Pardon the low quality pictures
I figured leading in with a full shot would help other novices understand my frustration.
While the blade looks pretty, the flaw in the spine made itself apparent during my fourth etching cycle:
The odd thing is the crack on the show side (this is for a lefty) is about a quarter inch--on the reverse side the crack is only a 24th of an inch, if that--it only appears as a slight dark spot, noticeable in the middle of this pic:
I used those methods well noted by members such as Stacy (Bladesmith), Rick Marchand, and Tai Goo (among others) after reading Kevin's Hypereutectoid thread once a day for the past month before setting to work with Aldo's 1/8th" inch 1095. I don't typically do stock removal, but as it was my first time experimenting with 1095, I wanted to learn what I was working with before I started messing around. After reading other threads by beginners with problems with this breed, I made coupons of the steel, both beveled and non to test my HT beforehand to ensure positive results.
Satisfied, I went through the following steps:
The blank was cut from bar and profiled on my 2x72 using a dull 60grit before flat grinding to the desired levels and cleaned up using files for a steady drop to edge so that it would be neither too thin nor too thick.
I then hand sanded to 400 after drilling and deburring the handle holes. All sharp corners were softly broken starting at 200.
Once satisfied there no stress risers and the contours properly softened, I triple normalized and cleaned the blade back up to 400 grit before applying clay: the base coat was a satanite and fireclay mix, same for spine with a dab of rutland cement added-- And perhaps this is where I failed.
Both normalizing and tempering were done with a Tai inspired chunk of 2.5" muffler pipe installed in my propane forge (venturi, one of Rex's 1" hybrid burners) so that the blade did not come into contact with direct flame.
As per Stacy's standard recommendation (in threads) the blade was brought to 1,500 and allowed to soak for four minutes--I did slightly pump the blade, edge up to keep it a consistent 1, 500 while checking with a fluke laser pyrometer to make sure I did not encroach 1,550--I triple checked the Fluke's calibration using a chunk of room temp AR500 as a base to its supplied zero.
Immediately at the 4-minute mark, the blade was transferred (less than 2 seconds) to the quench--canola heated to 130 degrees (checked by candy thermometer and laser)--edge quenched 7 seconds and then completely submerged 2-3 minutes until it could be handled. I agitated during quenching by using a cutting motion so as to avoid warps or cracks.
Kitchen oven had been preheated and the blade immediately transferred from the oil to the oven for two thermal cycles at 400 degrees (again verified by thermostat in oven [not the built in one] and laser). Each thermal cycle was 2-hours, allowing the blade to cool to room temp (70 degrees) before being returned to the oven.
At the end of the second cycle, the blade was allowed to cool before I removed any remaining clay and checked with RC tester files only the 60rc just barely getting a bite.
A quick and roughed edge was free handed, and I first checked for deflection against a brass rod, then 12 penny nail, and then...yes, I know, poor form...against the rat tail on a file without chipping but finally deflecting edge just slightly, confirming I'd hit that 59-60 boundary without being too brittle.
I also know such testing is practically useless against proper Rc testing, and especially after the file test had made its own judgement, but I had to know for sure.
Satisfied with HT results, I made the slow progress up to 2K hand sanding before etching in a 4-1 ratio of PCB grade Ferric chloride warmed mildly to 60-65 degrees. I etched in 5-8 minute increments, cleaning oxides off with 2k. By the fourth cycle, I felt the sandpaper catch and, horrified, immediately neutralized.
I've now spent the past 12 hours meditating on the cause.
Too much clay? The clay was less than an eighth thick at the spine, perhaps a hair under sixteenth across the flats.
Should I have interrupted the quench? Using a 3-5 second initial edge quench, removed for a 3-count, and then completely submerged?
Among the many threads I've read on 1095 from BF, the two that stick out in my mind the most (and made a significant impression on me leading into this project) were the "Water Quench Woes" thread, and the one where one of Tai's advanced students had cracks from quenching room temp #50. Based on those threads, I wonder if, the temperature below the clay reached higher than 1,600--between pumping and trying to maintain even heat along the edge, the laser may have only read the surface of the clay, the blade below it along the spine reaching too high a temp.
The partial crack is what is most confusing--my initial edge quench might have drawn off too much heat too quickly, so that when I completely submerged, the shock caused the spine to reach its cooling point, keeping the spine straight, but still trying to warp, applying torsion, and thus the uneven break.
Or was it the spine design in and of itself? Too gentle a slope and the blade tried to curve up--causing a pileup like a car wreck.
In the meantime I've contacted the customer and informed them of the flawed blade--I consider myself fortunate that he's understanding and allowing me to make another knife. For the time being, and despite the poor picture quality, I'd appreciate some insight into where I took a misstep and ruined this blade.
