Weapon Parts are materials scattered around the environment in Dead Space 3 that are used to craft new weapons with different abilities. 

Frames

• Compact Standard Frame: For one-handed weapons. No bonuses, but cheap to make.
• Heavy Standard Frame: For two-handed weapons. No bonuses, but cheap to make.
• Compact Elite Frame: A special frame for one-handed weapons, has all Circuits slots unlocked.
• Heavy Elite Frame: A special frame for two-handed weapons, has all Circuits slots unlocked.
• Weller's Compact Frame: A frame for one-handed weapons, has built in RLD +4. Only supports Top tools.
• Hammond's Heavy Frame: A frame for two-handed weapons, has built in CLP +3. Only supports Top tools.
• EarthGov Compact Frame: A frame for one-handed weapons, has built in SPD +3.
• S.C.A.F. Heavy Frame: A frame for two-handed weapons, has built in DMG +3.

Mk-II and Mk-V variants of the Compact and Heavy Elite frames exist. Both provide a RLD bonus, with Mk-V parts having twice the bonus.

Tool Parts

• Explosive Module and Electric Module: Activates explosion or electrocution on the last shot(s) (up to five) fired. So far, only applicable to: Rivet Gun, Javelin Gun(s), Rivet Shotgun, Line Gun Mine, and Anchored Bolas. Mk-II and Mk-V versions are also available.
• Hydraulic Engine: A bayonet-like attachment for stronger melee (for heavy frames and compact standard frame like the plasma cutter and only for lower tools).
• Military Engine: A military weapon used by S.C.A.F Forces.
• Plasma Core: A cutting tool that fires ionized plasma.
• Pneumatic Torch: An incendiary device fueled by compressed gas.
• Rip Core: A cutting tool that fires rotating saw blades.  KEY NOTE: This is not in the demo, but is on the final version of Dead Space 3.
• Rotator Cuff Module: Allows upper tool to rotate 90 degrees (so far, only applicable to: Plasma Cutter, Plasma Disperser, Line Gun, Rip Core, and Plasma Repeater). Mk-II and Mk-V versions are available, which decrease reload time.
• Survey Charge: A seismic tool that fires explosive canisters.
• Telemetry Spike: A mining tool fires tempered alloy bolts.
• Tesla core: An engine for high current electric welding.

Tool Tip Parts

• Conic Dispersal: Makes weapon projectiles fire with wide spread.
• Compressor: Allows weapons to have a more focused spread.
• Default Tip: Every weapon will start off with this tip.
• Diffraction Torus: Makes weapons have special properties specific to the weapons themselves.
• Directed Ejection Field: Fires very accurate and instant projectiles.
• Directed Suspension Field: Makes weapons that fire in bursts or with suspended ammunition.
• Precision Tip: Makes weapons with sniper rifle precision or with certain main weapon parts, a Cryogenic Torch that freezes targets.
• Rail Accelerator: Makes weapons fire specialized projectiles in slightly accelerated fashion.
• Repeater: Makes a rapid-fire tip.

All of the tool tips can be found as Mk-II and Mk-V variants as well. Mk-II tip provide a +2 SPD bonus, and Mk-V tips provide a +3 SPD bonus.

Compact Frame Weapon List

These are standard weapons created with the Compact Frame and its respectable tool parts.

Military Engine

• Default Tip [Submachine Gun] - Produces a rapid-fire compact submachine gun.
• Compact Directed Ejection Field [Revolver] - Produces a powerful revolver.

Plasma Core

• Default Tip [Plasma Cutter] - Creates a standard Plasma Cutter beam.
• Conic Dispersal [Plasma Disperser] - Creates a slightly wider and more damaging Plasma Cutter beam.
• Repeater [Plasma Repeater] - Creates a weaker fully automatic Plasma Cutter beam with reduced cutting width and compensates with a much higher clip size.
• Planet Cracker [Planet cracker tip] - Creates a more powerful Plasma Cutter beam than the default tip. This can only be earned by having a Dead Space 2 save file present on the same hard drive.

Pneumatic Torch

• Default Tip [Blowtorch] - Creates a blazing-hot Blowtorch.

Rip Core (Not in the DS3 Demo)

• Default Tip - A Saw blade is fired as horizontal cutting projectile. Functions identically to the Ripper Secondary Fire in the previous games.
• Directed Suspension Field - A Sawblade that can be steered while active. Has a very short range, but incredibly potent with an Electrocution Module. Functions identically to the Ripper Primary Fire in the previous games.
• Repeater - A Saw blade is fired as vertical cutting projectile.

Tesla Core (Not in the Dead Space 3 Demo)

• Default Tip [Tesla Pistol] - Creates a deadly Tesla Pistol. Building this weapon is inadvisable, as it is too weak to be viable on most difficulties. However, it does stun with each hit.

Telemetry Spike

• Default Tip [Rivet Gun] - Produces a semi-automatic Rivet Gun. Can be very powerful if properly upgraded.

Hydraulic Engine

• Default Tip [Hydraulic Knife] - Close combat tool that works like a knife. Each blow is similar to the regular melee attack, but deals more damage and uses ammo.

Heavy Frame Weapon List

These are standard weapons created with the Heavy Frame and its respectable tool parts.

