There’s a claim that the Record No. 6 is the best vise ever made. We wanted to see if that was true so we’re putting it up against the Fireball 510 Hardtail.
Today’s focus is on screw design, a critical factor in how smoothly a vise operates and how much clamping force it can generate.
Record No. 6 Screw Design:
Uses a fine-pitch, double-start thread which is when a screw’s thread has two starting locations on opposite sides of the screw.
Screw threads directly against the dynamic jaw.
The Record Number 6 relies on a small pin to help retract the dynamic jaw. The downside of this is a hole drilled through the spindle introduces a potential stress point under heavy load.
The handle shows visible bending and wear from users struggling to achieve higher clamping force.
Fireball 510 Hardtail Screw Design:
Uses a robust Acme thread which is thicker and more durable than the Record Number 6’s screw design.
The Fireball Hardtail 510 is equipped with two forward and return thrust bearings that can handle up to 45,000–50,000 lbs of force. The bearings minimize friction during clamping.
It utilizes an anti-backlash spring to reduce play in the screw.
The Fireball Hardtail 510 uses a heavy-duty collar instead of a small pin that requires drilling a hole through the spindle, eliminating stress points unlike the Record Number 6.
From an engineering standpoint, the Fireball Hardtail 510 screw design offers more durability and smoother operation compared to the Record Number 6.
