How to make a torsion spring

The tensioner on my belt grinder uses a torsion  spring right here that just twists up to lift   this wheel to apply tension. And when I built  this I didn't know how much tension I would   need so I didn't want to go out and buy a dozen  different springs just to try to find out. So I   used a spring that I could find around the place  which happened to be a hay baler pick up finger. Now I can't expect everybody to be able to  find a hay baler pick up finger in their   local hardware store so in the plans I said  that it's pretty easy to just bend a piece   of music wire around a mandrel to make your  own spring. So I'm going to demonstrate that. 1/2" pipe should work well as the mandrel  since it has an outside diameter of a little   less than 7/8" it will give me an inside  diameter on the spring of probably about   an inch because it will spring back some I  just clamped that down to a random scrap of   material here and I'm going to weld around  here and this hole is kind of convenient   because I can use a bolt to hold the end of  the music wire so then I can start wrapping   it around that mandrel and this whole piece  will clamp up in the vise quite nicely. I'll secure that in the vise I'll take the  music wire and put it on like so and then   start wrapping it around so we end up with a  torsion spring kind of like this. So I need   to secure this end so that it stays put in two  dimensions. Firstly it can't whip around like   this and it also can't pull like this. It'll  have a tendency to wind that tail in and make   it slip past whatever I have holding it. So my  solution to this is to use a bolt and that way   I can tighten the music wire in place so it can't  pull. To offset for this weld I'm going to stack   up a few washers and that should work. This is  7/32" music wire so to stop these washers from   tipping like that just put a 7/32" drill bit on  the other side. And then I can tighten the bolt. Be aware the end of this is small enough and  pokey enough it can break skin. If that gets   away from you when you got a bunch  of tension under it it can go fast,   so use your head. I mean not — not like that. I just put this clamp on top of here and  that's going to keep the coil moving straight,   otherwise it can get lopsided. And  I'll just move that up with each round. I need one more round but at this point the coil   is established well enough it's not  really going to go lopsided anymore. And I think you can see here why that would  be pretty bad if that gets out of my hands! And I'm going to try to end  these up with the two in line. There we go — hold on, this is actually wrong,  I should have gone further. I'll explain later. There's 1-5/8" of room on the grinder for the  spring and this one will easily fit in that. In order to fit correctly this piece needs to bend   out about here. I'll just clamp that in  the vise and I can use a piece of pipe   over it to bend that. This goes in  the opposite direction of the coil. I forgot to take this bend into account, so  I should have had this piece and the tail   over here parallel, and instead I have this  and this parallel. So I'm gonna have to bend   this a little bit more to try to make this and  this parallel. So don't make the mistake I did. And of course that's just bending this  straight but hopefully I'll get there. See how this spring is all lopsided? Remember   that. Now I'm going to disassemble this  whole hinge and put the new spring in. To keep the new spring from collapsing I'm just   going to put a little piece  of 1/2" PVC conduit in it. And that feels like about the same  amount of spring tension, so, awesome! You don't want to tighten this bolt,   just thread it on far enough the nylon  is holding it so it won't fall off. That's kind of all there is  to making your own spring. I feel a little bit silly about posting  this because it's so simple it doesn't   seem to be worthy of a video, but  I hope you got something out of it!   And hopefully the people who need  to build this grinder will see how   easy it is to get the spring. Because  I was getting some questions about it. Thanks for watching and I'll leave you  with the sticker from that music wire so   you can see what it is. I got it  from eBay. It takes about 3 feet   per spring and I would recommend you get  several of these because there's a good   chance you'll make several crooked  ones before you get the hang of it.

Channel: Jer Schmidt

Views: 434,401

Keywords: How to, spring, springs, coil spring, torsion spring, wind, make your own, diy, make, bend, music wire, belt grinder, tilting belt grinder, 2x72 belt grinder, tutorial, mandrel, jig

Id: aT8ET5t6f20

Length: 5min 38sec (338 seconds)

Published: Tue Aug 01 2017