Homebrew PCBs

Hello all,

Does anyone use the chat room at a certain time? Or does everyone 
just post on the messageboard?

a newcomer, Patrick

I am designing a board that will have two holes for
screws.  How can I place those holes in the PCB
without using pads?

Regards

Jose


	

	
		
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On Wed, 08 Feb 2006 17:42:18 +0100, Jose Fuentes  
<josecarlosfuentes@...> wrote:

> I am designing a board that will have two holes for
>
> screws.  How can I place those holes in the PCB
>
> without using pads?
>
>
> Regards
>
>
> Jose


I fear that depends on your software.

Mine has a feature for placing holes, but it is basically only a pad  
(usually) without electrical signal.
You can set copper diameter and drill diameter individually, if drill  
diameter is the same or larger there will be no copper ring around the  
hole.
It should be possible to use a normal pad if your software doesn't allow  
for special holes.

As for producing the PCB, i will usually print with option "centering  
holes only" which reduces the size of all holes to what is useful in  
centering the drill. Then i'll drill there with some small drill i use for  
other pads, and at the end enlarge the hole with the right size drill. I  
want a hand puch for punching them holes for ages, but they don't seem to  
find their way over the atlantic.


ST

Stefan,
what I was using were pads without copper, but maybe
this is not the best way if I'm going to send this
design to a PCB manufacturer.  Also, I found out that
clearance holes must be at least a 5% larger than the 
screw diameter.  A rule of thumb is to use clearance
holes 10% larger than screw diameter.

Regards

Jose

 --- Stefan Trethan <stefan_trethan@...> escribi\ufffd:

> On Wed, 08 Feb 2006 17:42:18 +0100, Jose Fuentes  
> <josecarlosfuentes@...> wrote:
> 
> > I am designing a board that will have two holes
> for
> >
> > screws.  How can I place those holes in the PCB
> >
> > without using pads?
> >
> >
> > Regards
> >
> >
> > Jose
> 
> 
> I fear that depends on your software.
> 
> Mine has a feature for placing holes, but it is
> basically only a pad  
> (usually) without electrical signal.
> You can set copper diameter and drill diameter
> individually, if drill  
> diameter is the same or larger there will be no
> copper ring around the  
> hole.
> It should be possible to use a normal pad if your
> software doesn't allow  
> for special holes.
> 
> As for producing the PCB, i will usually print with
> option "centering  
> holes only" which reduces the size of all holes to
> what is useful in  
> centering the drill. Then i'll drill there with some
> small drill i use for  
> other pads, and at the end enlarge the hole with the
> right size drill. I  
> want a hand puch for punching them holes for ages,
> but they don't seem to  
> find their way over the atlantic.
> 
> 
> ST
> 
> 
> Be sure to visit the group home and check for new
> Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
> 
> If Files or Photos are running short of space, post
> them here:
>
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> 
> Yahoo! Groups Links
> 
> 
>     Homebrew_PCBs-unsubscribe@yahoogroups.com
> 
>  
> 
> 
> 
> 



	

	
		
___________________________________________________________ 
1GB gratis, Antivirus y Antispam 
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Stefan,
I have a Roper Whitney hand punch that i bought here in the UK if
that's what you mean...  I wouldn't use it for pcbs though, a drill is
much easier. Where the punch scores is in thin sheet metalwork where
the drills tend to pull when they break through.

What I have found is that when drilling other than component holes in
pcbs, the best drills to use are the 'Bullet' type, they are easier to
centre on the hole, they do not bind and they break through more
cleanly...

I also tend to drill these holes with an old peice of MDF at the back.

I do have one board where the hole is 60 mm and for that I used to use
a hole saw. The two problems with the hole saw were a) hlding the
board as the saw grabs a good grip on the board.  and b) having to
stop to get the scrap out from the centre of the saw every few holes.    
I sorted a) by using another hole on the board dropping over a cut off
nail in the back board... and b) I now use the CNC mill to cut the
holes out with a slot mill.

