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Roger Moore

My first knife. Something I made over Christmas

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I've had it in mind for some time now to have a go at making a knife, so this Christmas I thought I'd have a go.

I've never made a knife before so this was my first attempt.

No forging, just stock removal using my CNC mill. I'm not really happy with the handle. I bought a piece of thuya burl, but when  it arrived  it was awful. not one face was parallel with another so there would have been nothing left to work with. I found an old lump of oak so decided to use that instead.

Decided to add a makers mark when the blade was all but finished and hardened and tempered. Engraving it was a bit scary but glad I did. Makers mark is my family crest, a rampant lion and my surname.

It's not ornate or fancy, I wanted something simple and clean for my first knife.

It's not yet sharpened .....I haven't decided what system to invest in. Tried Lansky diamond system on my kitchen knives, not really keen on using iton this.

Any comments, criticism or suggestions welcome.

Roger

 

 

Blade length 220mm

Thickness at spine 6mm

Width 48mm

Overall 355mm

Material 80CrV2 hardened and tempered to 60~63 Rockwell

Handle oak

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Outer contour cut and bevel roughed with a 6mm ball end mill

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Semi finishing the bevel with a 6mm ball end mill and 100 micron step over

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Finger guard machined from 25mm bar stock in 4th axis on mill

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Handle roughing outer contour with 20mm end mill

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Finishing  with 6mm ball end mill

all done using 4th axis so handle can be flipped.

handle held by tang slot on an aluminium spigot the same dimensions as the blade tang

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This makes me want a CNC mill. Nice work!!!

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Thanks for the reply Jeremy

CNC is ok, but it's not exactly "file print" ... sometimes making things the old fashioned way is easier (and quicker)!)

The blade looked almost finished when it came off the mill. Then took 3 days of wet and dry and blistered fingers to get it back after hardening it. ..... would have been a lot easier had I had a decent belt sander in hindsight.

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Cheater! :D

Just kidding.  There's always more than one way to get the job done.  Being a Solidworks designer with a past history of CAM programming I can appreciate the amount of work that you put in to designing and machining that out. 

A couple of tips for your next one;

Do the bulk of your hand sanding, out to 400 grit or so, before hardening.  It's way easier to sand on "soft" metal.  As long as everything stays straight during heat treat you'll be way farther ahead.

Along with that, use a hard backer for your sandpaper.  I have something similar to this (https://www.amazon.com/3M-05519-Sanding-Block-Rubber/dp/B002MDHECA) that I epoxied a piece of steel to.  It will help to keep your edges and your transition lines nice and crisp and I think it helps to speed things up as well.

Welcome to the madness!

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Great job, especially for a first! My college just got a CNC milling machine and learning how to use it I've really gained an appreciation for the time that goes into programming a part, let along making something as complicated as a whole knife. 

2 hours ago, Roger Moore said:

The blade looked almost finished when it came off the mill. Then took 3 days of wet and dry and blistered fingers to get it back after hardening it. ..... would have been a lot easier had I had a decent belt sander in hindsight.

From what I can tell, pretty much anyone using a ball end mill for roughing cleans up with a belt sander afterwards. Alex's advice about sanding before heat treat is solid. Steel is much more abrasion resistant after hardening, especially when it has additional carbide formers added. Depending on how much of the surface needs to be removed, a fine cut file may help.

I remember seeing someone who would rough bevels with a flat end mill by using a jig to clamp the blade blank at an angle. That would introduce the complexities like building the jig and finding a good way to set the origin, but it seems like that might be able to get a somewhat closer to final surface finish.

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awesome, the high tech approach to knife making. as has already been said, no less work than manually forging out. just a different type of work. 

as for sharpening, im a big fan of free handing on a belt sander. i had a Gatko for years, which is just another version of the lansky system. they do very well, but for me they are very time consuming and those clamps always leave some type of mark on a blade youve spent hours getting to mirror polish. with practice, you can put a really wicked edge on a blade in less than 10 minutes with a belt sander. heck, ive only got a 1x30, so a 2x72 should be even faster! just watch the heat very very VERY carefully. 

i go all the way to 800g on the sander then use an old belt reversed on the machine and loaded with PC1 buffing compound to strop and polish the edge to a mirror finish. hair popping right of the bat

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Many thanks to you all for your very kind comments and suggestions. All taken on board.

