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JohnCenter

How to- First Sharpening After Heat Treat

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If it makes you feel any better, 3 years and 40+ knives in and this is where I mess up more often than not....

Early days I mostly did high saber grinds and then put a convex zero-edge on using my baby belt grinder....which was all I had.

Spent 2+ hours recently and got nowhere trying to put an edge on 14C28N blades using a Lansky coarse diamond stone, resorted to the belt grinder and got a good result on the blade I started with the Lansky and recurved the other one to s#1t :angry:

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At 60 Rc you will probably want a set of stones from coarse to fine.  If it were me I'd just chalk it up to experience and let it sit until I had access to better equipment, as those stones are not cheap. 

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I used to use 60grit emery strips glued on a 2"x12" steel plate mounted on my file jig to final grind my bevels. It takes a lot of elbow grease and a lot of abrasive but it works. DMT stones are probably cheaper on the long run.

Edited by Joël Mercier

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Being the idiot that I am from time to time, it totally failed to occur to me that you could always temper it down a bit in your own oven.  What steel is it?

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Sorry to upset the apple cart with my post.  It was more me realizing that telling someone to leave the edge the thickness of a dime prior to heat treating is not very plausible if their only means of doing the final "Grinding" is by hand with abrasive paper. 

As a data point, I will use a 2x72 to do the final grinding and take the edge of a kitchen knife to 10 or 15 thousandths thick before I start hand sanding.  An hour of hand sanding both sides at 120 grit might reduce the thickness by another thousandth.  Trying to take off 25 thousandths by hand is pretty tough.

I'll be the first to tout benefits of a proper belt grinder over a 1x30.  However, we are talking about 3.5" long x 1" wide blades here.  With a 60-grit Norton Blaze belt, I'm pretty sure my clapped out old harbor freight 1x30 could still get those blades to the final dimension in less than an hour each.  $50 for the sander (less if you get a 20% coupon) and another $40 in belts would get the job done.

 

Edited by Brian Dougherty

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After spending the day trying to drawfile normalized O-1 with a notable lack of success I am beginning to think Brian might be right.  The 1x30 is more of a sharpener than a grinder, but with the right belts (that is the key here) they do move more steel than hand sanding.  

I am doing the prep work to teach a "knife finishing mostly unplugged" class for my local blacksmith's guild, and have determined that O-1 drill rod is not the steel to use for that.  Time to order some W-1 that I know I can get soft enough with primitive equipment.  Our shop consists of a coal forge, vise, and hand tools with one 110v outlet (living history farm), so I have to simplify...

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Really appreciate the followup everyone. I'm really leanring a lot. 

Luckily, where I'm at now is not so despaired as before. Out of the four blades, one of the sabre ground's edges was between 0.020-0.030". The 0.030" was mostly up at the tip, so this made for a small surface area to grind down. So I threw the 0.40" edged one in a dark corner and started over. Went down from 100 grit paper to 80 and this thinner blade evened out pretty good. By the time i polished it back up to 220 i was averaging 0.20" along the edge. I didn't take very long or much effort. Nothing compared to trying to break down a solid 0.020" on the other one! Then my Lansky with course diamond put a 25 inclusive on it while i watched tv. and now the blade shaves! 

 

I made a knife. I'lm quite happy right now!

 

i think a combination of a thinner more consistent bevel and  starting at 80 grit vs 100 made a big difference in work.

I had already send out a second batch to be heat treated (I'm enthusiastic, to say the least) and am now thanking the gods that i took the time to put clean 220grit bevels on them with a final edge consistently at 0.020" thick.  My hand filing had already improved a lot by the time i was working on these versus my first batch.

Thank you everyone for clearing so much up. At least for now 0.020" is doable, seems to survive heat treat so far, and allows me to finish up the knife with paper relatively easily.

 

So do these stats make a decent little bushcraft knife? Or should I try to aim for a thinner primary bevel and a smaller inclusive secondary bevel? Please share your opinions. Or is it also personal and experiential?

 

Funny, I measured the edge of a ESEE Izula I have and the primary bevel (flat gound) was roughly 0.030" and the secondary edge looked to be about 25 degrees inclusive. i was surprised to say the least. 

 

 

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1 hour ago, JohnCenter said:

So do these stats make a decent little bushcraft knife? Or should I try to aim for a thinner primary bevel and a smaller inclusive secondary bevel? Please share your opinions. Or is it also personal and experiential?

It depends on the overall geometry. The primary bevel angle also comes at play. If you take a look at scandi grinds, there's no secondary bevel, yet they make nice bushcrafters because the primary bevels angle is wide enough to allow enough steel behind the edge. I hope I am clear :lol:.

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