Help Making a Coil Spring

[mtnman31]

Can anyone give me tips on making a coil spring? I got a .577 Snider from IMA and the the spring for the locking plunger of the breech block is crushed. I know I can purchase a replacement for around ten bucks but would prefer to try my hand at making one. What do I need for material and how do I do it? My girlfriend is out of town this weekend so I have all weekend to play in the garage :razz: I'd like to finish this rifle up so I can justify to myself the need to buy a Martini next. Thanks.

[fourarmed]

Most of the old gunsmithing books discuss this. I am hazy on the details, but it involves wrapping music wire around a rod or bolt of appropriate size. I would expect that the wire would have to be annealed to get it to take the shape you wanted, then reheat treated.

[1hole]

Quality hardware stores carry lots of small items, some have assorted springs, take your old one on a shopping trip. MUCH easier and makes for a better spring too. (Or you could visit me in western NC, I have a large collection of coil springs in my loose parts bins! :) )

If you can find something close, understand that you can shorten them easily and you can stretch them to get the coils per inch close enough to work.

[Lee]

The mandrel needs to be smaller than the final size you desire. Music wire usually doesn't get annealed, the forming process does some work hardening. Oil tempered wire usually gets annealed after forming.
A spring making machine actually "pushes" the wire around a mandrel and point and plate "thingie" to form the coil. The mandrel sets the diameter, the point makes the curve and the plate sets the pitch. Simple seen, difficult described.
Large springs can be made by winding, small ones made by pushing, usually.
I worked for a spring company, light years ago and a different lifetime. That's how we made them.
Don't stretch them much, that lets some of the smoke out, and they won't be quite the same after that. Shortening? Yep, that's easy. Wire cutters, and careful bending if you require a "closed end" spring.
10 bucks? I think I'd go that way................Lee

[uscra112]

Piano wire can be bought from model airplane hobby shops, or online from McMaster-Carr. www.mcmaster.com

But I also recommend looking thorough your hardware store's spring assortment before trying to make one.

Trying to annealing and then re-harden spring wire is a waste of time. You'll never get the temper right, because there's so little mass there.

Lee, I was in the machine tool rebuilding business for many years, and I saw machines like you describe. They were amazingly fast, and could make a compression spring or a tension spring just by changing the guide. On the ones I saw the pitch could be varied while the spring was winding, so you could get a fully-closed coil or two at each end of a compression spring. Or you could get a variable-rate spring. (Such as are used in motorcycle suspensions). Gee, I never thought I'd ever run across anyone else that knew those machines exist.

BTW cutting a compression spring shorter will make it stiffer - just thought I'd point that out.

[deltaenterprizes]

Do you have a lathe?
You need to mic the old spring and determine the gauge of the wire. Next thin is determine the number of coils per inch. By trial and error determine the size mandrel needed to produce the diameter you need. Once the mandrel diameter is determined a small hole needs to be cross drilled to hold the wire as the spring is formed. Put the lathe in the slowest speed available and set the gears to the same pitch as needed for the spring. Holding the wire with a pair of pliers allow the tool post to guide the wire for the correct pitch as the lathe turns the mandrel.
The Home Shop Machinist magazine had a great article on making springs.

[abunaitoo]

What issue of The Home Shop Machinist????
If you have the issue, can I get a copy from you???

[deltaenterprizes]

Go to their site "The Home Shop Machinist" . I remember reading the article but it may have been 5 years ago, I can't remember. The cost of the copy of the back issue with the pics would be well worth the price.
The members on that board are like this one with vast spectrum of knowledge and backgrounds and very willing to help.

I posted a thread on the subject. This is a link to search results that may help:http://bbs.homeshopmachinist.net/search.php?searchid=408679

[Gee_Wizz01]

When I worked in a machine shop about 40 years ago, I watched an old machinist make coil springs on a lathe. He would turn a mandrel, drill a hole in it and insert the wire in the hole. He had a plate with a hole in it mounted to a tool holder that he fed the wire through. If I remember correctly he set the pitch by setting the lathe up for threading. I cant remember much more about it.

