We've all been there…
I work slow. First day I'd cut a blank from a large chunk of rusty old black plate local scrappy gave me. It was way too thick but a little squaring up and skimming would do..
Of course it was too wide for the horizontal band saw and had to be teased by cutting from both sides to hack out what i needed.
It was an opportunity to finally play with the bangood 50mm face mill I'd forgotten i bought 2 years ago..
well the darned thing wouldn't fit onto it's arbour. It all looked right and i still haven't figured out what was going on but eventually (before we get to volume 2) I whaled on the thing between two lumps of wood and got it assembled.
Carefull measurement and there seemed to be about .0015 discrepancy on one cutter. I worried about it for a while. With nothing to lose I gave it some more Birmingham Screwdriver… no change.
After two cups of tea I wondered if I'd ever get it apart and perhaps slip a shim in there to level it better – nowt to lose. Perhaps lever it off with a screwdriver?
I undid the bolt and it just fell off the arbour! I put it back on to make a shim position. As best i could measure it was all within .0005 I took it part – no marks or burs! Go figure. I re-assembled and gave it a shot…
I have a super lux mill. It was happy enough with a 1mm depth of cut and the finish was not tooo bad. It balked at 1.5mm depth full width. First th vibration built up, then the mill vice actually moved on it;s dogged down T-nuts- which got graunched up tighter and then the arbour nut loosened and put a gouge in my part!
Reassembled with blue threadlock.
The part was a tad over 50mm wide so two passes and a final skim at about 0.2mm actually gave a very nice finish I coudn't feel with a fingernail. And the gouge was gone.One day i might try some better quality carbide on it.
Well that was day 1 gone.
Next for this odd shaped bit I sketched it out and did my conversions to metric. I drew the part out in cad ('cos I'm not that good at cad) to be sure that my approach would work and then blued up the plate and drew it out on that to avoid blunders even though i was milling usng the DRO.
day 3 I actually got to dril and mill and bore the internal bits of this part and suprisingly without mistakes. all it now needed was the awkward outer shaping doing. I figured the neatest way would be to cut 2/3 round the 1.5mm diameter hole on my rotary table rather than grinding and filing.
I'd treated myself to a coaxial indicator – a chance to play with it.
First i had to create somewhere for the antirotation bar to sit against – the third clamp and rod I tried finally worked. Indexing to centre of the rotary table was a sweet doddle but clamping the part onto the RT and indicating the hole tn it was a mare- finding a clamping solution and tapping away. Well that wasted nearly an hour and a half – some days are just like that. Finally done.
So I dismount the coaxial.. except that as I removed the probe it slipped from me, bounced on the mill table, bouncd twice more and somehow managed to end up underneath the rubber concertina within the base of the bloody mill. Unbelievable!
Some dismantling later and the judicious use of one of those flexible grasper thingies for fishing nylon shirts out of gear boxes and I finally snagged it along with a hedgehog of swarf stuck to its magnets. Mill re-assemble.
That's when i find that the clamping solution on the RT causes it to snag on the t-nuts when rotated past the RT clamps. Separatly so as not to disturb the part I took of each clamp and hacksawed the t-nuts shorter – and they still snag and need skimming thinner. Oh, well. The DRO is set to RT centre so I can use the vice to do that without losing all my centres and then i can finally get that part finished up….
pgk