are a fair few videos and tutorials about the internet. I used a mandrel handle to turn the lathe, as it makes it easier to count the number of turns. and I used is tool for feeding and tensioning the wire.
a piece of 3/8 square bar to clamp in my lathe toolpost, M4 countersunk screws to tension the wire being wound, and the tension can be varied by different holes, the V is there to support the mandrel that the wire is being wound arround.
The springs I made needed to fit over a 1.9mm shaft, and the springs are made from 0.3mm and 0.6mm wire. If you want to know about the caluclations for working out spring rates and tension etc, there are plenty of sources on the net, but you can also get the information from online companies like Lee Steel Spring.
https://www.leespring.co.uk/uk_index.asp
when you make a spring, when the tension is released the spring will unwind slightly so the mandrel it is wound on needs to take this into account. I used a 1.6mm welding rod for the 0.3mm wire but used a 1.8mm drill for the 0.6mm wire (and it wouldnt fit over the 1.9mm shaft if I used the 1.6mm welding rod).
so these are my first 3 attempts at trying to wind a coil (spring) with a M4 screw for scale. this was done without change wheels for screwcutting, I used the mandrel handle to rotate the collet chuck in the lathe and or one turn moved the carriage on for the wire thickness. at this point I realised that I didnt need use the change wheels as the "pitch" of the coils would be 1.0 mm, when I turned the mandel handle half a turn, I'd need to advance the lathe carriage 0.5mm
lucky for me the wire would fit between the slots in the collet chuck, so bent the end of the wire 90 degrees and stuck it in. these pics are of a sprung being made with the o.6mm wire.
If I used the changewheels to advance the carriage, I'd have needed to run the motor in reverse to move the carriage away from the chuck, so to tension the wire, it went under the first screw, over the second and under the third. with the V supporting the winding mandrel (drill bit shaft)
the coils were wound on, half a coil at a time then advancing the carriageway.
and the completed spring, I wound a few extra closed coils at the beginning and end of the spring so that the end coils that are used would be more consistent. there is a lot of tension in the spring wire, so PPE is recommended. when cutting the 0.3mm wire, the cross slide was easy enough to retract and then cut the wire, but with the 0.6mm wire the wire is too stiff to do that, so the collet was untightened in the chuck.
the surplus coils were then cut off and the coil ends were squared by putting the spring in a cordless drill and using that against an abrasive belt. and here's my first attempts as spring making shown against 5mm squared paper for scale.
if you want to know the spring rate, my method is to use a kitchen scale on my milling machine, as you can get the force applied (from the kitchen scale) and the change in length of the spring from the Z axis on the milling machine. there is a mandrel in the drill chuck to stop the spring flying off.
https://www.kcsmith.co.uk/
I'd been putting off the spring making for a while even though there are a fair few videos and tutorials about the internet. I used a mandrel handle to turn the lathe, as it makes it easier to count the number of turns. and I used is tool for feeding and tensioning the wire.
a piece of 3/8 square bar to clamp in my lathe toolpost, M4 countersunk screws to tension the wire being wound, and the tension can be varied by different holes, the V is there to support the mandrel that the wire is being wound arround.
The springs I made needed to fit over a 1.9mm shaft, and the springs are made from 0.3mm and 0.6mm wire. If you want to know about the caluclations for working out spring rates and tension etc, there are plenty of sources on the net, but you can also get the information from online companies like Lee Steel Spring.
https://www.leespring.co.uk/uk_index.asp
when you make a spring, when the tension is released the spring will unwind slightly so the mandrel it is wound on needs to take this into account. I used a 1.6mm welding rod for the 0.3mm wire but used a 1.8mm drill for the 0.6mm wire (and it wouldnt fit over the 1.9mm shaft if I used the 1.6mm welding rod).
so these are my first 3 attempts at trying to wind a coil (spring) with a M4 screw for scale. this was done without change wheels for screwcutting, I used the mandrel handle to rotate the collet chuck in the lathe and or one turn moved the carriage on for the wire thickness. at this point I realised that I didnt need use the change wheels as the "pitch" of the coils would be 1.0 mm, when I turned the mandel handle half a turn, I'd need to advance the lathe carriage 0.5mm
lucky for me the wire would fit between the slots in the collet chuck, so bent the end of the wire 90 degrees and stuck it in. these pics are of a sprung being made with the o.6mm wire.
If I used the changewheels to advance the carriage, I'd have needed to run the motor in reverse to move the carriage away from the chuck, so to tension the wire, it went under the first screw, over the second and under the third. with the V supporting the winding mandrel (drill bit shaft)
the coils were wound on, half a coil at a time then advancing the carriageway.
and the completed spring, I wound a few extra closed coils at the beginning and end of the spring so that the end coils that are used would be more consistent. there is a lot of tension in the spring wire, so PPE is recommended. when cutting the 0.3mm wire, the cross slide was easy enough to retract and then cut the wire, but with the 0.6mm wire the wire is too stiff to do that, so the collet was untightened in the chuck.
the surplus coils were then cut off and the coil ends were squared by putting the spring in a cordless drill and using that against an abrasive belt. and here's my first attempts as spring making shown against 5mm squared paper for scale.
if you want to know the spring rate, my method is to use a kitchen scale on my milling machine, as you can get the force applied (from the kitchen scale) and the change in length of the spring from the Z axis on the milling machine. there is a mandrel in the drill chuck to stop the spring flying off.
