On Thu, 7 Mar 2019 11:41:33 -0600, you wrote:
On 3/7/2019 10:04 AM, Harvey White wrote:
<snip>
Thanks Harvey. I have a 52" shear (Grizzly) and an 8" plate shear and a
HF throatless shear. So I have the shears! My manual for my Grizzly states:
You went bigger than I did, so... that's good, no problem with that,
then.
I did a number of very thin PC boards for replacement LED strips for
otherwise CCFL backlights.
Everything worked well until I had about 2-3 of the 1/8 inch strips
left to cut, then it just didn't work well at all.
<snip>
You'll note that the material sheared off fares worse than the
material left behind, but that will vary with setups.
I may have to redesign my layout as I only have 3/16 between the pieces
I want to cut out. But I will try it anyhow just in case my shear
handles it nicely. Otherwise I may have to rethink the usefulness of 2x6
copper clad boards or have some waste.
I had/have somewhat of a source that got surplus 0.030 single sided
board, but I generally bought it in 2 foot square sections (they cut
it before it was put out). From that, I got any reasonable number of
boards.
How you cut the board and lay it out depends on what you're actually
doing, and how your tooling works.
All good info so I can get off to a good start. And I forgot about
mounting holes on this first project too along with a hole to hang the
board. I have room for that though. And while we are on the subject.
What are your thoughts on the 1oz vs 2oz copper.
If you're doing a power supply board with board mounted transistors,
heavy current needed, and it's too small for power dissipation
(conductor wise or whatever the manufacturer says when using the PC
board as a heat sink), then you may want 2 oz. I generally don't use
it or need it. It's often easier to make the board bigger and just
use fatter traces.
And when you print out
your pattern do you fill the pads or leave a drill hole. I am thinking
leave the hole.
I leave the hole. Firstly, it tends to center the drill bit, but at
higher RPMs, remember that the drill cuts rather quickly.
When I was making boards, and these were double sided, already epoxied
together boards at this step, (trimmed). I needed the light to shine
through the board from the bottom so I could see the hole in the
crosshairs of the TV camera at the top. Always left the hole in,
otherwise I did have to guess.
Another reason why drilling those pilot holes VERY accurately and
using moderately large pins to align the boards was very necessary.
(large pins tend to cant less in the pc board holes, so don't use
dressmaker's pins, use map pins at a minimum.
The crosshatch on the camera monitor helped with centering the holes.
Naturally, the smaller the hole, the worse the problem with accurate
holes. I think I used a #76 drill and #26 wirewrap wire (stripped, of
course).
Harvey
Thanks
