3D printing Rigging blocks

[AntonyUK]

Hi.

I cannot find any reference to 3D printing Rigging blocks.

Having no idea on where to start. I downloaded Tinkercad and went through the tutorials one by one.

Not sure on tinkercad .. maybe I need to try another CAD package like sketchup.

At this stage I am open to any advice.

Once I get the design I can easily get them 3D printed.

 

Regards Antony.

[rtwpsom2]

Rigging blocks might be pretty hard in normal scales, being so small. Most PLA type printers only work in resolutions down to .2 mm.  A 9 inch block in real life would only be 3 mm in 1/72nd scale. 

 

How big are the blocks you are planning on printing and in what scale?

[wefalck]

I have been toying with the idea of 3D-printing rigging blocks for years, but never got round to master the basics yet, that is 3D-modelling. I gather, one would need to model the basic shape first - for which one needs to refer to period references for getting the proportions right, and then add the roundings etc. with some sculpting software.

 

The nice thing is that one can model the shell and the sheave separately and then combine them for printing, as the sheave would not need to rotate, of course. This would lead the rope through the block without the sharp bents one sees so often in simple wooden blocks.

 

I don't think extrusion printers would be suitable for printing really small blocks, I would go for the technique that selectively cures acrylic resin with pulses of UV-light. With this, one should be able to print blocks down to a length of about 1 mm. The problem will be the bores, but one can always open them up with a drill, if needed. 

[thibaultron]

See my thread on Going From A 2D Drawing To A 3D Printed Part Tutorial using SketchUp

 

For how I created various ship fittings, that might help.

 

Having said that, I'm not sure the advisabliity of using plastic for blocks, I'm thinking long term creep or flow of the plastic under rigging tension.

[wefalck]

Acrylics don't creep due to the rigid cross-linking of the polymer during curing. That the nice thing about Plexiglas.

[fnkershner]

I would suggest either Onshape or Fusion 360 for this. And Wefalck I think you are over thinking the design. I can easily print the shape of a block with either of these Software choices including the Sheave. But I do agree the scale will be challenging. I also suggest you will be painting to get the wood look. make or buy out of wood is going to be faster and possibly cheaper.

[wefalck]

As I said, I don't have a lot of CAD-experience. Some packages may be able to generate the complex curves. Generating the shape of the sheave, of course, would not be a problem.

 

Making any number of 1 mm-blocks from wood would be a challenge in principle, including drilling the needed 0.2 mm holes, and it would be very difficult to score a 0.2 mm groove into the sheave in a way that leads to a realistic run of the rope. Not sure, how I would hold them to shape the outside. They are also too small and light to round off in a tumbler. Making one would be feasible, but not many of them.

 

BTW, buying means that someone else can make them - I would be ashamed the to admit, that I couldn't make them myself

[rtwpsom2]

Use the method that EdT uses on his Young America.  He uses a stick sized to two dimensions of the block, drills two holes in it for each sheave, then moves down and drills two holes for another, etc. until he has 6 or 7.  then he starts notching in between to shape them and eventually cuts off each indivdual one. Look at part 253 on this page:

 

https://modelshipworld.com/index.php?/topic/3453-young-america-by-edt-extreme-clipper-1853/&page=89

 

[wefalck]

Yes, that the classical method. But you still have to shape the sheave, so that the rope doesn't make a bent. I have done this on blocks down to about 2.5 mm length, where the sheave is around 0.4 to 0.5 mm thick. But, try to do this, if the sheave is only 0.2 mm thick ...

 

But we are veering off the subject, which is about designing blocks for printing and not finding alternative ways of making them.

[rtwpsom2]

AntonyUK, do you have drawings and a scale you are currently modeling?