Ht procedure questions
I have been doing much research here and elsewhere to educate myself on heat treating procedures of various high carbon steels for knife blades.
I am not new to technical data in general but I am new to knife making. My background is technical and electro/mech in nature with much experience in many different things in my 60 years of life.
I do NOT have any experience with doing any actual heat treating of high carbon steels although my brother in law and nephew had a large heat treat business for years and I did pick up some BASIC knowledge.
I am not only gathering info but also equipment and am currently building my own electric kiln. I have been known to be a rather "exacting" person and I always strive for excellence no matter what I'm doing/making. Sometimes this can cause me to be somewhat overly concerned regarding details that may not be super important, but none the less this is my nature. I believe in doing things right the first time if at all possible. I realize I will make some mistakes and will learn from them, but I am attempting to keep my mistakes at a minimum and gain some knowledge first from people who already know the answers and methods that work for them regarding heat treating and other knife making techniques. Not everyone's methods and techniques are the same but work for them.....I am keeping this in mind while gathering info.
Against all suggestions found on the type of steel to start out with as a newbie, I will be using CRA 1095 that I already purchased from Admiral Steel. I live in the Midwest and Admiral Steel is nearby which kept the shipping charge lower. I WILL be using 1095 so please do not attempt to steer me towards 1080/1084.....Admiral did not have any CRA 1080anyway and I would prefer 1095 for my own personal reasons. I am confident in my abilities that I will be able to successfully HT 1095 with the proper knowledge and a little practice. Compared to some other things I have accomplished in my long life (deliberately and not deliberately) I feel 1095 heat treating is very doable with the proper equipment and knowledge. I will no doubt perfect my technique in time with practice.
From what knowledge I have already found, here is my plan for 1095 HT. I would greatly appreciate input from 1095 experienced people.
1) Since I am using CRA 1095 I shouldn't have to anneal or normalize, but you tell me.
I will be doing my drilling and major grinding first before HT.
2) Heat Treat in my elect. kiln to 1475f and hold for 5-10 minutes.
3) Quench approx. 7 seconds total, and I realize I have less than 1 second (in the quench) to
have the temp drop to under 900 degrees.
4) Temper. I believe right away after blade is down to 150f or maybe hand holdable.
I will temper @450f for 2 hours, let cool to room temp. and then repeat.
5) Final grind and hand sand carefully to not overheat.
I have some questions regarding the heating up and cooling down procedures:
1) I have read some past discussions on this forum regarding "how" to heat up 1095. There seemed to be a difference of opinion at one time as to whether or not to heat up to 1475f quickly or not! Meaning, put blade in cold elect. kiln or preheated elect. kiln.
I am of the belief that I should put the blade in a cold kiln and just heat it up that way and that there is no worry about grain growth unless the temp. would get to 1525+f. Besides, if I were to put a cold blade into a very hot kiln at "X" temp., how would I know how long it might take for that blade to actually be at 1475f for 5-10 minutes?.....doesn't make sense to me!
What are your current thoughts on this?
2) Should the Tempering oven be preheated or not? Does it really matter?., as long as I'm sure the blade is actually @450f for 2 hours (twice) is what's important in my mind, but you tell me.
3) Is it important "how" to cool the blade down to room temperature between Temper's with 1095? Should it be done slowly and left in oven or taken out? Can 1095 be run under cool water to cool down between Temper's or not?
Yes, I am detail oriented and MAY be overly concerned about certain things.........but I want to do the best things that have worked for experienced people and put my mind at ease. I also don't want to waste a lot of time, effort and money needlessly.
Thanks for reading this very long write up and I apologize for any redundancy to previous threads but I just couldn't find definitive answers to my questions.
DAVID
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