Topics

Clearance Requirements on Small Components

Jim Osborne <jsundownr@...>
 

When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.
 
What is the best way around this kind of pad clearance problem with small components.
 
Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.
 
Thanks.
 
Jim

Harvey White
 

On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.
Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey


What is the best way around this kind of pad clearance problem with small components.

Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.

Thanks.

Jim

Jim Osborne <jsundownr@...>
 

Thanks Harvey. I appreciate the help.
 
Jim

Sent: Saturday, February 22, 2014 7:00 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 

On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

>When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.

Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey

>
>What is the best way around this kind of pad clearance problem with small components.
>
>Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.
>
>Thanks.
>
>Jim

Harvey White
 

On Sat, 22 Feb 2014 20:32:28 -0700, you wrote:

Thanks Harvey. I appreciate the help.
No problem. I have a custom library that I pull most of my parts
from, slightly larger pads when needed, and parts that EAGLE does not
have.

Harvey



Jim


From: Harvey White
Sent: Saturday, February 22, 2014 7:00 PM
To: pcb-gcode@...
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components



On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.
Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey


What is the best way around this kind of pad clearance problem with small components.

Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.

Thanks.

Jim

keith3125
 

I can't imagine how you'll get any satisfying results with a 1mm end mill. It's like 8 times a normal isolation tool for this. I doubt you'll have any pad left after cutting with one.

And that is one part of the solution to the problem you're looking to solve.

I mean, if I have 10 transistors rated at 250ma but my circuit needs to draw an amp through a transistor, I'm not going to use the ten transistors because I have them; because I know the results will be catastrophic to the transistor. 

Why waste pcb and 1mm end mills that you could use when you'll someday need a 1mm end mill?



On Saturday, February 22, 2014 10:32 PM, Jim Osborne wrote:
 
Thanks Harvey. I appreciate the help.
 
Jim

Sent: Saturday, February 22, 2014 7:00 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 
On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

>When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.

Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey

>
>What is the best way around this kind of pad clearance problem with small components.
>
>Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.
>
>Thanks.
>
>Jim


Jim Osborne <jsundownr@...>
 

KC
 
Like I said, I am trying to use these end mills. I am not contracting or selling boards, just making my own. I try compensate for the larger bit with larger clearances. 1 mm is my minimum trace width, and I use large pads. When you are old, like me, it is hard see and work with small things.
 
Jim 

From: KC
Sent: Saturday, February 22, 2014 9:12 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 

I can't imagine how you'll get any satisfying results with a 1mm end mill. It's like 8 times a normal isolation tool for this. I doubt you'll have any pad left after cutting with one.

And that is one part of the solution to the problem you're looking to solve.

I mean, if I have 10 transistors rated at 250ma but my circuit needs to draw an amp through a transistor, I'm not going to use the ten transistors because I have them; because I know the results will be catastrophic to the transistor. 

Why waste pcb and 1mm end mills that you could use when you'll someday need a 1mm end mill?



On Saturday, February 22, 2014 10:32 PM, Jim Osborne wrote:
 
Thanks Harvey. I appreciate the help.
 
Jim

Sent: Saturday, February 22, 2014 7:00 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 
On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

>When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.

Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey

>
>What is the best way around this kind of pad clearance problem with small components.
>
>Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.
>
>Thanks.
>
>Jim


keith3125
 

Oh believe me, I know all about 'old'. My eyes have increasingly deteriorated through the years and I blame my love of the 'miniature'. Wearing opti-visors for most of the day doesn't help eye health. But I'll never use through hole components again in my life (0603 smd is my hand soldering limit however).

I refuse to get glasses but just this week, I ordered these:
http://www.rawganique.com/Organic-Bodycare/natural-vision-eyewear-pinhole-glasses-bates-method.htm
They actually work (albeit with the person wearing them looking a bit suspicious)
Now all I have to be able to do is remember where I put them  : )

Well, as long as you can live with a 1mm path between traces, I suppose you're okay but I would still make my own libraries with extra 'fat' pads for some components, or you're going to be left with very little copper to drill and solder.It's a restriction that will dictate which components you'll be able to use or not use.-Keith 


On Sunday, February 23, 2014 12:08 AM, Jim Osborne wrote:
 
KC
 
Like I said, I am trying to use these end mills. I am not contracting or selling boards, just making my own. I try compensate for the larger bit with larger clearances. 1 mm is my minimum trace width, and I use large pads. When you are old, like me, it is hard see and work with small things.
 
Jim 

From: KC
Sent: Saturday, February 22, 2014 9:12 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 
I can't imagine how you'll get any satisfying results with a 1mm end mill. It's like 8 times a normal isolation tool for this. I doubt you'll have any pad left after cutting with one.

And that is one part of the solution to the problem you're looking to solve.

I mean, if I have 10 transistors rated at 250ma but my circuit needs to draw an amp through a transistor, I'm not going to use the ten transistors because I have them; because I know the results will be catastrophic to the transistor. 

Why waste pcb and 1mm end mills that you could use when you'll someday need a 1mm end mill?



On Saturday, February 22, 2014 10:32 PM, Jim Osborne wrote:
 
Thanks Harvey. I appreciate the help.
 
Jim

Sent: Saturday, February 22, 2014 7:00 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 
On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

>When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.

Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey

>
>What is the best way around this kind of pad clearance problem with small components.
>
>Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.
>
>Thanks.
>
>Jim




Jim Osborne <jsundownr@...>
 

Right Keith... it is something you have to learn to live with, although I hate building new libraries. In the next life I will use a 30 degree, pointed bit, and fine tune everything. All I want to do is invent a circuit and make it reality in less than a day, no chemicals or board factories included.
 
I live in Southeast New Mexico, along the Pecos River. Actually, the Pecos is becoming more like a small creek. I suspect it will be dry in the the not too distant future.
 
