ROP bulb alignment question

[TJJP77]

Hi,

Just got all of the pieces together yesterday to build my ROP based on a Mag 6D body. I'm using the Fivemega dual function cammed MOP reflector that has the bulb hole necked down to maximize performance of ROP or other small diameter bulbs.

Here's the problem though...when I assemble the bezel onto the flashlight body the high output bulb rubs against the edge of the hole in the refector and makes an audible scraping noise. The hole is machined properly as it turns perfectly circular - no wobble is noted when looking at the hole as the bezel is turned. I tried to re-position the bulb, but it pretty much fits only one way once you snug the retaining collar down. I noticed that the low output bulb fits somewhat better, but it too seems closer to one edge of the reflector hole as you turn the bezel, although it doesn't appear to make physical contact.

Is this just a defective bulb issue or are all the Peli bulbs subject to some variability in how the bulb is centered in it's base?

If the variability in the bulb construction is normal, then are there some other suggestions on how to make sure the bulb is centered better to ensure it doesn't rub against the reflector?

Or, do I have to get crazy and drill the hole out slightly larger in my brand new reflector?

Thanks!
Chris

 

[Brighteyez]

The 11W bulb is of a smaller diameter than the 24W bulb. Many of the third-party reflectors are designed to accommodate Carley and Welch-Allyn bulbs, and the bulb opening may be too narrow for the 24W bulb.

You might want to contact the reflector manufacturer regarding getting the hole enlarged rather than attempting it yourself and potentially damaging the finish of the reflector.

Is this just a defective bulb issue or are all the Peli bulbs subject to some variability in how the bulb is centered in it's base?
Thanks!
Chris

 

[willrx]

FM reflector you have is not designed for Pelican HOLA bulb. LOLA is smaller as you've noticed.

 

[tussery]

FM reflector you have is not designed for Pelican HOLA bulb. LOLA is smaller as you've noticed.

Really? The Pelican HOLA bulb is a perfect fit in my FM reflector.

 

[TJJP77]

FM reflector you have is not designed for Pelican HOLA bulb. LOLA is smaller as you've noticed.

Hmm...thanks for the reply, but the FM post states that the reflector is, and i quote:

"Bulb opening is 8.38mm (0.330") to accept many common Welch Allyn or even ROP bulbs. Advantages are more reflection surface and less light loss also heat sinked."

I thought by referencing "ROP bulbs" he meant both the HOLA and LOLA bulbs, but perhaps I shouldn't assume.

If I do attempt to grind/drill the opening out a bit, is there a way to clean the reflector surface without damaging it?

Thanks again,
Chris

 

[Mars]

It's a perfect fit for mine too, although the bulb is slightly off centre. It doesn't seem to touch/rub but given that once I've adjusted the focus to suit, it stays there so I don't care. Having it touching isn't really a problem is it?

 

[PhotonAddict]

I had the same problem with my high-output bulb in with my Modamag MS reflector (it was reamed to fit the larger HO bulb). When I checked the bulb I discovered that it was not mounted properly in its base - it leaned a little to one side. It would fit but just barely, and that section of the bulb did have a few marks from scraping the reflector. The low bulb was mounted properly in its base plus it's a bit smaller so there's more tolerance for minor errors in alignment. I never heard anyone else complain about so I assumed I was just unlucky and happened to get a dud.

 

[TJJP77]

Maybe I did get a dud of a bulb...unfortunately I don't have another high bulb to check it out. The reason why this might be an issue (at least to me) is that any shock to the flashlight when there's direct contact between the reflector and bulb may break the bulb. As a metter of fact, today the light fell over on it's side from a standing (on the bezel) position (on carpet) and the filament broke loose upon turning the light on. I realize that this light is going to be a bit more fragile than say a Surefire, but I would think that a minor shock like this wouldn't break the bulb if there weren't in direct contact with the reflector....right?

Thanks again,
Chris

 

[eebowler]

From fivemega's thread:

Bulb opening is 8.38mm (0.330") to accept many common Welch Allyn or even ROP bulbs.

TJ, I had that same problem. I believe that the reflector doesn't align perfectly in the head resulting in a slightly off center hole. Also, the cam when it pushes down on the little roller thingy, tilts the brass collar (the thing the bulb is attached to) to one side causing the bulb to rub when the head is screwed.

Take out the reflector and screw down the head on the light. Now, insert the reflector and window and screw down the top ring (with the maglite logo). Here is where you have to make sure that the bulb is centered in the reflector. In order to avoid scratching the bulb, get into the habit of turning the head one direction to focus and turning it the other direction to defocus. That way, the reflector wouldn't be making circles around the bulb increasing the likelyhood of scratching.

