PCB Libraries Forum : Lead Width on Axial Through Hole

PCB Libraries Forum : Lead Width on Axial Through Hole https://www.PCBLibraries.com/forum/ Mon, 13 Apr 2026 12:58:24 +0000 Wed, 20 Mar 2013 12:31:54 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=875 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Lead Width on Axial Through Hole : I agree that we need to clarify...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3294.html#3294 Author: Tom H
Subject: 875
Posted: 20 Mar 2013 at 12:31pm

I agree that we need to clarify Wmax for hole calculation and Wnom for Footprint Name.

]]> Wed, 20 Mar 2013 12:31:54 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3294.html#3294 <![CDATA[Lead Width on Axial Through Hole : I understand but I think the PDF...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3282.html#3282 Author: jameshead
Subject: 875
Posted: 20 Mar 2013 at 8:41am

I understand but I think the PDF for the PCB Libraries Footprint Naming Convention for Standard TH Components on page 3 confuses users since it says:

W = Maximum Lead Width (or Component Lead Diameter)]]> Wed, 20 Mar 2013 08:41:43 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3282.html#3282 <![CDATA[Lead Width on Axial Through Hole : The PCB Footprint Expert has...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3268.html#3268 Author: Tom H
Subject: 875
Posted: 18 Mar 2013 at 6:27am

The PCB Footprint Expert has a "Utilities" button in the Main Toolbar. Select the "Axial Leadform Calculator" option and this menu will appear -

I hope this helps...

]]> Mon, 18 Mar 2013 06:27:24 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3268.html#3268 <![CDATA[Lead Width on Axial Through Hole : Hi Tom, How to calculate pitch...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3264.html#3264 Author: Naveed Khan
Subject: 875
Posted: 18 Mar 2013 at 1:52am

Hi Tom,

How to calculate pitch for axial lead components? IF mounted horizontally and vertically?]]> Mon, 18 Mar 2013 01:52:21 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3264.html#3264 <![CDATA[Lead Width on Axial Through Hole : The Calculator requires Maximum...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3261.html#3261 Author: Tom H
Subject: 875
Posted: 15 Mar 2013 at 8:24pm

The Calculator requires Maximum to determine the hole size per IPC-7251 (which is currently on the table by IPC for review for release (finally)).

The component dimensions require the Minimum so the Calculator can determine the value for the Footprint name. Every value in the Footprint Name is a "Nominal" component package dimension with one exception - "Height"

]]> Fri, 15 Mar 2013 20:24:51 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3261.html#3261 <![CDATA[Lead Width on Axial Through Hole : This behavour in FPX hasn't...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3196.html#3196 Author: jameshead
Subject: 875
Posted: 11 Mar 2013 at 7:33am

This behavour in FPX hasn't changed in the v47 Beta today.

The PDF guide for IPC-7251 naming says:

Diodes, Axial Diameter Horizontal Mounting .......................................DIOAD + Lead Spacing + W Lead Width + L Body Length + D Body Diameter
Example: DIOAD800W52L600D150B
Diodes, Non Polarized Axial Diameter; Lead Spacing 8.00; Lead Width 0.52; Body Length 6.00; Body Diameter 1.50

And on page 3:

W = Maximum Lead Width (or Component Lead Diameter)

The way I read this was that W is always the Maximum whether it's the lead width or component lead diameter, but Jeff's saying W is nominal.

]]> Mon, 11 Mar 2013 07:33:12 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3196.html#3196 <![CDATA[Lead Width on Axial Through Hole : Hi Jeff, thanks for the reply.My...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3176.html#3176 Author: jameshead
Subject: 875
Posted: 07 Mar 2013 at 9:14am

Hi Jeff, thanks for the reply.

My observation is that the PDF guide for IPC-7251 says:

W = Maximum Lead Width (or Component Lead Diameter)

So, W should be taking the maximum and not the nominal dimension.
]]> Thu, 07 Mar 2013 09:14:00 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3176.html#3176 <![CDATA[Lead Width on Axial Through Hole : A maximum value is required to...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3175.html#3175 Author: Jeff.M
Subject: 875
Posted: 07 Mar 2013 at 9:11am

A maximum value is required to calculate the hole.

A minimum value is required to get the nominal value which is used in the footprint name.

]]> Thu, 07 Mar 2013 09:11:21 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3175.html#3175 <![CDATA[Lead Width on Axial Through Hole : The PDF for IPC-7251 states:W...]]> https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3167.html#3167 Author: jameshead
Subject: 875
Posted: 07 Mar 2013 at 2:40am

The PDF for IPC-7251 states:

W = Maximum Lead Width (or Component Lead Diameter)

In Through Hole > Axial though users have to enter both Min and Max values for b and the calculated footprint name uses the nominal value for b, for W, and not Maximum Lead Width as I expected.

IPC-2222 says "no greater than 0.7 mm (level A) over minimum lead diameter" so I guess that's why FPX has a mandatory field for a Min value for b in Axial (?) but if I'm creating a footprint in a program like FPX I am more concerned with the maximum lead diameter and the "No less than 0.25 mm over maxium lead diameter".
]]> Thu, 07 Mar 2013 02:40:19 +0000 https://www.PCBLibraries.com/forum/lead-width-on-axial-through-hole_topic875_post3167.html#3167