tempering knives..

[Mark]

Pran,


This is a common type of small forge here in the US, it is called a "riveting forge", you can google that term and find lots of information.



Notice that the fire is not deep at all, it is built up on the surface for teh most part. I do not know what type of coal you are using, but in general something that works with both bituminous and anthracite coals is to crush it, so it is the size of peas, then mix it with water to make a slurry or firm mud. Use this to build a mound like you see in the first scribble that I did.

You can try just putting clay in your current setup, to bring the level to an inch or 2 from the rim. use a piece of pipe to bring the air up to the surface or simply use some pop cans to provide support and keep the airway from filling in. When the fire is going the cans will burn up of course but the clay will keep its shape.

Here is something interesting regarding blade forging- if you take your blade shape in your pic, and hammer one edge into it, it will turn into a nicely proportioned clip blade, when the metal gets hammered thinner on the edge it has to move somewhere so it essentially gets longer, which gives it a curl to the front and changes the spear point to a clip point.

[Pran]

mark,
got the idea now i can move the blade/spring steel without restrictions.
that's good suggestion.haven't done any serious forging yet.i've been shaping my knives(this is the second one) using a bench grinder so far(painstaking job!).do you use a surface grinder to get an even surface after you have shaped the blade?
pran

[mehulkamdar]

Mark,

Having done some work advising coal companies on selling their stuff in India, I can comment on the bit about the type of coal available there alone. Indian coal from the North-Central and North Eastern regions is almost entirely sub-bituminous and there is lignite in the South. That said, India imports huge quantities of bituminous steam coal and semi anthracite from Indonesia, Australia and China for the country's huge steel industry as that is much cheaper than mining for Indian coal itself though, these days, businesses are encouraged to blend the two. Calorific values could range from 3900 to 4500 KCal/Kg for Indian coal while most imported coal sold there is from 6000 all the way upto 6800 KCal/Kg.

Hope this helps,

Mehul

[eljefe]

http://www.timken.com/products/specialt ... %20102.pdf
http://tutorial.customknives.org/
http://knifeart.com/forbyterprim1.html

[penpusher]

This is OT,but is there any way of making a good knife blade without having to temper it? Is there any easily and cheaply available material from which you can cut out a knife blade( about 6" in length) and still have a blade that can retain an edge without tempering?

penpusher

[penpusher]

http://www.alpharubicon.com/primitive/k ... serger.htm

http://www.primitiveways.com/pt-knives-1.html

http://www.hossom.com/tutorial/jonesy/

penpusher

[Mark]

This is OT,but is there any way of making a good knife blade without having to temper it? Is there any easily and cheaply available material from which you can cut out a knife blade( about 6" in length) and still have a blade that can retain an edge without tempering?

penpusher

penpusher,

Yes it is, as long as you do not get the metal too hot.

An example is there is a certain type of Eskimo wood-carving knife that is made by grinding down a small (6") file. The easiest way I have found to grind metal without losing temper is to always keep it wet. Have a pot of water next to your grinder and dip the steel frequently. What I like to do is keep it wet while grinding, and then when the water starts boiling off the steel dip it again.

Unfortunately files are not only hard but brittle too, and they will snap if you pry with them. However, if you keep those limitations in mind they make acceptable small knives.

You can also do the same thing with springs too.

[Pran]

[

You can also do the same thing with springs too.
[/quote]but springs need to be straightened.. files are good but a little too hard to work on(without lowering the temper)

[jonahpach]

one formula that works for me is salted water with a bit of surf added.
Jonah

[penpusher]

one formula that works for me is salted water with a bit of surf added.
Jonah

Why the shock Jonah Hope you did not drink it.

penpusher

[mundaire]

Why the shock Jonah Hope you did not drink it.
penpusher

At the rate you're going, the TV folks might want to reconsider which Sidhu they want to have on board the Great Indian Laughter Challenge

[Grumpy]

Mark, is this an April Fools spoof or what ? The only thing that would get tempered in that thing is a hamburger - You can`t fool me, I know a barbeque when I see one !

[jonahpach]

OK u dudes here is a quenching formula I received from a blacksmithy forum I belong to..

Jonah

[Grumpy]

Lye is extremely dangerous as a quenching agent and can cause very bad scalds.
You can use the simple 5:5:2 formula which is 5 gallons of water, 5 lbs of salt and 2 lbs of soap ( not detergent ) flakes. Why soap and not detergent I have no idea.
There is a similar formula which incorporates automobile anti-freeze but I have no idea what amount needs to be used.

[Yaj]

Pran,good show! You are doing something i've always wanted to but never got around to doing .The forge and right place for it has been a stumbling block.I've been thinking of modifying one of those coal brazier's the kababwala's use but I keep procrastinating.I even bought an anvil from a scrap metal dealer (must weigh about 75 kg),bought and read the books(5 or 6 of them) but still not got around to forging.
Anyway you've inspired me,would love to see how your project turns out.
Yaj.