Ok welcome to a screen capture of the upside down keyhole protector parametric 3D model, which I am using to hang pieces of work or a hanging method. I just wanted to make a quick video to explain how I design this and some of the features and how it works. So if I scroll around you can see essentially it’s a round disc with two mounting holes, to fit the disc onto the back of a board or a piece of (art) work, a cradled board for example, a canvas, something like that. And in the centre I’ve got a line which I use to level this so it’s square from the top edge of whatever is being hanged. And then if I zoom in a bit you can see the key hole. You have a larger hole at the bottom where the head of the screw will pass and when the work rests on the screw, which would be secured to a wall the shaft of the screw will rest on this section here.
What I’m going to do is just open the parametric window and you can see some of the things I’ve used to describe the relationship between various parts. And I’m really enjoying working and designing using this particular feature in Fusion because it means you can design something once and apply parameters which you can then change for various applications. So for example this particular model, if I move it across there. I have the width that I can change depending on the bit that I am using. So for example if I happen to have a 44mm that changes like that, very easily. I could go much larger or smaller. Up to a point, obviously that’s not working. I would then have to shrink that as well.
I also have the slot top which is this section here, and at the moment it is 4.7mm and I can make it wider or narrower depending on the screw that is being used to hang. Slot Bottom is the diameter of the head of the screw and I can make it much larger or smaller. That’s a bit too small. That’s unusual.
Essentially when you’re designing something with parametrics you try imagine ahead the various parts of the thing you are designing and write these down as expressions you can then assign to the vectors in the sketches you are doing.
So the width inner hole, if I slide you along here you can see I’ve got a line, sorry a circle and that is perforated so it is a construction line as opposed to a normal line. And this would be the second forstner bit that I would need, so the first would is the larger one for the disc to slot into the back of the material board, and depending on the thickness that is how far you will go down. The point on the forstner bit would locate the second hole you need to bore out which would be a little bit deeper and that’s where the screw fits within.
And there’s little things as well for example this section here I’ve had to fix the centre point of the circle so that when I change the size of that it stays centred and doesn’t shift on one side or the other.
What interesting in parametrics is you can essentially write equations. So I’ve worked out the offset of (mounting) holes and the equation is (widthinner / 2) + ((width – widthinner) / 4) and at the moment that’s 15.5 and when I change the width or the width inner or essentially the two sizes of the forstner bits I could be using this automatically works out the spacing of those holes and that’s a really useful ability in this software.
I’ve got a line there and screw holes. The champher for the head of the screws here. I’ve also put a champher inside here so the hole in the centre doesn’t have to be so deep.
And essentially that’s it. It’s not a new idea but it’s a way of making something like this a little more customisable. Lets just have a quick look at the last parameters I had. So the screw champher. You can see that changing depending on the bit that you are using and the overall thickness of the actual disc. I think 3mm is pretty good. Anyway I’ll put this 3D file up on the Patreon page, and if anyone is interested in using it they can. But it’s actually quite easy to design something like this as well. So it took me about 20 minutes to do but I’m not going to film doing that again. Maybe something else.