The Designated (JIS) Driver

The general guidance for vintage Japanese lens repair is to use JIS drivers to avoid stripping the screw heads so what and how many do we need?



The crosspoint screws used on Nikkor AI/AI-S lenses are typically JIS #0 and #00 and various slotted sizes, commonly 1.2mm for grub screws, but the older pre-AI lenses seem to have a wider range of screw heads. This means that, as for many hobbies, there's a minimun bar of entry. For me, these have been the options I've used to cover the various bases.

The Vessel 9900 #00 x 75mm and #0 x 100 mm / 150 mm plus a TD51 1.2mm is good core set. by the Vessel TD56-S driver set includes an alternative set of core drivers (JIS 0,00, 000, 0000, slotted 0.9mm and 0.7mm) minus the 1.2mm TD51 driver, required for the majority of Nikkor AI/AI-S screws.



An alternative is the Wera 2035/6A driver set that includes:

• Slotted drivers:
  
  • 0.30 x 1.8 mm x 60 mm Wera - 05118004001
  • 10.40 x 2 mm x 60 mm Wera - 05118006001
  • 10.40 x 2.5 mm x 80 mm Wera - 05118008001
  • 10.50 x 3 mm x 80 mm Wera - 05118010001
• Philips drivers:
  
  • PH #00 x 60 mm Wera - 05118020001
  • PH #0 x 60 mm Wera - 05118022001
    JCIS #0 compatable

To avoid confusion, it's important to point that the Wera PH #0 driver in the above set conforms to a 2020 abandonned JCIS standard, the Japanese Camera Industry Standard. The JIS (Japanese Industrial Standard) is a much more wide raging standard that includes a specific standard JIS B 1012 screw drive - the JCIS standard covered the JIS screw drive.

But theres more

Now that you've spent upwards of 30 GBP on some drivers, why not just use your Philips driver thats been in your toolbox for years? Wikipedia states:

The JIS B 1012[27] was commonly found in Japanese made equipment, such as cameras and motorbikes. JIS fasteners superficially resemble a Phillips screw albeit one with narrower and more vertical slots. Compared to Phillips screws these differences give JIS fasteners less of a tendency to cam out. The bottom of the recess is flat, and the point of the driver has to be blunt. A Phillips screwdriver has the same 26.5 degree cone angle but because of the tapered slots will not seat fully, and will damage the screw if forced. A correctly sized JIS driver will engage at full depth into a Phillips or Pozidriv head screw slightly loosely, but without damage. JIS heads are often but not always identified by a single dot or an "X" to one side of the cross slot.[28]

Researching the differences between Philips and JIS screws leads you down an Coke vs Pepsi rabbit hole so I'll let reader explore independantly.



However given personal experience, when starting lens maintanence, of stripping (JIS) lens mount scerws with a Philips driver I will follow common guidance of using JIS drivers on crosspoint camera screws.