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The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)

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Muzzerboy:
I assume you are using leaded solder? That melts at a lower temperature but either way, the reflow temperature profile is often given in datasheets these days. The actual reflow part of the process is typically around 230-250C for 45-90 seconds or so for lead free solder. Pretty much everything made these days is SMT, so all compts are designed to tolerate those temps without degrading.

awemawson:
As expected, soldering jumpers to the centre row (B) of the DIN4161 connector was a nightmare. Poking a soldering iron down between the pins inevitably scorched the  insulation of previously soldered wires. I thought perhaps I could use PTFE insulated wire - I have some the right size, but frankly I've never been able to satisfactorily strip the insulation neatly and to correct length - it always ends up a mess.

Then I thought, if I can find a crimp version of the connector, I can put it on pigtails off the board and solve the issue. Sure enough, Harting part number 09230483217 is the right part - but it's on a ten week lead time from all the normal UK suppliers so that rules that out!

OK the socket that I have has solder tails intended for a PCB, BUT 16 way female socket headers fit them rather nicely - three of those and I have a hopefully working solution. Solder the three headers individually thus making the 'middle row' a none issue, push them on the back of the socket and hang the socket off the board on a short umbilical cable This also makes inverting the board for test far easier.

But as the female jumper leads that I've been using with the Arduino were themselves rather unreliable - falling off at a mere touch, a better breadboard solution was also called for. I've found one with screw terminals AND header sockets so this may be the best of both worlds.

. . . . we'll see when it arrives !

awemawson:
The new breadboard with screwed terminals arrived today. Very confusing when you buy from eBay and an item is delivered by Amazon in Amazon packing !

I must say that I'm impressed by the build quality and it looks like it will meet my needs. I'm now waiting for a delivery from RS of '0.7 mm Boot Lace Ferrules' that will plug into the existing female push fit sockets AND go in the screw terminals (keeping my options open). I do have 1 mm boot lace ferrules but although they fit the screw terminals they are no good for the push fit ones./

. . . . getting there slowly - one tiny step at a time  :thumbup:

awemawson:
Things have been a little slow on this project - RS Components let me down on the bootlace ferrules that I'd ordered. Unusually for them they arrived a few days late and when they came they were not the same spec as described in the catalogue. I needed ones with an O/D of between 0.65 and 0.8 mm. There were two types catalogued with O/D 's of  0.7 and 0.75 respectively so I had ordered some of each. When they arrived they were 1.05 and 1.1 O/D. I/D had been specified by cable size and they had entered the I/D as the O/D in mm. They were gracious enough to acknowledge their error and the engineer even went to the trouble to confirm that it was only this size were mis-described. No big deal but it's cost me a few days when I could be getting on with things !

So I've reverted to 'Dupont' pins - which I don't particularly like as they are a bit fragile, but needs must, and of course this incurred a further few days of delivery delay.

OK we are where we are ! So today the coloured heat shrink arrived allowing me to code up the 48 wires. There are three banks of 16 wires, cabled in correctly colour coded wire, but being 1 to 16 each bank has two 1's 2's .... 6's. So each bank needs a sleeve to indicate which it is (A=Yellow, B=Red, C=Blue) and in each case wires 11 to 16 have a white sleeve to differentiate them from 1-6. This may seem pedantic, but believe me without this detail things rapidly get very confusing when fault finding !

So this morning I have done the wires and crimps of 'Bank A' and I'll give my eyes a rest until a bit later to stop me going cross eyed !

Meanwhile the programming of the test program has been progressing but isn't yet finished.

djc:
As a general observation on life, I have never understood why, when we have three things to distinguish between, we use three labels. Two labels and 'unlabelled' is sufficient.

Everyone wants to start counting at 'one', seemingly forgetting that 'zero' can be used.

When you see videos of people dismantling things (e.g. a chair), they label the legs 1, 2, 3, 4 when 1, 2, 3 and no label would do. How much masking tape is this costing the planet?

I wonder if there is any connection with a person's favourite computer language - whether arrays are zero-indexed or not?

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