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I Forge Iron

Drowning in Leaf Springs


MarkF

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New to forum and knife making. First some background: My son and I (15 year old) have embarked on knife making as a hobby.  We currently have limited tools.  No Forge/furnace or large anvil. I have a 5 lb anvil.  I am trained goldsmith/repair and diamond setter but have not worked in jewelry field for over 10 years (still have most tools and jewelers bench).  I do have Drill press, 4 inch belt sander, scroll saw, torches etc. with access to Machine Lathe, Mill, Bridgeport etc (Two of brothers have automotive machine shop and I grew up in one) For my sons birthday I bought an assortment of blank blades so we could start by putting handles on.  I do however have access to a multitude of different steels especially all the leaf springs i can shake a stick at.  I can anneal the leaf springs using an acetylene torch.

Problem: Is there a fairly easy way to cut down the thickness of the leaf springs to an appropriate thickness for a knife blank.  I thought about using the mill with an end mill but that would probably use up a lot of end mill bits and would get expensive quickly.

 

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I know this may seem odd since you visited a blacksmithing forum, but my favorite way to thin those leaf springs is to get them really hot (glowing orange) and smash them between a hammer and anvil.  Repeat until desired thickness is achieved.

If you want to stick with just stock removal then you have the tools to do the job after the steel has been properly annealed.  It may still be a little harder on the cutting edges than mild steel, but ..........

You didn't list surface grinder in there, but that's another option if you have access to one.

I should also give you the requisite warning on here about using previously used springs for blades.  Many of us, myself included, have done this, but be aware that any used spring material may have micro cracks in it which are not visible and could potentially become evident at the worst possible time.  In other words the material may crack/break in heat treat or, worse yet, under heavy use.

It also may be helpful if you put your general location in your profile.  There are people who visit here regularly from all over the world and it's entirely possible that someone with expertise valuable to you may live close enough to lend a hand. 

I can't recommend strongly enough that you spend a fair amount of time reading the stickies in the topics that interest you.  It is rare to see a question from a new forum member that hasn't been asked and answered before.

Other than that, welcome to the forum.

 

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Source only the thinner leaf springs or those with a taper already built in.  You have learned one important lesson already "free material can be quite expensive if it's not in the right shape to start with"   You might check to see if you can find any of the neotribal smithing videos where they start with almost no tools---we call a 5# anvil a hammer in these parts and suggest a 12 pound sledge hammer head to be used as an anvil... Remember a hole in the ground has been used as a forge for over 2000 years!

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Welcome Mark,

That's some sound advice from Buzzkill. Hold on to the leaf springs for when you have a forge set up, and you can use them to forge tools or practice knife blanks.

I will always discourage people from buying pre-ground and/or pre-heat-treated knife blanks and slapping a handle on them; that's not real knifemaking to me. Research coffee can forge and utilize your existing torches if possible so you can make the knife start to finish yourself. I promise it will be so much more rewarding for you and your son creating a tool and work of art from scratch :)

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Welcome aboard Mark, glad to have you. Ditto about putting your general location in the header you might be surprised how many of the Iforge gang live within visiting distance. You'll learn more in an hour with an experienced person than days trying to teach yourself. I'm not a bladesmith guy but I do love smooshing HOT steel with hammers. What kind of belt sander is it? If it's a bench sander it'll go a HUGE long way to shaping and thinning your steel.

A forge isn't rocket science it can be as simple as a hole, some charcoal and an old blow drier. Propane forges can be as simple as two soft fire bricks with a hole drilled lengthwise between them and a burner inlet hole in the side. People have used 2 brick forges to make blades for a long time.

An anvil is whatever you're beating the steal on, horn and heal are pretty recent inventions. A heavy sledge hammer head works a treat. Master Japanese bladesmiths use anvils that are square or rectangular blocks between 3"-5" on a side. The size is an eyeball estimate I made watching videos. I like a truck axle mounted flange up, a little grinding and it's actually a very effective anvil.

As has been suggested there is many hours of reading in the bladesmithing section. If you want to forge knives I suggest you learn to forge before you start making blades that way you only have one learning curve to climb at once.

Frosty The Lucky.

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     Thank you to everyone for your responses.  Updated profile to show I am in Naples, Florida.  I Started by buying blade blanks because I figured if i couldn't make a handle then I prob shouldn't be making knives ;-) also a way to get the no patience 15 year old interested. The primary purpose of the leaf springs is for practice, these knives will either be given away or re-used.  I am also approaching this from a slightly different perspective. After 13 years in the Jewelry Industry I want to take my experience there and apply to knife design as a form of functional art.

     Will be making a brick forge in the backyard over the weekend and use charcoal in it for now.  Have an old grill I can tear apart for parts to make a propane forge and attempting to anneal the leaf springs.  Bought a 2.5# blacksmith hammer at Lowes, also have access to a hydraulic press and a head surface (think gigantic belt sander with 18 " wide belt for sanding down automotive heads to make them flat)  and will root around at my dad's work (old semi, dump truck and loader parts everywhere) to find something that will work as an anvil.  Just have to get creative. 

     Just finished my first knife handle (feel free to critique, I know I can see a thousand flaws).  It is curly Maple and Mahogany with Linseed oil and beeswax finish.

Thanks you,

MarkF

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There is a lot of good stock in big rigs, just don't use a brake drum for a fire pot they're just too impractical.

Nice fit and finish on the handle, I'd opt for more subtle with the woods but that's a matter of taste not craftsmanship. The jeweler's arts go with knives like butter on bread. Have you messed with Mokume Gane? You can make spectacuarly flashy blade furniture with it as you can using pattern welded steels.

