rbent Forum - Fabrication of DuPont Delrin Chain Idler

jayg

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Fabrication of DuPont Delrin Chain Idler
May 20^th, 2018, 12:04pm

Replaced the stock double idler assembly on my Greenspeed Aero trike with a used single idler fabricated from some unknown plastic. After a number of miles, the used idler developed even more chain side-plate chatter marks in the rolling surface than it originally had. Accordingly, it was getting noisier and noisier. I know that Delrin is used by some idler manufacturers, so purchased a 2.75" x 12" cylinder of an unknown grade, and fabricated a new idler on my metal lathe. Cut a V-groove in the center of the rolling surface and installed a Nitrile O-ring to eliminate chain noise. Rode 42 miles on yesterday's Plano East Side Ride and couldn't hear any idler noise. Hope the idler will be as durable as a Bacchetta plastic idler. Should have read the MSDS sheet for Delrin, before I machined it - fumes and dust can be hazardous. Will take precautions the next time I machine an idler.

DuPont Delrin cylinder purchased off of E-Bay

Cutting 15-mm thick disk off of cylinder with carbide blade chop saw

Boring hole in chucked-up disk to receive 8-mm skateboard bearings

Cutting chain recess in disk

Completed idler

O-ring installed in center of chain recess rolling surface

Installed idler

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« Last Edit: May 20^th, 2018, 3:46pm by jayg »

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johnnybent Five Star Member rbent member Posts: 1032	Re: Fabrication of DuPont Delrin Chain Idler Reply #1 - May 20^th, 2018, 2:48pm Married men are not allowed to get near you and your tools....
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Phantom Rider Five Star Member Posts: 1056	Re: Fabrication of DuPont Delrin Chain Idler Reply #2 - May 20^th, 2018, 8:16pm Jay is one amazing dude!
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CruzbikeChris rbent member Posts: 97	Re: Fabrication of DuPont Delrin Chain Idler Reply #3 - May 26^th, 2018, 1:52pm Wow! Impressed as always with Jay's tool time.....
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Mdicke rbent member Posts: 207	Re: Fabrication of DuPont Delrin Chain Idler Reply #4 - May 28^th, 2018, 10:49pm Really nice job there Jay
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jayg

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Re: Fabrication of DuPont Delrin Chain Idler
Reply #5 - May 30^th, 2018, 8:25am

Quote from Mdicke on May 28^th, 2018, 10:49pm:

Really nice job there Jay

Thanks, Mike.

After several hundred miles, the Harbor Freight O-ring has disappeared, and the chain is chewing on the idler. Need to try a higher quality O-ring. Not making near as much noise as a toothed idler, even without the O-ring. Will see how long the idler lasts.

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« Last Edit: May 30^th, 2018, 8:25am by jayg »

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jrob_bent Five Star Member rbent member Posts: 953	Re: Fabrication of DuPont Delrin Chain Idler Reply #6 - May 30^th, 2018, 8:42pm How about using industrial grade polyurethane O-rings Jay?
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jayg Five Star Member rbent member Posts: 4127	Re: Fabrication of DuPont Delrin Chain Idler Reply #7 - May 30^th, 2018, 9:38pm Quote from jrob_bent on May 30^th, 2018, 8:42pm: How about using industrial grade polyurethane O-rings Jay? Are they solvent resistant? The chain lubricant Im currently using seems to soften the Harbor Freight O-rings I've been using. They're supposed to be Nitrile, which is solvent and oil resistant.
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jrob_bent Five Star Member rbent member Posts: 953	Re: Fabrication of DuPont Delrin Chain Idler Reply #8 - May 31^st, 2018, 7:30am I really don't know the answer to that Jay. It is used on inline skates and skate boards though. Here is a chart for different materials O-rings are of and what they are resistant to. https://www.allorings.com/o-ring-compatibility
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jayg

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Re: Fabrication of DuPont Delrin Chain Idler
Reply #9 - May 31^st, 2018, 4:55pm

Quote from jrob_bent on May 31^st, 2018, 7:30am:

I really don't know the answer to that Jay. It is used on inline skates and skate boards though. Here is a chart for different materials O-rings are of and what they are resistant to. https://www.allorings.com/o-ring-compatibility

Thanks, Jerry. Some good info.

