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Electronics => Electronics => Topic started by: Mastermime on July 08, 2013, 12:16:26 PM

Title: How to Read This Beaglebone Black Drawing
Post by: Mastermime on July 08, 2013, 12:16:26 PM
Hello everyone,

I'm designing a plate with mounting holes for the Beaglebone Black and I'm having trouble identifying what dimensions pertain to what on the drawing the have provided.

Here is what I identified

Length: 3.4"
Width: 2.1"
Fillet radii: .25" & .5"

So really what I need is the distance between holes and the hole size.  I suspect the hole size is .25" or .125", but I'm not sure which, or if its both.

Thanks
Title: Re: How to Read This Beaglebone Black Drawing
Post by: jwatte on July 08, 2013, 03:16:51 PM
The hole radius isn't set out at all. The left hole is 1/8" up from the bottom; the right hole is 1/4" up from the bottom.
The "R" measurements are for the rounded corners of the PCB.
If there are particular measurements you're uncertain of what they mean, you might want to mark them in red or something before posting the picture. MSPAINT for the win :-)
Title: Re: How to Read This Beaglebone Black Drawing
Post by: Mastermime on July 08, 2013, 05:05:52 PM
Oh now that you say that, I understand how the dimensions work now.
Shoot, I need the hole sizes though.  Can't find them anywhere!
 Thanks again for the enlightenment Jwatte. 
Title: Re: How to Read This Beaglebone Black Drawing
Post by: waltr on July 08, 2013, 05:15:24 PM
That is a PCB Drill Symbol diagram. Is there a Table on that drawing the gives the hole diameter for each symbol.
The four mounting holes use the 'diamond' symbol.

Title: Re: How to Read This Beaglebone Black Drawing
Post by: Mastermime on July 09, 2013, 09:56:37 AM
You're absolutely right Waltr!  Thank you.   The holes are 1/8" in diameter if anyone else is wondering
Title: Re: How to Read This Beaglebone Black Drawing
Post by: waltr on July 09, 2013, 06:13:37 PM
Ok. 1/8in holes are for #4 screws (most common is 4-40NC) in case you needed to know.
Title: Re: How to Read This Beaglebone Black Drawing
Post by: jwatte on July 10, 2013, 01:58:31 PM
Also, 1/8" holes are just the right size for clearance for M3 hardware, if you live in a civilized country or just prefer metric :-)
Title: Re: How to Read This Beaglebone Black Drawing
Post by: Mastermime on July 10, 2013, 05:19:44 PM
What exactly is M3 hardware?
Title: Re: How to Read This Beaglebone Black Drawing
Post by: waltr on July 10, 2013, 07:17:46 PM
M3 = Metric 3mm major diameter screw.
Yep, 1/8" is good for an M3.