Keyboard retainer and a bunch of fitting

Post date: Mar 20, 2017 2:45:18 AM

As it turns out, when you hand-measure parts, the results are full of errors. At least my results are. Maybe other people are better at these things.

Anyway, I got the part that holds the keyboard in machined- this is the last big piece:

Marking everything out and mounting on the mill

The "finished" pieces- lots of fitting to go...

The keyboard fits in there, after some relatively minor fitting

And the skeleton of a laptop

So everything looks good in the pictures, but a lot of fitting went into getting there. For starters, I used an old version of the CAD model for the keyboard retainer. Fortunately the dimensions didn't change too much, but it was missing a bunch of radii on edges. When you machine with a 1/4" cutter, you get 1/8" radii... so I spent a lot of time with a file trying to add those clearances back in by hand.

I also had to fit around the hinges in a couple of ways. Firstly, the aforementioned radius issue (though this time because I needed square edges and couldn't machine them). Secondly, to account for all of the measurement error. The good news is the critical dimension appears to be OK; that is, the distance between the hinge mount point on the base is correct for the distance between the hinge mount points on the lid.

If you look closely at that last image, you can see that the long supports coming off of the hinges don't fit into the machined slots. That's actually intentional- the idea is to undercut the slots slightly so that the ends of the hinges slide under it. That way the stress on the hinges when opening the lid isn't just one the two little screws right at the base. Or so the theory goes. I didn't get to undercut the slots because you can't do that on a 3 axis mill, and I let the magic blue smoke out of my rotary tool. With all the electrical problems I've been having in the shop, I'd swear it's cursed...

Still, good progress!