cutting/routing oblong hole in Eagle?

[peps1]

I'm working on a board in Eagle that need a oblong hole cut/routed through the PCB, but cant work out how to do it, any chance of some help?

[FelixK]

What exactly are you looking to use the hole for? Is it something that is part of the board cutout? If I recall correctly in Eagle anything that is draw in the "Dimensions" layer is considered to be part of the pcbs outline and will be cut and drill as such. However you don't tend to have control over the precise thickness as the fab will use whatever drill bit they use to cutout your PCB from the panels. I discovered this the hard way when I made my very first part in Eagle. I made the noobie mistake of believing that the dimension layer was where I would define the physical dimension of the part. Which resulted in this brilliant breakout board:
 

[Corporate666]

I'm working on a board in Eagle that need a oblong hole cut/routed through the PCB, but cant work out how to do it, any chance of some help?

Eagle really SUCKS for drawing tools.  One of it's many (many many many) failings and shortcomings.

But in short, you can create arcs at each end of your hole - specifying start point, end point and (IIRC) arc radius.  Then just manually type in coordinates for wires to connect them.  As long as the start of your arc matches the start of your wire, they will be "connected" and move together.

The other option is to use a CAD program to create your outline and try to use one of the years-old user programs to import it into Eagle.  Unfortunately I rarely have luck with this, as most of the import tools don't support splines or (sometimes) even arc segments, so they either import nothing or the straight lines only, which doesn't achieve what I want.

[peps1]

What exactly are you looking to use the hole for? [/img]

Well its quite a random reason so thought I best mock this up to help explain!

I want a small window so I can check what transistor is soldered onto the other side of the PCB when its mounted in an enclosure, so I can use the same PCB and different transistors, and just quickly tell one from the other by looking though the little window I cut in the PCB.

[Stupid Beard]

What exactly are you looking to use the hole for? [/img]

Well its quite a random reason so thought I best mock this up to help explain!

I want a small window so I can check what transistor is soldered onto the other side of the PCB when its mounted in an enclosure, so I can use the same PCB and different transistors, and just quickly tell one from the other by looking though the little window I cut in the PCB.

Draw the outline of the cutout on the dimension layer, stick the text "CUT OUT" within it so the fab knows what to do. Make sure the text is on the dimension layer also.

[peps1]

Thanks guys, guess if i just draw a square, the routing bit will give me the round edges! 

[Corporate666]

Thanks guys, guess if i just draw a square, the routing bit will give me the round edges! 

The toolpath will have the outside diameter of the routing bit follow your stated profile, but you should check with your PCB fab what bit diameter they use before relying on this.

Also, you can just draw a rectangle and use the radius tool, set to one half the width of your rectangle, to give you a full radius on each end.

[zapta]

Thanks guys, guess if i just draw a square, the routing bit will give me the round edges! 

A rectangle seems to be a better fit here than an oblong. Oshpark router is 0.1" in diameter but you can also round the corners using Eagle's Miter tool (and with a large radius you will get an oblong). 

I use the Mitar for a slight rounding of the external corners of my boards, to get rid of the sharp edges.