3D Printed Fixtures

Designed some 3D printed fixtures for carving 2 sided key chains. One for the top side and one for the bottom.

Have been working on a method to remove the need for tabs on 2 sided carves. These pieces are surfaced and below deck on both sides so there is no taping them down. No matter what I tried in post processing, you can always see where a tab was removed on a side wall as it has a vertical grain that I have not been able to replicate during sanding and polishing.

Plan was to design a system to allow for maximum accuracy and minimal mess giving the Sweepy dust boot lots of clearance, fastest machining times, advanced (for me lol) production methods and trying for repeatable results with minimal post processing. After quite a few renditions I came up with these 3D printed modules, I will fit 4 at a time on the HDM for now, they have quite a few features I have come up with I thought I would share.

Came up with this 1/4" post for setting my zero. I have 3 inch carbide blanks I use for zeroing with the Bitzero. I lower the blank down to this post and you can pretty much get a dead balls perfect zero with it. It is very easy to feel with your finger tips or a fingernail, if it is perfectly centered and lowering the Z is very easy with a piece of post-it paper, then drop it lower 4 times on .025mm setting after removal. This first test version the post was sticking up, I have since recessed it into the base for clearance.

Modeled small slots that go down to the deck floor on each corner of the stock and one for the zero post to insert a caliper to check exact height.

There are 4 slots with threads to clamp the stock in the fixture, using 3d printed threads for now. Planning on embedding nuts for reliability and strength in the next version. These can be accessed easily from the top with a ball end hex wrench.

And a set of 4 slots one on each side that allow you to take a screw driver and place it below the aluminum frame to pry it out for removal without removing the module. The 4x4" pieces I have been buying from Stoner Metals on ebay are so accurately cut I have not even needed to clamp them down they are so snug to my models. Just tap them in with a rubber mallet and pry them back out after. They must have a very nice saw, the edges do not look milled.

So the key to these coming out perfect is a super tight pin hole on the aluminum and the MDF base for the bottom side. Lots of test cuts to get the perfect hole that has some resistance to insert the pin with no wiggle room at all. If you can achieve perfect pin holes you can pretty much pull off a no seam 2 sided carve. Pin wiggle room = seam. I use 4 pins to minimize any variance.

I carve out the center of the top side and about half way down on the outside just enough to run a contour over top of the protruding key chain hole because there will not be access when it is flipped over. Then flip and finish the center first on the bottom side. Afterwards I clamp it to a center post on the bottom side fixture that sticks up and perfectly meets up with the bottom side of the key chain under the aluminum frame.
The photos of the models do not show the chamfered edges, the toolpaths are based off un-chamfered edges in a 2d toolpath.

Now I am free to carve out the rest of the frame with no tabs to worry about.

From this:

To this:

Could not be happier with the end results, they are completely smooth and feel really nice to hold in your hand, no sharp edges, no seam, right off the machine is stunning to look it imo. It can use some polishing, some light tool marks on the flat surface around the large heart chamfers need work and I will do a quick polish on the whole thing with a rotary tool and diamond paste, but I am just extremely impressed with the results from the HDM, it has been a very good purchase for me, my favorite machine ever.

So I got my inspiration for these key chains a while back, a few years ago I made a gift for my elderly mother one with a peacock engraved on a small disk embedded in a piece. I had made a second peacock, slightly rougher then the one I used, it was a test piece, I gave it to her with the gift as a extra to use for a paper weight or whatever. She has been carrying it around everywhere with her ever since.
I was thinking I could do better! A nice smooth rounded key chain made for handling would be a possible upgrade and she might want to retire her “pocket peacock” lol but probably not…

I found some nice key chain straps on Amazon, and designed a wooden gift box with a line art style heart design on the front and a engraved inscription on the inside. Here are some pics…

The plan is to start my CNC business off by manufacturing 100 of these to start for sale. I plan to include the strap and sell them in a 3d printed case with a magnet lid that I have yet to design.
I got the toolpaths down to 6 tool changes and 36+ operations per side, about 7 hours total for both sides in machine time with moderate settings. The 4x4 bars are about 6 dollars each when bought in bulk. I will make 4 at a time with 4 modules mounted in the HDM to reduce tool change time to start. I don’t think I want to try more then 4 at a time due to loss factor if something goes wrong.
Initially I will make these hearts design key chains but plan to make a ton of other designs for this key chain platform the near future.
Excited to get busy on these, will see how it goes!


Good luck with your CNC business Max! :crossed_fingers:
Great write up and fantastic work! I really admire what you achieve in these machines!

Please drop me a PM with a link to your site when its up and running

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Your setup is amazing, but I’m not understanding how you keep the second side from moving. Is the pattern you make on the first side the ‘pin’ you use for holding when flipped? I really like the custom jig you printed. I might try something similar in the future when I attempt double sided carves. I can’t believe your machine is in your house tho. :laughing:

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Max, as usual, not good but honestly extraordinary work. Inspiration indeed.

