Sunday, 22 January 2017

Dead-eyes progress

The first step to go from square to round is to cut the corners off to make the blank octagonal.

The important thing is that the newly exposed parts should be the same width as the remaining part of the original sides.

The traditional way of marking it up is to use a spar gauge. This will 'magically' draw the lines the right distance from the edges. This is really only necessary for a tapered spar. It just implements the 1/√2 rule that comes from cos 45°, or Pythagoras if you prefer.


In this case I just checked that was the right number and measured it. It came out OK.

Then it was a matter of planing the corners off until I was happy enough. I'm not making wheels here so roundish was good enough.
I measured it up - the old dead-eyes are 2" thick and I could get four from this piece so I sliced it into four equal pieces and then used the router to make the faces more parallel.

Now I have four thick discs.





Three steps left to go.

  1. round the edges - this worked well with a 'rounding-over' router bit last year.
  2. cut the groove for the wire rope to fit in - a 'core-box' bit does this nicely.
  3. cut the holes for the rope.
The holes for the rope are strictly 'blind sheaves'. This means they are doing the job of the sheaves (pulley wheels) of a block, so they should be as round as possible too. I'll have a go at using the drill at three 45° angles to make that octagonal (5 sides of an octagon) too. Then I'll try using abrasive cord to take the corners off.

Sunday, 15 January 2017

Dead-eyes

I finally made the effort to start making new dead-eyes for Robinetta. We got some nice cherry from the Birchanger Woods Trust last week. This cherry tree was damaged in the great storm of 1987 and was finally felled recently. Most of the wood is likely to be picked up by the local wood turning community.

I got a sample last year from a different tree and it made a beautiful and functional dead-eye which we used all season. While sweet cherry is nowhere near as hard as lignum vitae there is a lot to be said for using native species on a traditional boat.

The rather spectacular failure we had on the way from Douglas to Holyhead proved that Robinetta's existing dead-eyes are laminated plywood! That was about the fourth one to show some kind of wear so it is time to replace them all. If I make eight new ones we will have a spare.
 So far I've cut one piece to square. A hand saw is not a quick or efficient way of doing the rough cuts but it is a really good way of getting enjoyable exercise.

This piece should make four dead-eyes. I'll make it into a cylinder by sawing the corners off to make it octagonal and then either use the saw or the spoke shave until it's round, just like making a spar.

Then I'll slice it into four discs and drill the holes before using the electric router to round it off and cut the slot for the wire rope loop.

I'll work harder on these than I did on last year's one to make the holes into proper blind sheaves. I have some ideas about how to do that.