Working with D2

Stacy E. Apelt - Bladesmith said:
The difference from that small a thermal mass will only slow the cooling rate a bit. You would be better to pull the billet and place in vermiculite or ashes ... which I don't recommend as a good technique, either.

I'm with Matthew here, and think you are chasing unicorns, when good horses are already in the barn.
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I like that expression. Just experimenting. I have plenty of good horses, so I just felt like chasing a unicorn or 2. This is just a hobby for me, so I can afford to screw around. Most of the time I just have to learn things the hard way.

This is the first time I overheated it, and it was my own stupidity. having recently bought a 100 lbs bottle of propane, it really can dump heat into the forge much faster than the 25 pounders. Very fascinating to watch D2 turn into a cold solder. Wonder why the O1 wasn't as affected.

Can you tell me more about the vermiculite?
 
I may not give it up quite yet. The extra mass in the forge was enough to soften it up.
WeqlTDt.jpg

This is the original billet scratching the center D2 with a 65 HRC file.

Went to check the other files of the test set, and a 50 HRC file skates, but a 55 still scratches it.
 
Carbide will still machine it @ 55. I have cut fully hardened 1075 before. not my favorite, but doable.
 
Feels like your driving on the wrong side of the road, at night, with your lights off.

Even if you are able to make a knife out of that, it won't perform well. Knives like these seem to resurface and haunt the maker a few years later.

Buy some better, simple materials, and do the san-mai out of that. Shallow hardening steels are best for the guy with a forge in a small shop.

I'm not sure what you are expecting from the group, a few good smiths have pointed out that this is not going to work. Please give up on this project and do something we can get excited about.

Mayday, mayday,

Hoss
 
If you're after something tough and wear resistant, I'd be willing to bet a piece of unmolested A2 would be better in both areas than a D2 San Mai that has been through what your chunk has seen....

With air hardening steels in particular, you really can't stray all that far from what's published before you start really having problems.
I'm not a san mai expert by any stretch (made a small piece once for a woodworking tool) but I have dealt with air hardening tool steels a fair bit both in knifemaking and otherwise. I wouldn't stick a piece of D2 or A2 in a forge that didn't at minimum have a pyrometer, ideally PID control. I wouldn't even consider trying to anneal it without a ramping kiln.

If you want to do San Mai with your equipment, you'd have a lot more luck using that piece of O1 for the core of a low carbon stack, then the cladding of D2.
Personally I'd put the D2 up on the shelf until you have the means of handling it the way it needs to be handled, and have a better suited jacket steel
 
For what it's worth, I've made san-mai using D2, spray form D2, XHP, 440C, 40CP, S90V, S30V, A2, 52100, cru-forge-v, c125, W2, O1, PD1, M2, M4, AEB-L, Nilox, BG42, B75p, K390, vanadis 4 extra, etc.

Hoss
 
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And didn't you have fun doing all those combinations?

I love you guys. Seriously, you are all a wealth of information and quite helpful - but I am having fun & experimenting. How did you guys get to learn all that you did? By doing things right and wrong. Yea, this may not be the best combination, but I am enjoying myself and every time I turn the forge on... I learn something new. I have been doing this for close to 3 years and this is the first time I have touched D2.

We were all green banana's once. No need to pee in my cheerios. I have plenty of regular high carbon knives, damascus, and san mai. I am just having fun experimenting, and sharing the results. If for nothing else, someone doing a google search on D2 will come across this thread and say wow... that is some hard stuff to work on - let me skip it... or find some new combination no one else has thought of. who knows?

Either way, I appreciate all the comments and helpful hints. They have gotten me this far. When I get an oven, I will try D2 with more appropriate metals. I will not undo the space time continuum by experimenting with different (and possibly ill matched) steels.
 
You bet.

Currently Trying to drill out a broken tap in my knife fixture plate on my CNC. That slowed my groove down a bit. Giving the forge a break for a few days to do some stock removal projects.
 
Since you have a cnc, a center cutting carbide endmill, helical down .005" pitch works really well.
 
Failing that, a carbide spade drill can be a good option. Doesn't tend to grab the flutes of the tap and break itself off like drills can at times.
Of course a tap eroder is the easiest...
 
For this 4-40 hole I generally drop a 1/8" center cutting end mill down at 0.5ipm, and 200 rpm with lots of oil. Once the tap is out (and the end mill chipped/broken) I clean out the hole, drop another end mill down the hole (to function as a reamer to clean up the sides), drill and tap the hole with a 1/4-20 thread.

Then I insert aluminum threaded rod back in the hole with some loc-tite and resurface it once its cured. Re-drill and tap for the 4-40 thread.

never heard of a tap eroder.
 
For what it's worth I've always liked running a relitivly blunt piece of carbide as fast as your machine spindle will go for removing taps.
Take a dull carbide endmill, and grind two flat sides on it, basically shaping it into a crude spade drill.
Crank the mill up as fast as it'll run and really bear down on the quill. It looks and sounds horiffic, but usually works well.
That's on a manual Bridgeport sort of machine mind you. On a CNC I'd be inclined to use kuraki's suggestion.
As for a tap eroder (also called a spark eroder) it's basically a rather simplistic EDM machine specifically for removing broken taps and drills. Not cheap by any means, but the easiest way to go if you have access to one
 
A proper carbide spade drill (or a square die drill) will also work, they are just a lot more expensive and much more painful to ruin than an already trashed endmill
All you really need to do is get out the web of the tap, and then you can pick out the other pieces. Doesn't really matter how crude the cutting tool is so long as it'll chew/burn its way through the tap
 
Is this the Vermiculite that was mentioned earlier, or are there other types?
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pictures make it look like gravel, but the bag feels like cotton.
 
Yes, that is vermiculite. Vermiculite is a magnesium rick soft rock that is heated to a high temperature and becomes puffy. It then is used as a thermal insulation .... and as a water holding additive to potting soil.

Fill a large metal bucket with the vermiculite and plunge the red hot blade down the center. Leave in the bucket 10-12 hours. This will allow a slow cooling. The blade may still be warm when you take it out, so don't just reach in bare handed.
 
56 quarts of vermiculite
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an A2/O1 billet sitting in here until monday. Even left it in the sun to add just a bit more heat. There was some cracking in the edges of the A2, and i never let it cool down. Not a fan of A2/D2 so far.
 
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