Suggestions to fix a gear

**petersemple** · 23rd August 2012, 12:18 PM

I have a lens, and all the symptoms suggest the focus gear has some stripped teeth. It's not the same lens, but when I open it up, I expect to see something similar to the focus gear in this one Glaring Notebook Cubed

My lens is older (10 or so years) and this is a known problem apparently when putting this lens on a more modern camera (Sony cameras have the AF motor in the body, and the modern ones are more powerful than older ones). I could send it off for repair, or buy the part and replace it myself (maybe) but the lens isn't a particularly expensive one, and I also doubt the replacement part would last much longer. I would just replace the lens, but I'm not in a financial position to do so at the moment, so my options are to use as manual focus only, or try and repair the stripped teeth, hopefully with something stronger. My idea was to make a mold of the good teeth with silicone, and then use that mold to make new teeth. My idea is to use Araldite in the mold to form the new teeth. I imagine I will have some filing/clean up to do afterwards. I would love to know if anybody has ideas for a better way to do this, particularly if there is anything that would be stronger or less messy than the Araldite that I could use to build up the new teeth.

Thank you

**ian** · 23rd August 2012, 01:22 PM

in your place I'm not sure that I'd try and repair the stripped gears
firstly I'm not sure araldite is hard enough and stiff enough for the purpose. it might be too flexible for the purpose, meaning the new teeth would bend
secondly, if the lens is a good one, I'd be happy to revert to using it with manual focus, if it's only a so-so lens, I'd look to using an alternative.

**petersemple** · 23rd August 2012, 04:14 PM

Unfortunatley I don't have an alternative, and can't afford a replacement. It's not a great lens, but serves my purposes mostly. I mostly use it for photos of older kids at althetics, and a rapidly moving toddler, somanual focus would not be ideal. I will if I need to though. Any suggestions for something that would fill a mold, and be harder and stiffer that Araldite?

**Master Splinter** · 23rd August 2012, 07:55 PM

Rather than Araldite, I'd pick up a tube of JB Weld for the job. About $12, I know Masters has it.

**petersemple** · 23rd August 2012, 07:58 PM

I have some Milliput too. That dries very rigid. Does anyone know how well it adheres to plastic? Whatever I use, I think I will grind away whatever is left of the teeth, and grind down a bit further, so I have a larger piece, rather than just small pieces at the crown of each tooth.

**ian** · 23rd August 2012, 10:14 PM

Originally Posted by petersemple

Unfortunatley I don't have an alternative, and can't afford a replacement. It's not a great lens, but serves my purposes mostly. I mostly use it for photos of older kids at althetics, and a rapidly moving toddler, somanual focus would not be ideal. I will if I need to though. Any suggestions for something that would fill a mold, and be harder and stiffer that Araldite?

even with those constraints, I think I'd stay with using the lens manually rather than attempt a repair
I have a couple of auto focus lens that are easier to use with manual focusing because when the subject moves out of the focus sensor zone the lens doesn't refocus -- and even in manual the focus confirm function still works
and I've used these lenses at sports and with a toddler

**petersemple** · 24th August 2012, 08:39 AM

Yeah, change of plans. Last night I started to take it apart, and couldn't get either of the first 2 screws out (ones that hold the electrical contacts on). Don't want to damage them, so manual it is.

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