Head Threads on cheap lights (DX Elly, Ristoft, etc.)

[KWillets]

As an inveterate hardware store engineer, I've been taking apart some cheap lights I bought from dealextreme and checking the threads to see what fits where.

From what I've gathered, these all have the same size and pitch on the head:

http://www.dealextreme.com/details.dx/sku.1120 (Elly)
http://www.dealextreme.com/details.dx/sku.79 (Ristoft)
http://www.dealextreme.com/details.dx/sku.1255 (Lyckeby)

The diameter (of the lens) is 24.7mm, although the thread may be larger. A 26mm optic is slightly too big. The pitch seems to be around 1mm, or 24 -- I don't have a gauge.

I'm curious, is this some kind of standard head size and pitch? I was hoping to find an optic for the cree that would fit nicely into one of these, but 20mm appears to be the best I can do.

 

[gadget_lover]

Hi, and welcome to the Materials/Mechanical/Machining side of CPF.

1mm is a standard metric thread. Unfortunately, I've noticed that when it comes to mass produced lights the standards don't seem to matter much. I've seen a few where the threads matched none of my guages exactly. What counts when you are manufacturing is that your male threads match your femaile threads.

My Elly has VERY loose threads but did match a 1mm pitch thread guage. By loose, I mean that with it threaded 1/2 way I can move the head in and out one full thread. It does not have to survive any stress, so such a poor fit is not a problem.

I don't know if the 25mm inside that you have is a standard, but it is possible that all three manufacturers were designing to use the same reflector. It's also a possiblity that all three are made in the same factory.

Daniel