Cutting fork spring mod

[Guest]

This is just my take on how how I cut the springs and I think it produced a pretty good result and I hope it can serve as a reference to anyone looking for options on how to do it.

I don't have a dremel and I wanted to do the fork spring mod where you cut approximately 3" and replace it with a piece of pvc in order to increase the spring rate. I went to sears hardware to see if I could find something cheaper than a dremel or driving the 30min to HF for the $9 rotory tool and low and behold I found this for $4.06 (2.99 online)


So I purchased it, clamped my spring down and proceeded to cut it like so:


After that I wanted to make it as flat as possible so I decided to do this:


Which in the end produced what I believe to be a pretty good result.


After I had both cut I lined them up next to each other and found that one was about 1/4 turn longer than the other so I just went back to the way I flattened the end and I took it down until they were about even and then cleaned them up with a file.

Also a quick piece of advice, if you are using a circular saw which you use often for wood, clean the caked on saw dust from inside of your saw before doing this because I had some smoldering wood inside of my tool when I was done.

[salty_monk]

By cutting the closely wound end you have affected the initial spring rate but not the final spring rate...

Think of it like this....

Progressives are 35/50lb inch.

35lb until the closely wound coils bind & then the lesser number of coils (once bound the coils become the same as a solid spacer) makes it a 50.

If you were to cut off all of the closely wound coils the whole spring would be a 50lb. If you cut off 50% of the closely wound coils the spring would be a 42.5/50

See where I'm going.... If you cut the loosely wound end you affect the spring rate for the whole spring so cutting off the same 50% quantity of coils (which would be longer - i.e. you'd cut more spring length but same number of coils) would give you a 42.5/57.5

Hope it makes sense...