Hey, I just got a k40 but it arrived missing a lens.


I just got a k40 but it arrived missing a lens. Its the one on the stock laser head.
Can anyone tell me where I can get a replacement? Also anything else I need to know like what size, length etc. Just want to make sure I don’t get the wrong thing.
I’ve emailed the eBay seller but I don’t want to wait weeks for the part to arrive.


stock focus lens is 18mm i believe, can get off ebay or http://lightobject.com/ most eventually upsize to the 20mm/air assist nozzle. Helps tremendously with cutting.

@Domm434 I’m sorry I’ve been trying to post a pic but couldn’t until now. I think it’s the mirror that I’m missing.
Would you happen to have the size etc for that as well?

ahh that is a 18mm reflection mirror if i recall correctly. I replaced my stock mirrors pretty quickly.

Isn’t the stock lens smaller than 18mm? I recall that when people purchased the LightObject head that they had to get an 18mm lens also (or some spacer) due to the fact the stock lens is not big enough. If my guesstimation is correct, I think the stock lens is about 12mm in size. Mirror I would have guesstimated is 20mm… You can check one of the other 2 mirrors (located on the left Y carriage section or up the back near the tube). Only issue is it’s all going to be out of alignment now & require aligning once you replace everything.

Oh, you can try http://lightobject.com for parts too. Might be quicker than waiting for ebay seller.

your probably right @Yuusuf_Sallahuddin_Y , i think i used the stock head/mirrors for a total of 1 day heh.

@Domm434 @Yuusuf_Sallahuddin_Y
I just found the mirror. It was at the bottom of the box so it’s all scratched up anyways. Still have to replace it.
I did measure it, approx .75" so that’s about 19mm.

If I upgrade the damaged mirror, but keep the other two stock mirrors that’s not damaged, would it change the laser effect as far as usage? Not talking about a full upgrade as far as size…but just the material…going with Si or Mo.
How hard is it to change the other 3 mirrors?

pretty easy, just unscrew the retaining collars and swap. and as long as your mirrors are clean and relatively scratch-free you should be fine.

Are the stock optics that bad? It’s only $45 to replace the head and mirrors, worth it if the head already is air assisted?

its not terribly critical the stock ones can last a long time. if you have air assist already then start with that and see how it goes.

I upgraded all my mirrors to Moly from the start and added a lightobjects air assist head with upgraded lens. Been very happy with those upgrades.

@Nedman ​ how much for the moly lens pack?