Steel Designations and Bellows Back Flash

How to prevent bellows Flash back and basis of steel designation.

Hello David

Thank you very much for the valuable information you have provided me so far, I am always looking forward to your next subject

I do have a few questions, although I heard that when using bellows, the bellows may be destroyed due to gases forming on the inside If the bellows were hung higher than the forge, would this prevent this from happening?

2. what would be the best metal to use, cold rolled steel or hot rolled steel and what is the meaning of 1030 or other number associated to the steel?

Thank you for helping the newbie’s like me, it is much appreciated

Good questions.
Bellows
The bellows should be set up with a check valve inside so it can not draw gasses back in from the forge. The check valve originally was just a flap of leather on the exhaust that closes when the bellows is opened. This means all the air is sucked in through the inlet ports and none of the fuel gases from the fire which could be exciting indeed. Hanging the bellows higher than the forge will have little effect in preventing the problem.

Metal to use
The number designation refers to the type of steel and its alloy content.
The 1000 series means that it is just iron and carbon in the mix.
1018 or 1020 are both used for cold rolled and hot rolled. It is the same type of steel but as the name implies one is worked cold and the other hot. Cold rolled has tighter tollerances in size and requires more energy to make and costs a lot more. Hot rolled has more variation in sizing and has less stress put into the steel so it will bend easier. Once either are put into the forge they will work the same as there is no difference in the carbon content.

So back to the number designation. 1020 means a simple iron carbon mix with 20 points of carbon or .2% carbon. 1060 would have 60 points of carbon or .6% carbon.

5160 which is car or truck leaf or coil spring material is a different series. The 5000 series contains chrome. So 5160 has about 1% chrome and .6% carbon. Other series will have different major alloying components. Google knife making, and alloy steels, and metallurgy for information on each different steel series and their uses and properties.

Mostly for blacksmithing I will use hot rolled for general art work or 5160 if I am making cutting tools or hand punches. Other specific tools and punches I will use better suited materials such as S7 or H13 (yes there are letter designations as well).

Hope this helps
David Robertson
Ontario Artist Blacksmith

How To Make Different Damascus Patterns in Pattern Welding

Damascus Steel Patterns

Sorry to bother you so late at night (over here anyway)

But I was wondering what patterns you can pattern weld I have seen your ladder pattern and other patterns on the internet and was wondering if you could give me a few tips.

That you for your time.

There are hundreds of patterns and variations to work on.
Most are based on layering steel, then either modifying the surface such as the ladder pattern (cutting material away) then flattening and grinding to expose the pattern.
Or
flat layers that are twisted, then shaped, and ground to expose the pattern.
Both of these techniques can become very complicated depending on the layer count and the manipulation.
There is a third technique
Called Mosaic Damascus
This can be done with powdered metal or machined "pixels" put together to create a "picture" in the steel. It is a bit of a different process using a hydraulic press for the fusion weld to maintain the structure of the picture.

The best thing to do is get 2 colors of modeling clay and layer them together like a damascus billet and then twist and manipulate them. Then use a knife to cut some of the outside material away to expose the pattern (sames as grinding on the steel). Experiment with this but keep notes as you go so when you find a pattern that you like you can reproduce it in steel. This is a fast low cost way to experiment with these techniques.

A couple of very good books on the subject are
Damascus: Forging Techniques
or
The Complete Bladesmith: Forging Your Way To Perfection

You may want to check out some the knifemaking forums for some other details.
I hope this helps.

David Robertson
Artist Blacksmith
www.artistblacksmith.com

Blacksmithing Removing Scale, Tinted Glasses, Upsetting

Blacksmithing How to Remove Scale, Tinted Glasses, Upsetting

I have a few questions for now.

If you use hot rolled steel how do you remove the scale on the parts that is not heated for forging? Do you use a wire wheel, and acid bath or sand the area?

Do you wear special tinted or filtered glasses when you do blacksmithing and have to stare at the fire alot.

