Did everyone else start drinking when they got their K40?

2nd verse same as the first?

Well it has arrived!

After getting it unpacked from the two boxes it was sent in (one inside the other) I started setting it up with some help from @NedMan. It started easy enough, making sure it was well grounded and the air bubbles were out of the tube… well that took some high tech solutions.

As you can see from my technique, no expense was spared. Even with this setup there was still bubble issues.

A little jiggle jiggle and…

One bubble to rule them all!

As you know I am new, so I was dumbfounded on what to do, so I inquired some assistance from @NedMan. As always he had a solution, only one that someone with his background would know… He said to simply loosen the tube and turn it up slightly… :astonished:.

Then @NedMan notice something from the pictures I was sending him, so he asked: “Is that hot glue on your mirrors?!?”. Yes indeed it was.

There was hot glue everywhere, only thing I could think of is that it was to try and help on shipment keep everything from moving or getting damage?!?

Alright the moment of truth, time to fire this baby up!

Its alive!

:partying_face: :partying_face:

So far so good, I haven’t burned down the house or electrocuted myself.

Now the fun starts, alignment of the mirrors. Which wasn’t to bad this is what I had after the first test fire:

a little bit of a tweak and it was right on. Did a test burn on some cardboard and it “worked”. Just need more time to get use to how to work it with different medias. With the knowledge that it at least works, I had to call it a night.

Then today I got my new mirrors in:


Popped those babies in and got ready to start the alinement all over again, I mean hey it was simple the first time… This is where the question from the subject line comes from. lol. I mean by god! I’ll get the Y mirror lined up with the X mirror. Great centered up. Then I start to try and get the X mirror lined up with the head, and then nothing. Back track to the X mirror, well because I moved the X mirror to try and line it up with the head, it is no longer lined up with the Y mirror. Now I know that in floatingwombat’s instructions, the last four things you need are: Time (lots of time), Patience, More time and Patience, and finally several attempts. Which leads me back to my main question, how much do you all drink? lol

All in all, I am having a blast. I like puzzles so this is right up my alley. I still have some more items coming in, like my air assist, better exhaust fan setup, and some other mods for it. So here is to raising a glass with me as I get stuck head on in. Stay tuned for the next chapter:


:tada: The initial alignment is the worst. We’ve all been there. :grin:


I’ll also say that apparently his machine didn’t come with a temp probe for the tube. :astonished: Cost cutting must be getting serious. I did have him get a dual therm for the tube and cooling bucket.

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Yes, that should be here today or tomorrow.


By drinking do you mean “from a fire hose” yep that’s the K40 beverage of choice!


congratulations but please tell me that is not masking tape over your mirrors.

I see it over and over people being told to put tape over the mirror to align the mirrors and what they end up doing is liquifying the glue on the back of the tape which is then ejected onto the mirrors and is near impossible to clean off without scratching the mirror surface.

If using tape then stick a coin to the back side so the glue can not get onto the mirrors. Better is to use tape to hold paper in front of the mirror.


That rotary looks neat. That you can attach height-adjustable idlers on one side makes it a bit more versatile than the usual rolling pin rotaries.

It currently only costs $59 over at their official store and they can also ship from the US and Europe:


@tomatsu Thank you for the heads up. I have ordered it from their website! Always welcome money saving tips! :grin:


THE single most important thing you need to know as a beginner is…

Don’t overpower the laser - you can kill your tube dead in less than an hour if you massively overpower it. The maximum current for a K40 is 12mA (lower if it is a mini with a smaller tube). The digital display is NOT mA. So you need to fit a 20mA or 30mA meter as soon as possible., In the mean time, don’t run your laser over 28% on the digital display (for the standard K40 - less if a K40 mini).

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I also ordered one of those rotaries a few days ago. It arrived today. It’s really tiny, but looks pretty good. It’s a very compact design. The rollers are very grippy. The tensioning mechanism seems a bit fiddly, but it will do the trick.

The motor is rated for 0.95 A. So, it’s a basically perfect fit for a K40 (Y = 1 A).

The padded cardboard box it came in can be reused for storing it and the few extra bits. Very convenient.

So far I only plugged it into my Enter 3 and made it spin a can. That worked fine. Perfect traction and the can didn’t wander either.

Can’t wait to try it in my K40, but I need to fix the K40 first. Lol.

The biggest caveat is probably that you only get ~8 cm from the focal point to the floor of the machine (stock head, stock 2" lens). That rotary, while very compact, is still 3 cm tall. You can get about 23 mm of extra space if you use a 1.5" lens and a different head, but that’s barely enough room for the skinniest tumblers.

I’ll probably cut a hole in the floor and bolt some metal tub (some steam table pan or whatever) to it to make room for larger items. Since my worktable is attached to the XY stage, I can do whatever I want with the floor.


the K40 is a hackers C02 laser and as such many who use it with a rotary cut the bottom out of the sheet metal box and raise it up as needed.

The K50 and up will have the large/deep box and lots of travel on Z axis but you’ll pay about $1,200 more to get that.