How to temper a piece of spring steel to hold a good edge.. anybody?

D

Denastilus

Joined
Apr 28, 2011
Messages
3
i've just made several really nice knives out of some old leaf springs i found. with out a temper they get good and sharp but still get a rolled edge real easily, so i tried to temper the first two in oil and they got so brittle the tips shattered. any tips?
 
Read the Heat Treatment stickies. It is hardening, not tempering you did. The difference is explained in the stickies,too.

Filling out your priflie would be nice,too.
 
I'm just a beginner but I think you missed the last step. After you heat/quench/ you have to put it in an oven and heat it to about 400+ degrees for an hour or so to get rid of the brittleness you experienced.
 
Denastilus said:
i've just made several really nice knives out of some old leaf springs i found. with out a temper they get good and sharp but still get a rolled edge real easily, so i tried to temper the first two in oil and they got so brittle the tips shattered. any tips?
Click to expand...

You hardened the steel, but you didn't temper it. Tempering brings the steel back somewhat from that super-hard (but brittle) state.

There are some very good stickies you should read through.

For what it's worth, you probably have steel that is pretty comparable to 5160 steel; I'd use information on 5160 steel to address how you should temper your blades.
 
Already said above. Heating the steel to critical temp (non magnetic cherry red is the "shade tree" knife maker's way).

Quench in a suitable oil, then run it through a few cycles of tempering in your oven (make sure you clean it off of all oil first!).

Look for the temps you are shooting for in the stickys at the top of this thread. They will give you great info.

As already said, the steel you have might be close to 5160. That said, it might not. Some old spring steel is actually 5160, some is not. But I would use the info for 5160 steel as my starting point.

I did my first self made knife in 5160 that was of a known quality. I did a back yard hardening with natural lump charcoal broken down to smaller more uniform pieces, and an air source (fan) to get the coals hotter. I took the steel to non magnetic cherry red, then quenched in motorcycle oil (race oil from my motorcycle).

Then I did two tempers in the oven for 2 hours at 400 (ish) and let the knife cool to room temp in between.

It takes a great edge, and is actually much much tougher than I was expecting.

That said, without more control of the process (ie better temp control, an actual timed soak at the right critical temp) your heat treatment won't be getting the most out of the steel.

For example, buy a knife made from 5160 from a reputable maker who has the heat treat process down well, and it will out perform my shade tree made knife by wide margins.

But making your own has it's own rewards.
 
I hit most new posters with this & U think it may help you - especially this video

Heat Treating Basics Video-downloadable
Right click and save this. Watch it once a day for 10 days.

Heat Treating
http://www.bladeforums.com/forums/showpost.php?p=9143684&postcount=7

You can send blades out for heat treating at $10 or $15 per blade for perfect results, and avoid buying the equipment.

This PDF brochure gives a good overview
http://www.buckknives.com/resources/pdf/Paul_Bos_Brochure.pdf
http://www.petersheattreat.com/cutlery.html
http://www.texasknife.com/vcom/privacy.php#services
http://www.knifemaker.ca/ (Canadian)








The Standard Reply to New Knifemakers v14

The answer to a 13 year old student is different than to a 40 year old engineer.
We may recommend a local supplier, or you may have a helpful neighbour; but that depends on where you are. We have members worldwide.
Fill out your profile with your location (Country and State at least), age, education, employment.

Look at the threads stickied at the top; many are expired, but not all.

The basic process in the simplest terms
Absolute Cheapskate Way to Start Making Knives-Printable PDF-Right Click and Save
Absolute Cheapskate Way to Start Making Knives-Website


Web Tutorials
Detailed instructions by Stacy E.Apelt

The Things I Advise New Knife Makers Against-Printable PDF

Handle Tutorial - Nick Wheeler-Website

http://www.engnath.com/manframe.htm

Books
A list of books and videos

BladeForums - E-books or Google books


I like:
David Boye-Step by Step Knifemaking
Tim McCreight-Custom Knifemaking: 10 Projects from a Master Craftsman
These are clear, well organized, widely available and inexpensive too.

Knife Design:
See the Google books thread for Lloyd Harding drawings & the Loveless book. Google books thread


Forging Books:
Lorelei Sims-The Backyard Blacksmith
An excellent modern book with colour photos for forging in general - no knifemaking.

Jim Hrisoulas- has 3 books on forging knives. Check for the cheaper paperback editions.
The Complete Bladesmith: Forging Your Way to Perfection
The Pattern-Welded Blade: Artistry in Iron
The Master Bladesmith: Advanced Studies in Steel

Machine Shop Basics -Books:
Elementary Machine Shop Practice-Printable PDF

The Complete Practical Machinist-Printable -1885-PDF
It’s being reprinted now, you can get it for $20 ish

The $50 knife Shop
It confused me for a long time.
Forging is NOT necessary; you can just file and grind to create a knife (stock removal)

The goop quench is total Bull.
Use commercial quench oil & match oil speed to the steel type; even grocery store canola oil works much better.

