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Tuesday, March 28, 2017

Basic charts for forging steel

After updating the Water quenching page I figure I could post up the color charts used for heat treating and forging steel



Mirror polish knife

The joys of putting a mirror polish on a knife can be overshadowed by sore fingers.

Typical routine is to take the knife profile down to the finished state or very close with up to 400 grit, heat treat and protect from decarburizing with a anti-scaling compound.
Possible choices range from Tool wrap (stainless foil), ATP-641 a clay compound to Condursal a paint like substance. All work and need different degrees of surface cleaning and preparation.

Most important thing with any mirror polish is to change direction of sanding at each change in grit so you remove previous scratches with much greater ease.

Normally start with 400 grit then work my way up through the numbers, 600, 800, 1200, 2000 then either 2500 or move to the buffer.
Buffing is done with an assortment of wheels and compounds.
1) stiff wheel and White
2) Medium wheel and Green
3) Soft wheel and Rouge
4) Soft wheel with Pink for coloring


This knife still has a couple of scratches left over from the 50 grit belt, been slowly working them out so I do not change the profile to drastically.

Sunday, March 26, 2017

Kydex Sheath

Had a little fun today trying to make my second sheath in Kydex.



Not my favorite method even though it is much faster than leather but this particular knife is spending its life on board a sail boat.
AEB-L blade Alumilite and paper Micarta handle so not much to corrode

Quenching Knife Steel

Strange how encounters with different people lead you on a interesting path. spent two days working on a theoretical model for a new quench tank.

Now I have to read up on thermodynamics for heat transfer methods in steel and related alloys, going to be an interesting project and environmentally friendly quite by accident.



Goal is to take a steel from 1500F up to 1950F and cool down to 600F in six seconds or less without the use of water quench which can shatter some steels or the use of oil which has high cost of disposal.

Stage one and the longest I have lots of reading and building of the test facility, sounds like it will be a fun year.

From a previous subject the use of heated water for quenching tool steels. Temperature of the water and addition of Propylene Glycol can greatly influence the cooling rate of a knife blade.

The temperature of water-base quenching baths should preferably be kept around 70 degrees F, but 70 to 90 or 100 degrees F is a safe range. The temperature of the hardening bath has a great deal to do with the hardness obtained.
The higher the temperature of the quenching water, the more nearly does its effect approach that of oil; and if boiling water is used for quenching, it will have an effect even more gentle than that of oil in fact, it would leave the steel nearly soft.
When water is used, it should be “soft” because unsatisfactory results will be obtained with “hard” water.    

A little update, from a heat treating journal written in 1929 where they were looking into heated water to replace oil in some circumstances. All testing was done on a steel that closely resembles AISI 1095 which is a good knife steel that requires a fast oil quench.


Water at 60C is much faster than a fast oil (6 seconds), will have to start testing at 70C on a 1095 steel.



As you can see in the top right graph 80 degree Centigrade water is slower than a fast oil and approaching a 11 second mineral oil.
So a temperature of 70C may match up with a six second oil like a #50 parks. This temperature will be raised or lowered depending on the effects of anti-corrosion agents if used.
From this graph raising the water temperature up to 80C will be suitable for use with 01 steels that harden very well with a medium speed quenching oil.

Na OH = Sodium Hydroxide
Na Cl = Sodium Chloride

Thursday, March 23, 2017

Fillet Knife - Banksia Seed Pod

Todays little project is shaping and sanding a fillet knife handle. The handle is made from a Banksia Seed Pod from Australia that has been stabilized in Gator Venom then cast in Alumilite resin with orange fluorescent dye.

Knife is AEB-L Stainless steel 1/16" thick with a single sided bevel that is 3/16" high. Creates a medium flex blade unless given a distal taper.


The faceted surface is not bad comfort wise however I normally go for ergonomic and round all edges. Still have to make a final decision one way or the other.

Latest update on this fillet knife, it is right hand use and left or right hand carry. Para chord is used to either belt carry or secure to life jacket or simply toss into the tackle box.


Wednesday, March 22, 2017

Knife edge thickness before quench

A little project that will be ongoing for the next batch of knives is to determine the ratio of edge thickness to spine thickness of a knife that can be safely quenched.

Current practice is a dimes thickness with no regard to overall thickness of the blade. Now a dimes thickness on a 1/4" chopper makes sense but on a 1/16" fillet knife not so much.

So going on the theory that the spine and edge will have different degrees of shrinkage and this ends in the edge cracking when it is too thin then there must be a minimum safe thickness versus depth ratio.
Betting some engineer out there could answer this in 10 seconds but this old guy is going to have to use experimentation :) more fun anyway.

