Heavy Metal Head 115 – (NO Trigger, ErmesSub-Compatible) with Stainless Steel Accessories

Heavy Metal Head 115 – (NO Trigger, ErmesSub-Compatible) with Stainless Steel Accessories

This model has been developed for deep-sea spearfishing of large game. It is a heavy-duty speargun designed to absorb the considerable recoil generated by multi-band configurations. With a 115 cm shaft travel, it is not suitable for all types of spearfishing, but it is ideal for stable and precise shots. The gun is slightly shorter than the Simple Ferrule model, thanks to the metal head inspired by systems used in classic C4 and Meandros setups.

Metal Head Features

The stainless steel muzzle allows for parallel rubber alignment with the shaft, avoiding energy loss caused by oblique traction that creates detrimental friction on the shaft guide.
Designed to accommodate two pairs of rubber bands (up to 18 mm in diameter), it includes a built-in line guide that becomes visible after proper metal bending.
A line stop is also included, to be mounted as a washer behind the nut that secures the metal shaft wishbone (not shown in the drawings).
The speargun body features two through-holes in ferrule style for mounting two additional pairs of rubbers, for a total of four pairs: 2 metal head + 2 ferrule style.

3D Model of the Speargun and Handle

The design is optimized for carving into exotic woods such as teak, iroko, and mahogany. Files are also provided in .STEP and .STL formats for 3D printing or CNC machining using plastics like Delrin.

Included DXF Projects

• Covers for ballast compartments
• Muzzle accessories
• Plates for handle and butt
• Metal muzzle to be made from 5 or 6 mm thick AISI 316 sheet metal

All DXF files come with technical drawings in PDF format, including instructions for sheet bending and other processing steps. DXF files can also be used for CNC cutting of carbon fiber s when no bending is required.

Speargun Construction

The 3D model requires carving into hardwood. Use only 3- or 4-flute milling bits specifically designed for wood. Generic bits or those for metal/plastic may cause chipping.
With its 115 cm shaft travel, this speargun is not suitable for stalking techniques.

Important Note – ErmesSub Trigger Compatibility

The speargun is compatible with two ErmesSub trigger systems: Swings Double Roll and Future, including the more compact Future Double Roll.
Although the project was initially designed for the LDpro3D trigger system, the external dimensions are highly compatible with ErmesSub triggers as well.
As shown in the photos, structural compatibility is excellent.
Installing the ErmesSub Swings or Future systems requires only minor, non-invasive modifications that do not significantly alter the original design.
If you opt to use the LDpro3D trigger system, we strongly recommend purchasing the full set of files to ensure proper assembly and operation of the mechanism.

Wood Preparation

Careful preparation of the laminated wood is essential before carving. The gun’s structure allows for the use of laminates from the same wood type (no softwood alternation required).
Use only hardwoods such as teak, iroko, or mahogany, bonded with D4-grade polyurethane adhesive.
The muzzle is designed for quick rubber changes even underwater.
It can host up to 3 large rubbers (e.g., triple 18 mm) and up to 4 or more with a dual-line setup.

Propulsion and Performance

The previous model was tested with three 17.5 mm Sigal Extreme bands, delivering excellent power and penetration.
Its unique shape ensures orderly band placement, avoids line-of-sight obstructions, and enhances maneuverability.
For reduced bulk, vertical reels are recommended.
It s shafts up to 9 mm.
Custom-turned Delrin bushings are required at the muzzle -throughs to protect the wood during loading (Dyneema can damage the body).

Handle Finishing

Once carved, the handle is ready for assembly.
The only manual task required is sanding and shaping the grip saddle (highlighted in pink in the photos) to match the ’s hand anatomy.
Three handle sizes are included: small, medium, and large.
Handles can also be made from plastics such as Delrin or glass-filled nylon. In this case:

• Do not use epoxy resins
• Use D4-grade polyurethane adhesive
• Sand bonding surfaces before gluing

Main Dimensions of the Model

• Muzzle height: 40 mm
• Muzzle width: 50 mm
• Max body width: 88 mm
• Max body height: 45 mm

Included Files (STEP, STL, DXF):

• Speargun
• Handle (3 sizes)
• Handle and butt plates
• Metal Head muzzle
• Ballast compartment covers
• Line guide
• Muzzle line stopper

Included Technical Drawings (PDF):

• Muzzle accessories
• Metal Head muzzle

Technical Note: Bending must for the K-factor, bend radii (never less than metal thickness), and material stretch/compression coefficients.

WARNING:
This project is intended for private and recreational use only. It is ed under the domain LDpro3D, owned by Lombardo Davide.
Commercial reproduction is strictly prohibited. Violations will be prosecuted according to the law.

Technical Note:
Specifications and parameters for laser cutting and CNC milling depend on the type of machine and the operator’s preferences.
Standardized settings cannot be provided without knowing the equipment used.