A modular, 3D printed frame for attaching metal rails!
This is a simple 3D-printable design for homemade server racks. It was initially designed for 10" racks, per Jeff Geerling's Project Mini-Rack initiative, but in theory it could be extended to any width (including 19") if a butterfly of the appropriate length is used instead of the 2113 shown here.
A key feature of this design is its use of symmetry. Dovetail joints are used fix corner brackets together with a modular spacer, but since all corners are mirrors of each other, they all have identical dovetail pins. Two identical openings cannot be mated without a middle piece called a butterfly, which has the corresponding "tail" on both sides. These modular butterfly spacers can easily be extended to any length, making it very simple to build a rack with arbitrary depth or width. The height of the rack is determined by the length of the rails chosen: the minimum size is 2U, and there is no maximum.
- (4x) Corner Bracket
- (4x) Mirrored Corner Bracket
- (4x) 2113mil Butterfly (for a 10" rack)
- (4x) Butterfly (choose depending on desired depth)
- (4x) Server Rack Rails (e.g. these 8U rails)
- (16x) M6x16mm Bolts
- (16x) M6 Nuts
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Print all the necessary parts. Do not forget to mirror half of the corner brackets in your slicer. They are chiral. One set of four 2113mil butterflies is necessary to fix the width at 10", whereas the second set of four butterflies determine the rack's depth and can be any length. Using 2113mil butterflies again will make a rack that is 10" deep. The other pre-made butterflies in this repository are 0mil, which would make a rack that is approximately 8" deep, comparable to the DeskPi Rackmate. A 250mm-class printer like the Bambu X1 Carbon can print all 16 parts in just two jobs. Smaller printers can still do the job, however; the longest dimension of any printed part is just 4.5 inches.
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Press-fit four corner brackets together with four butterfly joints. A well-calibrated printer should produce parts that fit extremely tightly, but a drop of glue or epoxy could be added for peace of mind, if desired. Note that identical corner brackets should always be diagonal from one another, never adjacent. An example photo is shown below, with each part color-coded:
- Red parts are standard corner brackets
- Black parts are the mirrored corner brackets
- Blue parts are 2113mil butterflies, notice how they are aligned perpendicularly with the "flat" face of the corner brackets' uprights.
- Yellow parts are the depth butterflies, 2113mil in this example.
- Using a pair of M6 bolts and corresponding nuts, bolt one rail to each corner of the assembled plastic frame. The rail will sit flush with the top surface of the corner bracket; you may have to apply some force to make the lower hole in the bracket's upright align properly. The friction from the tight fit should prevent the need for lock nuts, but a drop of thread adhesive could be added if the rack is expected to regularly experience heavy vibration. The image below uses the same color scheme as above.
- Repeat step 2 with the remaining printed parts and then attach the second frame to the other end of the rails the same as in step 3, capping off the rack. Congratulations, it is now complete and ready for you to add your rack-mount equipment!
I've added a pair of handles to my rack. Those 8mm holes in the angle brackets aren't just there to add extra walls to the middle of the arm: they're secretly just the right size for M6 heated inserts! This allows us to attach items along the frame, so long as they have a pair of holes that match the distance given by the butterfly spacer, with nothing but some spare M6 bolts.
- (2x) Handle2113 (for use along axes with a 2113mil Butterfly spacer)
- (4x) M6 Heated Inserts (8mm OD, 8mm depth)
- (4x) M6 x 16mm Bolts
- Flip the rack upside-down and set out the heatset inserts as shown below:
- Using your preferred heating tool, heat up each insert and press it down until it seats flush. (Tip: Press it most of the way down with heat, then press it the rest of the way with a large, flat object to prevent over-penetration.)
- Flip the rack back over (upside-up) and screw the handles in place with the M6 bolts. (The bolts should be screwing into the heatset inserts from the opposite side of the one they were inserted from.)
