Turning an HDPE Milk Jug into a Motor Pulley

Gareth Branwyn

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and "lazy person's memoir," called Borg Like Me.

3992 Articles

By Gareth Branwyn

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and "lazy person's memoir," called Borg Like Me.

3992 Articles

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I’ve seen a lot of these videos where HDPE milk jug or other trash plastic is broken down and turned into new stock. We’ve run such videos and projects right here on Make:. But I’ve never seen the plastic turned on a lathe, as in this video by YouTuber The Small Workshop, and turned into a useful, relatively high-stress-bearing component.

The steps to the process couldn’t be simpler.

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The maker first cut down the jug into small chips using heavy-duty scissors. The entire broken down jug was used and one jug was enough to produce an ingot large enough for his turning project.

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He first heated up half of the chips in a tall tin can in an oven to reduce their volume, added the second half, and then melted down the entire amount.

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With the entire jug melted, he removed the can from the oven, placed a wooden disk in the open end, and applied plenty of clamping pressure to squeeze the plastic together for cooling.

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Once dry, the disk was removed, and the ragged end was sawed off, resulting in a nice plastic ingot he could turn on his lathe. He turned the stock into a pulley he needed on a shop tool motor. He claims that the pulley works brilliantly and that the HDPE (High-density polyethylene) is less prone to shattering than other plastic formulations.

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On the video page, he offers safety tips for working with HDPE plastic. If you’re going to work with this material (or any unknown material), it’s a good idea to read up on the safe handling of it.

Have you had any experiences with recycling plastic into working stock? If so, please share with us in the comments.