Whenever I've hardened anything in the past, its probably been lapped / cleaned up afterwards in the lathe, so fairly easy in comparison to a blade.

The un-machined part of the blade had a ground finish on it as it was ground flat stock. The machined bevel was actually a much better surface finish than the ground part. I Guess it was probably ground with something like an 80 grit or coarser wheel.

I pondered how far to go with the blade before heat treating but wrongly concluded that it would need a lot of work afterwards anyway so I may as well do it afterwards. Lesson learnt.

I'm not sure about the heat treatment. I confess that plunging a piece of red hot metal into oil kind of goes against my instinct of self preservation and was quite a traumatic experience. I used Illocut 486 cutting oil as it was all I had in abundance. Not sure how fast / slow or compatible it was for quenching. I also used an electric over which was set to 850 degrees. The blade was placed in uncoated laying on its spine. Oven temp dropped to around 780 then slowly rose back to 850 where I gave it 10 mins. May well have "overcooked" it. If you look at the picture of the blade after heat treatment, you can see some marks that look like puddles. It almost looked as if something had oozed out of the steel puddled on the surface and then set as it cooled.

CNC process want helped by the fact that my mill has an X/Y cutting envelope of 300mm and the blade and tang are about 350. Blade was held on a piece of sacrificial aluminium milled flat and then tang doweled in 3 positions so it could be registered. Many setups ....

 

 

 

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Yes, I would agree that 850° C. is a little warmish for an austenizing temperature.  You might want to drop it back to 800° C. and hold for just a couple of minutes if you have the capability of soaking at a constant  temperature.  However, I don't think that you overheated the steel.  Are the ~60-63 HrC approximate from some table or are they actual measurements from a hardness meter?  If they are actual I would consider them to be a bit high for a chopper lake that.  I would take it down into the high 50's.

I have to admit that I'm not fond of extreme clips like that but that's personal taste.  Others would love it and I do have to admit that it's well proportioned to the rest of the blade.  People who are looking for that kind of a knife are going to be expecting some sort of a guard on it even though evidence suggests that the "original" bowie knife didn't have one (it was doubtful that it had a clip either).  A guard would also make it a safer knife to handle if it was being used for something like hunting hogs of dogs.

For other changes, I would take the primary bevel farther up the blade.  That saber grind is nice but I think a full bevel would be nicer.  The other things is a lack of distal taper.  That thing must be a beast to handle.  As far as the handle goes, I wouldn't change a thing.

Doug

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Hi Doug

From the suppliers website:

80CrV2 is a high carbon tool steel with excellent toughness. It has an easier heat treatment process. Each piece is supplied surface ground and mill-scale free! It is also known as 1080+.

Heat Treatment Instructions:-

Heat to 840 to 880 degrees centigrade - hold for 5 - 10 minutes
Quench in Oil

Tempering Range (2 Hours):

150 degrees centigrade - 63HRc
200 degrees centigrade - 60HRc
250 degrees centigrade - 57HRc

I tempered at 160-170 degrees, so its calculated not measured.

" I'm not fond of extreme clips like that" - What's a clip?

" beast to handle" - I don't really have anything to compare it with other than a carving knife in my kitchen draw.... it's nice in the hand though.

" sort of a guard on it" it does have little finger guard :)

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850c is good. I use 1575f(860ish). This steel can be austenized from 1475 to 1575. You wont get all carbon into solution if you austenize at 1475, some will remain cementite. But a 10 min soak is a bit exagerrated and you'll get massive decarb if the steel is uncoated. 

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looking back at some video I took......

I went with 860 degrees as it was middle of the road between 840 and 880 as recommended.

