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| Chuck in E. TN:
I need to help an acquaintance find a replacement gear for her fathers lift chair. She describes the gear as plastic, 2 5/16” diameter, 3/8” thick, and 55 teeth. The bore is ¾”. I have tried Stock Drive Products with no help. She can buy an entire drive assembly replacement for the chair but the cost is prohibitive. Is there an easy way to enter these specs to find a gear, or am I missing an important descriptor like diametric pitch? Any help in finding a replacement would be greatly appreciated. Other than the description above, I do have a couple of pictures of the broken gear. Chuck in E. TN |
| Bluechip:
Hi Chuck IIRC DP = ( N+2 ) / OD where N = # teeth. Using that I get something like 24.6 DP which makes no sense, but... Allowing for small errors in measurement, it MAY be MOD 1 ??? It's hard to measure the OD of some gears as you are on a tooth tip one side and a gap on the other .. and they may not be exact to 'theoretical dimensions'. 'cos MOD 1 is 25.4 DP ... err .. I think ... |
| BillTodd:
That's very close to a 1 module gear size (check the dims with a metric vernier). Given that it is a person lifting device you may want to check if there are any insurance or safety issues with a DIY replacement. Bill |
| andyf:
Chuck, I have a 55T Mod 1 gear. Its OD is 56.8mm (should be N+2 = 57mm, but it's Chinese). 57mm is 2.244" , which is quite a bit less than your 2.3125", though you are relying on someone else's measurements, probably done with a rule. If you have a mini-lathe, its changewheels will be Mod 1. Can you try one of them against the broken gear to see how it meshes? Andy |
| Chuck in E. TN:
I have contacted the person to verify tooth count and measurements. I do not have the gear at hand but may end up going to get it. Here's the pictures she sent: By my count on the picture it is 55 tooth, but can't verify measurements from the picture. Thanks for your help. Chuck in E. TN |
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