Blocks: wood, card or 3D resin?

[georgeband]

I have been working on the rigging plan for HMS Whiting schooner and now know how many blocks I want of various sizes. The small ones are especially tricky, partly because there are so many of them.  

 

Block        Need for model

2mm S       3

2.5mm S   48

2.5mm D    7

3mm S      26

3mm D       7

4mm S      10

4mm D     13

5mm S        1

 

I have already used 2mm walnut blocks from HiS for the gun tackles and they are at the lower limit of what is available. 

 

The next size up, 2.5mm from HiS, matches the cheaper '2mm single' blocks from Caldercraft and other suppliers. I am happy to use either of these because the imperfections are not visible at normal viewing distances. Whiting (in my rigging plan) also needs seven double blocks of this size. I see four options here. 

1. I could get the blocks from HiS (2.5mm double). Advantages are no assembly or trimming and a known shape and material - walnut. Disadvantage is cost including shipping. 
2. I could sand down some '2mm single' blocks from Caldercraft and glue them together in pairs to make double blocks. Advantages are the material and size which matches the single blocks. Disadvantage is some careful sanding and gluing. 
3. Shipyard provide laser cut card layers that the modeller laminates together. Advantages are the shape and finish, although this might not be visible for a 2.5mm block. If it is visible and better then I would want to replace the single blocks I have with card. Disadvantage is that assembly of the layers might be difficult. 
4. Seahorse offer 3D printed blocks in brown resin that according to them 'do not need painting'. Advantages are no assembly and little trimming. Disadvantages are an unknown material which could look different from wood blocks in which case I would have to replace the single blocks. 

 

For the many 3mm single and double blocks the Caldercraft parts are probably adequate in isolation though they might show up badly against the alternatives. This is certainly the case for 4mm and 5mm blocks where the HiS parts look like proper blocks while the Caldercraft ones look like roughly shaped pieces of walnut. Should I choose HiS walnut, Shipyard card, or Seahorse 3D printed for 3, 4 and 5mm blocks? 

 

Has anyone else travelled this way and can offer their experience?

 

George

[BenD]

The Seahorse 3D-printed ones look really good. The only problem is they are slightly translucent at that size.

 

Shipyards card blocks are actually pretty decent. They do need a lick of brown paint to look better, and of course, they need to be carefully assembled.  

 

The HIS new rounded blocks look great. They only make the rounded ones from 3mm and up. If you have the money these might be the best option. If Syren made smaller blocks I would tell you to go all in on their CNC blocks. 

 

The Caldercraft ones are the typical European blocks that most kits use. They are not great-looking and need sanding, shaping, and re-drilling.

 

Some day I plan on getting a CNC machine and making blocks to sell, but that is a few years down the road. 

 

 

[Thukydides]

Model shipways also has some new blocks which are made from pear and look quite similar to the ones that Vanguard used to supply. Not as good as the Syren blocks, but they do have the smaller sizes you are looking for.

[tlevine]

Make the blocks you need.  Although tedious, it is not hard and does not require any fancy tools...just wood, a pinvise/drill and a razor saw.

[allanyed]

There is an excellent explanation of a common/easy method of making wooden blocks with hand tools as well as their proportional dimensions in The Fully Framed Model  Volume IV pp. 61-63.  For tiny blocks (1.5mm and smaller) McCaffery goes into some detail in his book Ships in Miniature on making punches for making paper blocks.

Allan

Edited May 10 by allanyed

[Gregory]

Here is one of my favorite references for making blocks from Mondfeld.  I had just about got to the point of going forward with this method when Chuck started selling his blocks.

 

You can see that taking it down to very small size is possible.

If you have a small table saw, i.e., Proxxon, Byrnes, etc.,  it will really help with the grooves..

 

[GrandpaPhil]

I use that method and carve the grooves in with a scalpel.

Edited May 10 by GrandpaPhil

[allanyed]

If you put them in a block/rock tumbler for part 6 it really helps to get a more rounded shape and easier than getting sanding by hand..

Allan

[wefalck]

I would go for similar appearance of all blocks. Though on a real ship blocks may have been obtained from different sources over time and as need arose, on a model this may look a bit 'unprofessional'.

 

While on 'artisanal' style models wooden blocks certainly would be first choice, I think for 'realistic' style models, particularly those in smaller scales, 3d-printing is the future. Such blocks would need to be painted, as the resin is always somewhat translucent.

 

The minimum size of wooden blocks you can machine on a CNC-mill is limited by the size of drills and milling cutters that are practical. I gather on hobby-machines the limit would be somewhere around 0.5 mm diameter for milling cutters and 0.3 mm for drills - from this you can calculate the mimium size of block you can make. 

[tkay11]

Can you provide a link for the Seahorse 3D printed blocks? I tried an online search but just came up with models of seahorses!

 

Tony

[GrandpaPhil]

Tony,

 

Seahorse has some really nice stuff.

 

Here’s their 3D printed stuff, to include the blocks.