I put some wood coals from my log burner in there as id read somewhere it helps to take the oxygen out and help with scaling. Oven temp dropped to 727 when I opened the door to put the blade in. I then waited for it to get back up to 860 and gave it a further 7-10 mins

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" massive decarb "?

" You wont get all carbon into solution if you austenize at 1475, some will remain cementite. "?

remeber this is all new to me .....

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25 minutes ago, Roger Moore said:

" massive decarb "?

I'll try to put this simply and I hope I get this right. At high temperature, the carbon atoms in the steel will prefer the oxygen atoms in the air over the iron atoms of the steel so it will ''move out''. The longer the steel is left at high temperature, the thicker the layer of decarburized steel will be. And the higher the temperature, the faster it will decarb.

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That's it exactly.

The blisters on the steel after hardening indicate slight overheating and/or decarb, but nothing you didn't fix by post-heat treat sanding.  

As for the oil, I'd suspect cutting oil is a very fast quench indeed since it is designed to move heat away from the parts.  Warm (45 C) canola/rapeseed oil is more what you want for that steel.

I'm quite impressed you did all that on a mill!  

If you want forging and grinding instruction, go to http://owenbush.co.uk/school-of-smithing/ and sign up for a class or three.  Owen is great, and he's on the southeastern end of greater London in Welling, Kent.  

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Ok... got it.

Cleary this is going to be something of an art rather than a science.

Maybe the way forward is for me to make some simple polished samples and try heat treating them with different parameters. A spot of trial and error with simple pieces rather than a part finished blade

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 Thanks Alan

Canola in the UK seems to be very expensive, rapeseed not so I think I'll give that a try as well.

Also need a bigger quenching pot. I had to commandeer the toilet roll holder and fill it with oil as it was the only suitable metal container i could come up with at the time. Since been reinstated for its designed purpose  - So glad I'm single :)

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Posted (edited)
15 minutes ago, Alan Longmire said:

As for the oil

I have been wondering why a fast oil would be too fast for that steel. Aldo's V2 has around 0.5% manganese and 0.5% chrome. I believe manganese improves hardenability at a much higher rate that chrome. And we know 1084(which has around 0.8% manganese) can be quenched in both canola and parks 50. 

Sorry to hijack your thread Roger! That's a very impressive first knife btw.

Edited by Joël Mercier

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" Sorry to hijack your thread Roger! That's a very impressive first knife btw."

Joël

Don't be daft, no hijacking at all ....

 I just set out to make something and did a bit of research beforehand. Thoroughly enjoyed making it and next time want to do it better. (oh dear, that sounds like I'm hooked!) I never imagined for a moment i would be talking to anyone on here or having the balls to post any pictures of the outcome of my efforts.

I absorb information and any scrap of it is useful.

 

Roger

parks 50?

https://www.ryeoil.co.uk/product-category/ancillary/quenching-oil/

or rapeseed?

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I believe what we call canola in the US is what you call rape seed over there.

I came to blacksmithing and knife making from an amature machinist background, so I love what you did. 

I've been racking my brain for the last two days trying to think of a cool James Bond knife quote to throw out, but "Q, someone seems to have stuck a knife in me" is the only one I can think of.  (I'm sure you've never hear that before ;) )

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Yep, rapeseed is canola.  They renamed it over here for PC purposes. :rolleyes:  It's pretty fast stuff on its own.  Parks 50 is what they call a seven-second oil.  Canola/rapeseed is a nine-second, and Parks AAA (the medium speed oil for 5160, 01, etc.) is an 11-second oil.  

Joel, just because you can doesn't mean you should. ;)  You can quench 52100 in water if you know what you're doing, and I have successfully quenched 5160 in water.  It's just not the safest way to go about things.  Parks 50 is also formulated for a fast initial quench followed by a long, smooth slower quench, so you can get away with using it on deep-hardening steels provided the cross section is thin enough not to risk surface cracks.  Since we're not doing 10cm ball bearings here either oil will be fine. 

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