JHCC

Another way to straighten coil springs

Recommended Posts

Straightening heavy coil spring can be a pain, especially if you don't have a forge big enough to heat the whole thing all at once and a tractor or forklift to pull it straight. I've tried working in sections on the anvil, with a bending fork, or using the hardy hole itself as a bending fork. All of these work, but they're awkward. 

I was thinking about this the other day, when it occurred to me that uncoiling into some kind of jig could be an interesting possibility.

And here it is:

IMG_3114.JPG

This is simply a piece of angle iron clamped in the post vice with a vice-grip at one end. Clamp the end of the section you want to straighten, and uncoil the spring into the angle, using a scrolling wrench for extra leverage. Given the size of my fire, I was able to uncoil about 4" at a time. Alternating between two workpieces, this went really fast and very well.

And here are two 18" sections of 5/8", fresh from the jig. Obviously not perfect, but they'll be getting straightened further later on.

IMG_3115.JPG

By the way, these are intended for a pair of Brazeal-style hammer tongs. Note the taper that's already in them; I realized I could take advantage of that to minimize the amount of drawing-out I'll need to do on the reins.

 

 

Share this post


Link to post
Share on other sites

Nice, simple fixture; I'd improve it by making it so you didn't need the vicegrips.  One way would be to cut the angle of the angle iron an inch and a half or so and fold the bottom tab up and drill the appropriate sized hole in it so slip the hot steel end into the hole and start unwinding it.  Remember that hot steel expands and so will need  a slightly bigger hole than the nominal diameter of the cold spring.

Share this post


Link to post
Share on other sites

That's certainly an interesting possibility. I've been thinking about a few options, but one advantage of the vise grips is how solidly they hold the workpiece. 

Share this post


Link to post
Share on other sites

Version Two: made a cut in the corner of the angle, about 3/4" from each end and bent the resulting sections backward. This creates a built-in holder for the end of the coil. 

IMG_3147.JPG

There's one at each end, to accommodate two different sizes of coil spring.

 

IMG_3149.JPG

And it works pretty well!

IMG_3144.JPG

 

The smaller coil can be moved with a bending wrench, but the heavier stuff does better if you slip a piece of pipe over the other end as a lever.

Share this post


Link to post
Share on other sites

I like version 2.0 even better. If I worked with coil spring often enough, I would definitely make one. 

Share this post


Link to post
Share on other sites

Me too.

(Especially since I don't have a drill that size.)

Share this post


Link to post
Share on other sites

Addendum: I have since welded a tab of 1/4" plate to the back of this tool, which can be gripped much more securely in the vise.

5F27FFAE-4856-4470-B388-7CBF3173640D.jpeg.231e886bd6e8a098278521a791b6c8e5.jpeg

Share this post


Link to post
Share on other sites

Nice tool, will remember this.:)

 

This guy makes it look easy. 

 

Share this post


Link to post
Share on other sites

Well... he certainly straightened the spring quickly. But with no gloves, no apron, short sleeves, and only a couple of vice-grips holding his stock, he's one small slip away from a serious injury. 

In the (US) Army, we say "If it's stupid but it works, it isn't stupid." That's well and good right up until it doesn't work (or doing so gets you hurt). ;)

 

JHCC, I've been thinking about straightening some springs. When the time comes, I'll certainly give your jig a go.

Share this post


Link to post
Share on other sites

I first ran across the method shown in the video in Weygers' blacksmithing books back in the '70's as I recall. For smaller springs---like garage door springs it's possible to grab the end and run out the shop and down the alleyway getting 20-30' of straightened spring with practice---and with everything arranged so you can grab and run.  The propane forge helps a lot to get a goodly length of spring up to temp to start.

Now I have a spring  made from 1.5" stock that will probably take a press even hot...(from a dirt mover)

Share this post


Link to post
Share on other sites

We welded a piece of pipe over some 2" sq to fit the hitch receiver in a pickup truck and welded a ring to the end of a coil. We had a short chain on the pull truck and the anchor truck parked at 90*. When the spring came out of the fire two guys ran it to the anchor truck, hooked the chain to the ring and the guy driving the pull truck pulled up the driveway. Took maybe 30 seconds from forge to laying on the ground. 

I salvaged a coil spring from a lot near by, it weighs in excess of 360 lbs. the wire is 2.375" dia, the coil is 12.75" in dia, c-c of wire. I think a big fire ad a couple dozers would work a treat but . . . A couple minutes with the torch and I have plenty to make a few hammers. Less than 1/2 turn on the coil that is. I don't know what I'm going to do with all that spring and there's another just like it on that lot. 

Frosty The Lucky.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.