Steam Frame PD100 Mount

3D-printable mounts that hold a BoboVR PD100 (the PD100 dock with a B100 battery) on the rear battery pod of a Valve Steam Frame. Each mount slides onto a dovetail key on a clip that wraps around the pod and leaves room for the rear cushion:

• Under mount: hangs the PD100 below and behind the pod. It suits fast-paced games, since there is less movement low on the head.
• Over mount: lays the PD100 over the top of the pod at a flat angle. Very little sticks out behind your head, so you can lean back against a headrest.

Under mount	Over mount

Sections through the middle of the pod, with the head to the right. The pod is gray, the clip is blue, the mount is orange, and the PD100 is shown as a yellow block. The clip is drawn as printed, so its spine overlaps the pod.

How the clip works

The clip is a remix of SpanishPotato's Steam Frame back clip, whose file is in cad/ref/SteamFrameBackClip.stl. Only its attachment is changed: its two slots are filled in, and our 30 mm dovetail key takes the place of one of them. Everything else is as in that file:

• A cap with a long lip hooks over the pod's top edge.
• A thin spine runs down the side of the pod that faces your head. It has two windows, and a slit under the cap lets it flex.
• At the bottom, a block with a short lip hooks only the outer shell's bottom edge. Legs at the clip's ends join it to the spine. In the middle, the head side of the pod's bottom edge stays free, so the rear cushion can go back on.
• Three small pegs face the pod from the spine and legs.

There are four versions. clip_over has the key on top of the cap for the over mount, and clip_under has it under the bottom block for the under mount. Each mount slides onto its key from the side.

The other two are versions of clip_over with a different outline, for an over mount that rocks less. Seen from the head side, the original is a trapezoid: about 32 mm wide at the cap and 59 mm wide at the bottom. Both versions have a cap 59 to 60 mm wide and a 55 mm key, the full width of the over mount. At every height, the cross-section is the same as the original's, so the cap, lips, slit, and bottom block grip the pod in the same way. cad/ref/reshape.py makes these changes.

• clip_over_straight is 59 mm wide from top to bottom. Its bottom is the original's, so the cushion fits the same way as with clip_over.
• clip_over_wide is the original turned upside down: 60 mm wide at the cap and about 32 mm at the bottom. The narrow bottom brings the legs and end bars in to about 10 to 16 mm from the middle. In clip_over, that part of the pod's bottom edge on the head side stays free for the cushion, so the cushion may not go back on with clip_over_wide. The two small pegs at the bottom also move in, from about 22 mm to 13 mm out.

What you need

• A Valve Steam Frame.
• A BoboVR PD100 charging dock. This listing is the dock only, without a battery.
• A B100-style battery for the dock, such as this DMMNS 10000 mAh two-pack, which is sold as a replacement for the BoboVR B100.
• 3M Command strips to hold the PD100 on the mount.

Parts

File	Quantity	Notes
stl/clip_under.stl	1	Clip with the key underneath, for the under setup
stl/clip_over.stl	1	Clip with the key on top, for the over setup
stl/clip_over_straight.stl	1	Instead of clip_over: 59 mm wide at the top and bottom, so the over mount rocks less
stl/clip_over_wide.stl	1	Instead of clip_over: wide at the top and narrow at the bottom, so the over mount rocks less
stl/under_mount.stl	1	For the under setup
stl/over_mount.stl	1	For the over setup

Print the clip and mount for the setup you want, or both pairs.

Printing

• The STL files are already oriented.
• The clips print upright like the original file, 100 mm tall: clip_over, clip_over_straight, and clip_over_wide stand on the bottom block and clip_under on its key. clip_over_wide stands on a block only about 15 mm wide under a 60 mm cap, so use a brim. They need supports under the end bars at the bottom, under the tip of the long lip, and under the cap. If supports end up in the slit under the cap, clear them out completely, since the spine flexes there.
• The mounts print on their side with no supports, 55 mm tall, so the layers run in the direction that carries the battery's weight.
• PETG is recommended. PLA can soften over time from body heat and a warm battery.
• As solid plastic, clip_over and clip_under are about 11.5 cm³ each, clip_over_wide about 15 cm³, clip_over_straight about 17 cm³, the under mount about 26 cm³, and the over mount about 14 cm³. Your slicer will report the actual weight for your infill.

Assembly

Fitting the clip

1. With the spine against the side of the pod that faces your head, hook the cap's long lip over the pod's top edge.
2. Press the bottom of the clip toward the pod until the short lip snaps over the outer shell's bottom edge.
3. Center the clip on the pod.

