Homebrew PCBs

On Sun, 21 Jan 2007 08:38:07 +0100, David McNab <rebirth@...>  
wrote:

>
> I tried a jigsaw mounted upside down under a table - worked great for a
> few cuts, till the teeth wore out - I gave it up because I knew the cost
> of blades would quickly start to add up.


Also, you get glass fiber dust into the machine, which i'm sure makes a  
great grinding paste combined with the grease.

There are two options - sawing and shearing.

Sawing gives a better edge, but is usually slower, more noisy, and dusty.  
You can use a carbide blade in a small circular saw - that gives an  
absolutely perfect smooth, square, straight edge. Looks even better than  
professionally milled IMO. Proxxon makes such a blade and saw, for  
example. Some also reported reasonable success with diamond blades in  
tilecutters (wet), i have not tried that myself yet.

The second option, shearing, is quick, clean, quiet, and has virtually no  
wear on the blades used. The only disadvantage is the edges are not as  
clean, they are "broken". After a quick sanding they are nice enough  
though. You can use bench mounted shears, for example bungard makes one  
specially for PCBs but the sheetmetal ones work too. That type has a wide  
blade that cuts the whole width at once. You can also use a bench mounted  
lever shear, which is much cheaper, and has a blade about 15cm long, so  
you may need to use several cuts for the larger boards, not a problem  
since a lever shear is designed to let the sheetmetal run through. The cut  
of the lever shear looks slightly worse than of the guillotine version to  
me, i expect it comes from the slight twisting action of the cut. Another  
option is a handheld sheetmetal shear "tin snips". Sturdy ones that are  
designed to let the metal run through straight work quite well. I used  
those for a while before the lever shear. Some people have also reported  
success with larger paper cutters.

I can recommend the shearing, since there is no noticeable wear and no  
dust. But the carbide blade in the circular saw made a fabulous cut, i  
just wouldn't want the dust and noise all the time. For me the quality of  
a lever-shear cut is easily sufficient, and i got one free, so that is  
what i currently use.

ST