I want to flare out a 3/4 square bar so that it will form a pyramid type base. If I heat it should I slam it on to a thick steel plate to flare it out. Is that the best way to do it?

Removing Scale
There are couple of options, they mostly depend on what coating you are putting on it.
Wire wheel for clear coating.
Sandblasting for paint.
Acid etch for galvanizing but this is done at the galvanizer.

Mostly it depends how you want the finished piece to look. Complex shapes may not get completely cleaned of for clear coat and painting.

Tinted glasses
Yes I wear rose dydimium glasses. This is the old filter style originally designed for glass blowers. There are other filters that are better recommended for blacksmithing such as AUR-99 from www.auralens.net. I have not used this lens so can't really comment on it. The exposure to UV and IR are generally minimal in blacksmithing, but it does become important with lots of forge welding as the temperatures are so much higher.

Upsetting 3/4 inch square bar
Depends on the length. short can be done on the anvil or clamped in the vise and a light hammer used.
Long bar yes heavy steel plate on the floor and it is sort of bounced on it.
It must be at yellow heat. You should also taper the edges (basically knocking the corners off the end of the bar) this lets the force go deeper into the center of the bar instead of being dispersed at the end. Upsettting is tricky to do well. Practice first and easier to do on a larger bar than a smaller one.

I hope this helps
David Robertson
Ontario Artist Blacksmith

When Can You Call Yourself a Blacksmith?

What Does Define a Blacksmith?
I know you probably had this question asked of you many times.  But at what point in metal working are you really allowed to call your self a blacksmith?   I mean going out and pounding on a few pieces of metal isn't really blacksmithing.  What does define a blacksmith?

This is actually a tricky question.

In North America there is no governing body of blacksmiths, so legally
anyone who works with steel could call themselves a blacksmith. This
causes a whole lot of confusion with the general public. A cold
fabricator calls themselves a blacksmith but charges 30% of what a
person who works with hammer and anvil and shapes the hot steel. The
fabricator only has 30% of the time into the project.

There are measurable fundamental skills associated with blacksmithing.
Do all of these have to be mastered for a person to call themselves a
blacksmith?

There are tools required for the work. Can a person call themselves a
blacksmith if they don't have the tools required to do the job?

Should a person call themselves a blacksmith until they are making an income from the smithing? Should it be a full time income?

Is it more esoteric? Such as when a person has to smith. When they are
drawn to it as a passion. Some would say "When it is their blood". A
number of smiths have told me of this calling back to the anvil when you
have been away from it for a while.

My Opinion

A person can call themselves a blacksmith when they have a good ability with the basic techniques with hot steel.

Drawing out, pointing, shouldering, flattening, punching, twisting,
square corners, hot cutting, splitting, curve generation, tool making,
upsetting, forge welding. They also have the facilities to do the work.
This may be as simple as a back yard forge, anvil and hammer.

It really is a gray area and each person has to make their own decision
when they can call themselves a blacksmith. There is no-one to call them
on it ( In North America) except their customers, which often are not
well educated in the difference between hot work and cold work.

David Robertson
Artist Blacksmith
www.artistblacksmith.com

Blacksmithing: Carbon Migration in Forging Blades

Is there Carbon Loss In Forging Blades in a Gas Forge?

Hi David Merry Christmas and thank you for an ongoing 'live' tutorial. It is very generous of you and I want you to know that I appreciate the time you put into it for us!

I do have a question at this point. One issue that you haven't addressed (perhaps you just haven't gotten to it yet and if so I apologize for jumping the gun) is that of carbon loss with a gas forge. When I was training in Japan, I watched a Bladesmith produce kitchen Kata-ha blades with a gas forge. He explained, however, that he had to work extremely fast and could only afford one heat for the forging process (he uses a spring hammer) or he would lose too much carbon. When I say fast, I mean it. I took a video of him forging 4 - 5 blades every 7 minutes. He is not an amateur, but rather the person who is considered to be (within Japan) the best kitchen knife forger in the world, so I trust his word.

