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[rmaddock]

Hello Mayhemmers!

Elsewhere, I have been mostly building a scale model of a 100 year old sailing trawler and I found that suitable blocks could not be found.  So, in the spirit of great British lunacy I set out to make my own and promised to document my twisted techniques.


Prototype #1

So here goes!  Note that the blocks I'm making are (about) 1:9 and will end up about 8mm x 10mm.  You'll have to adapt to your own requirements.

The Materials

Lime wood strips - 8mm x 2mm  -  this will form the body of the block...you could change wood for a different effect but you need to be able to carve it neatly.

Brass sheet - 0.016mm - I cut the 3mm straps from this that pass through the body of the block.

Brass rod - 1mm - this forms the axles for the sheaves and was chosen to suit the sheaves used in my examples.

Sheaves - 6mm dia, 1.8mm thick - note that the sheaves are marginally narrower than the timber used.

Note that the link above are simply the sources of materials that I chose and should not be taken as any indication of bias on my part...although I would complement them all on their service.

Beyond the items listed above, you'll need various tools, glues, varnishes etc but I'll point these out as I go along.

[rmaddock]

Step 1: Cutting A Groove

The brass strap which passes through the block needs to be bedded into a groove in the outer cheeks of the block.



I started by carefully marking the centre line on a length of the lime wood strip and then marking a 3mm strip around that (1.5mm to either side of the centre).  I then carefully cut along the edges of the 3mm marks with a knife being careful not to cut right through the wood.  We are merely trying to form a nice, sharp edge for our groove here.



I've used a narrow gouge for cutting the groove this time.  In the prototype I did it with files but it took longer and didn't provide as good a finish.

You're looking to make the groove just deep enough to take a strip of the brass sheet flush with the top surface.

[Neil]

great stuff Rob, I shall watch this with much interest.
neil.

[rmaddock]

Building The Carcass

The next step is to glue the wooden pieces together to form the carcass of the block.

First, cut two lengths of the previously grooved lime wood; my examples shown are 12mm long.



Each of these pieces will form one side of the block.  Between them will go the sheave and two smaller wooden spacers.  It was pointed out to me that the sheave is not actually central in most blocks; rather it is slightly below centre assuming the block is hanging downwards from a shackle.  In the example below, I've marked the spacer positions at 2mm and 3mm from the ends.



The spacer pieces I cut oversize from ungroved limewood strip.  They need to be glued first to one side...



...and then the other...



[cod Australian accent] Can you tell what it is yet? [\cod Australian accent]

[Netleyned]

Great work and very lucid commentary.
Its obvious you and Neil are teachers.
One point (or lack of point) please change
the blade in the Stanley Knife unless you only
sharpen pencils with it.

Ned

[rmaddock]

One point (or lack of point) please change
the blade in the Stanley Knife unless you only
sharpen pencils with it.

Ned

  You know Ned, I looked at it as I set up the photo and thought I should change it...just for show.  I knew some so-and-so would point it out! 

[rmaddock]

Double Block

So, nice new Stanley knife blade in hand, I have been making up the carcasses of the five additional (to the prototype) blocks I need, as a minimum, to be able to hoist the mainsail.  As I was cutting pieces out, I realised that it might be better if the filler blocks' grain ran across the finished article.  So in the picture below you'll see a change to that way of doing things.

I'm also prototyping the double block required.  As you can see, it is basically the same as the single blocks.  Only the two outer cheeks are grooved.  I'm not sure about this yet as it means the loop in the brass strap will be very wide.  However, as this strap provides much of the strength, just inserting it into the top block at a narrower position will not do.  I also wonder if the central piece of lime wood should be thinner.

[Jerry C]

I don't know if you ever found a copy of "The Bosuns Manual" but I've just had a look at metal bound wooden double blocks and they show center piece same thickness as outer cheeks. Metal as you show with a large joggle on top to fit shackle or fitting. Can't post you a scan as scanner being a "B".
Jerry.

[rmaddock]

Thanks Jerry

I looked at the Bosun's Manual but there were actually two books by that name.  Can you give me more details; author, publisher?
Thanks for the info too!

[Jerry C]

I sent you a pm 2nd Nov. just sent you another.

[rmaddock]

Brass Strapping

As the title suggests, the next stage was to cut out the brass straps.  These provide a solid attachment point onto the block but also, passing right through, carry the axle for the sheaves and so pass all the forces through the block.  The wood is there for show...almost.

I cut them from the 0.016" brass sheet listed using a mini drill/tool fitted with a cutting disc (a nice new cutting disc).  It's a slow process and I'm sure people have tools or techniques to do it better but it does work.

The strip I cut was 3mm wide to match the grooves in the woodwork.



The strips are cut roughly to length and then bent into the narrow "U" shape shown.  I tend to make the straps over-length and trim/file them down afterwards rather than trying to be clever with my cutting....because I never am.

Most of the straps need only protrude slightly from the wooden carcass at the "open" end. However, the left-most example shown has a longer strap as it will also have a nut & bolt fitting on that end...as per the prototype.

