The safety valve seat cutting tool was made and heat treated in oil. It was then tested successfully on brass and produced a good result.
My AL330a lathe which I bought almost 15 years ago has served me well but yesterday I noticed it has been producing some chatter marks even on finish cuts in the last few weeks, without any audible chatter. Faint marks but noticable. In machining the first cut on the outside body of the safety valve the depth of the chatter in waves was measured at 0.01mm and had approximately the same pitch as the carriage rack and the same number of ripples as the bearing rollers.
So the spindle bearings have been adjusted. Some seals are being replaced (leaks oil...finally have been able to trace where it comes from). The gear change levers had O-rings on the shafts and have found at least one was cut allowing oil to capillary past it. The O-ring grooves had razor sharp corners and they were chamfered to prevent it doing it again.
Grey flecks were noticed in the oil well and when the gear change levers were dismantled it was noticed they had drilled the dimples for grubscrews in the shafts and had left the swarf in the holes and jammed the grubscrews in!
I'm hoping the grey flecks in the oil well are leftovers from "running in" with the included bits of swarf coming from manufacture. The oil will be changed.
I had made the mistake of topping up with any thin motor oil over the last year rather than a hydraulic oil being a bit frustrated with the leaks becoming worse and not knowing where they were coming from and how much down time required to fix. As I learned yesterday the oil with detergents such as a motor oil holds particulate in suspension rather than a hydraulic oil letting it stay in the sump. I had typically used a gear oil previously and have a 20L drum of hydraulic so should be an easyish job to clean out and refill.
Some power feed shaft seals will be replaced as will the o-ring behind the bullseye sightglass as that was leaking too. I have found they are not a standard width but I can get narrower ones from a bearing supplier. The bullseye O-ring didn't have much chance as the spotface and threading operation left some burrs that had cut that one too.
Just goes to show the basic machine parts are probably fairly reasonable but as everyone tells me the Chinese lathes such as what I have has been put together in a hurry and has sharp burrs and could include swarf in the headstock. It would be a nuisance to strip down a brand new lathe but it might be worth the effort in the long run to not have cut seals and swarf where you don't want it.
Hopefully today (Wed 18/4/18) will be back in business with a repaired lathe.
Happy steaming!
Nigel
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