What has to be determined:
  1. The minimum thickness an edge can be and safely survive the quench.
  2. Air and oil quench will behave differently, oil be much faster and therefore harder on the edge.
  3. Depth of blade, the deeper the knife the greater the apparent lever effect on the cutting edge as the spine cools. This can cause the edge to tear open or crack.
  4. A general rule of thumb might be easier to sort out, time will tell.
  5. Use of blade will play a factor here but I don't foresee anyone using a fillet knife as a chopper. I tried it once and the knife was not happy, edge held up on mine but without the pins in the holes and the heavy impacts I did eventually break it. (should have chamfered the holes)
The next batch of stainless steel blades made from 0.10" material will have a bevel with 0.01" thickness left before air quenching.


Also have to find a dime and measure it, and this brings up another question. A dime from which country? Sticking with Canada for now unless I have an American coin hiding here somewhere.

Canadian dimes measures in at 0.047" for simplicity that will be rounded up to 0.05"


Will be updating success or failures as they happen

23 March 2017
Knife #1 CPM154,  0.10" thick - edge 0.02" depth 1.28"
Knife #2 CPM154,  0.10" thick - edge 0.03" depth 1.55"


Ready for the furnace
 
 


Ready for tempering
 
 
Testing was 100% successful on both blades, Top blade needed a little cleaning for the picture since the Condursal blew off as I was removing from the furnace. First sign I did not get the blade clean enough second was a light brown coating that needed to be sanded off.
 
Actually very surprised that the knives both came out nice and straight. This can be attributed to use of quench plates and a air cooled steel which has a two minute window tooreach a temperature below 600F ideally and up to 30 minutes for room temperature.
Clamping between two plates and tossing out in the snow bank after a minute of air blast to get the stainless below 1000F makes short work of reaching below room temperature.

Really liking the color of the lower blade now if it was only adhered well enough to leave but unfortunately it takes very little to remove the coating.

Tuesday, March 21, 2017

Shop visitor

Not sure he is much help but anytime I am in the shop and buffer is running I have this large black object blocking my path.


 
They do love licking up the buffing compound once it lands on the floor. Not the best for them too say the least and if they eat a large chunk it is yard time for the day until it passes.

mirror polish a knife

Finishing a knife with a mirror polish can and is usually time consuming, going through numerous grits of wet and dry sandpaper.
Becomes almost frustrating when you get to the last grit and scratches appear that you never noticed before so back to the beginning and run through the grits double checking all scratches from previous grits are removed. Get to the end and there is a scratch.

Then the old brain kicks in something has to be really wrong and go through all the paper and toss it, clean buffing wheel for the second time and everything is good.

Well except for the sanding bar that has a burr so small it only hits the blade when using a 2000 grit paper or higher. Time to refinish the sanding bar and find a safe place for storing it instead of just leaving it on the steel work bench.
On that note going to be looking for a rubber sheet to cover the work bench from this point on.


Trying to achieve a slightly different finish with this knife going from a normal mirror finish and transitions on the flats to a textured (240 grit) that gets a mirror finish on the high points.

Monday, March 20, 2017

Super Quench for Railroad Spikes

SOAP SOLUTION QUENCH

The Forgery School of Blacksmithing
For mild and low carbon steels

Whether it’s on the internet group "the forge", at ABANA chapter conferences, or just general discussion between a couple of friendly smiths, when the subject of Robb Gunter's "Super Quench" comes up, most of it is fact, but some of what is passed around is erroneous. Yes, there are some errors, but generally minor. There is often a great deal of disbelief as to the efficacy of this Super Quench. Here's what he had to say about it at the Guild of Metalsmiths 1997 Fall Conference: 
 
Before the Bessemer process made it feasible to effectively control the amount of carbon in steel, blacksmiths generally had only iron or tool steel to work with. The Bessemer process gave the steel manufacturers the ability to produce steel in a variety of carbon levels. Mild steel (1005, 1018, and the like) was touted as the all-purpose steel destined to replace wrought iron. The manufacturers claimed that it was also suitable for many tools, but that it should be quenched in a solution of sodium hydroxide.
 
At Sandia Labs, Robb and his cohorts experimented with this lye quench and, a bit to their surprise, they found that mild steel hardened considerably more than expected. Metallurgists and others will tell you quite readily that mild steel won't harden. It may get a little harder than if annealed, however it doesn't harden in the typical toolmaker's sense of hardening.
 
Generally speaking, in a plain water quench you shouldn't expect to get more than Rockwell ratings in the low to mid 30's. Robb found that the sodium hydroxide quench resulted in average Rockwell ratings in the 43-45 range, with an occasional test result as high as 48.
 
So, Robb started using this solution at Sandia Labs, but installed a vented hood system over the quench tank. This stuff is pretty harsh and the need for a vented hood was a no-brainer.
 
