When a light just doesn't want to be built but persistance pays off - FINISHED

Yikes! :open_mouth:

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 . :wink:

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 :frowning:

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 :person_facepalming:

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 :blush:

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 :beer:

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.

“SPT”…. :question: I use Carbide

Yes, threading does likely generate more force than centrifugal. The parting off tool generates even more force than threading. However I don’t think either of those had much effect when I had it mounted in the mandrel. The mandrel was a tight fit even without the chuck clamping down on it.

That’s an interesting concept but why such low temperatures? As far as I’m aware layered metals are forged at a little below melting point. Melting point of copper is over 1000 celsius and even more for nickel.

Have no ideas how it works with such sandwich, but I think tempering is common solution for all materials that have internal tensions due manufacturing process. And yes usually it is made with temperature that is much lower than melting point. Idea is to get metall internals relaxed so they wouldnt like to change their position after each small bump.
Also, using coolant is very recommended.
Another way - avoid all forced machining operations. Drilling, turning etc. Use angle grinder with cutting disc instead of parting tool. Sanding paper instead of skim cut. Rotary tool with mill in toolpost for internal pockets and threads.

SPT = Single- point threading.

As illustrated here, this reduces radial stress a lot:

Have you tried HSS? General purpose carbide tooling tends to have some intentional cutting edge radius, this is okay for steel and high speeds but since both Cu and Ni work harden like crazy I’d go with the sharpest tooling possible, plus both Cu and Ni need a sufficiently positive rake angle* (>15°) so hand-ground HSS tooling might work better that GP carbide.

*The internal inserts are 15° positive I think which might be enough, but I’m not so sure about edge sharpness.

And what Kirill says is worth consideration, although grinding away copper will gum up any disc pretty fast and I’m not sure how I’d tackle milling an internal thread with a rotary tool in the toolpost, that would be hell to set up.
But… if you have some liberties with thread shape etc there’s a way I’m sure.

Ah I miss the days when I had the Emco…

Aah yes, the ‘relaxing’ of metals. I think I read about that once but forgot all about it. I will think about how to do that without using the kitchen oven (the missus will have a fit).

I’ve never tried that threading method though I have seen it before too. Lots of advice there, cheers :beer:

It seems i’m back on that steep learning curve. Thanks for the help guys :student:

Well, the “relaxing of the metal” aka “annealing” is done a lot differently for different metals. Steel is done like Kirill suggested above. But IIRC, Copper is annealed in a quench, which ironically is how steel gets hardened. Just heat cycling Copper doesn’t soften it. For other metals, it might be another method. So, you need to know exactly what’s in your Mokume-gane blend, and search for annealing process for that specific blend. It may be that the two metals in your bar are enough different in how they are annealed that effectively annealing the bar is impossible. Hopefully not.