Ohhh… ouch. I feel your pain.
Any way to salvage this, like silver soldering? If the crack is wide enough the silver might flow in there… if flux manages to get in first.
F*! 
The only right reaction
And return to this project in a month or two. It always helps.
Man, that sucks. Maybe with the right temperature and some clamping tools you can resolder the pieces. But you have to do some research to get the temperature right Mokume is not easy.
Good luck.
It is hard to predict how a flashlight build goes, some go way easier than planned, some never work. My builds do not have lathe work in them, but I have had several projects coming to a grinding halt after breaking too many things including cracking the pill beyond repair of a fairly expensive host (Eagletac D25 Ti).
But after so much work souping up more and more of a nice mokume bar is extra sour of course. 
Yikes! 
Pinkpanda, thanks for this, it puts my mistakes into perspective.
And djozz, ouch. I love my D25C Ti. Was yours the D25C or D25A? And, dare I ask, how did you crack it?
That’s an idea. I’ll consider it but honestly don’t hold much hope.
Aah, the silver lining. I make other people feel better about their failures :laughing:
Thanks guys
You can mail eagletac, maybe they are willing to send a replacement pill. I ruined the reflector of my d25c once and they were happy to send a new one.
Thanks pp,makes me feel better . 
The pill (it was a D25A Ti) is brass and glued to the bezel, it cracked when holding it with pliers (with rubber strip around it) getting the bezel off. It is not round anymore either :person_facepalming:
But that is still nothing compared to wasting a good chunk of mokume after lots of machining work 
This afternoon I thought maybe I could salvage the last bezel with a ti ring. I was thinking to cut it real thin once it was mounted, shape it and make it a bit of a feature. I cut 0.5mm off the diameter off the bezel and slipped this on…
However, the problem I mentioned above has come back to haunt me
I can straighten this out with a small vice but the pressure of the ti ring makes it all too easy to warp out of shape again.
Well I’ve got 2 more lives left to salvage a mokume bezel 
All I can say is: I wish I had your patience.
Generally in life, not just for modding lights!
Wishing you all the best with this light.
Patience is what I exercise when waiting for deliveries or for a new light etc (….FW3A……). This is more like a niggling frustration that I can’t let go of 
You my be frustrated, but it's still impressive work to me :P
While I am not an expert in this 
and this is not my war, it could be that different density metal layers in the mokume does not play well with high rpm lathe crafting. If the stuff cracks in the lathe that means it is fragile for such treatment, or at least that very mokume is. 
Maybe at ½ the speed, or ⅓, or ¼… going slow can be fast. 
Cheers and good luck ^:)
If it was just fragile the titanium mandrel would’ve been successful.
I think centrifugal force (high rpm) did played a part in the bezel bending open but the fact that it bent and ‘hung on’ indicates that it is not brittle nor fragile. What could be a possibilty is the weak points are weakened further by tiny vibrations. Vibrations that are caused by the layered metals. High and low spindle speed will just vary the vibration frequency and not something I can eliminate.
I do appreciate the suggestion and thought gone into it though, cheers 
How do you do your SPT? Top slide set to 1/2 thread angle?
Carbide or HSS?
I think stress during threading generates forces much bigger than the centrifugal ones (a quick calculation gives me < 50 g @2000rpm for a 20mm tube, not THAT much) so I’d try to minimize those.
And even thermal expansion might be able to generate enough force to open that crack if it’s a weak bond to begin with.
Im not damaskus steel expert but after first crack I would find or build oven, heat it up to 200-250C and leave till tomorrow.
I think what he’s using is Aluminum and Copper Mokume-gane. It doesn’t have any steel in it.
What does the suggested heat-soak do for the steel? I’m curious. I’ve never heard of doing that before.