Then OSHA arrived on the scene and insisted that the use of the sodium hydroxide solution cease. The result was that Robb and the Sandia Labs metallurgical lab crew went to work to find a replacement solution. It had to give hardness results comparable to the sodium hydroxide solution, and it should be bio-degradable if possible. The result of their experimentation was what is now generally referred to as Gunter's Super Quench. The formulation is as follows:

  • 5 gallons of water (This a good volume to work with for quenching, and there are plenty of buckets and pails around just the right size.)
  • 5 lbs table salt (plain or iodized, canning salt or rock salt, it makes no difference.)
  • 32 oz Dawn Liquid Dishwashing Detergent (blue. Blue was chosen because that's what happened to be available at the moment. It was noted later on that as the solution deteriorated to the point that it should be disposed of, the color slowly changed to green. Hence, the blue detergent is recommended. Any other blue colored liquid detergent could work just as good.)
  • 8 oz Shaklee Basic I. (The solution needs a surfactant to maximize contact between the solution and the piece being quenched. Amway Basic H will also work. Your local farmer's supply should be able to help here, as similar surfactants are used to facilitate the distribution of fertilizer in soil. In response to a question from the viewing stands, Robb said that just about any wetting agent should do, even the stuff photo film developer’s use. Just follow directions on amount of agent to be added to a given amount of water, then scale up or down to the 5 gallons of water used in this formulation.)
Heat your iron to 1550 degrees Fahrenheit, and quench. No tempering is needed.

So, he mixed up a batch right there in front of us and used it for his next demonstration. He took a piece of 1/2" 1018 and cut off a piece about 3" long. This piece was heated in the gas forge, and a cold chisel end was forged on to it. Robb heated the piece to 1550 (critical temp for mild steel), and quenched it in the solution. He then took his new "chisel" and proceeded to use it to cut almost through the parent bar. Then, he did it again.

The cut bar and the chisel were passed around for all to take a good look at. The edge on the chisel was not deformed in any way. The top had not mushroomed, nor did it even show any evidence of having been hit with the hammer. But, so as not to mislead us, Robb said that a chisel of this type might be good for 7 or 8 cuts maximum. He recommends this quench for tools such as spring fullers and many treadle hammer tools/dies/fullers. He showed, and used, one such spring fuller that is made of mild steel and quenched in the solution. He has been using this particular fuller for several years with no ill effect. The fuller is unmarred, and the spring is still strong.

I was impressed, to say the least. I was not the only person there who was "wowed" by this little "trick". Robb said the quench is good for anything up to 50 points of carbon. Above this carbon level this quench should not be used.

The above is from Robb Gunter at the Guild of Metalsmiths 1997 Fall Conference.

Railroad Spike knives


Railroad Spike knives

To get it out of the way right off the bat:
1) not a high carbon steel, the HC simply designates a spike with higher carbon than a conventional spike.
2) no magical properties, HC spikes have on average 0.33% carbon and minor alloys.
3) holding a rail in position does not require super strong steel or even super duper strong.
4) Paper can cut you that does not make it the ultimate material for knife making.
5) passing the blade smith test with a spike knife is not testament to the high quality of railroad spikes. It simply shows that pretty much any steel can be used if prepared properly.

Now the good parts? If you are given a few hundred pounds of spikes and want to make something with them then go for it.
Things I have seen to date range from knives, forks, flowers and coat hooks. fact is like any mild steel they can be shaped into anything you heart desires.

One word of caution though is that walking the tracks can be hazardous to your health and is considered trespassing so if you get arrested and charged don't be shocked.
Visiting the rail yard and talking with the crews is better but you have to also consider how many people go wandering through the yard every week looking for free steel. Imagine being at work and having several people walk in each day looking for free stuff and you can see they might be less than friendly.

You can buy bar stock from any steel supplier in the AISI 1040 or 1045 category and have a steel that will work easier without having to deal with rusty spikes. If you want the head then either forge the head manually or make a swage block, best part is you can use a swage block to shape any tool steel into a spike and have a functional knife in the end that looks like a spike.

If you would like to show off your spike knives or anything else made with a spike check out this Facebook group, that is if you tolerate Facebook.
https://www.facebook.com/groups/1767250816868753/

Realized wall of text is boring :) If you want some very high end railroad spike knives check out Andy Alm on eBay or Facebook
http://www.ebay.com/usr/top_quality_knives?_trksid=p2047675.l2559



https://www.facebook.com/andy.alm.1

Since you have to use a forge when making a spike knife this is a good time to learn how to forge weld. Welding in a piece of 1080, 1084 or 80Crv2 will give you a good cutting edge while maintaining the spike knife appearance that many people like.