G

[Lee]

uscra112. Yep! you da man! Running full tilt, those machines would spit out a spring every 1-2 seconds or better. I learned on some that were around from the Big War. They were used to make springs for.....well..... war materials.
You could adjust pitch, diameter, and length while they were running. Length could be controlled automatically within limits with the available electronics at the time, which would vary pitch (slightly) to maintain +/- length tolerance. Diameter was up to the operator. And if you weren't good with calipers...you were looking for work pretty soon. Hardest to get/set right was the ends!!
The next generation machines used servo controls, but still required a human to monitor diameter, etc. They easily applied a hook or loop at the end of the spring, something not easily done on the basic spring making machines. (Usually required a secondary operation.)
Don't know what todays machines can do.:lol:

[robroy]

+1 on deltaenterprizes. The lathe works great. IIRC Macheneries Handbook can tell you what mandrel dia for a given finished od

[deltaenterprizes]

Did you make the spring yet?

[mtnman31]

Have not had a chance to work on the spring yet. I have access to a lathe at work but I am away from work until Mar 22nd. I also need to find some material for the spring. I need to find a decent metal supply shop locally as I wouldn't expect to find much at Lowe's or Home Depot.

I have found some decent articles on the net about making springs but still need to check out the Home Shop Machinist's website. Most of the articles left me feeling like it is definitely going to be a "try it and see if it works" project. Not too concerned about that as experience (both good and bad) is the best teaching tool. Doing it on the lathe sounds like it will be easy to play with and figure out.

[deltaenterprizes]

There are some new posts on that thread on HSM site that my interest you.

[JIMinPHX]

IMHO the best material for getting you what you need is a ten dollar bill. If the correct spring is available for ten bucks, then buying it is probably your best bet.

If you insist on doing it yourself, like I often foolishly do, then the hard part to get right is likely going to be the heat treating. I'll assume that a resourceful & motivated person will find a way to get a piece of music wire twisted into the right shape. Getting it to the right temperature before quenching it & then tempering it to a spring state after the initial hardening will be the tricky part.

Depending on the actual alloy you end up using, the hardening temperature, tempering temperature & tempering time will vary. Once you get a piece of wire to bend & know what alloy it is, google "spring temper" & look up the necessary process. Or maybe you should look that up before you buy the wire. It might help you understand just how cheap ten bucks really is. For a guy that has a temperature controlled muffle furnace kicking around, that's probably a small job. For a guy that doesn't have one, it's a horse of a different color. Either way you decide to go, good luck.

[koehn,jim]

Go to any good sized fishing supply and get steel leader for fishing it comes in different dia. and it should work as well as piano wire. Hope this helps.

[mtnman31]

I thought hard about just buying the spring, but keep in mind that this is a Nepal cahe rifle. If I got another spring there is the chance that it could be a lemon. Considering that the parts for these rifles are mostly the same age, I'd just as soon make one myself and learn something new in the process. Sort of a labor of love I guess.

[Beekeeper]

I made a lot of springs when I was in the Navy.
Check the inside diameter of the spring.
Find the next size smaller bolt with sufficient threads to make the spring. Use all thread if nothing else but it is kind of soft and will bend.
Measure the wire size and go to the nearest hobby shop that sells parts for model airplanes (the kind that fly) and buy a section of control wire the same size.
Hold one end on the bolt with pliars (channel locks work best) and turn the wire around the bolt keeping it in the bottom of the bolt threads.
Caution : wear gloves as if it gets loose from your hand it will whip back and do serious damage (don't ask how I know that.)
When it is long enough add a couple of more coils as you need to create a flat end on both ends of the spring.
Cut it off and check diameter and legnth.
You might have to do it several times on diferent bolts to get the exact diameter as there is a lot of spring back.
Heat the ends red and quickly place them on a flat surface to flatten the coil and give you a flat end. I use a 2inch thick piece of aluminum as it sucks the heat out right now.
Grind the tips to ensure you have a flat surface and you have a decent spring.

Jim