This shows gates, not knit lines.
What Nav88 shows and what I have are different.
As well as a picture I received from Hank when reporting what I got:
ADDED: Also, in the quoted post Hank shows a lens drawing from Carclo. The gate is on it, with a maximum protrusion size specified. There is no mention of knit lines.
There appears to be many imperfections in both the optics in the picture you showed. Just look at all the bubbles and shadows. I think it’s pretty normal for a cheap injection molded acrylic optic. You would likely find the same imperfections in an optic in a $600 Oveready. Keep in mind too these are $40 budget lights. I think your expectations might be a little high.
If you can’t see the difference in the beam profile or output, I really don’t see how it could possibly matter.
I have used many many quad optics and never found any of the bubbles or slight visible imperfections to amount to anything. Looking into my D4’s optics with it on in moon mode the main thing that stands out is the fingerprint on the side of one of the TIR’s that I didn’t get wiped off before reassembly. I’ve had this one apart and re-modified at least 4 times now, so big deal. It works, and works well.
There’s a pretty big difference between a technical perfectionist and just being anal retentive. 
I should know. I’ve been one or the other for half a century…
Edit: It might be prudent to add that as I get older I realize something important, not necessarily good at the application of this but I do realize it…. when you yourself become perfect you can then raise the bar of expectation on others. I find though that to be perfect I’ll probably have to die first. And so it goes…
I say the knit line is of no consequence simply because it doesn’t result in any noticeable artifact in the beam. I suppose I could really go looking for one, but as King Lear said, “that way madness lies.”
It may be possible to design a mold and develop a process that’s entirely free of knit lines, but I suspect that if that were the quality standard, this light would not cost $40.
ToyKeeper - What sort of evidence of poor electrical connection might I find on the tail cap or driver contacts?
^ dirt. You may wipe the contact surfaces with a tissue, or even lightly sand the sides of the battery tube with fine grid sandpaper.
There should be a contact ring around the edge of the driver and the edge of the tailcap where the battery tube touches it. If one side of the ring appears worn while the other side appears brand new, it might have a contact issue.
It’d be a good idea to clean the surfaces first though, to rule out things which don’t matter, before looking for wear.
I’m only aware of one case where this sort of thing was an issue, and in their case it wasn’t the tube. It was the driver resting at an angle inside the head. But if the issue followed the tube, maybe the tube’s surface was covered or not flat… both of which would resolve themselves with abrasion.
Most imperfections that you see are just dust. The only real ones are on the new light. The knit line is well shown on the image. The gate actually is slightly deformed and has tiny bubbles in it. I did not mention it before because I considered it a non-issue.
The consensus is clear, knit line is a non-issue too. I will withdraw my RMA then. Thank you guys and gals.
But nevertheless I will try to replace the lens as I want the present to be free from such imperfections.
I’ll keep an eye out for uneven wear. I suspect the poor connection was at the tailcap end, because I removed the tailcap and touched the battery negative terminal to the tube with a test lead and got the normal two blinks.
I also tried covering the end of the battery tube with black Sharpie and tightened the tailcap down, expecting to see where contact is being made. Strangely, the ink seemed untouched, even when I did the same on the good D1 tube. Maybe there’s some flaw to that method.
> covering the end of the battery tube with black Sharpie and tightened the tailcap
If you’re hoping to transfer something from the battery tube to PCB ring, to tell where it does and doesn’t touch
try a dab of conductive lubrication around the end of the battery tube over the shiny metal that should be making contact…
That goop shows up the contact area pretty well when it transfers — shiny!
Of course you could just use mayonnaise or something
I’ve looked at a dozen injection molded plastic parts and knit lines are everywhere.
Just thought I’d share another method of safely traveling with a D4 shorty (18350 tube), without fear of accidental activation or damage to the flashlight. It fits perfectly in a small pill bottle from Walgreen’s.
Nice find, good armored protection that’s water proof.
Completely agree!
Reflowed my xp-l hi V3 3c onto the MTN quad board and put it into my D4. I did this with nichia as well and the beam is much improved over the stock board.
Anyone have a picture of the new screwed down mcpcb? Tempted to order another and mod it but wanted to know how the board is screwed down.
If I understand correctly, the board is screwed down by using two of the holes for legs for the optic. The optic then stands on two legs instead of four.
Ironically that’s pretty much how evolution works.
Nah… that’s called genetic MODification. :sunglasses:
Got my Emisar D4 today 
I bought it from Neal on 16/10/2017 (18 days to arrive :partying_face: )
Body: Gray ; Emitter: XP-G2 S4 3D - 4885K ; + 18350 tube (of course!)
First impressions about the tint: on lower and “medium” levels, the hotspot tends to be slightly “yellowish”, corona has a mix of white and rosy/”pinkish”, and spill is also rosy/”pinkish”; on higher levels, the hotspot tends more to white (Neutral) and the spill is more white as well, although some rosy remains.
So far I like the flashlight, despite I’m still getting used to the UI! It is very well made and has allows a nice feeling on the hands
And it heats a lot when on max output!I didn’t configured it yet, so it comes preset from factory.
I’m using the 18650 tube with a Convoy S2+ clip, and the 18350 tube with a Jaxmnve M3 clip. Both clips have heatshrink tube to “delay” scratching
I’ll use Sony US18650VTC6 and Aspire IMR18350 batteries!
I made some tint comparison bewteen the D4 and other “Neutral White” flashlights.
Sofirn SF14 > Sofirn SF10 > Emisar D4 > Convoy S2+ Desert Tan (XPL-HI U6-3A) > Sofirn SP32
Emisar D4 > Convoy S2+ Desert Tan (XPL-HI U6-3A) ||||| Emisar D4 > Sofirn SP32
To show how tint interacts with colours!
The lens has some “artifacts” but that doesn’t interfere with the beam!
Bonus, with green tube
Thanks to all involved in this design (inside and outside) and production :+1:
I put together a XP-G2 3D-ish model too, and I’ve certainly noticed a lot more tint shift on it than on my Nichia units. I think the tint still looks better in either case, but going from low modes to high modes it almost looks like two different lights due to the tint shift.
I’m hoping that the tint shift will be less noticeable on 3-channel drivers, or generally anything with higher regulated output. As is, it shifts fairly quickly from the warmer rosier 350mA tint to the colder FET tint, and it’d be nice to have a middle ground between. The hybrid PWM it uses helps make the color change at least somewhat gradual, but it’s still pretty noticeable.
Also, digging the shorty clip you found. 
Can anyone comment on the difference in heat produced with the Nichia 219c’s vs. the XP-G2 (neutral white)? i.e. would the XP-G2’s be able to run significantly longer on max before stepping down?