Tightening a Yashica slip-on lens cap

Yashica rangefinders and SLR lenses of the sixties and seventies were supplied with a semi-flexible plastic slip-on lens cap. Over the years those old caps have lost their grip and no longer stay on the lens. Here's how to tighten them so they fit like new again.

At any automotive supply store, buy a worm-drive hose clamp large enough to slip around the lens cap. Finger-tighten the clamp until the cap stays inside it. Heat a cup or two of water to boiling, remove it from the heat, and drop the cap and clamp into it. Let the whole thing sit for a minute, then pour off the water and tighten the hose clamp half a turn or so until the cap is squeezed a little. (You may need to handle the hot parts with gloves or a towel.) Don't tighten so much that the rim of the cap bends or folds or the face of it buckles. A little tightening is better than a lot.



Let the cap and clamp cool until you can handle them without protection, then remove the clamp. Dry the cap thoroughly and try it on the lens. If it doesn't fit tightly enough, repeat the process.

I've used this method to tighten the lens caps of several Electro 35s and a Yashinon-DX SLR lens.