Sunday, March 19, 2017

Tool Steel Designation Letters

Tool and Special Purpose Steels


WX   Water-Hardening Steels
SX   Shock-Resisting Steels
OX   Oil-Hardening Steels
AX   Air-Hardening Steels
DX   High Carbon-High Chromium Tool Steels
HXX   Hot Work Tool Steels
TX   High Speed Tungsten Based Tool Steels
MX   High Speed Molybdenum Based Tool Steels
LX   Special Purpose Tool Steels
FX   Carbon-Tungsten Tool Steels
2XX   Chromium-Nickel-Manganese Stainless Steels
3XX   Chromium-Nickel Stainless Steels
4XX   Chromium-Stainless Steels
5XX   Low Chromium Heat Resisting Stainless Steels

Steel designation letters

Carbon steels10XXPlain carbon, Mn 1.00% max
11XXResulfurized free machining
12XXResulfurized/rephosphorized free machining
15XXPlain carbon, Mn 1.00-1.65%
Manganese steels13XXMn 1.75%
Nickel steels23XXNi 3.50%
25XXNi 5.00%
Nickel-chromium steels31XXNi 1.25%, Cr 0.65-0.80%
32XXNi 1.75%, Cr 1.07%
33XXNi 3.50%, Cr 1.50-1.57%
34XXNi 3.00%, Cr 0.77%
Molybdenum steels40XXMo 0.20-0.25%
44XXMo 0.40-0.52%
Chromium-molybdenum steels41XXCr 0.50-0.95%, Mo 0.12-0.30%
Nickel-chromium-molybdenum steels43XXNi 1.82%, Cr 0.50-0.80%, Mo 0.25%
47XXNi 1.05%, Cr 0.45%, Mo 0.20-0.35%
Nickel-molybdenum steels46XXNi 0.85-1.82%, Mo 0.20-0.25%
48XXNi 3.50%, Mo 0.25%
Chromium steels50XXCr 0.27-0.65%
51XXCr 0.80-1.05%
50XXXCr 0.50%, C 1.00% min
51XXXCr 1.02%, C 1.00% min
52XXXCr 1.45%, C 1.00% min
Chromium-vanadium steels61XXCr 0.60-0.95%, V 0.10-0.015%
Tungsten-chromium steels72XXW 1.75%, Cr 0.75%
Nickel-chromium-molybdenum steels81XXNi 0.30%, Cr 0.40%, Mo 0.12%
86XXNi 0.55%, Cr 0.50%, Mo 0.20%
87XXNi 0.55%, Cr 0.50%, Mo 0.25%
88XXNi 0.55%, Cr 0.50%, Mo 0.35%
Silicon-manganese steels92XXSi 1.40-2.00%, Mn 0.65-0.85%, Cr 0-0.65%
Nickel-chromium-molybdenum steels93XXNi 3.25%, Cr 1.20%, Mo 0.12%
94XXNi 0.45%, Cr 0.40%, Mo 0.12%
97XXNi 0.55%, Cr 0.20%, Mo 0.20%
98XXNi 1.00%, Cr 0.80%, Mo 0.25%

Saturday, March 18, 2017

Quenching oils

The most often recommended quenching oil tends to be Canola Oil second in line is a dedicated fast quench oil like #50 Parks. Canola is available at the nearest grocery store while #50 parks is available in two locations in North America.

The #50 Parks is almost as fast as water for a quench right at the 6 second mark while Canola comes in second and ahead of the 10-12 second medium speed oils.

If you search the following "quenching speed for canola oil" you will find information like this link below with lots of valuable information on Vegetable oils for quenching and it is not all bad news as some would have you believe.
While not the best for steels that need a fast oil like 1080 to 1095 it will be adequate. However if you start selling knives then it is a good time to upgrade to a high speed oil so you are putting out the best product possible.

The links provided lead to professional research that has been carried out on Canola oil Quenching for both its environmentally friendly foot print both in acquiring the product and during its disposal when depleted.

advances_in_quenching
Quenching and Heat Transfer Properties of  Aged and Unaged Vegetable Oils
Vegetable oil structure and antioxidants

Friday, March 17, 2017

Suggested Reading Material

As a very first book and to get your feet wet in the art of knife making I would suggest purchasing a copy of:
Wayne Goddard  $50 knife shop.
ISBN: 1440224919, 9781440224911

This covers the basics very well although the $50 price tag has gone up unless you find lots of the tools you need from local yard sales
Figured today would be as good a day as any to actually figure out what it costs too make a knife or at the minimum just how long it takes.
Counting breaks and assorted other activities around the house what seems like weeks may not be quite so long in reality.

The joys of time studies writing down each and every step and recording duration.
Will be updating a list of links for Canadian sites of benefit to Canadian knife makers