Monday, September 21, 2015

Armor

I don't post a lot about the unusual and odd things people commission me to make here on the blog.

However my new project started this week seems to be very interesting.

It involves making light weight armor plates and testing some rather unusual  yet common materials.

Next week will involve a trip to the range.

It started when I was making these really tough knives.  I have a source of steel plate that is somewhere in the AR600 grade.  It is made in Austria and comes in pre tempered.  Perfect stuff to make a blade if one does not want to risk messing up a job from some idiot messing up a heat treatment on tool steel.

We grind the knives with a jig on a surface grinder at a tool and die shop using diamond wheels and lots of water for cooling.  End result is a crazy tough blade. 

The batch of steel I use for these is so tough that machinists break carbide bits on it.  I personally have broke several carbide bits on it trying to drill holes in the handles. 

I cut it with a CNC plasma torch.  Now before you tell me that I will ruin the temper of the steel using this method, hold your horses.  There is a way to cut it and NOT lose the temper.  It involves cutting the steel under water.  It does not have to be deep under water either, a couple mm of water on top and the tank underneath being a few inches is sufficient.

The water catches the sparks and the steel is literally cool to the touch with the ability to immediately grab the steel out of the table after the cutting is done.

The slag on the back of it is a bear to remove, however a dunk in diluted muriatic acid for a few hours cleans up the mill scale and slag perfectly.  After that it is a clean water rinse and sending to the tool and die shop. 

After grinding it is to either powder coating, or ceramic coating.  I can also get teflon coating but have not had anyone requesting that yet.  Then cloth or paper micarta handles are fabricated, a final sharpening, kydex sheath and its ready to go. 

Anyways back to the armor project.  I wish I could publish photos of some of this stuff, but if I do, ill prob be out of a job.  However I can report back with some of the results. 

I am testing to level 3 and level 3a with this project along with spalling resistance.

We have a variety of materials to test.  Most are common industrial materials, however some have not really been re-purposed to be used for armor. 


Stay tuned....

2 comments:

Reg T said...

Those knives sound really interesting. Can you provide any info on price and availability?

admin said...

As of right now, I don't have much time to mess with them unless it is a good size order of 100 pieces or more knives.

Like I said most machine shops won't touch the work unless they are tool and die shops.

However I can water jet a batch of blanks out in whatever shape you want and you can hand grind them.

It takes a lot of patience and water quenching (or one of those grizzly knife grinders with a diamond wheel) to grind them if you don't have a surface grinder.

Basically it would go like this: send the blueprints in a cad file over. (pm me thru the contact form for the details) I'll work up the machine time for water jet, and you can decide if its worth it.

We have tested it side by side with Buse knives. Ours were a tad bit tougher. The shop owner that commissioned the job is a friend of Buse and is the Philippine distributor. Buse knives are great so don't take it to say that ours was better. That batch we didn't have as many tricks up our sleeves for fabrication as we do now in the fit and finish department. Cnc milling micarta handles , laser engraving, etc...

Those knives have been tested doing some crazy stuff including chopping a 6 inch hardwood log in two with a blade that is essentially paring knife size.

The shop owner (American guy) took them to some US Army SF guys who are stationed in Philippines and they shot a cpuple up. They ended up buying a bunch of them as personal purchases.

The steel tests out to 60 Rockwell using the hand tester.

I do have access to brinnel hardness testers and mass spectrometers if you really want to do a bunch of them.

A buddy with a die stamping shop uses it for his punches telling me he gets maybe 10,000 punches from tool steel and 50,000 punches from this stuff.

Unfortunately I am unable to tell you the foundry or original supplier other than it is made in Austria.