It would be useful to hear your thoughts from a Western perspective.

This is an advanced question for sure.

I do make knives but there are many people much more skilled than I. I am sure the fellow in Japan is one of them but here is my view point.

My take on is a bit different. Yes I do agree if the gas forge is running too lean (too much oxygen then yes at high temperatures there is carbon loss but really only in the outer 1 mm of the steel. The carbon migrates to the lower carbon areas and if low carbon in the atmosphere of the forge then it can jump to the atmosphere, causing a net carbon loss in the blade.

There is an old saying to "forge thick and grind thin" once you start grinding you are getting back into the high carbon steel.

By keeping the forge running neutral or a bit rich there is extra carbon available and carbon migration is less of a concern but you don't have infinite heats to work with. I agree completely that you should forge out the blade in the minimum heats possible as a best practice.

Different steels will behave differently as well. Some steels need to soak a long time at high temperatures to allow the carbon to jump to a face centered cubic crystal. Think here S7 or H13. Neither would I use for knives but the high alloys do change things a lot. So in part the alloy of his knives would make a huge difference in the final quality of the piece as well as the number of heats he takes.

One heat is pretty fast! And shows a great deal of control on his part.

When You get a chance look up the article on heat treating in the members area. There is a pdf at the bottom of the page that you should download and read as it goes into much more detail than I possibly could.

Link To Blacksmith Members Sign In

I hope this helps but do check out the pdf as it goes into great detail.

Merry Christmas and Happy Holidays to all!
David Robertson
Artist Blacksmith

Hydraulic Press as Power hammer for Armor Making

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I was wondering if I use a hydraulic press for plate armor will it give the same effect as a hammer and stake or will it stretch and thin the metal?

Interesting question.
I have only worked a little with a hydraulic press but will pass on what I know.
It should work fairly well for simple dished forms. So this is changing flat sheet into bowl shapes. You will have to be careful of wrinkles developing in the steel sheet. If a wrinkle starts immediately press it out or it will get out of control. Hydraulic press have the advantage of being very slow so you can see things develop. The extra pressure means that once an unwanted shape starts to develop it needs to be corrected right away.

The hydraulic press wont work well when using a raising technique on the sheet steel. You may have to do this by hand on a stake as usual. The raising techniques involve closing a piece of sheet over a form or stake with very light repetitive hammer blows. This is actually thickening the steel as the pipe or cone is created. The press tends to deform the steel either by thinning if it is trapped between two dies or by depressing it into open space between two dies. A lot will depend on the types of dies that you make for the press.

For simple armor forming I would think about a mushroom shaped top die and a matching bottom die that could be made from heavy pipe with 1/2 inch round bar welded around the top edge to provide a round surface of contact. The diameter of pipe I would try would be about 3 inch but this would vary depending on the work you were doing.
You will have to experiment here.

Like power hammers any dies that you make should have the edges well radiused so the edges of the dies do not cut into the steel. This will give a smooth transition to overlapping pressings.

Hydraulic Press as Power Hammers.
A hydraulic press is very different from a hammer and does have a different action. They will do some of the same things. Other things not as well. Advantages of the press is the tremendous force that is developed and there is no pounding so they are relatively quite. This can be important in a residential neighborhood. The main disadvantage is that the presses are slow.

You can work hot metal under them and many people use them to develop mosaic damascus with the controlled pressure. The press will work for drawing out but not as fast as an air or mechanical hammer. The press will work very well for punching holes or shearing (splitting) or for decorative veining or punching. All can be done hot provided your dies are set up for it.

Of course a press will work very well for flattening or controlled repetitive shaping if the the dies are exactly made for a specific purpose. Hydraulic presses also have a relatively small footprint in the shop.

