---------- Arc of Josiah---------

Thanks for showing how the knurling is made. The tool and the knurling you created are just too . Sure seems like it would take a lot of pressure and consistency to get it right.

WOW!! Fantastic work! Thank you for sharing VOB. I dig the Grizzly

Excellent work really and it was interesting to read how knurling is achieved too. I wondered how it would be done in simple manner. I’ve never used a lathe but I can see how useful it can be for such work.

Another knurly beauty from VOB’s workshop. Looking forward to more lathe, and tooling info… very interesting.

Coming along nicely!

Quite a large update added to the OP. Including LUM 5-90 and more on the head.


Gr8 build man! Your reign has started!

looking good! :slight_smile:

I like the reverse tapered head. I dont think Ive seen that done in a light of that size before.

Thanks for the update. I'm glad l'm not a mini lathe in your hands.

that is a bad * club!

great work…

That is going to be one big light! Thanks for sharing it all :-)

About the abandoned XHP35: if at 2.5A the led is at its maxiumum output and 3.5A is well over its max , PWM-ing down from 3.5A will cause the led still to run at 3.5A, just switched on and off by the PWM, and so it will have the diminished output that goes with the 3.5A. In your battery set-up you need true current regulation to get the max out of the XHP35.



Thanks djozz. You could put what I know about driver science in a thimble so your probly right.

My theory on why I get improved stability by PWMing the current down like that is not because the LED cannot handle the 3.5A. but because the heat cannot dissipate quickly enough. I was thinking the off time allows the cooling time between pulses?

When I bench tested this emitter in my sphere I reflow soldered it to a very heavy duty copper rod and got this result.

Cree XHP-35 HI C4 Measured Lumens Cree Chart
500ma 675 641
1000ma 1177 1116
1500ma 1577 -----------------------
2000ma 1888 -----------------------
2500ma 2010 -----------------------


I wish I had recorded the numbers at 3.0 and 3.5 now, but I did not because even on the copper rod they fell like a rock.

When I put this in the 4x26650 light it gave me only around 1600 lumens ( I get around 1300 from de-domed XML2) hence my disappointment.

Now that I think about it 400 lumens does seem to represent a bit wider margin (20ish %) of loss than what I got from the XML test. However I think that in this case even If i would have been able to harvest a couple hundred more of those lumens the result would have been the same. For this light I wanted to reach for the stars and in a host this big a single XHP-35 just wasn't going to get me there.


djozz, what kind of margin do you typically get from a straight emitter test to an install in a light?

Off topic but nice work on the lathe, i had one just like it but i could not stand the plastic belt when u get in a jam lol

Thanks for the output numbers. These may actually be the first real life output numbers of the XHP35. At least I'm not planning a test. A maximum at 2.5A sounds logical because it is four XP-E sized dies in series, and 2.5A is about the max for the XP-E2 as well.

I must admit that I never directly tested that, most emitters die during testing, and the ones that have ended up in flashlights are running on FET-drivers, making it harder to measure the current. I will have a go at that one of these days.:-)

Knurling the tube must have been nerve wracking.




There are worse things, but you do have to keep it on track the whole way down. Since there is some slight flex in the center of the tube I actually increased the pressure slightly when I got to the center portion, and then backed it off a hair toward the other end. If it does come loose from the bar any the pattern can get off track and it can be tough to pick it back up again.

I put an XHP-35 in my M2X-UT Javelot back on Aug 10th running 4 Efest 18350’s in series. It’s showing 2456.4 lumens at start and 302.75Kcd for 1100.45M throw. I used the LD-2 with proper modifications for 4 cell and 3A output and am seeing 3.10A at the tail.

I’ll have to double check it as my notes don’t show a break down with run time, I’ll do that and see how it holds up.

A runtime test would be interesting on this mod. If the 3.1A is over the max you may actually see a temporarily increase of output when the LD2 gets out of regulation and the current goes down. :-)



Thanks Dale.

The 300k lux seems about right if the Dereelight has an AR coated lens ( the one I had was not), that would give around a 12% gain over what I was getting at around 256K.

I recall hearing you mention this light before and also that you have calibrated your light pipe off a couple of other people who get very similar results.

So this leaves me wandering if my sphere needs to be re calibrated or if your actually just kicking my tail.

Is there any chance you might loan me that light so I can test it in my box if I paid the shipping both ways?

If you dont want to loan it out I do understand.