Minolta lens cap for the front lens: fix for broken spring

Original lens caps for Minolta MD, whether for the front or rear lens, are relatively rare and therefore expensive.

Inferior replacements are no joy.

It is therefore worth repairing a damaged lid.

While the back covers are made from one piece and are therefore robust, there is a weak point in the covers for the front lens.

Namely the plastic spring that spreads the cover in the filter thread of the lens and thus fixes it.

This spring can break. Then the lid no longer holds on.




The original from Minolta






The breaking point

Since I haven't had good experiences with gluing here in terms of durability, I'm going to weld it now.






Lever out the broken spring.




Clean the area under the spring with Aqua Purificata or tap water.






The Dremel Versatip, a butane gas burner, with a hot knife attached.




The two broken ends are then heated and joined together.

Then smooth the area with the scalpel.








Fine work with the Dremel Stylo, with the hard rubber polishing tip attached.




The spring goes back into the lid.

This puts some stress on the welded plastic when the spring is compressed, but the connection holds.






Sits


I had to try using the Versatip until it worked.

I separated and put the spring together several times, compressing or losing material in the process, and thus shortened the spring somewhat.

But the cap stays on the lens.

Heat the area with the hot knife and then spread it at full power, like butter on bread, that's how it worked best.

Open the window wide - the process creates a smell


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All information provided without guarantee and use at your own risk.

Post note:

You can also use the Dremel Versatip without an attachment. Then the two spring ends can be connected directly as soon as the plastic melts. But the material can also be shaped at the same time with the hot knife.

Excellent work! Filed away in my memory for future reference.

Flighter said:

Excellent work! Filed away in my memory for future reference.

Click to expand...

Thank you

This could be a business idea.

Buying broken lens caps and repairing them at home

I have so many Minolta broken lens cap springs. Need to try this

Good ventilation is important because the fumes produced are certainly not beneficial to your health.

I really like(d) the old Nikon caps with metal springs. Over time I have lost all but one of them. I would have thought what with all the lost lenscaps in the world that I would find one for every one I lost. - that only happened once when I lost a Leica cap and found a cheap & cheesy Voigtlander cap that surprisingly fit my old Elmar.

There should be no sharp corners where the 'spring' meets the buttons - a sharp corner creates a 'stress riser' where a very small point in the spring carries most of the mechanical load/stress. In this case the stress is greater than the plastic can bear over time and operations. The engineer or designer responsible for the Minolta cap should have had his knuckles rapped with a large Majestic tripod. Even the machinist who made the injection molding die should have screamed bloody murder - not just because of the stress riser but also all the extra work involved with making sharp inside corners in tool steel.

In fixing the cap it would be good idea to smoothly fair the spring to the button. An old lenscap might be a sacrificial donor for the extra material.