WIP, Machined knife

[Nathan the Machinist]

This is a thread for you guys over here to see how knives get machined in my shop. Milling is an uncommon approach to knife making, but I’m a machinist and that’s how I do it.



This is the knife I’ll be making:

It is a 6” fighter in the same family as my 8” shiv. This will be new pattern.




I won't delve into the design process here because I’ve covered that topic before and this thread is really just more about pictures.

After a design is developed a computer model is made because 3D data is just about a prerequisite for 3D milling.

This is being machined in an old vertical machining center. These have carousels loaded with cutting tools, in this case on a chain, that get touched off and can then be called out in a program and used to cut a work piece. I’m mostly using drills, endmills and facemills in this project.

Roughing down the top of a work piece with a small inserted facemill

This removes the mill scale and major surface flaws and gets the material flatter and closer to net shape.

Some holes drilled

Some pockets milled out

Running a finish pass across the top

This is CPM 3V here and it is a bear to finish.

Then I engrave my signature and the steel type

And flip it over and finish out side 2

While I was at it I ran some ELMAX too. It finishes out very clean, but it is abrasive on tooling.

The next step is milling the bevels. This is a pretty cool operation, I hope you'll check back in later.

More to come...

 

[John White]

Whoa, Nathan, show 'em how it's done in the new machine age!

(love that disc you made for us old hand types)

John

 

[Dawkind]

Very nice my friend....looking forward to seeing more.

 

[gga357]

Excellent. Looking forward to more.

 

[Phil Dwyer]

Bravo! :thumbup: Try keeping the chips out of our popcorn this time please.

 

[Nathan the Machinist]

Before I can mill the bevels the first step is to cut the profile of the cutting edge.


This is a simple one-time-use fixture to hold the blank so I can make that cut.

This is a fast operation but it still takes a while to run all of these

Cutting the belly on a knife blank.

[video=youtube_share;2O7WBCXoRUs]http://youtu.be/2O7WBCXoRUs[/video]

This is ELMAX being pealed off dry with a 3/8" stubby at 41 IPM and 3800 RPM.

ELMAX is a very high carbon high alloy stainless steel. It is abrasive and it work hardens badly, so a high chip load maximizes the number of parts you can get out of a cutter. This cutter was good for 45 parts.

It is a bit counter intuitive, but modern cutting tools last longer in applications like this if they can be run dry, without coolant. The coating is more abrasion resistant when hot and coolant creates thermal shock issues. This isn't a particularly smooth sounding cut, but the cutter held up half a day like this. Considering the material being cut, that is good cutter life.


Next post: milling the bevels edge up

 

[The Amazing Virginian]

Nice thread, Nathan! Thanks for posting it here for us.

I am curious - what is the thickness of the blanks that you started with before doing any facemilling?

 

[SBranson]

Fascinating stuff...

 

[gga357]

Love this stuff.

 

[SharpByCoop]

This is fantastic. Sure, there is automation and repeatability, however, the amount of head smarts which is required gives them admirable allure.

Thanks Nathan. Staying fully posted.

Coop

 

[Patrice Lemée]

Love your WIPs Nathan, even if 99% goes right over my head. Thanks again for sharing and looking forward to more. :thumbup:

 

[Brian Avila]

wow, that is awesome.

 

[A.l.e.x.]

Hello Nathan!

Great thread! Thank you for sharing the construction process of your new design!

Best regards,
Alex

 

[wdtorque]

Love your WIPs Nathan, even if 99% goes right over my head. Thanks again for sharing and looking forward to more. :thumbup:

Well said, same here. Perscribed.
Dozier

 

[Mike157]

Very interesting and educational. This is great Nathan. Thanks for taking the time to put this together. Can't wait to see the finished product. I'm prescribed/subscribed also. Mike

 

[Nathan the Machinist]

Whoa, Nathan, show 'em how it's done in the new machine age!

(love that disc you made for us old hand types)

John

John,

It is profoundly satisfying to me having talented makers of your caliber using my grinding gear in their work. I remember when you got that disk, I felt a little giddy about it.

 

[Nathan the Machinist]

Nice thread, Nathan! Thanks for posting it here for us.

I am curious - what is the thickness of the blanks that you started with before doing any facemilling?

The 3V was between .170 and .180 and cleaned up at .160. The Elmax was between .190 and .210. It is a 3rd generation powdered metallurgy steel made in an austenitic stainless can that gets rolled out with it. That can has to be removed by milling or grinding. It also cleaned up at .160.

 

[Nathan the Machinist]

This is the part I get asked about the most: milling bevels.

There are several ways to go about doing this including standing the blade edge up and surface milling it and laying it down almost flat and face milling then grinding it, but for this design the best approach is to stand it up at an angle and cut it with the side of an endmill.

Angled soft jaws here:

Holding two blades at an angle

The milling process. Video, if you're curious :

[video=youtube_share;1nQo7ZQMJxo]http://youtu.be/1nQo7ZQMJxo[/video]




freshly cut bevel

This is why I take this approach:

The plunge is perfectly symmetric, the edge is perfectly straight and centered and exactly the thickness I intended. Don't get me wrong, I'm not saying that my way is better or that I think I'm a better knifemaker because of it. I'm saying that, for my goals and priorities, there is literally no better way to do this.

Next: finishing the profile. It will start to look more like a knife.

 

[Les George]

no way! I hear that when you have a CNC the machine does all the work for you!

Youre supposed to be drinking coffee and screwing knives together... You must be doing it wrong!!!






good lookin as always man!

 

[Lorien]

I think it's so cool that, in this forum, we can have two concurrent WiP threads by two different guys approaching the craft from two completely different standpoints; one using charcoal and recycled steel, the other using CAD/CNC and super steel. I love the insights to be gained from the contrast.

Nathan, your designs are really excellent! This is going to be a sweet knife when you're done.