Which plastic to bond to brass.

[Ed DuffnerParticipant @edduffner79357]

Thanks guys,

Michael, I've pondered the plain sleeve method and willl have to have another look at it. My original concerns were that I wanted the knobs as per the exisiting, but I realise now that making allowances for updates and changes to original parts will require some compromise.

The 10mm sleeve OD is just a figure I pulled from my head, thinking that a bigger OD will have more surface area and a better bond strength. If I go for the push fit I'll not need to worry about that. Some testing will have to be done.

Neil, thanks for the photos and info. Is that a rubber/neoprene type sleeve inside a plastic sleeve, or just a counter-bore?

Ed.

[Neil WyattModerator @neilwyatt]

It's just a counterbore, Ed. It appears to be a nylon insert. As it is probably 25+ years old*, I don't know if the insert was splined originally or has just taken a set from the pot spindle.

Neil

*wow, that's scary. Just worked out that I've had my acoustic for nearly 33 years, I thought it was old at about 10 when I got it.

[Ed DuffnerParticipant @edduffner79357]

Ok, thank you Neil. I ordered some nylon rod last night and will see what I can accomplish when it arrives.

Ed.

[Sam StonesParticipant @samstones42903]

Hi Ed,

When you machine nylon, make sure your cutters are really sharp and with steep angles. More like tools for wood. Otherwise you'll find that you have to do a lot of work de-burring.

Sam

[Ed DuffnerParticipant @edduffner79357]

Will do, thank you Sam

[Ed DuffnerParticipant @edduffner79357]

I spent some time on the lathe today and I think I'm just about there using the press fit method.

I drilled 10mm holes which finish at 10.14mm and turned down some 10mm nylon rod(10.34mm as supplied) to 10.24mm, so an interference fit of 0.1mm ish.

The plastic inserts are then drilled 5.8mm and are a good push fit onto the splined pot shafts, a bit tight actually so I might try a 5.9mm drill. As a bonus if I mess up a plasic insert I can just drill it out and replace it. If I can get consistency, the jobs a good `un, then it's off to the local laser etcher to have some characters added to one knob in each set.

I think I might owe a couple of beers to few people here

Thank you all again for your expertise and encouragement.

Ed.

[Neil WyattModerator @neilwyatt]

All you need now is a genuine CRUD sticker

Neil

[Sam StonesParticipant @samstones42903]

Nice work Ed!

I'm also impressed with your clean knurling. That's a job I never enjoyed doing.

Sam

[Neil WyattModerator @neilwyatt]

And a nice Guitar, can't figure out what it is…

N.

[Ed DuffnerParticipant @edduffner79357]

Thanks chaps.

Neil, it's a Westone Thunder 1A (A for active circuit) 1984 I think. Refinished in Nitro Cellulose Laquer, various shades.

Ed.

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