 

https://seahorse.pl/en/14--3d-printed

 

[georgeband]

Tony and GrandpaPhil,

Here is another link for Seahorse 3D printed blocks. It's a model shop in Poland though I have not used it yet. 

https://modelnet.co.uk/collections/marine-fittings-1 . There is a filter option for '3D' which selects the Seahorse parts. You can also find them on Ebay if you search for 'seahorse block 3D'. 

 

Wefalck,

I agree entirely that the blocks should have a family resemblance and mixing the cheap, kit blocks with the finer examples is visually distracting. This is more obvious for the larger blocks where the shapes are easier to see at normal viewing distances but less of an issue for a 2mm block which is a 'blob' unless you get really close. What I don't know is whether blocks from HiS, Shipyard or Seahorse look OK next to each other. I might just have to buy some of each and see which I prefer. 

 

George

 

[Gregory]

Pricing at that ModelNet site looks very competitive….

Edited May 13 by Gregory

[georgeband]

I have placed an order with Modelnet for 2mm, 3mm and 4mm blocks. As Gregory says, their pricing is competitive and their shipping charges are also very reasonable. Once I have them I will try some macro photography to compare them with HiS blocks that I have. 

 

George

[georgeband]

I have to commend Modelnet for rapid delivery of some Seahorse 3D printed blocks. I had not realised that they also ship from UK so my small package only had to contend with Royal Mail. The blocks themselves are finely printed and do not have any translucency that others have mentioned.

The photos below are of 4mm double and single blocks, and 2mm single blocks. You can see the layers from the 3D printing with this level of magnification, but it is finer than the roughness on walnut blocks. 

One downside of these blocks is that the sheaves are too small in diameter and the holes for the rope should be much smaller at one end of the block; the blocks are not double ended. 

Overall I am very impressed and these blocks will be my choice in future. Does anyone want some Caldercraft wooden blocks?

The proportions of the Seahorse blocks are close to what Steel outlines in his descriptions of block making. The CNC blocks from HiS are also well proportioned but the roughness of the wood does show up on close inspection. The card blocks from Shipyard are much too thin (cheek+sheave+cheek) and do not look right alongside the others.

The spreadsheet below shows the dimensions of blocks and their ropes as described by Steel. A second tab lists the dimensions of blocks from different suppliers. I hope this helps with your decisions. 

blocks.xlsx

 

George

 

 

 

[wefalck]

Yes, I don't understand why people drill holes or provide for them in their CAD-files at both ends of the blocks. There is no need for this and the sheave should almost touch the slot on one end.

 

I gather there is a tendency to make the sheaves/holes wider than the textbook dimensions, because it makes it easier to fiddle the ropes through. In theory, the sheaves would only be a tad wider than the rope for which they are meant.

 

It would make sense to make the sheaves to scale in 3D-printing and then to leave to the buyer to open up the hole with a drill or a watchmakers reamer, if needed.

[Dr PR]

Be sure to paint the 3D printed blocks. Some (all?) printing resins deteriorate with time and exposure to ambient UV light (especially sunlight).

[0Seahorse]

Thank you @georgeband@ for the review of the blocks.

 

1. They are not translucent because we use an opaque gray resin with additional pigments to make them dark, "more or less" brown. This makes painting easier (although we do not paint blocks in test models)

2. Visible layers should disappear in the second half of the year, as we plan to buy new printers with much better resolution (the old ones don't want to break down 🙂

3. The size of the sheave is a bit too small (as George pointed out), and this is due to the fact that there are holes on both sides of the block. As "wefalck" rightly pointed out, the hole for the rope should be on one side, but many modelers praise the holes on both sides of the block because it does not require inspection during assembly. You take a block and attach it, and that's it (it will always be OK).

4. The size of the holes themselves, which are proportionally too large especially in smaller blocks, result from the fact that it would be very difficult to pull the rope through a hole of the correct diameter. For a rope with a diameter of 0.2 mm, the hole would have to be 0.22 mm. It's probably not impossible, but extremely difficult.

 

Thank you once again for the positive criticism and we will certainly work on correcting some parameters with the new machines.

 

Greetings Tomasz Weremko

[wefalck]

"but many modelers praise the holes on both sides of the block because it does not require inspection during assembly. You take a block and attach it, and that's it (it will always be OK)." ... well I think, a modeller who opts for this kind of quality of blocks would/should take the time to look at the blocks before stropping them ... we are not making chains with beads, but each block needs to be treated carefully and individually.

 

My practical experience (not with 3D-printed, but with blocks machined conventionally from bakelite) is that for a 0.2 mm rope, the hole/passage should be something in the order of 0.25 mm or even 0.28 mm. Even with stiffening the point with varnish or CA glue, the 'rope' always become a bit thicker when pushed through a block and hence gets stuck. This is unfortunate and I have not yet found a good way around this.

Edited May 23 by wefalck

[georgeband]

'Visible layers...'  It took a lot of effort to photograph the blocks with enough magnification to reveal the layers. My eyes with spectacles and a magnifying glass could not see them and at a 30cm / 1 foot viewing distance with naked eye the layers are irrelevant. Tomasz, save your money, the resolution on your existing printer is quite good enough for this model maker. 