Chris  (-=Spiyda=-)



--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@...> wrote:
>
> On Wed, 08 Feb 2006 17:42:18 +0100, Jose Fuentes  
> <josecarlosfuentes@...> wrote:
> 
> > I am designing a board that will have two holes for
> >
> > screws.  How can I place those holes in the PCB
> >
> > without using pads?
> >
> >
> > Regards
> >
> >
> > Jose
> 
> 
> I fear that depends on your software.
> 
> Mine has a feature for placing holes, but it is basically only a pad  
> (usually) without electrical signal.
> You can set copper diameter and drill diameter individually, if drill  
> diameter is the same or larger there will be no copper ring around the  
> hole.
> It should be possible to use a normal pad if your software doesn't
allow  
> for special holes.
> 
> As for producing the PCB, i will usually print with option "centering  
> holes only" which reduces the size of all holes to what is useful in  
> centering the drill. Then i'll drill there with some small drill i
use for  
> other pads, and at the end enlarge the hole with the right size
drill. I  
> want a hand puch for punching them holes for ages, but they don't
seem to  

> find their way over the atlantic.
> 
> 
> ST
>

----- Original Message ----- 

From: "Jose Fuentes" <josecarlosfuentes@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, February 08, 2006 4:42 PM
Subject: [Homebrew_PCBs] Holes for screws


>I am designing a board that will have two holes for
> screws.  How can I place those holes in the PCB
> without using pads?

The Pulsonix software I use has a mounting hole part. You could use free 
pads with the drill hole the same size as the pad.

Leon

On Wed, 08 Feb 2006 18:34:19 +0100, Jose Fuentes  
<josecarlosfuentes@...> wrote:

> Stefan,
>
> what I was using were pads without copper, but maybe
>
> this is not the best way if I'm going to send this
>
> design to a PCB manufacturer.  Also, I found out that
>
> clearance holes must be at least a 5% larger than the
>
> screw diameter.  A rule of thumb is to use clearance
>
> holes 10% larger than screw diameter.
>
>
> Regards
>
>
> Jose


The PCB house will usually be fine with that.
In the gerber files my mounting hole is the same as your pad, a large hole  
in the drill file and no copper in the copper layers.
I admit i'm not entirely certain what happens with plating if you have  
PTH, they will drill the hole first, then plate into it, but when applying  
the resist there will be none tenting the hole, so it should be etched  
clear again.

ST

I saw some boards that are attached to chassis by an
L-shape piece of sheetmetal.  Do you know where can I
buy them?

Regards

Jose

 --- Leon Heller <leon.heller@...>
escribi\ufffd:

> ----- Original Message ----- 
> From: "Jose Fuentes"
> <josecarlosfuentes@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, February 08, 2006 4:42 PM
> Subject: [Homebrew_PCBs] Holes for screws
> 
> 
> >I am designing a board that will have two holes for
> > screws.  How can I place those holes in the PCB
> > without using pads?
> 
> The Pulsonix software I use has a mounting hole
> part. You could use free 
> pads with the drill hole the same size as the pad.
> 
> Leon 
> 
> 
> 
> Be sure to visit the group home and check for new
> Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
> 
> If Files or Photos are running short of space, post
> them here:
>
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> 
> Yahoo! Groups Links
> 
> 
>     Homebrew_PCBs-unsubscribe@yahoogroups.com
> 
>  
> 
> 
> 



	


	
		
___________________________________________________________ 
1GB gratis, Antivirus y Antispam 
Correo Yahoo!, el mejor correo web del mundo 
http://correo.yahoo.com.ar

----- Original Message ----- 

From: "Jose Fuentes" <josecarlosfuentes@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, February 08, 2006 6:20 PM
Subject: Re: [Homebrew_PCBs] Holes for screws


>I saw some boards that are attached to chassis by an
> L-shape piece of sheetmetal.  Do you know where can I
> buy them?

They used to be readily available many years ago. I've made something 
similar by drilling angle aluminium and chopping it into small lengths.

Leon

On Wed, 08 Feb 2006 18:46:02 +0100, Chris Horne <chris@...> wrote:

> Stefan,
>
> I have a Roper Whitney hand punch that i bought here in the UK if
>
> that's what you mean...  I wouldn't use it for pcbs though, a drill is
>
> much easier. Where the punch scores is in thin sheet metalwork where
>
> the drills tend to pull when they break through.


Yes such a hand punch is what i mean. Aren't sold anywhere here, not even  
mail order, and shipping from the US and taxes is a bit much. Are they  
common in the UK? Since you (sort of ;-)) joined the EU there shouldn't be  
any customs fees, but i'd have to buy where they take paypal, bank  
transfers are too expensive 'cause you don't have the euro and all that...


> What I have found is that when drilling other than component holes in
>
> pcbs, the best drills to use are the 'Bullet' type, they are easier to
>
> centre on the hole, they do not bind and they break through more
>
> cleanly...

bullet type?? You mean a glass/tiles drill?

ST