Under setup

1. Fit clip_under.
2. Slide the under mount onto the key under the clip from one side until it is centered. Its upper part sits just behind the pod's outer shell.
3. Stick the PD100 to the mount's angled face with 3M Command strips. The PD100's flat bottom goes against the mount, with the display edge toward the pod.

Over setup

1. Fit clip_over, clip_over_straight, or clip_over_wide.
2. Slide the over mount onto the key on top of the clip from one side until it is centered. On clip_over_straight and clip_over_wide, the key runs the mount's full width.
3. Stick the PD100 to the platform with Command strips, with its display edge at the back of the platform.

The dovetail fit is tight on purpose so the mount stays put by friction. If a mount will not slide on, lightly sand the sides of the key, or increase dt_gap in cad/common.scad and reprint the mount.

Fit and customizing

The clip's fit is the original file's and has not been changed. The pod measurements come from calipers on one Steam Frame and place the mounts and the assembly views. The main numbers:

• The pod's outer shell is 87.0 mm tall at the seam, and the part that faces your head is 84.5 mm tall.
• The pod is 12.0 mm thick at the middle of its top and bottom edges, and the outer shell is about 6.5 mm of that.
• The outer shell bulges about 1.6 mm at mid-height.
• Seen from above, the pod curves with a radius of about 117.5 mm.

The design is written in OpenSCAD. Settings you are most likely to change:

File	Setting	What it does
cad/pod_dims.scad	all values	Pod measurements
cad/common.scad	curve_radius	Curve of the pod seen from above
cad/common.scad	dt_gap	Dovetail clearance per face
cad/common.scad	mount_width	Mount width (55 mm by default)
cad/common.scad	key_len	Length of the key on clip_over and clip_under (30 mm by default)
cad/common.scad	key_len_wide	Length of the key on clip_over_straight and clip_over_wide (the mount's width by default)
cad/under.scad	under_tilt	Angle of the under mount's face, from vertical (30 by default)
cad/under.scad	corner_below	How far below the pod the PD100's front corner may reach. This is the part that can touch your neck when you look up.
cad/over.scad	over_tilt	Angle of the over mount's platform, from vertical (60 by default)
cad/over.scad	platform_len	Platform length from its back end to the tip (40 mm by default)
cad/over.scad	back_reach	Moves the PD100 back and down along the platform, away from your head (0 by default)

Building the STL files

Use a recent OpenSCAD development snapshot. From the repository folder:

openscad -D 'part="clip_under"'  -D print=true -o stl/clip_under.stl  cad/clip.scad
openscad -D 'part="clip_over"'   -D print=true -o stl/clip_over.stl   cad/clip.scad
openscad -D 'part="clip_over_straight"' -D print=true -o stl/clip_over_straight.stl cad/clip.scad
openscad -D 'part="clip_over_wide"' -D print=true -o stl/clip_over_wide.stl cad/clip.scad
openscad -D 'part="under_mount"' -D print=true -o stl/under_mount.stl cad/under.scad
openscad -D 'part="over_mount"'  -D print=true -o stl/over_mount.stl  cad/over.scad

clip_over_straight and clip_over_wide are built from cad/ref/SteamFrameBackClip_straight.stl and cad/ref/SteamFrameBackClip_wide_top.stl. Those files only need rebuilding if you change how the original's slots are filled or the pod's curve. Rebuilding them takes Python with numpy, trimesh, and manifold3d:

openscad -D 'part="clip_filled"' -o /tmp/clip_filled.stl cad/clip.scad
python cad/ref/reshape.py straight /tmp/clip_filled.stl cad/ref/SteamFrameBackClip_straight.stl
python cad/ref/reshape.py wide_top /tmp/clip_filled.stl cad/ref/SteamFrameBackClip_wide_top.stl

Opening cad/under.scad or cad/over.scad in OpenSCAD without any settings shows the assembly with the pod and a block the size of the PD100. Opening cad/clip.scad shows the clip on the pod with both keys.

Disclaimer

This project is not affiliated with Valve or BoboVR. It holds a lithium battery on your head, so check the fit and the Command strips before each session, and stop using it if anything cracks or loosens.

License

MIT. See LICENSE. The MIT license does not cover SpanishPotato's clip: cad/ref/SteamFrameBackClip.stl, cad/ref/SteamFrameBackClip_straight.stl, cad/ref/SteamFrameBackClip_wide_top.stl, and the clip STLs built from them (stl/clip_over.stl, stl/clip_over_straight.stl, stl/clip_over_wide.stl, and stl/clip_under.stl). See the original post for its terms.