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SKU: ft-nw-10in-ar500 Categories: Robotics, Weapons Systems Tag: nightwing_maint Brand: Fingertech Robotics

FingerTech NightWing AR500 Weapon Disc

Name: FingerTech NightWing AR500 Weapon Disc
SKU: ft-nw-10in-ar500
Availability: InStock

FingerTech NightWing AR500 Disc

The FingerTech NightWing AR500 disc is the battle-proven undercutter weapon at the heart of one of the 3lb class’s most feared and entertaining robots. Cut from AR500 steel — the same material used in 250lb BattleBots™ weapons — this 10in four-toothed disc is a genuine 3lb undercutter weapon disc that hits hard and holds up. It’s the standard disc included with the NightWing kit, and a smart spare to have in your pit bag before every event.

$56.99

2 in stock (can be backordered)

Just Cuz RevvitRC 50A AM32 ESC with BEC FingerTech Nightwing 3lb Undercutter Assembly

The NightWing AR500 Disc

The FingerTech NightWing AR500 disc is the standard weapon included with the FingerTech NightWing Kit — and it’s not subtle. Cut from AR500 abrasion-resistant steel, the same material used in full-sized 250lb BattleBots™ weapons, this 10in four-toothed disc is engineered to deliver maximum punishment in the 3lb class. Paired with the NightWing’s belt-driven weapon system, it spins up to 8,000 RPM on a 3S LiPo — that’s 240mph at the tips. You can also check out our new Nightwing titanium disc!

AR500 Steel — Why It Matters

AR500 is a hardened abrasion-resistant steel with exceptional toughness and edge retention. It doesn’t deform on impact the way mild steel does — it bites, bounces back, and stays sharp. For a 3lb undercutter weapon disc spinning at this speed, that material choice isn’t a luxury, it’s the point. This is the same spec that makes full-sized combat robot weapons so destructive, scaled down to beetleweight class.

Four Teeth, Optimized

The disc’s four-tooth geometry isn’t arbitrary. Tooth rake and relief angles have been optimized by FingerTech for the ideal balance of bite and durability — aggressive enough to catch and launch opponents, tough enough to survive the hits that come back. The undercutter profile keeps the disc low to the ground, sneaking under opponents’ armor where it does the most damage.

Compatible Mounting Options

The disc includes a 4-hole screw and slot pattern that works with the FingerTech Blade Mount, the FingerTech 60T Weapon Pulley, or your own custom hub — so if you’re building a custom undercutter chassis around this weapon system, you’ve got options.

Stock a Spare

Combat discs take hits — that’s their job. AR500 is tough, but a bad impact can nick a tooth or bend a disc beyond reliable use. If you’re competing with a NightWing, having a spare FingerTech NightWing AR500 disc in your pit bag isn’t paranoia, it’s standard practice. Pair it with a spare FingerTech 67T Timing Belt and a FingerTech Safety Clamp and you’re ready for whatever the arena throws at you.

Safety Warning:

Spinning weapons generate extreme kinetic energy. Always engage a weapon lock and test only within a secure arena or test box. Never operate a spinning weapon in an unsecured area.

Features

FingerTech NightWing AR500 disc — used as the standard NightWing weapon
AR500 steel: same material used in 250lb BattleBots™ weapons. See also our new titanium disc.
10in tip-to-tip: maximum reach for a 3lb undercutter weapon disc
Four-tooth geometry: optimized rake and relief angles for bite and durability
240mph tip speed at 8,000 RPM on a 3S LiPo battery
Compatible with FingerTech Blade Mount, 60T Pulley, or custom hub
4-hole screw and slot pattern for secure, repeatable mounting
308g (10.86oz) — substantial hit weight for the beetleweight class

Specifications

Specification	Value
Material	AR500 Abrasion-Resistant Steel
Diameter	10in (254mm) tip-to-tip
Thickness	0.125in (3.0mm)
Bore	0.75in (19.06mm)
Tooth Count	4
Screw Hole Pattern	0.875–1.5in (22–38mm), 6-32 screws
Weight	10.86oz (308g)
Compatible Mounts	FingerTech Blade Mount, FingerTech 60T Weapon Pulley, custom hub
Fastener	4× 6-32×3/8in button head screws

Frequently Asked Questions

Is this the same disc that comes with the NightWing kit?

Yes — this is the exact disc included with the FingerTech NightWing Kit. It's the standard AR500 weapon for the NightWing undercutter system, and it's the most common spare to stock if you're competing regularly.

What is AR500 steel and why does it matter?

AR500 is a hardened abrasion-resistant steel used in full-sized 250lb BattleBots™ weapons. It's extremely tough, holds its edge well under impact, and doesn't deform the way mild steel does. For a spinning undercutter disc at 240mph tip speed, material hardness isn't optional — it's what keeps the disc functional after hits that would destroy a lesser blade. Love Titanium? We have the same disc in light and durable Titanium.

What hubs and pulleys does this disc mount to?

The disc uses a 4-hole screw and slot pattern compatible with the FingerTech Blade Mount, the FingerTech 60T Weapon Pulley, or your own custom hub. Mounting uses 4× 6-32×3/8in button head screws.

Can I use this disc on a custom undercutter build?

Absolutely. The disc's 0.75in bore and standard screw pattern make it compatible with a variety of custom hubs and pulleys beyond the NightWing system. If you're designing your own 3lb undercutter chassis, FingerTech recommends 3.18mm (0.125in) top and bottom plates with 30.35mm (1.19in) tall walls, with the motor axis spaced 46.13mm (1.82in) from the weapon axis.

How often should I replace the disc?

AR500 is extremely durable but inspect the disc after every event. Look for nicked or chipped teeth, visible bending, or any wobble when spinning. A damaged disc affects both performance and safety — don't compete with a disc you're not confident in. Having a spare on hand means you're never caught out at an event.

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