K40 CloudRay K Series Optics Upgrade

So after my recent unexplained optic alignment shift.

I decided to look to see what I could find for better mirror mounts. I knew CloudRay made the K series optic mounts that supposedly would fit a K40. On Amazon they were like $50-60 USD but on AliExpress I could get a set for $36. Then I found there was a CloudRay clone company called FireRay. I could get the apparent same set mounts for $24. Decided to give those a shot.

I know this set is not a true drop in replacement and will take some work to install.

Looks like I might need to print a new carriage plate for the laser head as it apparently sits up higher then current head. Several versions available on Thingiverse.

Even a laser cut version.

I’ll keep everyone posted after these arrive some time in the next month or so. If anyone has experience installing these in your K40 please feel free to chime in with any tips. :slight_smile:

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I have one of these mounts in cad.


Anything is better than the flimsy mirror mounts used in a stock K40.

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Yet another thing to consider in my K40 rebuild.

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I have found the rotary mount design to be stable and easy to adjust.
I made these all by hand (from 1/4" acrylic) and have one designed in Fusion (untested).
They should be able to be cut on a K40 although I never had a need to …

I can provide dimensions for the others or add them into CAD if they get used.

As a common problem seems like it would be useful to design these once and for ALL k40 users.

I also wanted to redesign the objective lens holder to make it adjustable.


Well they arrived today, faster than I was expecting. Initial impressions are good as they seem well made.

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How much work does it take to mount these? Are any modifications required?

@JKKDev I just got these today so I’m in the process of figuring it out, but here are my thoughts so far

  • As far as I can tell the second mirror is going to be a direct drop in, will just need longer M3 screws to mount.
  • The first mirror would probably need some holes drilled to mount, but I’m considering doing something like what @donkjr posted above in his blog about Mirror # 1
  • The laser head mount is going to trickiest part. It has 4 M3 screw holes under the mirror housing that is used for mounting. The head sits up higher that the standard K40 head, ~7.5mm, so the head would need to be lowered with a different mounting plate, like I mentioned in my original post at the top. Alternately keeping the laser head higher mirror placement and raise the tube, 1st and 2nd mirrors to match.

The only thing I don’t like about the laser head is that there is about 40 mm of extra length above where the lens sits (indicated by the arrow). So you are losing about 30mm of available z-height in your machine compared to a standard laser head. If you use a mount that lowers the head you are probably looking at losing another 7-8mm of working height.


I’m going to 3d print some adjustable laser tube brackets so I’m probably going with keeping the same mounting plate and raising the tube and other mirrors to match

I’m also considering cutting down that top section of the down tube and recut threads (M20x1) to minimize the working z-height loss.

Also considering just going ahead and cutting the bottom out of my laser and raising it up. Building an adjustable z table and just leaving the head as is.

So that’s where I’m at. Thoughts and comments welcome :slight_smile:


Watching with interest. I concluded that head would not fit … but I wanted it to ! :frowning:


Someone did a cad model of these mounts and put it up on thingiverse. The cad files, stls and technical drawing are available in the link below for anyone interested. The technical drawing will save me from having to do the measurements I will need for my installation.



Sweet. Wish I had seem this years earlier :slight_smile: I always seem to forget to check Thingverse :frowning:
I have an untested cad model for #1 mirror mount.


Someone else modeled them as well. He provided a bunch of other file formats other than .step for Solidworks.


None of these have a rotary mount adjustment. I found that to be valuable for coarse adjustments.


Yeah I like your design and may use it myself. :slight_smile:

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Decided cut down the top part of the down tube to reduce loss of available z-height. The top of the tube has a M20x1 mm thread. I didn’t have a metric die that big so I had to order one. The cheapest one I could find was this one from Amazon.

The outside dia. of the die is 45mm so my current die wrench wasn’t big enough. Rather then spending the money for bigger die wrench I decide to make one from laser cut plywood.

Rather than cutting the tube and then cutting threads I decided the easiest thing would be just to cut thread down the whole tube and then cut it to length. To hold the tube while cutting the threads I installed the adjustment ring on the bottom threads, which are different, tight as far as it would thread. Clamped the ring in my vise and cut threads until about 3mm from the start of the bottom threads.

The ring was jammed tight after cutting the threads and to loosen it up I grabbed the top of the threads, I just cut, with some plies, since I don’t care about the top, and the ring with some other pliers.

Marked a line at about 5mm of thread from the bottom. Inserted a 0.5" dia. wood dowel, to hold and steer, and carefully cut the tube on the bandsaw. Left with about 8mm to the start of the bottom threads.

Worked out beautifully. Reduced the length of the down tube by about 18mm.


Nice craftmanship at work!

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Nice watching with interest …

Is that tube adjustable at all?
Do you have to change anything if you change FL?

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You can move the bottom section, which contains the lens, and up and down about 5mm. You would have to disconnect the air hose to do it though.

From the bottom of the lens to the tip of nozzle it’s about 42mm so you could do a longer FL lens but not a shorter one.

For a shorter one can you cut the tube down further or is the coupling to big?

The bottom tube and coupler are one solid piece as the lens sits at the bottom of that coupler section. So you would be looking at cutting a section out of tube and then somehow rejoining the sections.