Appreciate you posting this with the detailed description.

Hats off.


Hi Dustmite,
Sorry was getting late I missed a few steps lol.
Here is the bottom side module, it has this post in the center with 8 threaded holes.

I place a blank piece of MDF I machined previously into the fixture and secure it, then cut out the four pin holes.

I then place the 4x4x1/2" frame onto four half inch stainless pins I inserted into the MDF.

And bolt down the top clamp to hold the aluminum 4x4 frame in place.

It will look like this before I start carving on it…

After I carve out the inside of the bottom side of the key chain and some of the outside, I bolt it down to the module center post with this clamp that has 8 countersunk holes.

It will look like this at that point:

At that point I am ready to carve the outside of the key chain, no tabs necessary, with this as the end result.


Thank you Kenneth, have to thank Rob, Luke and all the guys at Carbide3d, the HDM is everything I ever wanted in a CNC machine, such an amazing design.
Will be working on a online store very soon, and will PM you asap.

I just got a S5Pro 4x4, so I am expecting big things in the near future haha!

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Thanks Griff, the forum has taught me well. Hope I inspire others to advance their techniques.

An artist, engineer and a craftsman, well done Max!
Please PM that link to me as well when your site is up.


Your work never disappoints and the amount of time you have invested in this jobs various part / fixture design and cam really shines.


The amount of care and labor you put into each keychain is amazing. Have you ever looked into creating a negative mold for casting? I’m not sure what melts lower than aluminum, but if you are mass producing these, streamlining your process would save a lot of time. I had LEAN manufacturing beaten into me in previous jobs, and they’d have a heart attack at so many steps.

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Molds are a bit above my pay grade, I would not know where to start.
One reason there are so many steps is Fusion starts acting funny when you have multiple heights running different contours on different levels, I end up just separating every tool path.
Many are less then a minute long… Also on the curved surfaces, I start with a ball mill using ultra fine stepover on top and use multiple stages to gradually raise the stepover as it converts to vertical surfaces. Makes a big difference for smoothness.

this is super cool. gives me some ideas for doing my worry stone again in the future.

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Some software accomplish this strategy by varying the step over by maximum scallop height desired. I’ do not have Fusion so I do not know if this is possible in that software but it is very common with software designed for mold making and 3D milling. This feature is very useful when using a barrel mill that contains multiple profile radius’s. Cycle time is greatly reduced when compared to a constant step over strategy as well as better surface finish and greater tool life.

Add: I should mention that barrel cutters are predominately used in 5 axis mold making.

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In Fusion 360, it’s called Cusp Height, and available in Parallel surfacing.


Got a Bambu Labs X1 printer, wow that thing is impressive. Incredibly fast with really nice prints. When I say it prints fast, I mean it is really really really fast.

So I potentially think I can do 9 at a time of these on the HDM. The machine has been so dead on for me, I am gaining confidence in it’s ability to run perfectly forever, but everything is pinned so what could possibly go wrong?

So I ordered two more HDMs to help speed things along. Now I have way too many CNC machines, if anyone wants a 4 PRO XXL with HDZ’s and water cooled 1.5kw VFD spindles with custom brackets and drag chains for a great price? Have 3 for sale. Lol.


Where are you located and how much do you want for a machine what size machine is it?

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WOW. How do you get the fixture square to the machine? Are the hole placements of the printer that accurate, and is your threaded table perfectly square too? Do you think this would be achievable with a normal 3d printer?

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In addition to the sick jigs, which I just want to reiterate are quite dope, that enclosure(s) with all the 8020 and doors really caught my eye . . . .
Keep up the good work.


I have 3 of the S4 Pro XXL’s, not set on price yet, around 33 percent off retail cost seems fair? If seriously interested contact me we can work out a very good deal for you.

Hi Doodlin,
The SMW spoilboards have a very accurate thread pattern, I am fairly sure it is about as close as you can get to perfect spacing on the threaded bolt holes.
The jigs all use flat head socket cap screws, 8 on each module. The cone shape heads assure centering when tightened, x8 that’s a lot of centering! I use a small torque wrench to make sure the modules are all seated evenly.
When I print out a 4 inch square, it comes out 4.003 or something along those lines, so the printer is very accurate. I measure surface heights to the corners when the aluminum blanks are clamped down and get a height variance of around .005 to .01 which is quite acceptable for these pieces. I attribute most of the variance to the extruded flat bar surfaces, but it is all good, I am not making airplane parts haha…
You could definitely use a normal printer, just slice for quality, use a raft to avoid elephants foot, tape down the raft to avoid corner lift/warping.

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