YEHWson

Before printing

This design is mostly tested, but still a WIP.
You still need a set of parts from original blasters:

• YEHW - Y12_Griddle
• YEHW - Y10_Rail_Max
• YEHW - Y16_Trigger
• Wildstyle - Ejector_buttonversion (other ejector types should work too)

For minimal reprints version, you need to print only:

• YS0_BaseL_MR (or YS0_BaseR_MR)
• YS1_Plunger
• YS13_Yoke

Also, you need the additional hardware for Base and Plunger (O-rings, pen spring and an M3x20 screw).

Hardware list

1. 1x 50/47mm polycarbonate tube, 88-90 mm long
   There's some allowance for tubes as short as 85-86 mm, tubes longer than 90 mm will fit, but the holes on base/toprail/wunderbar won't connect.
2. 19x M3x10 countersunk screws
   For general assembly.
3. 1x M3x20 countersunk screw
   For holding the shell extractor lever
4. 4x M4x27 binding screws
   These replace nylon spacers (and corresponding screws) in cammer, conrod and base assemblies 
5. 1x K25 spring, 64 mm long
   As K25s are not available for me, a generic 25mm OD, 1.8mm thick carbon steel spring was used for testing
6. 1x Ballpoint pen spring
   These are 4 mm OD, 0.4 mm thick, 30 mm long springs
7. 3x 131-size O-rings
   Can be replaced with a metric 41.7x48.7x3.5mm O-ring. One of these is used as a shock pad (bent and inserted into two slots on the back of the Base part). Seals can also be produced with two 30x35x2.5mm O-rings stretched into the undercut.
8. 1x 016-size O-rings
   Can also be replaced with a 16x19x1.5mm metric O-ring 
9. 1x 3/32" elastic cord
   Can be replaced with 4mm shock cord

Printing instructions

Most parts are covered by YEHW assembly instructions.
Base is to be printed facing upwards, may be printed without supports, but be careful with a wide bridge where extractor sits. All parts are to be printed with 5 perimeters and 25% infill.

Assembly instructions

Mainly follow the original YEHW assembly instructions, dropping the part with cylinder assembly.
Be careful that partially threaded binding screws are hard to pull out once inserted and tightened.
Base part requires:

• Assembly of extractor mechanism (described in Wildstyle assembly instructions)
• Addition of face seal (016) O-ring - simply inserted into the slot
• Addition of “shock pad” (131) O-ring - bent and inserted into two slots on the “strike face” of the print
• Addition of tube seal (131) O-ring - pulled over the part into the groove

Known issues

• Designed for 9 cm tube exactly - too short a tube makes the blaster distort on cocking, too long a tube leads to misalignment of base-wunderbar-toprail connection holes.
• On low resolution/unsupported prints overhang sagging may lead to shells not inserting properly or locking in forever. Fixed it as much as possible, two blasters run without such issues.
• Some shells point a bit to the extractor side due to shorter and thicker carriage walls compared to the Wildstyle. Definitely not a precision blaster, yet haven't tested how much it affects accuracy.

Changelog

14/08/25

Changed “Base” part to use a single M3x20 countersunk screw as an ejector lever axle.
Changed “Hardware list” to include M3x20 countersunk screw (earlier there was no detail on head type).
Added “Minimal Reprints” files with nylon spacer compatibility.

15/08/25

Fixed BOM, as metric 42x47x2.5mm O-rings do not produce an adequate seal, they were changed to 41.7x48.7x3.5mm or stacks of two 30x35x2.5mm.
Elongated TopRail front screw hole 0.5mm to compensate for tube cutting tolerances and/or edge unevenness.