Wednesday, December 30, 2009

New yard

It became apparent that the original Yard I made was far too flexible, and I've posted some photos below to prove it! As mentioned in my post on 27 December 2009, I wanted to make a new one and I had found some quite nice 42x42mm Radiata Pine at Bunnings which was quite cheap too.

This afternoon's therapy was turn this Radiata into a new Yard, and I must say I'm pretty chuffed with how it's turned out. At Bunnings I had picked through all the staves and found the most dense and heaviest ones as being most suitable. This proved the way to go, as the resulting Yard has turned out pretty well. I even made it to the original specs in the plans and this one has a round section. (The previously made Yard was left square with just the edges rounded off). I haven't encountered Radiata quite as hard as this before. This stuff was quite hard to plane with my #6 Bailey that had been freshly sharpened to a very keen edge.

After making the tapers and turning it into 8 sides, then 16, and finally rounding it with a #40 grit sander belt, I decided to test its flexibility. To round the Yard I wrapped the belt around the yard twice and set to with the task using a sawing motion. Pretty stupidly I did not wear gloves and consequently now have sore finger tips from the 40 grit 

Here is the almost completed yard. The taper is is not very evident from the shot, but it is tapered both ends! Just a final sand and varnishing to go. In this pic I am measuring the flex in the Yard for the sailmaker. This Yard weighs 2.2kg compared to the previous Hoop version which was 2.0kg, so even though the timber is quite dense and hard for Radiata, it's still turned out quite light. Better still, it is twice as stiff for only a 200g weight increase.

To measure the degree of deflection for the sailmaker, on his advice I suspended the Yard#by it's ends and suspended a 10kg weight from its centre. The easiest way to do this is to fill a bucket with 10 litres of water. I have a digital fishing scale, so used this to check that the final weight was 10kg.

47mm deflection. I'm very happy with that!

By direct comparison, this is the flex measurement for the original Yard, 97mm. Twice the deflection!

After sanding the spar round with the cut 40grit sanding belt (Quite a work-out!), I made 3 finishing sanders from used paint rollers. These were split and 3 different grades of paper bonded to the insides with PVA glue.  They were a little small for the larger sections, but this is easily fixed by heating the tube with a heat gun and spreading the tube wider, like this:-

Nice comfy sanders they make too! Given the somewhat worn state of my fingertips from the sanding belt, this was a relief :)

1 comment:

  1. Nicely done. That is an impressive difference in stiffness between the two yards.

    I like the paint roller sanding tools, too.