1095 problem

Sam Salvati

Sam Salvati

Joined
Aug 6, 2007
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My problem may stem from the fact that I do not have very consistent control over what is going on, no way to judge temperature of the blade itself before quenching(coal forge), no way to judge hardness acheived(other than the old file test), and I also think my other problem was the fluctuating temper temperature. Did a nice 1095 bowie, soaked it at temperature for about 8 to 10 minutes, then quenched in hot oil. Started to temper at 450F, then got called away and came back 30 minutes later and it was at 480, so i lowered the flame and got called away again(walk ins) and when I came back after the next 30 minutes it was at 420, and that was when i took it out and let it cool down. Even after the temper cycle which I am guessing was just too low, I did not notice any change whatsoever in the file resistance (i know the lack of precise measuring instruments is killing me too), should I bump up the tempering temperature and keep a friggin eye on it this time and try again? One of the very first times I have tried soaking a blade at temperature before quenching, is this what real hardness is like? I have never seen a blade this hard before.


PS, That seax is gonna pay for the insulating wool for the drum forge style heat treating oven as well as the pyrometer and thermocouple and stuff.
 
How sharp is your file?? Also another test is the brass rod test. It can be a better judge of hardness.
 
My worn out file I use for hot filing. Would the brass rod test risk cracking or breaking of the blade? I apologise for my massive amounts of poor planning and execution, and haphazard crapshoot techniques, I am trying with what I have.
 
The brass rod test if done properly will not break or crack the blade. You have to sharpen the knife unless the edge is pretty thin. Then you push from the side with enough pressure to flex the edge. If it chips out put it back in at 25F hotter. If it does not return to straight then normalize and re HT. The file test should be done with 2 files. A dull one (not a hot file) and a sharp one. The sharp one should barley cut and the dull one should slide. Compare the cuts to a piece of mild and it will give you and idea of how well it cuts. If the sharp file still slides then put it back in at 25F hotter.
 
Sam Salvati said:
My problem may stem from the fact that I do not have very consistent control over what is going on, no way to judge temperature of the blade itself before quenching(coal forge), no way to judge hardness acheived(other than the old file test), and I also think my other problem was the fluctuating temper temperature. Did a nice 1095 bowie, soaked it at temperature for about 8 to 10 minutes, then quenched in hot oil. Started to temper at 450F, then got called away and came back 30 minutes later and it was at 480, so i lowered the flame and got called away again(walk ins) and when I came back after the next 30 minutes it was at 420, and that was when i took it out and let it cool down. Even after the temper cycle which I am guessing was just too low, I did not notice any change whatsoever in the file resistance (i know the lack of precise measuring instruments is killing me too), should I bump up the tempering temperature and keep a friggin eye on it this time and try again? One of the very first times I have tried soaking a blade at temperature before quenching, is this what real hardness is like? I have never seen a blade this hard before.


PS, That seax is gonna pay for the insulating wool for the drum forge style heat treating oven as well as the pyrometer and thermocouple and stuff.
Click to expand...


Sam do your test with a brand new sharp file, at the temperatures you are drawing it really should bite a bit. How hot is "hot" oil? If you are quenching 1095 in an oil that is above 250F and your file isn't biting then you really need to get a sharper file (well maybe, pearlite can be problematic). The curve is just too tight on 1095 to expect to marquench it in any traditional manner and avoid making pearlite. If "hot" means around 130F then keep trying and watch the scaling and decarb and leave 400F wesson to the guys who like pearlite and hate eyebrows.

Don't sweat the low tech approach, it has worked for 2000 years with simple steels. You have just challenged yourself using a trickier steel with simpler tools, if it gets to be too much take a day off to play with some 1084 in the forge to get the feel of things working well again.
 
Kevin, you read me like a book. I'll try it out with a brand new file, the oil was eyebrow roasting hot;), what I acheived is probably mostly pearlite and martensite mixed together right? I'll normalise and try again with 130F oil. Thanks Kevin.
 
Sam, Quit frying your chicken in the quench tank!
1095 does not need a 8-10 minute soak, either. 3-5 minutes is plenty.130 (max. ) oil temp -FAST oil.
Stacy
 
Yeah I know, i should have known better, I thought i'd be a thickhead and give it a try, but consider me a new man from here on out, old habits........are dead, honest. When my gift card from Darren Ellis get's here, you can bet a gallon of parks#50 is on it's way, no more peanut/corn/wesson for me except for giving a nice finish on blacksmithed stuff and cookin' lunch.

Thanks guys.
 
Sam,
Do you quench more than one blade in a HT session?? If so then you really need more oil than 1 gallon. It will get hot fast and lose it's efficacy. Parks 50 does not like to be heated too much. At least according to their literature. I also found that I lost the Hamon after 120f in the parks. Now I make sure it is below 100f.
 
I usually do, getting the fire tended just right can be tricky so I like to do as many as I can each time. maybe I should go with the 5 gallons then, thanks Chuck. With the small quench tank I use now I find the oil to jump as much as 50 degrees per blade, then I let it cool while the next blade is heating up, sometimes help it along with some cold bars to heat sink.
 
If you have extra oil you can remove some of the hot oil and replace it with cold. It is really nice to have the extra heat transfer with more oil also. My tank holds about 4 gallons and warms up about 15F or so over HT of 5-7 knives or so. It also takes a while to get them up to heat but the oil only cools a couple of deg in the time between quenches. 5 gallons will be plenty. Have you thought of a retort inside your forge. Just a pipe with one end sealed. Put it in the coals and bring it up to temp. It will transfer the heat a little more evenly. Tai Goo had a great tutorial on his site at one time.
 
That is a good idea Chuck, replacing with some cold oil that would bring the temp down much quicker. I have seen the pipe trick, I'll try it out but I can get a nice even heat with fine coal quite well.
 
Sam
Your file - the one you use for hot-filing - might not be the most reliable measure of hardness. The teeth on that thing have probably been drawn back a bit from repeated close contact with hot steel.
 
The other nice thing about the pipe is if you decide to modernize a little, a thermocouple can be slid down into the pipe to check temps. I just make sure it is away from the sides and close to the blade.
 
Why don't you just use your kitchen oven for tempering?
 
Low tech does work. I used a torch and magnet and color for many years. Used motor oil and then peanut oil. Took me 4 years and like ron too many failures to even think of. I began using more high tech consistent methods when I started thinking of getting my MS. I felt I owe it to my customer to give the absolute best I can. I began buying the right materials and equipment to provide those results. Low tech can be great and do not mean to run it down. This was my evolution.
 
Thanks for the tips guys. i tried again witha brand new file today, and it bit but only a little bit. JDM, I cannot stand to waste electricity using the oven, it's much cheaper for me to use the gas for the torch, usually it is more reliable but I got called away from watching it to keep it in check. Let's just say I look FORWARD to getting the HT oven going, and proper quench oils, I am constantly striving to want to make the best blades I possibly can with what I have.
 
That sounds good Sam. Sharp File just barely cuts. Translates to 2-3 RC under file. Most Files are RC 62-63 so it should be 59-60 RC. Now just for the heck of it do the brass rod test for a backup....
 
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