Well, here we are again.... a straight 10 hours at the mill today, and I'm bushed. I did get a fair bit done, though, so for those of you on dial-up connections, I apologise in advance for the 10 new pictures which will take ages to download...
Dave - hmmm, melt it down? Shall I? Let me think about that for a moment...
Jim - I can empathise with that, I'm looking forward to it myself. But I'm really glad I did this wax one, it's taught me loads - both about machining in general, and the manoeuvres I'll have to make with the ali sump too. I know I sound like a broken record, but I can really recommend this wax stuff for try-out type machining.
Anyway, on with today's fun & games. First job was to bring the height of the wax block down to dimension. Originally, I was going for a 2.5" deep sump; but I've managed to fit the whole thing into just 2". Which is great (it's going to lead to a scandalous waste of aluminium, though, I will have to face off a full 0.5" from the big piece - about 20% of it), means the weight comes down and so on.
So, here we are about half way into the job:
Notice the chipping & cracking in the lower right corner; that's where the expansion crack is. Typical, it's just in the main block.... Never mind, it's still going to get nailed later on.
So, having faced the block down to 50.8mm, what next? I decided I'm fed up with having to add my "spare material" dimensions every time I dial the piece in... it's already led to one cockup - the tubes and the slots which the tubes end in are all ~4mm out of position, because I forgot to add the 4mm "spare material" measurement a couple of days ago.
So, obviously the first job is to mill the nice rounded edges - 35mm radius. Out with the rotary table, & find it's centre point. It's all a bit rough & ready... I used the quill to get it within 0.5mm of true. No dial indicators here! Once the rotab was about right & bolted down, I loaded the sump on, and put the centre of the theoretical 35mm circle, and clamp down. Now that was a palaver.... I think I'll need help when it comes to the ali version... Finally got it all lined up, angled up, etc:
Cut (took maybe 1 minute). Done.
Rinse & repeat for the other corner. Managed to start turning the rotary table the wrong way on BOTH radiuses. The second time, I carefully worked out that I needed to turn the wheel clockwise - then turned it anti-clock as soon as the cutter was in play
What an eejit.
Aaaanyway. Dump the rotab, re-set the sump straight & true on the table (sitting on some parallels, so I can mill to full depth), and dimension the sides:
While it was there & dialled in, I drilled the holes the rest of the way through the wax, so I could do a trial fit on the engine. I also cut & dimensioned up the front & back of the sump; so now it's the correct size all round (except the tabs).
Here it is on the engine, at last! The exhausts are in place to make sure there's clearance room (there will be, when the side is milled to an angle):
Notice the various calculations, which I wrote on the piece itself. At least I don't lose them that way (until, that is, I come to mill the material away!).
So... it all fits! The drill holes are good, at any rate, and it sits flat on the engine, so the rods don't seem to be interfering. Tomorrow, I'll take the plugs out of the engine, put the sump in place, and rotate the engine through a complete 360, to make sure none of the parts touch anywhere.
Back to the mill, and it's time to slope the outside. Here I'm checking the deepest hole (the depths got a bit random for some reason), to make sure I don't break into it.
This depth then gives me the angles for both sides (22.6 and 13.2 degrees respectively). Milled the first side, flipped the sump around, and problem! Can't get the clamps to grip, they slide off the sloped bit, and the remaining flat parts are off the edge of the angle plate... So I had to mill a flat edge, where the bolts go (which had to be done anyway, but I'd planned it for later). Now I had somewhere to clamp, so on with the second cut. Here it is in progress:
At this point, the pucker factor is turned all the way up to 11.... Much earlier on in the "build", you may recall I cut a 2mm deep "pocket" in the centre of the sump. Whilst this proved very useful for ensuring I wasn't wildly off-target with my other measurements, now it's causing problems: Because underneath that sump, the only bit that's actually touching the angle plate, is the part under the clamps! That 14mm wide by 16mm deep strip, is taking both the entire weight of the sump, and the machining operations! Pucker? I certainly did.
But, fair play, despite the fact I'd actually cracked the wax earlier (too much clamping while the expansion crack was still in play), it all held, and we got to the end with no soiling in evidence:
That picture shows just how little gripping room there was; the wooden spreaders are about the same width as the flatted section. After that photo, I flattened the edge on the other side the same.
So, close of play today:
Looks the same as yesterday on that side!
Tomorrow, I hope to finish off the front end (most of that lump on the front will be cut off, and a bolt-on block added to turn the oil pipes through 90
o.
One last bonus photo, for the album:
I love this wax stuff
