Repair.IT of course – Corsair H100i liquid cooling standoff

There is a kit from Corsair that would contain the standoffs that we could use to replace the one that broke.  We checked a couple of computer shops but these were not in stock, with no information about when the kit might be available.

The results are in – the majority of votes (being one) are to “” – great, another use for my machinery.

Alright – lets get into it.  The standoff that had the screw stud snap off, has a M3 thread, i.e. metric 3mm thread.  I happened to have M3 machine screws in my cupboard of different lengths.  I chose to use a 20mm machine screw.  First thing is to put the standoff in my lathe chuck, then face it off.


Face off in metalworking terms means to make the end face flat, i.e. remove the remaining threaded portion.  Next, I use a 2mm centre drill – to start a hole in the end face.  A centre drill is used to put a starting hole exactly in the centre – as it means.  If I start with the 2.5mm drill that I will require, I may end up with an off-centre hole.  After doing this, I followed up with the 2.5mm drill that was needed.  To work out what hole is needed to tap a particular size thread, we refer to a tapping chart.  To tap a M3 thread, I needed to drill a hole that is 2.5mm in diameter.  Actually a 2.46mm drill would be ideal – but these don’t exist, hence the nearest one being 2.5mm.


The above photo shows the standoff after tapping.  I use cutting fluid on the tap as I am tapping, backing off from time to time as recommended.  After tapping is completed, it is necessary to clean the tapped hole – I use a duster spray on a thin nozzle to blow out the metals bits.  Next step – to screw my M3 machine screw into the tapped hole.


Now I cut the end off with a hacksaw, the length needed is not so important as long as it is similar to the original – it does not have to be exact.


Then the end is cleaned up with a metal file.  I try a M3 nut to make sure that the threads will engage without difficulty.


This photo shows the two side by side, the repaired standoff is on the right – you can see the different silvery screw.  Yes, the one on the left – the bottom thread appears slightly bent because it is – it shouldn’t be that way though, but I won’t try to straighten it.  Great – I have ““.  Overall time it took – about 20 minutes because I did not want to rush.

[Note]  When using metalworking machinery – it is always important to be safe.  Wear eye protection – the little bits of metal can be so small that you might need a magnifying glass to see them, especially when spraying into the tapped hole.  My lathe does not have a very low speed, the minimum speed is 100rpm, which is a bit too high, so it is necessary to tap manually.  I disconnect the power plug to the lathe, then install a spindle handle so that I can manually turn the chuck that is holding the standoff – in this manner, I can hold the tap handle in my right hand and turn the chuck with the left.  When working manually on machines like this, it is so easy to forget what you are doing and accidentally hit the power button – often with disastrous results.

Reassemble.IT – Black & Decker GL570 Line Trimmer

…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.

SONY DSCSo 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.