BOM for non-printed parts?

[Darkhand81]

Awesome project! Do you have a BOM or list of the non-printed parts, such as the quantity and dimensions of the rods, screws, etc, as well as where you sourced the pistons, cylinders, and valvehead?

[0x23]

No, unfortunately I dont have a BOM but you can lookup all the dimensions in the CAD file and if you like to contribute create a BOM for the project yourself. The Pistons and Cylinders were taken from this cheap car tire air compressor: [image: epap03-air-pump.jpg] But be warned - the thing is really low quality (The cooling fins are fake and made from Plastik) and it did not seal very well making it unusable for low RPM. Thats why I have only taken the seals and the Cylinderpipes and discarded the rest.

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On Fri, Apr 12, 2024 at 4:49 AM Darkhand81 ***@***.***> wrote: Awesome project! Do you have a BOM or list of the non-printed parts, such as the quantity and dimensions of the rods, screws, etc, as well as where you sourced the pistons, cylinders, and valvehead? — Reply to this email directly, view it on GitHub <#1>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB2YJW2USY5K55Q55EJZSIDY45DSXAVCNFSM6AAAAABGDLKN3WVHI2DSMVQWIX3LMV43ASLTON2WKOZSGIZTQOJUGA4TSOA> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[KKobel]

I have been compiling a 'BOM' for the purchased parts.
The following are Amazon ASIN numbers:
Connecting Rod Bearing: B07TJFK68V
Main Bearing: B07FDWW9D9
Pullys and Belt: B0D97C6HFJ
M3x10: B01MFA9YEP
M3x16: B077XVVWYW
M3 Flat Washer: B015A39NCC
M4 Threadall: B09LH7PX55
M4 nuts: B0CMC61C9D
2 & 3 mm dowel pins: B0BKZND42Z

Please verify these.

What I am having trouble with is the piston seal.
Can anyone help with that.

[0x23]

I used the seals and the cylinder pipes from a cheap air compressor. The seals look very similar to something like this: B07ZSB5ZFC (not correct size, just an example). Such seels are very common in hydraulics and if possible I would lean towards a softer seal material (NBR). Maybe this helps.

[KKobel]

Thanks,

I found this:
https://www.mcmaster.com/9505K22/
Interestingly, the 'loaded' seals are cheaper than the 'unloaded' ones.

BTW - I am making the cylinder and head from scratch and using and external check valve on the output.
I'm using a DC brushed motor. The length is perfect. I had to modify the brackets.
I 3D printed all the parts for a fit-up.
So far, so good.

My use case is a 1.5" scale RS3 for the air brakes.

Again, thanks for a great project.
Karl

[0x23]

Nice, It would be cool If you send me some pictures of compressor when its done. Also make sure to minimize the volume between the cyclinder in the up-position and the (external) checkvalves. Any volume there will reduce the compression ratio and thus the maximum pressure you can reach. Good luck with cour project!

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On Fri, May 16, 2025 at 3:37 PM KKobel ***@***.***> wrote: *KKobel* left a comment (0x23/QuietAirCompressor#1) <#1 (comment)> Thanks, I found this: https://www.mcmaster.com/9505K22/ Interestingly, the 'loaded' seals are cheaper than the 'unloaded' ones. BTW - I am making the cylinder and head from scratch and using and external check valve on the output. I'm using a DC brushed motor. The length is perfect. I had to modify the brackets. I 3D printed all the parts for a fit-up. So far, so good. My use case is a 1.5" scale RS3 for the air brakes. Again, thanks for a great project. Karl — Reply to this email directly, view it on GitHub <#1 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB2YJW7CDKHYO2NNQ5C2NZL26XSZDAVCNFSM6AAAAAB5EV2SK2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDQOBWG42TEOJUGY> . You are receiving this because you commented.Message ID: ***@***.***>

[KKobel]

Thanks for the heads-up on the check valve.
I probable would have had to learn that the hard way ;)

I'll take some pictures when I get closer to finishing.

Karl

[KarlJKobel]

Can you send me a link to the cheap compressors? McMaster doesn't seem to have the right seal.