Frosty The Lucky.

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   No, but thanks for the idea. Iv'e been out of the jewelry biz for over 10 years so there is a lot for me to remember/relearn. :-) . At this point not really sure which direction I will be going, was thinking of incorporating some enamel work, pave` setting or other gem setting or wood mosaics, not sure.  Just getting started. Trying to get this going as cheaply as possible (just got married and have a lot of expenses to deal with right now) and working with my hands is very useful for stress relief.  Have to find the rest of my tools (plating machine, casting equipment, etc, etc)  unfortunately quit a bit of them are gone for good due to moves over the years and merging two households recently.  Got married last Oct, third times a charm.

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6 hours ago, ThomasPowers said:

Fellow has been posing here about his using 3D printing for blade furniture----hmmm anyone working with a 3D EDM system?

That'd be Theo and I believe he's making patterns for investment casting.

Uh, you just got married and have a 15yr old son. How fast is the boy growing!? :rolleyes: I can't resist a good straight line even if I have to stretch to reach one.

Frosty The Lucky.

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Mark, have your son reach out to me, I would be more than happy to speak to him about the process. School's typically have extrusion (FDM) printers that produce hollow, brittle components which can be risky as a handle material if not stabilized with epoxy or polyurethane - a medium needs to permeate all the internal cavities all the way to the core and make it solid and uniform.

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You might find a good but used up file laying around one of the shops. You can do regular stock removal after tempering the steel softer of annealing the steel even softer. If you anneal, you will need to re-harden and temper the blade.

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  • 2 weeks later...

Again thanks to everyone that replied with provided tips and inspiration,  I was able to anneal the leaf springs.  Cut them into manageable sections with angle grinder and then put in the bottom of my burn barrel and loaded it with old lumber, yard trash that needed to be burned anyway.  Refilled barrel three times throughout the day before letting it sit overnight.  Now can cut into them with hacksaw reasonably well now.  Will straighten using a my dads blow torch and his 10 ton hydraulic press and then use bandsaw to cut down into blanks and reduce thickness.  I also snagged his old 6 inch vice that has a 1 inch think hammer plate on it to use as an anvil. ;-)

In the meantime i have been busy making a knife from an old broken file I had laying around.  Annealed it with my jewelers torch (had to buy a new melting tip).  Then shaped blank using heavy duty dremel cut off discs.  Hardened using torch and peanut oil (motor oil would have stunk) left over from my fryer.  Then tempered by putting blade into vice with wet towel and heating up spine with torch.  Attempted to do a 20 degree angle on edge by hand.  Tested edge by carving slivers off of a piece of PT lumber (third of way through a 2x4) and the edge still cut paper afterwards.  

 Turns out that polishing steel is pretty much the same process as polishing platinum and I used the same standard rouge es for it.  (black, yellow and white with a final of red rouge.  Polish not great but it was a learning experience and brought memories of hours in front of buffer polishing jewelry.  Please point out anything that I need to do differently or did not do quit right.

Also experimented with Mokume Gane and had limited success with small pieces of brass, copper, nickel using my jewelers torch, although i did cheat on one and used silver solder ;-), which worked very well.

Thanks again to everyone for you feedback and support.

 

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NO, NO, NO! The anvil like flat thing on the back of your vise is NOT an anvil, it's a legacy shape from way back. Modern vises, made in say the last 100 years or so are cast iron and will not withstand hammering on that flat. Nothing harder than straightening nails and such very light work. don't do heavy hammering in the jaws either, I don't take more than about a 16oz. hammer to my bench vises. Keep your eyes open for a leg vise while you're looking for an anvil. Look up the TPAAAT method of anvil and tool location here, it's a proven method and works a treat.

I'm surprised you couldn't cut the spring with a hack saw right from the pile. Springs aren't heat treated for hardness they're purpose in life is rebound strength through millions of cycles, hard is brittle and every bounce pushes it beyond it's yield point so it work hardens fast fast FAST. I brush the dirt off the blade and use my horizontal vertical cut off band saw to cut sprig of all types.

Brushing off the dirt is important or it'll dull a blade almost immediately. Same for RR rail clamp it in flange up so the blade doesn't try cutting the hardened cap and the blade can pop through it from behind/underneath. I try to NEVER cut dirty steel I can't afford to waste blades.

Frosty The Lucky.

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  • 2 weeks later...

Well here is my first full attempt at this.  Want to some more of these from files and other spring steel before I try my hand at forging.  Rosewood handle, was going to do brass on each end but decided to stick with all wood for a couple more before moving on to more complicated.

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8 hours ago, Frosty said:

Looks pretty darned nice. How'd you heat treat it?

Frosty The Lucky.

Hardened it using Peanut oil.  Has a similar consistency to motor oil but doesn't stink.  Actually makes me hungry because it smells like french fries. ;-)

Tempered by putting edge in vice with wet towel, heated spine and waited till glow went away before quenching.  I tested edge by getting grabbing a 2x6 piece of PT wood and cutting off slices until about 2 inches into it.  Edge held way better than I expected.

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Got my first two commissions, sort of.  Friend gave me a 14" bandsaw in exchange for making him a knife, and a local cabinet maker/remodeler  agreed to give me all of his cuttoffs (bamboo, mahogany, maple, cherry, douglas fir, black walnut, etc) for a knife as well.  Now have enough handle material to last a couple of years.  Also made a coffee can furnace last night from refractory cement/perlite so will be able to try forging as soon as I come up with something to use as an anvil.

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