3D print design help needed

That looks fun ... but I think I would just make something out of plywood. Cut a hole in it a bit smaller than the lens diameter, then have three or more wooden 'clips' spaced around the circumference, each slotted for the lens diameter and screwed down to the larger sheet.

Ignore this if you remain keen on a 3D printing approach...

J^n

The learning curve for 3D design is very steep and I find that, having got part way up the curve, it's very easy to slide back down after not using it (F360) for a while. If you're already up-to-speed with a suitable bit of S/W, and have access to a 3D printer, then it should be a quick design. But, for your application, I'd suggest simply making something out of wood or metal - perhaps a couple of hours in the workshop compared to a long time staring at a screen.

I thought about this but as it happens following big garage clear-out, I don’t have any suitable wood. Isn’t it always the way? ;-)

It would also make it a bit heavy for a three year old.

Tim

Bear in mind, most 3D printer beds are 256 mm square or less.

What about this approch?

I think I would go with some kind of handle, a number of "corners" and a small ratchet strap of some kind. So the strap passes through the end of the handle, which has a suitable profile to allow the edge of the lens to locate in it. Then it does a perimeter of the lens with additional segments that locate on the lens edge and support the strap. Tighten the strap to hole all the bits together. That way your printed parts can be much smaller.

(you could alternatively do interlocking segments of the perimeter as 3d prints - that way you don't need to print the whole round bit in one hit)

You could also drill the edge of the lens and bold the handle it it. Then you don't need a frame at all.

You need a CAD like design package... you could use one of the "easy" online ones like tinkercad. Or you can download FreeCAD for Windows, Linux or Mac, then start watching some youtube tutorials.

It looks to me like you need a nearby friend or relative with a PC and a printer. As said, most hobby printers aren't all that big, often limited to about an eight-inch cube. You'll need to do this in segments with maybe lugs to screw then together.

OpenSCAD uses geometric solids (or 2D extrusions) with positioning, add and subtract commands to make complex designs, I don't know if others are similar. You would need to come up with a paper drawing with that in mind, and *take* it to the helper. You both need to be sure of what's needed, and it's easy for poor communication to be an issue.

I'd go for the mechanical solution, though if you come up with a good

Not if he doesn't have a PC...

Yeah, don't try describing the requirement over the phone ... I'd imagine the results being like some game of pictionary gone wrong ...

The first question to ask is how big is the print volume on his 3D printers? Many budget models print 256x256x256mm or thereabouts, which may mean you can't print a 310mm diameter thing in one go. That means you have to be more creative in terms of building something out of pieces that are small enough to fit in that volume.

I think most 3D design software wants to run on a computer (Windows/Linux/Mac) and not a phone/tablet, so if you only have those then it's going to be more annoying.

One way is to think about what you would build out of basic shapes like boxes, cylinders, spheres etc. For example, to hold the lens you might have a cylinder with another cylinder cut out of it, making a ring. Then cut out a second shorter but wider cylinder out of the middle, forming a groove around the inside of the ring. Get the diameters right and the lens will snap into the groove.

I tend to use OpenSCAD for this sort of thing as I find it easier to express the relations between dimensions in code than trying to make a GUI do what I want, eg:

// all dims in mm id = 310; od = 350; groove_d = 5; // depth of groove groove_w = 10; // width of groove thickness = 30;

$fn = 60; // circles are polygons with 60 sides

difference() { cylinder(h=thickness, d=od, center=true); // outer body cylinder(h=thickness, d=id, center=true); // cut out the middle cylinder(h=groove_w, d=id+groove_d, center=true); // cut out groove }

gets me:

So if it were me, I'd be looking at making something out of a plywood sandwich or similar, as jigsawing a big hole takes barely longer than making a small hole, and as you only need one of them you don't need repeatability - you can make adjustments to your one wooden one there and then, without having to reprint.

Theo

Id print that diagonally across the bed with the handle sticking up

Trivial piece of design, But not without a decent screen and mouse

Long ago, I found a rather good lens glass, and botched a handle in a broadly similar way...

Except, I used a peace of that U profile plastic channel, sold for holding loose sheets of paper together. I heat formed it round the lens, the lens fitted into the U, with the surplus forming the handle. As an handle, I just slipped a peace of plastic pipe, over the channel, tightly clamping it together.

That did cross my mind which is why I thought a catapult style handle might be printable. The lens doesn’t need to be supported all the way round.

Tim

Something like eBay 298064710922 or 298235134520, perhaps?

That depends on how you interpret the "don't have a PC" statement - Some mac owners might make a similar statement...