In general I would say a hydraulic press is a useful addition to a blacksmith shop but it will mostly depend on the type of work that you are doing. For the armor it may work very well but you will have to experiment with die shape and size to make it work effectively for you.

Sample Hydraulic Presses

Hope this helps.
David

Knife Making Belt Grinders

Recently I have had many inquiries about knife making and belt grinders.

Knife making is one of the most interesting parts of blacksmithing and is actually how my interest was peaked. Had I had a knife making belt grinder when I started it would have been so much easier.

In general there are four different steps in blade making.

1. Forging the blade from the original bar. This is where the rough shape is created. You may have heard the old saying 5 minutes at the forge saves half an hour grinding. For me that certainly is about right.
   
   
2. Primary and secondary grinding of the blade. This is creating the finished shape of the blade through a series of grinding and sanding steps. For me this takes the longest time and is the most exacting.
   
   
3. Heat Treating. This is the hardening and tempering of the blade.
   
   
4. Final sanding and polishing. This is when the blade is actually sanded to a perfect finish. You may choose to buff to a mirror finish as well.

So a lot of questions have come from people just starting out in blade making. They are wondering about the grinding steps.

Belt grinders are the best solution for blade making. They give you a flat surface to work on and remove material quickly with coarse grit. Fine grit can leave a satin finish to shiny if you go super fine.

The problem is that knife making belt grinders usually range in price from $1200.00 to $2500.00. Now that is a lot of money if you are just trying this out as a hobby. If you are committed then I would suggest looking at this price range. The standard in knife making is the 2 inch by 72 in belt grinder with usually a 1 hp or 2 hp motor.

Back when I needed a knife making belt grinder I couldn't afford to pay the $1000.00 plus for a factory built one, so I choose to build my own. So on a shoe string budget I built one. Does it work? Yes fairly well. There are things I should change on it, but in general I am satisfied with the finished piece. I used no plans and scrounged as much as I could.

I recently found good plans for a nice belt sander that requires no welding. It all bolts together!

Just Click on the above image to be taken to more information.

These plans provide simple construction just with cutting and drilling and bolting everything together. Of course you could weld the joints that needed welding, if you had a welder. It would only make it better.

Now you will have to recognize that some of the parts are expensive. Motors and contact wheels do start to add up, but this is the cheapest way to build a good quality grinder.

I also found this tool


This is very similar to a belt grinder that I started with before I built my big one. If you want to try knife making as a hobby and are on a tight budget this sander will work.

Now this is a light tool that bogs down if you are really trying to hog metal off and the small belts ( 2 inch by 27 inch) wear out quickly, but it will work. This one has 1/2 HP motor. The belts are pretty economical and this is a good way to see if you like knife making.

If you do like knife making and knife grinding then you will probably want to upgrade fairly quickly.



Now I did come across this machine and WOW! This is an industrial metal belt grinder. It sells for only $695.00 and has a 4 HP motor. This is twice the power of the best knife grinders at a 1/3 the price. It is solid and versatile. It uses a large 3 inch by 79 inch belt and has both contact wheel and flat platten for smooth grinding. Had I come across this knife grinder years ago I would have bought it.

There is a downside to it. This is 220 volt, 3 phase. Now 220 volt may not be a huge problem as most shops with serious equipment have 220 volts. 3 phase is usually limited to industrial areas. So now you would have the choice of replacing the motor, or buying a phase converter.

Both are about the same price. The phase converter for this belt grinder is recommended as
So we get back to about the $1000.00 mark but with a 4 HP motor to chew through the metal.

From everything that I have looked at, this is the most cost effective knife making belt grinder on the market. So I hope I have given you some options to look at if you are starting out in knife making or if you are looking to up grade to an industrial level.

Oh yes the most recent blacksmithing course I taught, the students were interested in making a knife as their Sunday afternoon project. They did quite well. I will put up a picture of mine when I get it finished. I still have some grinding left to do.

David Robertson
Artist Blacksmith