Least expensive source for lenses?

[Kev Williams]

Since Murphy seems to be every where I go to make sure his law is properly enforced, I've found out the hard way--twice now-- that lenses are quite fragile.

I just broke my second 50mm lens for my Triumph, so now I'm down to the 4" cutting lens. 11+ years with the other machines and no problem, but my butterfingers have cost me 2 within 6 weeks...

Anyway, I can get lenses from Triumph for $65 each plus $32 shipping. I'm pretty sure I can't beat that from a US source, but if I can, I'd love to know about it!

[Scott Shepherd]

Interesting. I thought Mr. Murphy was working full time for us. I didn't realize he was burning the candle at both ends.

I'd fire him if I could.

[Dave Sheldrake]

Lens can be had from $10 + shipping from China (another $10 ) but to be honest lens quality can vary by a huge amount. Go with RMI or II-VI and the difference in both lifetime and quality can be surprising.

cheers

Dave

[Brian R Cain]

Have you found out yet what's causing your lenses grief, Kev? There's always a reason. I once had an instance where a machine fitted with the ULS HPDO was being used exclusively for vector making steel directly and running long shifts. It worked fine for about six months then the marking became intermittent. Typically a 20 minute file would run for a few minutes marking as expected, the stop marking for a while them start again.

We tried swapping the tube, the power supply and the CPU but couldn't resolve the issue. The machine was being used in a poor environment to get to grips with the problem. Tucked into a corner with barely any light and surrounded by such a din of other machines you couldn't think straight. Nowhere to lay anything down safely and a constant avoiding of fork lift trucks and whatever. A busy environment to get your thinking cap on.

In the end I said it was impossible to find out what was going on unless we had the machine in our workshop and could look at it sensibly. Back there, we took off the lens and looked at it under a microscope. It was pitted with tiny holes caused through spatter. I came to the conclusion that the anti-reflective coating had been burnt off so sometimes out of phase reflections of the beam cancelled out beam power. Changing the lens resolved the issue, but trying to study it in a dark situation without a way of magnifying it would have been a guess in the dark, and to be honest, before you've been there, not obvious.

I have to say that this is the only occasion I've encountered this problem and as it turns out, the extraction the customer was using was a joke and a half.

[Kev Williams]

I must confess I busted out laughing when I read your first sentence there, Brian! My problem isn't quite so complex..

... I have butterfingers. ;)

First lens was the spare, still in the tissue wrapper. I decided to open it and put it one of new lens tubes I ordered. I was standing over my one XT table, and it sorta squirted out of the paper, onto the table. Broke into 3 pieces.

Today wasn't much different. I was changing lenses in the tubes- got the 4" put in fine, and I picked up the 2" lens, got it into the tube, started tightening the ring, then said to myself, "now, be careful not to drop THIS one..." and just about then, I dropped it. And the lens was still loose in the tube. And no, it couldn't have landed on the wood table I have setup in the machine, it dropped just past the edge of the wood, straight to the bottom of the catch drawer, about an 18" drop to hard steel. When I picked up the tube little yellow pieces of glass fell out...

Yup, Murphy works full time here too, not sure how he has time to bother anyone else. My best guess, him and Santa are brothers...
:)

[Mike Null]

http://www.iiviinfrared.com/

[Dave Sheldrake]

+1 for Mike, I use II-VI stuff almost exclusively

cheers

Dave

[Robert Walters]

I'd fire him if I could.

Murphy is a dead man when I catch him!

[Robert Walters]

And no, it couldn't have landed on the wood table I have setup in the machine...

I once had to reload-by-hand a leadscrew ballnut. You know, the one with 68 itty-bitty precision chromium balls (that are near-impossible to get JUST ONE if you need it) one-by-one with a pair of tweezers.

I grabbed the biggest, fluffyest towel I could find. Layed it out so it was as poofy as possible.
The idea was that if/when I dropped a ball, at least it wouldn't bounce all over the place, and hopefully would land and stay in the folds of the towel.

Ironically, I didn't drop a single ball. But you know darn well that if I didn't have have that towel Murphy would have been alive and well, and I would have dropped a few of those suckers! :p

So, try not to feel too bad, lay off the buttered popcorn, and get yourself a fluffy towel! lol