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PubInv / general-purpose-alarm-device

A general purpose alarm device (with software) as a module for medical devices (and others)
https://www.pubinv.org/project/general-purpose-alarm-device-gpad/
GNU Affero General Public License v3.0
5 stars 12 forks source link

Gauging Enclosure Screw Holes, JLCPCB Nylon Enclosure of 202303 #220

Open ForrestErickson opened 1 year ago

ForrestErickson commented 1 year ago

Notes on the JLCPCB Enclosure Screws.

For the PCB mounting holes.

Using drill bits as gauges I find that a 7/64 " - 0.109 drill enters the holes to near but not quite to full depth. A number 34 drill bit, 0.111" (2.82mm) enters the holes only about 1/8' to 3/16 with noticeable sliding resistance.

A #4 has no grip. A #5 would have about 14/1000 interference. A #6 would have about 27/1000 interference.

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A metric M3 will have about 0.18mm or 7/1000" interference.

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ForrestErickson commented 1 year ago

Lee has only 12 M3 screws in stock and they are too long (10mm) for the application.

Looks like Lowes has something that will work, 3mm x 8mm. https://www.lowes.com/pd/Hillman-3mm-0-5-x-8mm-Phillips-Drive-Machine-Screws-14-Count/999994896

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ForrestErickson commented 1 year ago

Before driving to purchase M3 screws, I tried some of my too long M3 screws with a nut on them to shorten them and found that they are too small. Some of them slid down into the hole even under light pressure on the Philips head screw.

I finally used some 6-32 which I cut to length. They had good retention force and acceptable torque.

I ran out of the tiny screws for the side connection but used some screws I think are # 2 machine screws on one unit.

LokiMetaSmith commented 1 year ago

We will need a different BOM for hardware for different 3D printing techniques. Good to know!

On Tue, Apr 25, 2023 at 1:46 PM Forrest Lee Erickson < @.***> wrote:

Before driving to purchase M3 screws, I tried some of my too long M3 screws with a nut on them to shorten them and found that they are too small. Some of them slid down into the hole even under light pressure on the Philips head screw.

I finally used some 6-32 which I cut to length. They had good retention force and acceptable torque.

I ran out of the tiny screws for the side connection but used some screws I think are #2 https://github.com/PubInv/general-alarm-device/pull/2 machine screws on one unit.

— Reply to this email directly, view it on GitHub https://github.com/PubInv/general-alarm-device/issues/220#issuecomment-1522254298, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABGR5JGZTQCBPTQX4JYCISTXDALZVANCNFSM6AAAAAAXLDBE5I . You are receiving this because you were assigned.Message ID: @.***>

-- Lawrence Kincheloe