Tuesday 13 June 2023

Rudder | Making The Pivot Rod

I noted in a previous post that the stainless steel rod provided in the kit for the rudder pivot was the wrong diameter (at 10mm) and the wrong length (too short). It should be 12mm in diameter and 33" long.

I contacted Fyne Boats and they sent a replacement, but I decided to practise drilling holes for the cotter ring keepers in the 10mm rod, which was now scrap.

I wanted to find out the correct size hole for the keepers, and also how hard it would be to drill stainless steel.

This is me trying, with a standard 4mm HSS drill bit.

It did not go well. The HSS bit made hardly any impression on the rod, although well lubricated with oil.

Some research soon revealed that we actually need a much superior type of bit to drill stainless, such as cobalt.

I duly purchased a set of Guhring cobalt bits. This is them.

I was assured by the vendor that they are "the bee's knees" of drill bits, and so they should be at the price!

I also invested in some proper lubricating fluid. This is it.

I was now equipped to tackle the stainless rod and started by practising on the scrap 10mm rod. I drilled two holes at 3mm and 4mm.

The cobalt bits cut effortlessly, and the cutting fluid kept it cool and easy to drill.

This is one of the keepers in the 4mm hole. The 3mm hole is too small.

Armed with this knowledge I set up to drill the 12mm stock, like this.

I had received a 1 metre length of rod which was heavy, so I supported one end on a block of wood.

I also made sure it was correctly aligned by using a level, as here.

This is the first hole being drilled.

An old toothbrush is useful for clearing the swarf from the hole. I found that applying a continual flow of cutting fluid to the workpiece made for very effective drilling.

Here is one of the keepers in place on the new rod.

That looks good.

Here is the second hole being drilled.

The blue tape marks the required length for the finished rod, at 33".

So in the end it all went well!

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