Oster Ice Cream Maker Gear (no supports)

This project is what inspired me to purchase a 3d printer.

Back in 2013-2014, we bought an ice cream maker, but had only used it a handful of times. In 2018, we were making a batch of ice cream and it suddenly stopped turning the canister. I took the motor housing off and found that one of the plastic speed reduction gears had broken into three pieces. I searched online to find a replacement, only to find out that the manufacturer doesn't sell a replacement gear. They expect you to buy a whole new motor. After reading reviews on the manufacturers website, I saw that this seems to be a fairly common issue. There were 7-8 reviews claiming that their machine broke the same gear that mine had. The mfg usually responded with a contact phone number so they could get them a replacement if it was within the warranty period. Mine was not, so I decided to model my own.

I used Sketchup to model the new piece, taking measurements from the broken part. I had to super glue the pieces back together to take some measurements. In Sketchup, I installed an extension that generates gears. The rest was just basic modeling.

I printed this with basic PLA. I did have to run a drill through the bore as my printer wasn't dialed in perfectly so the hole was a bit undersized. I installed the printed gear which meshes with the existing gears perfectly. It's been too cold this winter for anyone to think about making ice cream, but I did test it out by turning the motor on and providing some resistance against the canister. I held it firm enough to get the teeth to skip. I disassembled the motor again to see if my little test caused any damage to the gear, but there was none that I could see. I'll post an update after we make our first batch of ice cream to let you know how it holds up to extended use.

Update 7/4/2023 : 

I needed to reprint this as the original that I printed finally failed. I noticed that the original STL that I created in Sketchup wasn't ‘water tight’ but I went ahead and printed it to see how it’d print on my new printer. While it was printing, I recreated it in Fusion360. I used the spur gear add-on with Metric standard, 20 deg pressure angle, Module 1.0, 48 teeth (big gear) and 11 teeth (small gear) with a .5mm root fillet radius.

V3 is the same as V2, just split in the middle of the large gear so each piece can be printed individually without using supports. The small gear tends to wear more, so you could just reprint that part as needed. Added 3 holes to use 3mm screws to hold the halves together.