I figured leading in with a full shot would help other novices understand my frustration.
While the blade looks pretty, the flaw in the spine made itself apparent during my fourth etching cycle:
The odd thing is the crack on the show side (this is for a lefty) is about a quarter inch--on the reverse side the crack is only a 24th of an inch, if that--it only appears as a slight dark spot, noticeable in the middle of this pic:
I used those methods well noted by members such as Stacy (Bladesmith), Rick Marchand, and Tai Goo (among others) after reading Kevin's Hypereutectoid thread once a day for the past month before setting to work with Aldo's 1/8th" inch 1095. I don't typically do stock removal, but as it was my first time experimenting with 1095, I wanted to learn what I was working with before I started messing around. After reading other threads by beginners with problems with this breed, I made coupons of the steel, both beveled and non to test my HT beforehand to ensure positive results.
Satisfied, I went through the following steps:
The blank was cut from bar and profiled on my 2x72 using a dull 60grit before flat grinding to the desired levels and cleaned up using files for a steady drop to edge so that it would be neither too thin nor too thick.
I then hand sanded to 400 after drilling and deburring the handle holes. All sharp corners were softly broken starting at 200.
Once satisfied there no stress risers and the contours properly softened, I triple normalized and cleaned the blade back up to 400 grit before applying clay: the base coat was a satanite and fireclay mix, same for spine with a dab of rutland cement added-- And perhaps this is where I failed.
Both normalizing and tempering were done with a Tai inspired chunk of 2.5" muffler pipe installed in my propane forge (venturi, one of Rex's 1" hybrid burners) so that the blade did not come into contact with direct flame.
As per Stacy's standard recommendation (in threads) the blade was brought to 1,500 and allowed to soak for four minutes--I did slightly pump the blade, edge up to keep it a consistent 1, 500 while checking with a fluke laser pyrometer to make sure I did not encroach 1,550--I triple checked the Fluke's calibration using a chunk of room temp AR500 as a base to its supplied zero.
Immediately at the 4-minute mark, the blade was transferred (less than 2 seconds) to the quench--canola heated to 130 degrees (checked by candy thermometer and laser)--edge quenched 7 seconds and then completely submerged 2-3 minutes until it could be handled. I agitated during quenching by using a cutting motion so as to avoid warps or cracks.
Kitchen oven had been preheated and the blade immediately transferred from the oil to the oven for two thermal cycles at 400 degrees (again verified by thermostat in oven [not the built in one] and laser). Each thermal cycle was 2-hours, allowing the blade to cool to room temp (70 degrees) before being returned to the oven.
At the end of the second cycle, the blade was allowed to cool before I removed any remaining clay and checked with RC tester files only the 60rc just barely getting a bite.
A quick and roughed edge was free handed, and I first checked for deflection against a brass rod, then 12 penny nail, and then...yes, I know, poor form...against the rat tail on a file without chipping but finally deflecting edge just slightly, confirming I'd hit that 59-60 boundary without being too brittle.
I also know such testing is practically useless against proper Rc testing, and especially after the file test had made its own judgement, but I had to know for sure.
Satisfied with HT results, I made the slow progress up to 2K hand sanding before etching in a 4-1 ratio of PCB grade Ferric chloride warmed mildly to 60-65 degrees. I etched in 5-8 minute increments, cleaning oxides off with 2k. By the fourth cycle, I felt the sandpaper catch and, horrified, immediately neutralized.
I've now spent the past 12 hours meditating on the cause.
Too much clay? The clay was less than an eighth thick at the spine, perhaps a hair under sixteenth across the flats.
Should I have interrupted the quench? Using a 3-5 second initial edge quench, removed for a 3-count, and then completely submerged?
Among the many threads I've read on 1095 from BF, the two that stick out in my mind the most (and made a significant impression on me leading into this project) were the "Water Quench Woes" thread, and the one where one of Tai's advanced students had cracks from quenching room temp #50. Based on those threads, I wonder if, the temperature below the clay reached higher than 1,600--between pumping and trying to maintain even heat along the edge, the laser may have only read the surface of the clay, the blade below it along the spine reaching too high a temp.
The partial crack is what is most confusing--my initial edge quench might have drawn off too much heat too quickly, so that when I completely submerged, the shock caused the spine to reach its cooling point, keeping the spine straight, but still trying to warp, applying torsion, and thus the uneven break.
Or was it the spine design in and of itself? Too gentle a slope and the blade tried to curve up--causing a pileup like a car wreck.
In the meantime I've contacted the customer and informed them of the flawed blade--I consider myself fortunate that he's understanding and allowing me to make another knife. For the time being, and despite the poor picture quality, I'd appreciate some insight into where I took a misstep and ruined this blade.
