Inova X1 tailcap play measurements

I've read a few comments about the amount of in-line play of the tailcap on the new Inova X1s compared to the old models.

I did some measurements with a old style X1 with optics, a new-style X1 with reflector that was packaged with a holster (I'm assuming this was one of the first off of the production line), and a new-style that was packaged with a lanyard (and was bought a month after the first new-style).

The designations are:
Old-Body, Old-Cap
New0-Body, New0-Cap (this is the early production run)
New1-Body, New1-Cap

All measurements were taken with the tailcap turned out by 1 turn from fully seated. The early reflectorized model will activate even when the tailcap is backed off by over 3/4 of a turn, due to the huge play in the threads.

The threads on the body of the newer reflectorized model are cut the same as the optics model, and stop about 1.5mm from the O-ring. The early reflector has threads that come up all the way to the O-ring. The old optics model has the narrowest threads cut in the tailcap- they are extremely precise and thin, and I would assume would not thread over anything other than absolutely perfect threads on the body.

Overall, the precision of the Inova flashlights is amazing, but the mating tolerances on the early reflector model seemed to be abnormally large.

As the chart below indicates, the old model has absolutely no tailcap play, and momentary activation is entirely through the rubber cap. The new model has so much play you can activate it by pushing the solid end of the tailcap- the rubber is nearly superfluous. This makes the light feel a lot cheaper and more rattly when using it in momentary mode. The better of the new models has little enough play that it's not annoying, BUT extended signaling use of the light tends to force the tailcap to walk on the threads, and eventually it will need to be adjusted again so it doesn't start flickering the light ON when unwanted.

The old tailcap/body are clearly the best of the bunch.

I don't know the best way to keep this table in monospaced format; sorry for the kludge:

Very interesting findings/measurements.

Just to show some sample variations - I have an Inova X1 Spot (lensed ~circa Sept/2005 from Target) and it has quite a lot of play in its tailcap threads.

I think there has to be some play in the threads - this is most easily seen/felt when one backs the tailcap off the O-ring -

I've done this recently with a lot of my well-fitting flashlights to find once off the O-ring there is noticable play in the tailcaps (other brands including Fenix and Nuwai).

I don't know how to do the measurements that you took....
however here's an idea of play on my Inova X1 Spot compared to some of my tightest fitting lights -

Turns from just on/off that can still turn light on by depressing solid part of tailcap

Inova X1 Spot - ~1/4 turn.

Inova X5 - ~3/16+ turn.

Fenix L1 - ~1/4 turn.

Both the Fenix and the X5 feel a lot tighter than the X1 - but as you can see the difference is fairly minimal for the ability to turn the light on without using the central button - in fact for the Fenix L1 - this is the way some users are getting the momentary ON ability despite the reverse clicky switch.

Some have found difficulty using the momentary ON with the Inova X1 - I think this may have to do with the small size of the central rubber button and lack of grip on the smooth body - whereas the X5 is a bit easier due to the larger sized button and wider body.

In fact my optimum position for the Inova X1 Spot is actually a 1/4 turn from just on/off - which as you see, is a position where one can still actually turn the light on without using the button - this just makes the momentary easier for me - and allows me to hold that use without flickering.

If I do back the tailcap more to 1/2 turn from full on - the momentary does still work well for signalling/flashing - but I find it hard to hold without flickering....

Like I said sample variations.......