…continued from yesterday…
I put the actuator into the vise on my milling machine, then milled the worn pin off it.
Then I used a 2mm drill and drilled the initial hole for the pin to go into. I do this so that if the first hole is not centred, I can still adjust the position when I drill for the final size.
I drilled the final 2.5mm hole into the actuator. The pin that I made is just over 2.5mm in diameter so it should press in and be reasonably firm.
I inserted the pin into the actuator, then milled to the appropriate height. Here is a photo of the repaired actuator.
Now some of you might not have a line trimmer, so I have a photo of it installed into the line trimmer head.
So the question in everyone’s mind is “Does it work and do the job?”. A very good question – since the pin is slightly longer, it will be a little heavier. My scales can only measure to the gram, and it shows the weight of the entire actuator is 2g. Anyway, the acid test is to try it out.
I have to say that the this was an oustanding success. I trimmed more than 10m of edge and the line did not break. It would advance the line from time to time – I inspected the actuator afterwards, and I can see no real wear. Not bad what a couple of thousand dollars worth of machinery can do!
The nylon material I used is from a kitchen cutting board – I bought one some time ago as a source of cheap nylon. I put it in the lathe to turn it down to size, 2.5mm and 3.9mm, then the rest was on the milling machine today.
[Edit] When turning soft materials like nylon and other plastics on a lathe, it is best to turn down the diameter in stages. I wanted a final 3.9mm diameter so elected to first turn to a 5mm diameter first, then I turned a section to 2.5mm. This is because plastics are not as rigid as metals, so will move away from the cutting bit, hence turn down to 2.5mm in small sections until the length of that section is correct, before turning the 3.9mm section.