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Smokedaddy
11-13-2016, 10:59 PM
I know absolutely nothing about gears. Anyone know where I can find one of these and/or what do I have to know to start searching. It's operates the fine focus on a Nikon MM-11 toolmakers microscope. The focus block moves 200 micrometers (aka microns), or 0.2mm, per fine focus knob turn. The measurements are approximately; bore .118", the diameter .237" and length .268".

http://i688.photobucket.com/albums/vv241/TheOriginalSquattingDog/aaaSlab-01_PMax__7944-_7957_1.jpg (http://s688.photobucket.com/user/TheOriginalSquattingDog/media/aaaSlab-01_PMax__7944-_7957_1.jpg.html)

http://i688.photobucket.com/albums/vv241/TheOriginalSquattingDog/aaaIMG_7938_1.jpg (http://s688.photobucket.com/user/TheOriginalSquattingDog/media/aaaIMG_7938_1.jpg.html)

http://i688.photobucket.com/albums/vv241/TheOriginalSquattingDog/aaaDSC_2653_1.jpg (http://s688.photobucket.com/user/TheOriginalSquattingDog/media/aaaDSC_2653_1.jpg.html)

LKeithR
11-13-2016, 11:13 PM
Try these guys...

http://www.sdp-si.com/products/Gears/Index.php

elf
11-14-2016, 12:26 AM
SDP-SI won't have anything this small. A module .3 18 tooth gear will have an outside diameter of 6mm or .236".

Puckdropper
11-14-2016, 02:39 AM
It looks like Northwest Short Lines does not have a .3 mod 18T gear. It's worth mentioning because you might be able to contact them and get one made, but it won't be cheap. The quality will be excellent, though!

http://nwsl.com

RWO
11-14-2016, 01:14 PM
How about this? http://www.microscopesolutions.com/_p/prd1/2768807501/product/nikon-replacement-fine-focus-shaft

RWO

Smokedaddy
11-14-2016, 01:46 PM
RWO ... I've seen that link before but didn't read it carefully enough and blew it off. Now that I read it again I see they do mention Nikon MM-11, pricey little sucker. IF I had the knowledge to make a gear I'm sure it wouldn't be very expensive.

Thanks,
-JW:

Baz
11-14-2016, 02:39 PM
This is a pretty standard size in a clock. Check those suppliers. Most (non-hobby) clock repairers don't make their own pinions so there should be sources.

Paul Alciatore
11-14-2016, 02:57 PM
OK, I suppose you already tried Nikon.

Judging by the rough finish on the gear, I don't think it is a high precision component. And it appears to be molded in place on that shaft or perhaps molded and then pressed on which would require an exact size hole to fit properly.

There is an old trick for making a replacement gear. You take a strip of thin sheet metal and form it into a rack shape by meshing the gears with it between them. In this case I think we are talking about aluminum foil to get it thin enough. Cut a strip the width of the gear. You have enough of the original gear left to make about 3/4 of what you need and then shift it to make the rest. Probably good to overlap one tooth so it locks the ring together.

Press the old gear off. Try not to harm it as you may have to do this a second time, or even a third. Add some side plates (washers?) as you put it in place on the shaft. Pour some good epoxy, perhaps with some reinforcement media added to it (chopped fiberglass?) and let it harden. Bingo, new gear.

Centering will be a problem. You may have to make a special step washer to fit the shaft on one end and the OD of the gear on the other.

mars-red
11-14-2016, 05:05 PM
This is a pretty standard size in a clock. Check those suppliers. Most (non-hobby) clock repairers don't make their own pinions so there should be sources.

Yes, this is right on the money. Specifically, search for "pinion wire", it's what is typically used. It's formed into pinion leaves the entire length, and you cut/machine to suit your application.

Robin R
11-14-2016, 09:38 PM
OK,

There is an old trick for making a replacement gear. You take a strip of thin sheet metal and form it into a rack shape by meshing the gears with it between them. In this case I think we are talking about aluminum foil to get it thin enough. Cut a strip the width of the gear. You have enough of the original gear left to make about 3/4 of what you need and then shift it to make the rest. Probably good to overlap one tooth so it locks the ring together.

It sounds like you are suggesting making a whole new gear, if so it might be a better bet to just fit the form around the bad part of the gear and re-form the missing teeth.

Zahnrad Kopf
11-14-2016, 10:03 PM
Anyone know where I can find one of these and/or what do I have to know to start searching.

If you can not find any love, we can make one ( or more ) for you. We are well versed in small ( and normally sized ) gear manufacture.

Smokedaddy
11-14-2016, 10:04 PM
They don't make pinion wire in 18 teeth module 0,3 drilled at 3mm to my knowledge. In any case someone sent me a link to a fellow on eBay that remanufactures this particular gear.

Thanks for all the suggestions,
-SD:

PStechPaul
11-15-2016, 12:04 AM
Might be moot, but using this (http://www.globalspec.com/specsearch/SearchForm/Motion_Controls/Power_Transmission/Gears/Gears) I found two custom sources for these gears:

http://www.globalspec.com/Supplier/CustomProducts?comp=2220&vid=116389&sqid=18844426

http://www.globalspec.com/Supplier/CustomProducts?comp=2220&vid=96892&sqid=18844426

The gear appears to be module 0.3, 18 tooth, 3 mm bore, which is equivalent to 84.6 DP

Smokedaddy
11-15-2016, 12:59 AM
Thanks Paul .. will end up going this route as a couple other have done.

http://www.ebay.com/itm/172380707947?ul_noapp=true#shpCntId

Black Forest
11-15-2016, 05:22 AM
Thanks Paul .. will end up going this route as a couple other have done.

http://www.ebay.com/itm/172380707947?ul_noapp=true#shpCntId

Are you sure you can trust this seller. He is from Germany!:cool:

Smokedaddy
11-15-2016, 09:26 PM
I can deal with that. <g>

Paul Alciatore
11-16-2016, 03:44 PM
Been there. Done that. And with only occasional use, the teeth broke off about six weeks later. A tooth formed from weld or braze may last a long time if properly done, but if you are trying to bond epoxy to an existing gear, even with added reinforcement, it will not last for long.

The repaired gear that I talked about above did last long enough for a new one to be ordered and to arrive so I was able to just replace it at that time. And the TV camera lens it was in was in use for those weeks so I considered it a success.




It sounds like you are suggesting making a whole new gear, if so it might be a better bet to just fit the form around the bad part of the gear and re-form the missing teeth.

Evan
11-17-2016, 01:56 AM
It's a shame my CNC mill is in storage. That would be easy to make from brass. I am hoping I can get it set back up next year some time. That will in part depend on how busy I am with other pursuits. I'm not even sure I want to get back into machining. That remains to be seen.

What about removing the pinon, cut in half, rotate a half 180 degrees and fasten the halves to the shaft in some manner so the join of the halves lines up with the center of the thickness of the driven gear? Then there will always be at least a half length of tooth engaged.