Steel/Heat Treat/ or Use Issue

colu41

colu41

Joined
Dec 24, 2014
Messages
1,598
So I made a buddy at work a knife when I first started out. Just a simple blade with paracord handle. Anyways. I get my knives shaving hair sharp before I sell them and thats how he got his. He's really young, so has no available ways of sharpening his own knife, so I have been doing it for him. Hes having me sharpen it nearly every week and a half to 2 weeks. And its dull as a butter knife at this point. We do put our knives to great use at our work, but is this normal?
Its 1084. Was hardened, (magnet tested) and heated further before quench in 130* canola. And tempered at 400* twice for an hour.
We cut a lot of plastics and cardboards at work, so me still being a hardcore amature, I'm not sure if the blade was treated and tempered incorrectly, or if thats normal for the heavy use that is put on it....

I see people with knives that somehow chop a bunch of wood with them, and are still shaving hair!:eek: (granted not sure if HC steel was used)

Thanks for any info.
 
Cardboard is super abrasive and 1084 has very low abrasive wear resistance, once it loses it's initial edge it dulls quickly due to it's low quantity and lack of harder carbides.

No matter how perfect the heat treat 1084 is always going to need sharpening often when seeing heavy use on cardboard.
 
ridges said:
Cardboard is super abrasive and 1084 has very low abrasive wear resistance, once it loses it's initial edge it dulls quickly due to it's low quantity and lack of harder carbides.

No matter how perfect the heat treat 1084 is always going to need sharpening often when seeing heavy use on cardboard.
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Ok. Understandable. I hope in time I can trust myself enough to keep getting better and eventually get a decent oven so I can build with better steel....Thanks a lot
 
If you've done a lot of sharpening, you may have brought the edge back and now it's thicker than it was.
 
I have seen tests of various knife steels by sharpening them to a known point and then cutting rope with them, and comparing the results. I've seen some less formal tests cutting cardboard, and I've done a few crude tests myself. If you have a knife of known ability, you can sharpen it and your friend's knife to similar angles and sharpenss, then start cutting cardboard with them. See which one stays sharp the longest. Then you will have a better idea. Or you could send your friend's knife to have its hardness tested.

I don't think there is anything wrong with 1084 but it is not the one to pick for good edge-holding while cutting cardboard and so forth. My impression of 1084 is that it is a good steel for hard use and won't break easily, and it would be normally heat treated to less hardness than a knife/steel intended mostly for cutting.
 
how do you sharpen? Please consider that power sharpening, expecially with simple carbon steels like 1084 is detrimental for the edge.
When sharpening, doing it under coolant is mandatory if you don't want heat damage to the edge.
Aside that, if your buddy only cuts cardboard and plastic is fine, but if the edge is used also against hard countertops, concrete floor, ceramic and the like, is gonna get dull in no time anyway.
 
jobasha11 said:
I hope that's inclusive... 50 is way too thick for any knife IMO.

How thin is the grind? Tok thick edges will lose cutting ability much faster than a thin one.
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I take all my grinds down all the way to about .01". I never have any warping issues and depending on the style knife I'm making theres no need for post HT grind. Just a lot of hand sanding.

And I have the Lansky Sharpening set and use the 25* set angle for all my knives.
 
You grind the edge to .001, then heat treat, hand sand and sharpen, without further grinding? You might very well have decarb'd steel at the cutting edge.
 
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