What I would like for the future is some 3D printed cleats, especially shroud cleats which are difficult to fashion from wood. 

 

George

[tkay11]

I'll second the request for cleats. I find making them at 4x1 mm much trickier than 2mm blocks. But I admit it could be my finishing skills!

 

Tony

[tkay11]

I've just received my order for 2mm blocks from Seahorse Poland. I have to agree with George and others that they are excellent. I am amazed at the detail at this small scale and I can't imagine that improving the detail with a new machine would be worth it. I just had to wait a bit for our slow customs in the UK.

 

Tony

[tkay11]

Just to give measurements of the 2mm blocks, as near as I can with these fiddly things:

Height - 1.83mm

Width - 1.4mm

Thick - 0.8mm

Sheave holes - 0.4mm Ø

 

If I take block height as 12 x rope diameter, this would be suitable for 1.83/12 = 0.153mm Ø rope, which would be the equivalent of 15.3mm Ø rope when at a scale of 1:100.

 

Similarly, a rope size of 0.4mm Ø would need a block 4.8mm high.

 

It would be interesting to know if others agree with these calculations, and, if they have the measurements of other blocks from Seahorse, to know what those are.

 

Cheers

 

Tony

[georgeband]

Applying Steel's convoluted information about proportions of blocks (see the spreadsheet a few posts up) the length of the block is 8.8 times the diameter of the rope. This would be the maximum diameter of rope so Tony's 12x formula is quite plausible. Using the spreadsheet, I find that a block that is 1.83mm long is designed for a rope that is 0.208mm diameter. It would also work with 0.15mm rope 🙂.

 

Does anyone have an alternative to Steel's proportions?

 

George

[wefalck]

Depends on the period …

[Gregory]

 

2 hours ago, georgeband said:

the length of the block is 8.8 times the diameter of the rope.

.. Forbid it should be 8.6..😁

 

For modeling purposes, I think once the shape of the block is good,  while keeping the size of the rope in mind, I think the size of the block is more a matter of " what looks good, is good"..

[georgeband]

I have expanded the spreadsheet to include the measurements of Seahorse blocks that Tony and I have made. 

blocks.xlsx

The tab labelled 'sizes' is based on information from Steel's treatise on blockmaking. You can find the original here https://maritime.org/doc/steel/part5.php and it is a bit convoluted. The spreadsheet version looks like this 

Further down this page in the spreadsheet is information from Steel about the rope sizes for strapping the blocks. Again, it is a bit convoluted and also throws in a couple of inconsistent results for 11" and 12" blocks. I have assumed that Steel's rope sizes are for the circumference of the rope; the model sizes I worked out are for the diameters.  

The other tab in the spreadsheet 'suppliers' shows the dimensions of blocks from various suppliers. Some such as Shipyard are from the manufacturer's website. Most of the others are from actual measurements (thank you Tony for filling a gap for the smallest blocks). The values with a grey background are my interpolated estimates based on results for other blocks from that supplier. 

Gregory,

We all do what looks right to us and sometimes try to to justify it. The rambling discourse that follows is my justification...

I agree that it is possible to become too much of a purist when it comes to scale accuracy. I think that the attitude can be summarised as 'If it is more detailed than what I do then it is over the top, if it is less detailed than what I do then it is sloppy'. We all find our level and accept that it is different for different people. For block and rope sizes I am guided by Steel's writing because I have not found another contemporary source and, vitally, I do not have experience of full size ships apart from HMS Victory. And in the case of Victory the blocks might have been replaced in the last 200 years, possibly using what was available at the time from naval stores in Portsmouth. For my model of Whiting I am using three sizes of blocks (2mm, 3mm, 4mm from Seahorse) in all places except one where I have a 5mm block which is a cleaned up Caldercraft example. (The cannon and carronade tackles use HiS 2mm blocks because that is what I had a couple of years ago.) I don't like the look of 'big blocks' which look too heavy to my inexperienced and distorted eye and tend towards choosing smaller sizes. The 8.8 ratio gives a minimum size for a block to go with a given rope, though the rope size itself is another matter and involves its own judgment. 

 

George

 

 

 

[tkay11]

That's very useful, George. Thanks. Could you provide the Seahorse 3mm block sizes?

 

Tony

[georgeband]

I shall get onto it at the end of the week, Tony. 

 

George 

[georgeband]

I have measured the other 3D printed blocks from Seahorse that I have. I used a vernier gauge with a resolution of 0.05mm and repeated my measurements up to four times to check for consistency - it is tricky to align the blocks with the jaws of the gauge. My results for the 2mm single blocks (2.00mm long, 1.00mm thick, 1.55mm wide) are larger than what Tony measured so I checked that my gauge shows zero with the jaws closed. It does, so either the parts are different or it is from our measurement methods, but this is not an ISO9000 audit so I shall let it rest. 

Here are my results. The Seahorse blocks are highlighted. 

The revised spreadsheet follows. 

blocks.xlsx

 

George