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03-09-2017, 02:13 PM   #16
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QuoteOriginally posted by UncleVanya Quote
What is that made of?
It appears metal?
yes, it is metal

03-09-2017, 02:37 PM   #17
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Medex, this is out of your 85? Looks like brass?
03-09-2017, 10:46 PM   #18
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QuoteOriginally posted by dcpropilot Quote
Medex, this is out of your 85? Looks like brass?
Yes, dcpropilot, I removed tris gear from my fa85 after careful inspection. And I'm sure the problem and that abnormal sound is due to that crack

---------- Post added 03-10-17 at 08:22 AM ----------

QuoteOriginally posted by dcshooter Quote
Brass 13 toothed brass spur gear, splined bore.

If you can manage to take some of the following measurements, as well as the overall diameter of the gear, it should be possible to find a match, or in a pinch, to have one machined:
Thank you for the picture. I will try to make some measurements.
Actually the lens is in good working condition and focuses normally even with this crack. But I will contact friend in local service, maybe he will find replecement gear.
03-10-2017, 09:33 AM   #19
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QuoteOriginally posted by dcshooter Quote
Brass 13 toothed brass spur gear, splined bore.

If you can manage to take some of the following measurements, as well as the overall diameter of the gear, it should be possible to find a match, or in a pinch, to have one machined:
So, here are dimensions of the spur gear:
- Outside diameter 4.5 mm
- Aperture 2.0 mm
- Thickness 2.0 mm
- 13 T (tooth)
I reassebled the lens. It focuses perfectly despite that sound.

03-10-2017, 11:28 AM   #20
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QuoteOriginally posted by dcshooter Quote
Lookee what I just found:

Pentax Genuine Replacement Spare Parts SMC FA 85 1.4 | pentax lens parts | uscamera.com

Is the broken gear the one shown on the face of the assembly on the right?


The gear assembly is $57.44 plus shipping from U.S. camera.
thank you, dcshooter. The broken gear is better visible on the left picture, it is under the screw drive shaft, that has direct contact with screw drive motor in the camera. That on the face of the assembly on the right is bigger.
03-11-2017, 01:38 AM   #21
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QuoteOriginally posted by dcshooter Quote
Ah, so the one directly attached to the screw drive shaft.
After long search on the internet I found this page:
Unlimited Drive Systems -
Brass gear or other material (aluminum, steel, POM). The description of the spur gear should be 13 T, MOD 0.3, bore 2,0 mm, (outside or tip diameter 4,5 mm), but Unlimited Drive System has just bore 1.5 mm. The hole can be reworked. The price for 1-4 units is 131 euro. WOW! +shipping and +taxes If I understand correctly, 1 unit contains 10 gears. So minimum 13 euro per gear +shipping and +taxes.

Another possible decision could be plastic gear.
Here is the link: Pojezdy.EU - Odvalované ?elní kolo z Delrinu - 13 zub?, modul 0,3mm na osu 2mm, ?í?e 2mm
According to description, measurements are the same, just bore is 2,0 mm (actually 1,95 mm). The price with shippment included is about 3-4 euros.
Type of plastic used - Delrin.

Last edited by Medex; 03-11-2017 at 02:13 AM.
11-11-2017, 01:42 PM - 1 Like   #22
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I've just had the same issue, but my FA 85 stopped autofocusing altogether. The crack had caused the gear to widen, which caused it to become too big to mate with the other gears. I opened the lens up and used a plier to squeeze the gear together a bit and this has patched the issue for the meantime. There's an ugly noise while focusing and I will try to avoid using the lens until I can find a replacement. I have ordered a gear with the dimensions 13T Spur Gear (Brass), 0.3 MOD, 2mm bore, 2mm thickness from: kkpmo - KK Produktcja Mikroantriebe Zahnrad, Schnecken, Mikro Getriebe und Car System Hersteller.

I really hope it'll be a decent replacement. It's not costing much so I'm not too worried if it doesn't turn out perfect. Maybe I'll just go for original parts if I can find them.

11-11-2017, 02:30 PM   #23
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QuoteOriginally posted by HarisF1 Quote
I've just had the same issue, but my FA 85 stopped autofocusing altogether. The crack had caused the gear to widen, which caused it to become too big to mate with the other gears. I opened the lens up and used a plier to squeeze the gear together a bit and this has patched the issue for the meantime. There's an ugly noise while focusing and I will try to avoid using the lens until I can find a replacement. I have ordered a gear with the dimensions 13T Spur Gear (Brass), 0.3 MOD, 2mm bore, 2mm thickness from: kkpmo - KK Produktcja Mikroantriebe Zahnrad, Schnecken, Mikro Getriebe und Car System Hersteller.