Junkyard steels require skill and experience to identify the steel and heat treat it properly.
You can buy proper steel like 1084FG from Aldo very cheaply.

I like cable damascus, but that advanced project has no place in a beginner’s book.

The grinders are the best thing about this book, but there is a huge amount of info for 2x72” belt grinders on the web, including free plans.


Videos

Heat Treating Basics Video-downloadable
Right click and save this. Watch it once a day for 10 days.

Safety-video
Right click and save this. Watch it once a day for 10 days.

Many specific how to knifemaking videos are available, some are better than others.

The best overall Knifemaking video I have seen is
“Steve Johnson-Making a Sub-Hilt Fighter”

The best video on leather sheath making I have seen is
“Custom Knife Sheaths -Chuck Burrows - Wild Rose”
-(Paul Long has 2 new videos, his sheath work is fantastic. I hope the videos are too)

Green Pete's Free Video
Making a Mora bushcraft knife, stock removal, hand tools, neo tribal / unplugged heat treat.
"Green Pete" posted it free using torrent files.
Be sure to look at the other titles too-The account index has disappeared, but search for LOTS of info.
Greenpete Knifemaking Basics-on TPB

How to get that video
http://www.utorrent.com/help/guides/beginners-guide

You can see a list of videos and reviews at this rental company; some are worth buying, some renting…
http://smartflix.com/store/category/9/Knifemaking

Draw Filing Demonstration
YouTube video -Draw Filing-for a flat finish

Steel
The “welding steel” at Home Depot / Lowes… is useless for knives.
If you send out for heat treating, you can use O1, A2, D2, CM154, ATS34, s30v, 440C, plus many others.

If you heat treat yourself, find some 1070, 1080, 1084,
1084 FG sold by Aldo Bruno is formulated for knifemaking.
http://njsteelbaron.com/
Phone # 862-203-8160

You can find a list of suppliers here

Heat Treating
http://www.bladeforums.com/forums/showpost.php?p=9143684&postcount=7

You can send blades out for heat treating at $10 or $15 per blade for perfect results, and avoid buying the equipment.

This PDF brochure gives a good overview
http://www.buckknives.com/resources/pdf/Paul_Bos_Brochure.pdf
http://www.petersheattreat.com/cutlery.html
http://www.texasknife.com/vcom/privacy.php#services
http://www.knifemaker.ca/ (Canadian)


Grinder / Tools

Hand Tools
You can do it all by hand with files and abrasive cloth like the Green Pete video.
Photo of a nice bevel filing jig

Entry Level Grinders
Many makers start with the Sears Craftsman 2x42 belt grinder

Commercial Production 2 x 72” Belt Grinders
http://www.prometheanknives.com/shop-techniques-3/grinders

Mapp arm – Grinder Toolrest


DIY 2 x 72” Belt Grinders

KMG Clone Free Plans
http://www.dfoggknives.com/PDF/GrinderPlans.pdf

NWG No Weld Grinder
http://www.usaknifemaker.com/plans-for-the-no-weld-grinder-sander-nearly-50-pages-p-723.html

EERF Grinder (EERF =“Free” backwards)
http://wilmontgrinders.com/EERFGrinder.aspx
http://blindhogg.com/blueprints.html
http://www.atlasknife.com

Buy the kit
http://polarbearforge.com/grinder_kit.html


Safety Equipment
Protect your -Eyes, Ears, Fingers, and Lungs – remove jewelry and put on safety gear.

Respirators
Chronic lung disease and cancer really suck the joy out of life.
The minimum I would consider are the 3M 7500 and North 7700 silicone half masks with a P100 Filter.
Use a VOC & P100 combo cartridge for protection against acetone and solvents.

http://www.bladeforums.com/forums/showthread.php?t=788837
http://www.bladeforums.com/forums/showthread.php?t=726309


V13 Edited dead links
 
Denastilus said:
i've just made several really nice knives out of some old leaf springs i found. with out a temper they get good and sharp but still get a rolled edge real easily, so i tried to temper the first two in oil and they got so brittle the tips shattered. any tips?
Click to expand...

Just cuz I'm nosy, how did you harden the blades? What did you use for heat, when did you decide they were right for quenching?

When did the tips shatter? Was it during the quenching or after, when you had put handles on? What were you doing with/to the blades when the tips shattered?

I have little doubt that the other replies are correct about the lack of tempering.

- Paul Meske, Wisconsin
 
I know that you have tons of info here to weed through. Welcome to this never ending learning curve! When I started I thought knive making was simply make it, heat it, cool it, finish it. There is ALOT more to it than just that though. Always remember however, GOOGLE is also your friend in this modern age! Try a search of Heat Treatment of 5160 Steel for example. Save the articles you like in a binder with tabs on topics you find useful. Good Luck!

Brad
 
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