Inserting the straps is straight forward but care needs to be exercised.  I find there's a tendency for the brass to spring the woodwork joints unless you're very careful. Nothing that a bit more glue won't cure though.

REMEMBER the closed end of the "U" goes next to the wider filler block.

You might also notice that I have begun to smooth the insides of the block where the ropes will pass.  I won't do much more of this just now as I'll fit them individually once they're ready for rope.

[dreadnought72]

I'm sure I'm not the only one taking notes here. Many thanks for the detailed instructions!

Andy

[rmaddock]

I'm sure I'm not the only one taking notes here. Many thanks for the detailed instructions!
Andy

[longshanks]

Very interesting, keep up the good work 

[rmaddock]

Drilling for the axle

I suspect "axle" is the wrong word but...you know what I mean.



The first thing I did was to mark the points I want to drill on each side of the block.  These should be centred both on the brass strip and in the gap left for the sheave.  Now, I'd like to tell you that all of my precision woodwork is spot on but I'd be lying     I made the marks partly by measure and partly be eye and then used a sharp file tip to pre mark the holes.



I'm not lucky enough to own a drill stand for my hobby tools so I used my little hand drill and eyes.  If you have a drill stand then you only need mark one face and can drill right through...and also get lovely square holes.



This is a test fitting of a sheave.  As you can see, my holes aren't perfectly in line but there's enough play in it that it doesn't matter and as long as none of you notice, it won't be a problem.

[rmaddock]

Assembly

Now is the time to glue everything together 



A sheave goes in each one and a short length of the 1mm wire.  I then put a dab of the good old super-stuff on each end of the axle as well as liberally allowing it to soak into everywhere else too - just to compensate for my poor workmanship.



Once dry (enough not to stick to) I used my non-dremmel to trim the worst of the protruding brass away.  I then find that sandpaper works very nicely to remove the rest of the brass.

Also visible in the photo above are the extended strap ends with their holes drilled too.

[rmaddock]

Shaping



I've got slightly out of order here.  Before you glue everything together, it's advisable to get your circular file into the slots and make sure there's enough room for your chosen rigging line to pass through unhindered.  There are no points to anybody who points out that the lines are through the wrong end of the block.  I blame the professional photography studio I employ to take all the pictures.



I start by shaping the bottom of the block into the classic oval shape using either paper of a file.  Shaping the top is the same but more fiddly as the strap is in the way.  Round all the edges off nicely...use your artistic abilities here to get the look and finish you want.



The last thing is to get out the circular file again.  Use it to shape the side of the block below the sheave.  The line will come off the sheave and, hopefully, lie nicely in this groove without chafing.

I haven't shown it here as you may not need to do it, but I still need to trim the loop of the strap to fit the shackles that I'm using.  I decided to leave the strap 3mm to give it plenty of material inside the block but it is too wide as it is.

[ardarossan]

Thank you for the nice clear photos, but I must confess that due to their clarity, I hadn't really appreciated quite how delicate & fiddly your components were.

Having just held a ruler against the screen for comparrison, I can see that the displayed images are about 4x greater than reality. Therefore, I have to ask, which hurts more, your eyes or your fingers? 

Andy

[Jerry C]

I think you've cracked it. To be honest there is a pic you showed earlier that I had to really look twice. Thought it was a real one. Even has that silver grey weathered look. Superb.
Jerry.

[rmaddock]

...I have to ask, which hurts more, your eyes or your fingers? 

My brain hurts! 

Actually, I find my fingers okay, but my hands cramp up trying to hold little bits for any time.  I've got one of those daylight magnifying thingies for the really fiddly stuff.

I think you've cracked it. To be honest there is a pic you showed earlier that I had to really look twice. Thought it was a real one. Even has that silver grey weathered look. Superb.
Jerry.

You are too kind....especially as the authentic finish to which I think you refer comes from handling untreated wood with dirty fingers 

[vnkiwi]

quote "You are too kind....especially as the authentic finish to which I think you refer comes from handling untreated wood with dirty fingers   "
 
That's the proper way to weather wood      
vnkiwi 

[rmaddock]

Et Voila!

Just as a final "Hurrah!" for this thread, here's a picture of the new blocks in situ on the boat.  Obviously I need to add a few more shackles to get the angles right, but it's looking good! It could almost have been worth the effort 

[Thelegos]

This is lovely work, I'm impressed and inspired!
Thank you

Roger

[Neil]

Pure brilliance, Rob...............now I have to make some myself when I get round to rigging the lifeboats.........do you mind if I copy and paste your photos for future refs, please....they'll be handy to look at when I get round to them, having them sat in front of me.
neil.

[rmaddock]

...do you mind if I copy and paste your photos for future refs, please...

I don't mind in the slightest Neil.  I realise that they have huge artistic merit and could win valuable international awards but...hey!...share and share alike, eh?

I'm just genuinely happy that I'm not talking to myself...

...although the entire internet could just be a figment of my imagination. It'd explain a lot of what's on there