Alex

It took more than a day’s work to dismantle, clean, reassemble and adjust the Taig mill. Funny how sometimes you don’t realise just how filthy a thing is until you start scrubbing the layers of grime off it (in this case, dried oil and grease with swarf and dust embedded in it):

Shiny clean parts ready for reassembly:

I also replaced the leadscrew bearings in the Y axis because they had gone rather lumpy. I’ll probably do the other two axes as well soon.

Reassembled mill, bolted to an offcut of kitchen worktop and ready to start a precision drilling job.

I need to drill about 120 holes, precisely located by eye (under magnification), 1mm dia or less in 1.5mm thick sterling silver. Annoyingly I broke two expensive Swiss 0.7mm HSS bits within the first few holes (not entirely sure why – it doesn’t help that you have no feel at all for how much torque you are applying). I am now using a 0.9mm carbide PCB drilling bit (which is bigger than I would prefer), and have successfully made it through about 40 holes by peck drilling and feeding very slowly indeed. I’m probably spending about a minute on each hole. CNC would certainly make the job easier, even if I was only using it to manually jog to each hole location before running a few lines of code to automatically drill the hole at a consistent feed rate.

I’m back at my parents’ house for Christmas, and while I’m here I’m hoping to make a start on converting my Taig benchtop milling machine to CNC. It has been stored under a sheet of plastic in a damp shed since I moved out of my previous workshop about five years ago (crikey, has it really been that long?). Fortunately I smothered everything in oil at the time, so it hasn’t suffered too badly from rust – the worst bits are the handles, which I’ll be replacing with motors anyway. The oil has gone sticky and attracted a lot of dirt though, so my first task is going to be to completely dismantle, clean, oil, remantle (is that a word? if not, why not?), and adjust everything to run smoothly and accurately again. I have a little job coming up where a manual precision drilling machine would be very useful so I’m planning to do the first stage quite soon.

The thing on the spindle is a first generation HighTechSystems rapid tool changer. Unfortunately it’s now discontinued, though I already have a decent selection of holders for it and I think once I have converted my Taig lathe to CNC it shouldn’t be difficult to machine bespoke ones to hold different sizes of tool. The idea is you have a specific holder for each tool used in a job. You set up in advance a software table that tells the machine controller exactly how far each tool sticks out of its holder, so you don’t have to waste time re-zeroing it each time you change tools (which is a manual process but only takes a couple of seconds).