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jrob_bent Five Star Member rbent member Posts: 953	Re: Fabrication of DuPont Delrin Chain Idler Reply #10 - May 31^st, 2018, 5:27pm No problem Jay. Hope it helps.
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rmillay Five Star Member rbent member; go Clowns! Posts: 2179	Re: Fabrication of DuPont Delrin Chain Idler Reply #11 - May 31^st, 2018, 6:46pm I think Terra's use neoprene O-rings.
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jrob_bent Five Star Member rbent member Posts: 953	Re: Fabrication of DuPont Delrin Chain Idler Reply #12 - May 31^st, 2018, 7:49pm https://sciencing.com/urethane-vs-polyurethane-6020141.html .
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FlyingLaZBoy Moderator '16 ICE SprintX fs, '16 Rocket, '12 KHS Mocha Posts: 5803	Re: Fabrication of DuPont Delrin Chain Idler Reply #13 - Aug 23^rd, 2018, 9:00pm good work, Jay!
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jayg Five Star Member rbent member Posts: 4127	Re: Fabrication of DuPont Delrin Chain Idler Reply #14 - Aug 24^th, 2018, 3:05pm Quote from FlyingLaZBoy on Aug 23^rd, 2018, 9:00pm: good work, Jay! Thanks Paul. Just finished manufacturing and installing the idler on the left in the left photo. Replaces the broken idler on the right that I removed from Key L's Performer low racer.
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bob wand

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Re: Fabrication of DuPont Delrin Chain Idler
Reply #15 - Aug 24^th, 2018, 4:58pm

Quote from jayg on May 30^th, 2018, 8:25am:

Quote from Mdicke on May 28^th, 2018, 10:49pm:

Really nice job there Jay

Thanks, Mike.

After several hundred miles, the Harbor Freight O-ring has disappeared, and the chain is chewing on the idler. Need to try a higher quality O-ring. Not making near as much noise as a toothed idler, even without the O-ring. Will see how long the idler lasts.

Parker O-rings, Nitrile: (Buna-N) The most commonly used elastomer for O-rings because of its resistance to petroleum fluids, good physical properties and useful temperature range.
Back in the early nineties I tried a few and came to the conclusion that my chains were just plain hungry. T-cycle Idlers with a metal core work the best for me until somebody perfects a belt drive.

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jayg

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Re: Fabrication of DuPont Delrin Chain Idler
Reply #16 - Aug 24^th, 2018, 5:46pm

Quote from bob wand on Aug 24^th, 2018, 4:58pm:

Quote from jayg on May 30^th, 2018, 8:25am:

Quote from Mdicke on May 28^th, 2018, 10:49pm:

Really nice job there Jay

Thanks, Mike.

After several hundred miles, the Harbor Freight O-ring has disappeared, and the chain is chewing on the idler. Need to try a higher quality O-ring. Not making near as much noise as a toothed idler, even without the O-ring. Will see how long the idler lasts.

Parker O-rings, Nitrile: (Buna-N) The most commonly used elastomer for O-rings because of its resistance to petroleum fluids, good physical properties and useful temperature range.
Back in the early nineties I tried a few and came to the conclusion that my chains were just plain hungry. T-cycle Idlers with a metal core work the best for me until somebody perfects a belt drive.

Some of the elastomeric O rings on my recumbents' idlers are resistant to the chain lubricants I use. Don't know what they are made of. I do know that Harbor Freight's "Nitrile" O rings are not resistant to the lubricants. Even though I have to replace the rings occasionally, I prefer idlers that use them to T-Cycle idlers, because they are much quieter.

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Action Lad

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Re: Fabrication of DuPont Delrin Chain Idler
Reply #17 - Aug 28^th, 2018, 5:21pm

Quote from jayg on Aug 24^th, 2018, 3:05pm:

Quote from FlyingLaZBoy on Aug 23^rd, 2018, 9:00pm:

good work, Jay!

Thanks Paul. Just finished manufacturing and installing the idler on the left in the left photo. Replaces the broken idler on the right that I removed from Key L's Performer low racer.

http://i.imgur.com/XxoirOM.jpg http://i.imgur.com/oEVfFeo.jpg

And that drivetrain is shhhh! Whisper quiet! That cockpit is a peaceful place to focus on the work at hand.

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"You can't see paradise if you don't pedal!"
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