What bevel before heat treat

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SRWeldon

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I'm making my first knife out of 5/16 01. I have the profile of the knife ground out and am going to move on to the bevel. Here is my question, how far down should I grind it before heat treat and secondary bevel? I would like to put a 20 degree edge on it. Is there a rule of thumb? A certain percentage of spine thickness?
 
What tools do you have to put the bevels in and how do you plan to ht the o1? It’s makes a difference, you could take it down to .04-.05 before heat treating then finish after if you have a grinder but if your following a proper recipe for 01 and doing a long soak then you may want to leave it thicker and do most of your grinding after heat treating so you don’t have to worry about decarb or use a anti scale compound. If you are using files and doing a torch heat treat by eye take it down to .02-.03 and just heat the edge up with the torch then once the heat goes about half way up the blade and it’s past non magnetic quench it, after ht you can use a coarse 120 grit sharpening stone to work your bevels done to .010-.015 depending on what size knife it is before putting the edge on the blade, if it’s a small knife you could even just take it down to sharp then put a small micro bevel at 20 degrees. If you are doing a torch ht with o1 you really won’t get the best performance from that steel, it will get hard and work but you could get a better knife out of a simpler low alloy steel like 1084 or 8670, they are both easy to ht and 8670 is very forgiving on temp and soak time.
 
SRWeldon said:
I'm making my first knife out of 5/16 01. I have the profile of the knife ground out and am going to move on to the bevel. Here is my question, how far down should I grind it before heat treat and secondary bevel? I would like to put a 20 degree edge on it. Is there a rule of thumb? A certain percentage of spine thickness?
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I grind post HT but that's mostly in AEBL. I think a general rule is 0.030" but O1 may be different. You have to keep enough strength to avoid bacon edge and also need a bit to get through the scale and decarb but that should only be a few thousands per side. When in doubt, leave more on and grind more off during post HT.
 
I've done both grind to about dime thickness before heat treat and also no bevel at all before heat treat and all grind afterward. Im leaning toward preferring grinding everything afterward because it limits warping and stress during heat treat. I won't argue that it's harder on the belt budget and time consuming watching your temper during the grind afterward. I'd suggest grind to about dime thickness this first time then try all grind afterward the next time.
 
The knife I'm making is a large bowie. The spine is .3125 thick. So I should take it down to roughly the size of a dime, heat treat then put my finish edge on it? Thickness of a dime on both sides of center or total thickness of a dime?
 
I'm no expert by any means but I never feel much more comfortable going much thinner than that before HT. What say the experts here?
 
The total edge thickness is what we refer to. A dime is over .05" thick, That is a good bit more than you need. Most folks do .03 to .04.
In that monster thick Bowie, there is no bacon-edge issue to really worry about.
 
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I think it depends on the type of grind you will do.
I have two in progress with thick spines like that (0.330"), but I did a strong distal taper.
I think you should consider a distal taper. The balance and weight will be much improved.
I went to about 0.045" FFG before HT and then convexed to zero after.
 
I don't know how that got changed to .15??? It was supposed to be .05". I corrected it. I may have been typing "about 1.5mm.
 
SRWeldon said:
The knife I'm making is a large bowie. The spine is .3125 thick. So I should take it down to roughly the size of a dime, heat treat then put my finish edge on it? Thickness of a dime on both sides of center or total thickness of a dime?
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0.3125" THICK!!!. Holy cow, you prying the turret off scrapped WW2 tanks or something? That is a heavy blade. I'd love to know what you have planned for it and I pity the thing on the receiving end.

I don't know what thickness this blade is but my guess would be 0.25"

 
Stacy E. Apelt - Bladesmith said:
The total edge thickness is what we refer to. A dime is over .05" thick, That is a good bit more than you need. Most folks do .03 to .04.
In that monster thick Bowie, there is no bacon-edge issue to really worry about.
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Stacy, does the 'bacon' effect only happen in 10xx or carbon steel blades? The newer cpm steels don't have this issue right?
 
scott kozub said:
0.3125" THICK!!!. Holy cow, you prying the turret off scrapped WW2 tanks or something? That is a heavy blade. I'd love to know what you have planned for it and I pity the thing on the receiving end.

I don't know what thickness this blade is but my guess would be 0.25"

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Thats hilarious! I just love bowie knives and i definitely love FAT knives. So i thought for my first knife i wanted to combine the 2 things that I love.
 
Measure some knives you think are thick. You will be surprised how few are ever over .125".
 
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