Military Engine

• Default Tip [Carbine] - Creates a durable semi-automatic rifle. Very accurate due to being semi-auto.
• Repeater [Pulse Rifle] - Produces a fully automatic Pulse Rifle. Resembles the Pulse Rifle from previous Dead Space games but fires bullets instead of energy packets (empty cartridges are ejected from the Dead Space 3 variant).
• Precision Tip [Seeker Rifle] - Creates a sniper rifle with high precision and damage but slow rate of fire.
• Conic Dispersal [Shotgun] - Produces a reliable shotgun. Knocks enemies back.
• Compressor [Assault Rifle] - Produces an assault rifle with spread fire. Fastest reload of Military Engine weapons.
• Directed Suspension Field [Galvanizer] - Produces a burst-fire rifle (3-4 shot bursts). With good accuracy and ROF, long fire distance, high damage and decent clip size it appears as an extremly useful universal multi-task weapon (even poorly upgraded). With strong upgrades becomes one of the most powerful weapons in the game.
• Rail Accelerator [Bullpup Rifle] Like the Assault Rifle but much more accurate, but slower reload and ROF.

Plasma Core

• Default Tip [Force Gun] - Produces a kinetic shotgun with knock-back energy. Weaker than the previous Dead Space variants. Has very good knock back damage.
• Compressor [Kinetic Projector] - Creates a charged weapon that fires a kinetic impulse. The impulse behaves like a Hollywood-style railgun, piercing enemies with a bright white beam.
• Precision Tip [Contact Beam] (upper tools only) - Produces a devastating beam of kinetic energy. Functions the same as the Contact Beam's Primary Fire in the previous games.
• Diffraction Torus [Ground Diffractor] (lower tools only) - Creates a tool that knocks back all nearby enemies with a ground pulse. Functions the same as the Contact Beam's Secondary Fire in the previous games.

Pneumatic Torch

• Default Tip [Flamethrower] - Produces an intense cloud of white-hot flame. DS1 Flamethrower.
• Compressor [Magnesium Afterburner] - Fully upgraded DS2 Flamethrower, but thinner.
• Precision Tip [Cryogenic Torch] - Produces a cryogenic torch that freezes its targets. The "freezing" is actually an upbuilding stasis effect. Fires in an arc.

Rip Core (Not in DS3 demo)

• Default Tip [Ripper Secondary] - A sawblade that can be steered while it is active. Very short range.
• Directed Ejection Field [Ripper Primary] - A sawblade is fired as a horizontal cutting projectile.
• Repeater [Ripper Secondary Vertical] - A aawblade is fired as vertical cutting projectile.

Survey Charge

• Default Tip [Grenade Launcher] - Fires explosive grenades. DS2 Pulse rifle secondary.
• Directed Ejection Field [Detonator] - Creates trip mines that stick to surfaces. DS2 Detonator
• Compressor [Line Gun Mine] - Creates a timed mine that sticks to surfaces.
• Rail Accelerator [Knockback Detonator] - Creates trip mines with knockback damage. DS2 Detonator but with kinetic force instead of raw damage.
• Diffraction Torus [Incendiary Grenade] - Produces incendiary grenades. DS2 Flamethrower secondary.
• Directed Suspension Field [Rocket Launcher] - Creates a rocket launcher. Extremely hardhitting, but with low ROF, very small clip size and noticeable projectile travel time. Can easily kill the shooter if used indoors or at close range.

Telemetry Spike

• Default Tip [Javelin Gun] - Fires an impaling javelin like the Dead Space 2 Javelin Gun without the ability to electrocute and detonate the last shot. These abilities can be added with the Electrocution Module or the Explosion Module.
• Conic Dispersal [Rivet Shotgun] - Produces a shotgun that fires rivets. More projectiles than the military shotgun but less knockback.
• Diffraction Torus [Chain Gun] - Produces a chain gun that fires impaling spikes. Very high magazine capacity and ROF with respectable damage, but low accuracy. Can be one of the most powerful and efficient weapons once upgraded properly.

Tesla Core

• Default Tip [Line Gun] - Fires a wide beam of electric energy. DS1/2 Linegun primary.
• Precision Tip [Tesla Beam] (upper tools only) - Produces an electric pulse that discharges violently. Behaves almost identically to the Plasma Core with a Precision Tip, but deals less damage. It charges faster and inflicts splash damage, however.
• Compressor [Bouncing Bolas] - Creates a bouncing electrified bola. The bola bounces at every target, even enemies, can cause more damage the more it bounces.
• Directed Suspension Field [Anchored Bolas] - Produces an electrified bola that sticks to surfaces. Creates a short lived electrical trap with very high damage but short range.
• Repeater [Bolas Cutter] - Produces an electrified bolas cutter. Like the Linegun and Plasma Cutter, but as a Bola.
• Diffraction Torus [Chain Lightning Gun] - Shoots an electric arc that jumps to 3 nearby targets. DS-Extraction Teslagun. Immensely powerful multi-purpose weapon once properly upgraded.

Hydraulic Engine

• Default Tip [Hydraulic Eviscerator] - Close combat tool that works like a chainsaw. Each blow is vertical.
• Conic Dispersal [Hydraulic Hammer] - Close combat tool that swings like a hammer with strong knockback. Each blow is horizontal. Both the Hammer and the Eviscerator require ammunition like any other weapon.