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I have a paper shredder with some damaged gears, which are from the CD shredding slot.

Damaged shredder gears

There are some info over the web about how to repair plastic gears with resin. However, I'm not comfortable whether such repairs would handle the strength required.

And looking for new ones, I've found out a plethora of gears suppliers. However, it seems very unlikely to find out one with the same specifications.

Any recommendation on how to repair these gears?

Gear Measurements

  • Gear 1

    • Number of teeth: 24
    • Outside Diameter: 40.0mm
    • Pitch height: 3~4mm
    • Pitch thickness: 5.6mm

  • Gear 2

    • Number of teeth: 25
    • Outside Diameter: 40.5mm
    • Pitch height: 3~4mm
    • Pitch thickness: 5.1mm
Mark Messa
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    It it quite unlikely that the gears can be repaired when so many teeth are missing. Perhaps the supplier or manufacturer can provide spares for the actual model. – Weather Vane Aug 01 '20 at 15:32
  • Buying recommendations are off-topic. However, as asking two questions at once is also not permitted on any SE site, I've removed your supplementary question. – Chenmunka Aug 01 '20 at 17:31
  • @WeatherVane > "Perhaps the supplier or manufacturer can provide spares for the actual model." This is another problem. I don't know the actual manufacturer. All I have is the contact of the local dealer which, most likely, imported the shredder from a Chinese manufacturer. – Mark Messa Aug 01 '20 at 17:54
  • I see the problem: my shredder is branded by a (UK) office supplies chain and the 'plate' says "made in China". The supplier went out of business last year. But as mentioned, sourcing parts isn't a "Life Hack". – Weather Vane Aug 01 '20 at 18:02
  • You should be able to get both from a gear supplier. You'll need to specify the diameter, # of teeth, kind of gear, kind of shaft, etc all selected from a catalog to make things easy. Any machine shop should be able to find one in a stock parts catalog. No manufacturer uses non-standard parts when it can be avoided. These appear to be 25 tooth Delrin spur gears. You'll have to do the other measurements. – Stan Aug 01 '20 at 20:21
  • @WeatherVane Ok. Any recommendation which StackExchange would be better to post this message? – Mark Messa Aug 01 '20 at 20:22
  • When my previous shredder broke in a similar same way, I bit the bullet and bought another more heavy duty one. I know you said the 'CD shredder' broke it but in general if the blurb says it will shred "5 sheets of paper at a time" that means "5 sheets of the thinnest paper ever made [2 sheets in general use]." Make sure the shreds in the bin do not get too high: it could be they prevented new shreds coming through cleanly and put too much load on the device. – Weather Vane Aug 01 '20 at 20:34
  • @Stan > "You'll have to do the other measurements." Just edited the OP with some measurements. Let me know what you think. – Mark Messa Aug 01 '20 at 20:37
  • @Stan > "Any machine shop should be able to find one in a stock parts catalog." I'm having a hard time trying to find such machine shop .... – Mark Messa Aug 01 '20 at 20:38
  • @WeatherVane Mine has several automatic protections. Ex: overload, overheat and full trash bin. In the specific case of the aforementioned gears, they broke when I switch to reverse mode in order to do some cleaning (no load at all). Immediately there was a very loud (and scary) sound. – Mark Messa Aug 01 '20 at 20:46

2 Answers2

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I honestly doubt you'll find replacement parts for 2 reasons:

  • Most people don't bother repairing any appliances anymore because buying new is cheaper than paying for repairs.
  • Manufacturers don't want you to repair broken appliances because they only make money from sales of new appliances, not from sales of spare parts.

What you could do is:

Browse ebay or a local market platform for someone offering a used paper shredder of the same model. I suspect most people only use the paper slot so you may be able to scavange the gears from the used machine.

Or order these specific gears to be 3D printed or laser cut according to your specifications. There are several tools available online that can digitally design gears of the same dimensions as the ones you want to replace.

If you go for 3D print, the gears must be resin printed to be able to withstand force. The cheaper extrusion prints don't form strong enough bonds between layers and would probaly break at the first test run. Resin printers print a whole layer in one go and the layers adhere to one another very strongly. Make sure your digital gear is completely filled in the center (to form a strong solid body) or the printer may replace all that material with a grid pattern, which is sufficient for most applications but not what you want.

Laser cuts offer insane precision and a wide range of materials that can be cut, but I'm afraid you'd have to go for steel (more expensive) because acryllic sheets (cheaper) are known to be brittle, especially at sharp angles, and I doubt wood (cheapest) would do much better.

Elmy
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    The technical problem I see with 3D printing or laser cutting is taking the measurements. My guess is that there would be some trial$$ and error$$ until fine tune them. – Mark Messa Aug 03 '20 at 15:25
  • @MarkMessa If you take a well lit photo from far above (to minimize error due to perspective), you should be able to get accuracy good enough to match your photo with a rendering of your design. Diameter will be the only precise measurement you need, and precisely measuring a diameter without calipers is a separate question. – piojo Aug 04 '20 at 05:03
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I am pretty sure you can find replacements on Amazon or ebay with those specific dimensions. I'm sure they have the correct gears. There is a step by step guide to replacing the gears on this site- ifixit.com/guide/amazonbasics+B0050BPWBQ+Shredding+Gears+Replacement/60193

wilkvolk
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    This step by step guide only explain how to disassemble the shredder. However, as mentioned several times in its comment section: "Taking the shredder apart is easy, finding and procuring the replacement gears is next to impossible" – Mark Messa Aug 03 '20 at 00:18