My relfector is cammed. Maybe you can try removing the cam to see if that helps too. Go through the same process as above and let us know what happens.

My ROP Hi bulb shattered after less than an hour of use. I'll bet it happned because of the scratches on it. Be careful.

 

[TJJP77]

Luckily the bulb didn't physically shatter, the filiment just flashed breifly and fell into the bottom of the bulb....maybe more a result of the light tipping over and falling (albeit on carpet, mind you) than the scratches on the bulb....

Thanks,
Chris

 

[eebowler]

From the same pack, my Low bulb decided to die in it's sleep one night. It refused to turn on and after checking batteries, I tested continuity of the bulb and nothing. I had to use a high power magnifying glass to actually see the break in the fillament. Again, less than 1 hr of use.

 

[Icebreak]

Wait a minute.

First off, eebowler is spot on. I have a little to add.

Even non-custom potted lamps will sometimes be tilted a little...that's one challenge.

The opening being so small is another challenge.

The fact that a cam will rock the lamp holder slightly catywampus is yet another challenge.

Here are some solutions:

Lateral focus is very important and I think it's often overlooked. I see beamshots all the time where I can tell the lateral focus is wrong. You can bend the flanges on the PR base to correct this. For tiny changes bend the flange up on the side you want the lamp to come to. For larger changes bend the flange down on the opposite side to push the lamp away from the reflector hole's side wall. I bend the flanges with pliers in three or four adjacent places forming an arch when viewed edgewise.

On your light I would, without turning it on, focus it until the lamp touches the reflector. Eye that filament while you take the head off. Remove the reflector. Keep your eyes on that lamp while you remove the retaining ring. Keep your bearings by noting that V shape cut out.

It might take a few tries at bending the flanges to get it right.

Here's another solution:

Drill that hole bigger. It's pilot hole already. It's easy to do. Don't worry about the dust. Blow it out with liquid air if you want to but don't wash it.

The other solution eebowler already mentioned is to not use the cam part of the reflector. I like that solution the least. I don't have that unit but since it's a FiveMega I know it must be a sweat piece of engineering. Also, without the cam you'll need shims to get proper axial focus.

Scratching the lamp is a concern. Shock is also a concern. Here's a greater concern. If the lamp has cleared the hole and it's being run it will get hot of course. During the run if you try to focus the reflector and it touches the hot envelope it's going to rapidly cool one spot. It's highly likely that the lamp will fracture if this happens.

Bad grammar and mispelling probably but I was typing fast. Sasha's about to shut the board down to do some work.

I hope this was of some help.

- Jeff

 

[eebowler]

Ice, bad lateral focus results in what type of beam? Mine is eye shaped with the white part of the eye containing the loops of fillament while the iris is a bright spot. (LOP reflector)

 

[Icebreak]

Yours sounds correct. For a WA01185 or especially a WA01166 using a smooth or a LOP reflector a pupil appears as a super spot revealing 3 or 4 filament spirals.

Bad lateral focus can be seen when the artifacts seem heavier on one side than the other. With less powerful bulbs like 5 cell Mags or a 1499 the beam looks like a comet.

My blabberings are almost worthless without pictures.

 

[Lips]

Here's a pic of centered and not so centered



It takes me forever sometimes to getem centered

 

[Icebreak]

Thanks, Lips. Excellent comet shot.

 

[sb0007]

My first mod of the ROP LE also has the HO bulb rubbing as my MS reflector. I was very careful to screw the cap with the lens. but apparently some scratches were still made on the bulb. truly after less than 3 usages....poof the bulb exploded and I had to clean up the mess it left on the reflector and lense. good thing the lens borofloat ones, didnt break too.

 

[moontroll]

The bulb has a lip that goes around the entire circumference.You can bend it slightly to center bulb,bend it up on the oposite side of lean and down on side of lean.

 

[TJJP77]

The bulb has a lip that goes around the entire circumference.You can bend it slightly to center bulb,bend it up on the oposite side of lean and down on side of lean.

I did play around with that a bit, but the problem with the mag is that the bulb holder does rock back and forth a bit as it goes up and down. I ended up "reaming" out the bulb opening with of all things my trusty pocketknife (no really! it worked better than you might think!) to make sure it cleared all the way around. I hated to have to do this, but I don't want the darn thing to be super fragile....I realize it's not going to be a robust as the light was in it's stock form, but I'm not willing to completely write off reliability in the name of performance.

Thanks everyone!
Chris