Between googling and forums, finding good information has become really easy, and it is a pleasure talking with experienced people.
 
Thanks for the input. I really appreciate it.
 
Jim

From: KC
Sent: Sunday, February 23, 2014 7:22 AM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 

Oh believe me, I know all about 'old'. My eyes have increasingly deteriorated through the years and I blame my love of the 'miniature'. Wearing opti-visors for most of the day doesn't help eye health. But I'll never use through hole components again in my life (0603 smd is my hand soldering limit however).

I refuse to get glasses but just this week, I ordered these:
http://www.rawganique.com/Organic-Bodycare/natural-vision-eyewear-pinhole-glasses-bates-method.htm
They actually work (albeit with the person wearing them looking a bit suspicious)
Now all I have to be able to do is remember where I put them  : )

Well, as long as you can live with a 1mm path between traces, I suppose you're okay but I would still make my own libraries with extra 'fat' pads for some components, or you're going to be left with very little copper to drill and solder.It's a restriction that will dictate which components you'll be able to use or not use.-Keith 


On Sunday, February 23, 2014 12:08 AM, Jim Osborne wrote:
 
KC
 
Like I said, I am trying to use these end mills. I am not contracting or selling boards, just making my own. I try compensate for the larger bit with larger clearances. 1 mm is my minimum trace width, and I use large pads. When you are old, like me, it is hard see and work with small things.
 
Jim 

From: KC
Sent: Saturday, February 22, 2014 9:12 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 
I can't imagine how you'll get any satisfying results with a 1mm end mill. It's like 8 times a normal isolation tool for this. I doubt you'll have any pad left after cutting with one.

And that is one part of the solution to the problem you're looking to solve.

I mean, if I have 10 transistors rated at 250ma but my circuit needs to draw an amp through a transistor, I'm not going to use the ten transistors because I have them; because I know the results will be catastrophic to the transistor. 

Why waste pcb and 1mm end mills that you could use when you'll someday need a 1mm end mill?



On Saturday, February 22, 2014 10:32 PM, Jim Osborne wrote:
 
Thanks Harvey. I appreciate the help.
 
Jim

Sent: Saturday, February 22, 2014 7:00 PM
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 
On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

>When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.

Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey

>
>What is the best way around this kind of pad clearance problem with small components.
>
>Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.
>
>Thanks.
>
>Jim




Zulfqar Ali <zulfqar.ali@...>
 

Hi KC ,

 

Pinhole glasses sounds very interesting. Please update us when you receive them.

 

Cheers

 

Zulfqar

 

From: pcb-gcode@... [mailto:pcb-gcode@...] On Behalf Of KC
Sent: 23. februar 2014 15:22
To: pcb-gcode@...
Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 

 

Oh believe me, I know all about 'old'. My eyes have increasingly deteriorated through the years and I blame my love of the 'miniature'. Wearing opti-visors for most of the day doesn't help eye health. But I'll never use through hole components again in my life (0603 smd is my hand soldering limit however).

 

I refuse to get glasses but just this week, I ordered these:

They actually work (albeit with the person wearing them looking a bit suspicious)

Now all I have to be able to do is remember where I put them  : )

 

Well, as long as you can live with a 1mm path between traces, I suppose you're okay but I would still make my own libraries with extra 'fat' pads for some components, or you're going to be left with very little copper to drill and solder.It's a restriction that will dictate which components you'll be able to use or not use.-Keith 

 

On Sunday, February 23, 2014 12:08 AM, Jim Osborne <jsundownr@...> wrote:

 

KC

 

Like I said, I am trying to use these end mills. I am not contracting or selling boards, just making my own. I try compensate for the larger bit with larger clearances. 1 mm is my minimum trace width, and I use large pads. When you are old, like me, it is hard see and work with small things.

 

Jim 

 

From: KC

Sent: Saturday, February 22, 2014 9:12 PM

Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 

 

I can't imagine how you'll get any satisfying results with a 1mm end mill. It's like 8 times a normal isolation tool for this. I doubt you'll have any pad left after cutting with one.

 

And that is one part of the solution to the problem you're looking to solve.

 

I mean, if I have 10 transistors rated at 250ma but my circuit needs to draw an amp through a transistor, I'm not going to use the ten transistors because I have them; because I know the results will be catastrophic to the transistor. 

 

Why waste pcb and 1mm end mills that you could use when you'll someday need a 1mm end mill?

 

 

On Saturday, February 22, 2014 10:32 PM, Jim Osborne <jsundownr@...> wrote:

 

Thanks Harvey. I appreciate the help.

 

Jim

 

Sent: Saturday, February 22, 2014 7:00 PM

Subject: Re: [pcb-gcode] Clearance Requirements on Small Components

 

 

On Sat, 22 Feb 2014 18:18:19 -0700, you wrote:

>When I set a transistor (e.g. BC547) in Eagle 6.5, the clearance between the transistor pads are so close I have to mess up my DRC file to accommodate the bunched up pads.

Create a custom library and copy the BC547 to that library.

Edit the pads and move them out, they ought to be on a 0.1 inch grid,
with 0.2 inches between the two outside pads, and the center pad
displaced up by 0.1 inch

If those are too close, then move them, then save

Replace (a command) your existing transistors with the ones in the
library, then do a library update all. This should move all the
transistor pads out to where they are comfortable for you.

Eagle has tolerances set up for plated through holes and commercial
board houses, giving spacing (and occasionally pads) that are too
small for hand work.

Harvey

>
>What is the best way around this kind of pad clearance problem with small components.
>
>Note... I use a 1mm end mill. I know it is a little large for fine pcb work, but I have a bunch of these end mills I need to use up.
>
>Thanks.
>
>Jim