PCB Libraries Forum : "b" Dimension in Mounting Hole https://www.PCBLibraries.com/forum/ Mon, 20 Apr 2026 20:51:11 +0000 Wed, 30 Dec 2020 14:16:15 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=2765 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA["b" Dimension in Mounting Hole : A Plated Through Mounting Hole...]]> https://www.PCBLibraries.com/forum/b-dimension-in-mounting-hole_topic2765_post11132.html#11132 Author: Tom H
Subject: 2765
Posted: 30 Dec 2020 at 2:16pm

A Plated Through Mounting Hole the b = Hole Size. 

b > than Hole size for Non-plated holes. 

There is a Hole Size Calculator in the main toolbar "Tool Box". 

]]> Wed, 30 Dec 2020 14:16:15 +0000 https://www.PCBLibraries.com/forum/b-dimension-in-mounting-hole_topic2765_post11132.html#11132 <![CDATA["b" Dimension in Mounting Hole : So, if i need the Plated Mounting...]]> https://www.PCBLibraries.com/forum/b-dimension-in-mounting-hole_topic2765_post11131.html#11131 Author: Batiskaff
Subject: 2765
Posted: 30 Dec 2020 at 2:02pm

So, if i need the Plated Mounting Hole with loose fit of M3 screw i should add a bit to 3 mm. For example: b=3+0,5=3,5mm. After that i should enter 3,5mm in "b" field, will it be correct?]]> Wed, 30 Dec 2020 14:02:49 +0000 https://www.PCBLibraries.com/forum/b-dimension-in-mounting-hole_topic2765_post11131.html#11131 <![CDATA["b" Dimension in Mounting Hole : For Plated Through-hole the &#034;b&#034;...]]> https://www.PCBLibraries.com/forum/b-dimension-in-mounting-hole_topic2765_post11120.html#11120 Author: Tom H
Subject: 2765
Posted: 30 Dec 2020 at 10:35am

For Plated Through-hole the "b" dimension is equal to the hole size. 

For Non-Plated Through-hole the "b" dimension should be larger than the hole size. Probably the hole tolerance +/- 0.05 annular ring. 

If the hole is non-plated, you want the drill bit to go through FR4 material and not touch any copper to avoid copper slivers in the hole. 

]]> Wed, 30 Dec 2020 10:35:35 +0000 https://www.PCBLibraries.com/forum/b-dimension-in-mounting-hole_topic2765_post11120.html#11120 <![CDATA["b" Dimension in Mounting Hole : What does mean &#034;b&#034; dimension?This...]]> https://www.PCBLibraries.com/forum/b-dimension-in-mounting-hole_topic2765_post11118.html#11118 Author: Batiskaff
Subject: 2765
Posted: 30 Dec 2020 at 6:05am

What does mean "b" dimension?

This is hole dimension that I want to get in MTG or this is diameter of screw that will be insert in MTG?


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