[pentaxus]

The very best blades are supplied by the Society of Photo Technologists or SPT. A handle and blade will cost you around $30. Expensive, but the best.

Standard Length Crosspoint Blades ?. 50mm - 2 inches long | SPT / C&C

[TwoUptons]

This is great! Thanks very much everyone.

That's interesting! It's a wonder I got so far into the lens before it became a problem. I wonder what the benefits are of each type of head.

I've read that Phillips heads are designed to release the driver in the event of over-torquing (though my experience has been that it never works without damaging the head).

JIS assume you will not apply too much torque

-Eric

[torashi]

Just a caution that the screws on the mounts of manual Pentax lenses (especially Pentax-M it seems) can be difficult to remove because they've been locked with thread-locker. I've managed to strip out several heads by applying too much torque.

If I can't easily loosen a screw, I find that carefully heating the screw heads with a soldering iron or micro-flame torch (the burner torch, not the 'flashlight') is effective.

- Craig

Thanks for the tip. My recently acquired M4/20 needs some love. The aperture ring is a bit sticky.

[FozzFoster]

Thanks for the tip. My recently acquired M4/20 needs some love. The aperture ring is a bit sticky.

I've had good luck with the M series by simply working the aperture lever back and forth quickly and multiple times. Not so much luck moving the aperture ring back n forth..
The m42 lenses are especially difficult - pushing the pin in quickly and multiple times doesn't seem to have the same effect as working the aperture level in M series..
YMMV!

[Jean Poitiers]

All cross-head screws on Asahi and Pentax product are JIS standard* and they range from very small to not so small. I don't have experience with the set linked above, but am a strong fan of Moody Pollicis drivers. These are available in both long and short shank and are notable in being static discharge safe and bearing a lifetime warranty. A 4-driver long shank set (JIS #000, #00, #0, #1) is available from iFixit for less than $20 USD. Similar short shank sets are available from Amazon, Micro-tools and other vendors for about $30 USD.

iFixit | JIS Driver Set

Amazon | Moody Tools JIS Pollicis 4-piece

Steve

(...no relationship to Moody, iFixit, Amazon, or Micro-tools except as a satisfied customer...)

* While JIS is visually similar to Phillips head, both ramp and depth of the slots is different. Use of a Phillips driver on a JIS screw will likely result in the screw head being stripped and much weeping and gnashing of teeth.

I have had a Moody (long) set for a longtime. All OK, except one point lost a plane and Moody's never replied to my email about this screwdriver breaking ... guess I should try again.

I also bought another set (short shank) off of eBay that seem quite nice and I will try to find again the name/packaging for reference here.

[c.a.m]

I have had a Moody (long) set for a longtime. All OK, except one point lost a plane

A blade on one of my Moody JIS drivers (#00) also fractured. I didn't think I had applied a strong torque, but I guess I stressed it just a bit too much. This was the type of driver with the plastic handle. I didn't bother trying to get a replacement.

- Craig

[torashi]

I've had good luck with the M series by simply working the aperture lever back and forth quickly and multiple times. Not so much luck moving the aperture ring back n forth..
The m42 lenses are especially difficult - pushing the pin in quickly and multiple times doesn't seem to have the same effect as working the aperture level in M series..
YMMV!

Focusing is smooth, it's the aperture ring that feels gooey. The lever action is fine. It stops down with good force and speed.

[torashi]

As for the M42 lenses, it's always best to do a CLA. The pin and the different balancing parts need their contact surfaces to be well lubricated -and by well I mean not too much, not too little, and with the correct lubricant according to the material- in order to work fast, precise and in a responsive manner. It's always best to leave it to a well reputed, experienced professional if the item is valuable, or if it's just not your area of expertise.

[ChristianRock]

I just bought a set of Moody drivers, four JIS drivers. I intend to start working on my M 150mm f3.5 that has fungus in a middle element, hopefully I don't ruin it!
Next is the M200 f4 and the M 100 2.8 also needs cleaning.
Finally my K 50 1.2 - not sure I will have the courage as it seems a very difficult lens to work on...

[photolady95]

I bought a set a few years ago, but my brother insists they are just regular screw drivers and look like Phillips head to him. I know better so I just ignore his comments.LOL