Monster bowie made of GNiCr40Al4

H

hammerfall

Joined
Oct 2, 2010
Messages
221
when i say monster, it acctrully meant it. the knife size is: 460mm long, 50mm wide, 6.5mm in thickness. she is made of cold rolled GNiCr40Al4 alloy. hardness is arround 62~63Hrc. the unnotched impact toughness of this alloy is 36j/cm^2(10x10x55mm test sample).

the original design of this knife was aimed at using S7 or S5 shock resistance tool steel for higher impact toughness. however, this knife is going to be a gift for my friend's father who lives in a harbor city and he is not very good at taking care of knives. it forced me to pick up a stainless steel or alloy. i picked up this alloy since its has high hardness, with ok toughness and almost immune to rust. another very important reason i picked this alloy is the outstanding mirror polishing preportie can make the blade a prettier gift lol.

since it is a big blade, and very wear resistance, it took 3 people 2 weeks to finally finish the whole thing. here are some photo i took.

knife1.jpg

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knife2.jpg

knife3.jpg

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Hammerfall, you're doing some beautiful work. I don't envy you shaping and polishing that big blade out of this alloy. Nice fittings, too.
 
Salem Straub said:
Hammerfall, you're doing some beautiful work. I don't envy you shaping and polishing that big blade out of this alloy. Nice fittings, too.
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yeah, shaping and polishing took most of the time. fortunatly we had 3 people working on one knife in turn, make it less a pain.
 
rane-dig said:
Nice Finish. Do you mind laying out the steps you took to bring it up that fine?
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sorry for the delayed reply. i wasn't able to log on this website for a long time.

the polishing steps are:belt grind to 600 grits. then rub it with 800 grits sand papper from guard to tip, follow with 1000 grit from edge to spin, 1500 grits from guard to tip. finally use angle grinder and wool wheel polishing it with W0.5 < 0.5 polishing paste. do it until you see completely mirror reflection. the angle grinder i use was 1500w one. well, i did not use it. it took really strong arms to control that thing. i got a 200lb muscle guy did that part for me lol. but i don't think you big americans will have problems using it. just locating your knife really tight, so you don't blow it away like a bullets with your angle grinder. i had tried 800w angle grinder, it doesn't work as good and take much longer time. the sand papper does matter much. i polished one side with $1 german sand papper, another side with the 8 cents one made in china. german papper has a much better result before using angle grinder. but once both side is angle grinded, the difference is very very little.
 
Glad to see that you got the internet problems fixed. Government firewalls and filters can be a problem.
 
bladsmth said:
Glad to see that you got the internet problems fixed. Government firewalls and filters can be a problem.
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luckly its only temporaly banning. i think i had post some overacting comments about a knife brawling in this forum. they might banned me because of that.
 
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