I really hope it'll be a decent replacement. It's not costing much so I'm not too worried if it doesn't turn out perfect. Maybe I'll just go for original parts if I can find them.
Thank you. I looks very good source for different gears. My gear is also cracked but focusing still works
11-11-2017, 02:50 PM   #24
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QuoteOriginally posted by Medex Quote
Thank you. I looks very good source for different gears. My gear is also cracked but focusing still works
That's actually good to hear. I wonder how many of these lenses have faulty gears without diagnosis?
11-12-2017, 06:40 PM   #25
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QuoteOriginally posted by HarisF1 Quote
I have ordered a gear with the dimensions 13T Spur Gear (Brass), 0.3 MOD, 2mm bore, 2mm thickness from: kkpmo - KK Produktcja Mikroantriebe Zahnrad, Schnecken, Mikro Getriebe und Car System Hersteller.

I really hope it'll be a decent replacement. It's not costing much so I'm not too worried if it doesn't turn out perfect. Maybe I'll just go for original parts if I can find them.

I'd be really interested to hear how this goes. My FA 85 also has this issue and I have tried to find an original replacement part but in vain.
11-23-2017, 12:05 PM   #26
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I would like to share my joy about successful replacement of cracked spur gear with the dimensions 13T Spur Gear (Brass), 0.3 MOD, 2mm bore, 2mm thickness from: kkpmo - KK Produktcja Mikroantriebe Zahnrad, Schnecken, Mikro Getriebe und Car System Hersteller.
kkpmo - KK Produktcja Mikroantriebe Zahnrad, Schnecken, Mikro Getriebe und Car System Hersteller

BIG THANK YOU to HarisF1 for providing very good source to buy the gear. The shippment was done in 1 week from Poland to Lithuania.
I bought metal (brass) and plastic gear. The procedure of the replacement was not difficult, but tricky. In fact the new spur gear is about 0,2 mm toller/higher than original and I shaved it with sandpaper.
You do not have to disassemble the entire focusing gear mechanism. Instead, you should first climb a pinch to the gear's hole and roll it off at least twice so that the axis then enters the same pockets under the strong pressure with fingers or some kind of hard flat tool.
11-23-2017, 01:21 PM   #27
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QuoteOriginally posted by Medex Quote
..
.
This is great news! I've been waiting to see how it went.

Did you have any troubles with the splines in the bore? Are they similar to the original gear?
11-23-2017, 02:44 PM   #28
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QuoteOriginally posted by krazykat Quote
This is great news! I've been waiting to see how it went.

Did you have any troubles with the splines in the bore? Are they similar to the original gear?
sorry, i didn't make pictures, I was very focused on precision-driven work.
I'm not fluent in english. Trying to translate what "splines in the bore" mean
If you ask about the surface of the gear's hole, then I should say, that it is smooth. But the screw drive axle has small grooves and is slightly thicker than the gear's hole. The axle should be inserted into the hole, and then the hammer must be used in order for the axle get inside completely. In this way grooves are made that prevent the axle from rolling in the gear's hole. Bras is softer metal than steal.
11-23-2017, 03:35 PM   #29
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QuoteOriginally posted by Medex Quote
sorry, i didn't make pictures, I was very focused on precision-driven work.
I'm not fluent in english. Trying to translate what "splines in the bore" mean
If you ask about the surface of the gear's hole, then I should say, that it is smooth. But the screw drive axle has small grooves and is slightly thicker than the gear's hole. The axle should be inserted into the hole, and then the hammer must be used in order for the axle get inside completely. In this way grooves are made that prevent the axle from rolling in the gear's hole. Bras is softer metal than steal.
Explained very well I'll be looking forward to doing it myself. I actually ordered 5 gears to make it cost effective per gear. If anyone in the UK needs one then I'll be able to get it out to you at a reasonable price + PnP.
11-23-2017, 03:43 PM   #30
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QuoteOriginally posted by Medex Quote
If you ask about the surface of the gear's hole, then I should say, that it is smooth. But the screw drive axle has small grooves and is slightly thicker than the gear's hole. The axle should be inserted into the hole, and then the hammer must be used in order for the axle get inside completely. In this way grooves are made that prevent the axle from rolling in the gear's hole. Bras is softer metal than steal.

Yes, this is what I meant. Thanks for the explanation, that helps a lot.


I'll be getting some gears too, I'm in Australia.

---------- Post added 24-11-17 at 09:14 AM ----------

QuoteOriginally posted by HarisF1 Quote
Explained very well I'll be looking forward to doing it myself.

Excellent news. I'm not that handy, although I have pulled apart a few lenses before. If you end up taking some pics when you do yours, I would be most grateful.
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