LHL-14: A horizontal long-stroke

[ths]

Very sorry to hear that, so terribly disappointing.

Hugh.

[MuellerNick]

Hi!


Base is milled and finished (except two small bores).


Now, I'll have to make a few more cores and do two castings …




Nick

[b.lindsey]

That is just pretty Nick!!! Those castings look as good or better than most of the comercial ones I have seen...as I said before....most impressive!!

Bill

[MuellerNick]

Those castings look as good or better than most of the comercial ones I have seen

But not all of them! 
That's the remains. In the left front, you can clearly see the cylinder head. Looking from the bottom, one can even see the channels. Must have been by about 50 °C off. I'll check and see wether the control just overshot. Because the last run was 2.5 kg aluminium with the crucible. And the temp-controller has an auto-tune. Maybe he remembered the mass from the day before and was just too enthusiastic.


Last year, at one of my casting-parties, a friend took along a relative of him. He is working in the QC-department of a foundry. Global player! He didn't believe that someone can cast in his backyard (well, many do so). When he saw my castings, he could not believe. He said, mine are better quality than theirs. He couldn't understand how I make better cores than they do. He said, he'd like to send their apprentices to me, so they can really learn something.
I didn't learn that trade, I just experimented a lot of time and observed and analyzed all my mishaps (there are a lot of them).


Nick

[NickG]

Nick, brilliant patterns and castings. Sorry to hear about the temp sensor. Like the engine concept, would be nice to see a really slow runner.

[MuellerNick]

Checked the furnace, and it actually is off by 50 °C. So I had 530 °C in it. You can go up to 520 °C, but then the parts need a support, or they will sag. I baked the binder at 500 °C already, but somewhen decided to go to 480 (just takes longer, but is more secure).


Looking back, I always had a layer of sand in the furnace, but not this time. As I need to bake out the binder (don't want to machine sand), next time, I'll cross-check it with an external sensor and keep well away from the evil temperature.


Too late to cast today, I'll do that tomorrow morning. But I have prepared the cores. Then, I'll make the crankshaft.




Nick

[MuellerNick]

Got two new castings to ruin once more. 


Head went "as usual".
Cylinder, I improved the runners. Now it looks like, as if I can go down by 10 °C with the casting temperature. Surface finish in the upper half is getting rough and matte, that's a sign for too much temperature. Overall, result is better than the previous one.




Nick

[b.lindsey]

Nice results (again) Nick!!  From the last pictures, it doesn't look like you used the exothermic powder this time. Does it just not show up in the pictures or did you make some changes to avoid having to use it?

Bill

[MuellerNick]

No, I used the powder again. You might see that at the left riser (of the cylinder). Also used it with the head.
Maybe I'll risk leaving out the exothermic with the cylinder. There are coming out just two bubbles *blubb* *blubb* and then the melt rises and it stops bubbling. It takes 3 seconds for me to put away the ladle and grab the powder. But at that moment, all has already happened.


With the head, it makes more sense. But I think I can leave that out too. For the first castings, I want to reduce risk.  When I got all settled, I can simplify the process.
I have a casting (different engine), that takes half a day to assemble and make. I had 4 failures until I found out the right procedure.


And a quick mockup, before they magically disappear once more.


Nick

[NickG]

Love it, great stuff.

[steamer]

Nice Castings Nick!

Dave

[MuellerNick]

Quite a few delays ...
The day before yesterday, I wanted to start with the crankshaft's web. Went to my stock and wanted to grab the ø140 mm material. But it turned out to be 120 mm. 20 mm too little.
So I asked a friend wether he has some, and how I could get it fast. So he cut 4 disks with ø150 and, as his wife was nearby, asked here to bring the material to my door. DAMNED nice people!
Only drawback, there was a note saying "material unknown". Already being conservative with the cutting parameters in the lathe, one insert didn't survive too long. Going down a bit more, it machined really nice. But it was tough! Picture of a disk in soft jaws.
Milling was even tougher, the carbide endmill started to glow with coolant. Bores were circular milled, and all went well. Diameter of the web is 135 mm.


Started some periphery work, but nothing finished, like the crankshaft. I'll have to harden and grind the pins for the crankshaft. But as I will leave this evening to Austria for an engine fair, there won't be enough time. If I rush the job, the risk of ruining it will just increase. And I won't finish anyhow. Still enough half-finished for a nice mockup.


So, 'till next week …
Nick

[steamer]

Sounds like 4150 HT or some other Chrome alloy...ouch!

Sure turns well!   Nice work Nick!

Dave

[MuellerNick]

Sounds like 4150 HT or some other Chrome alloy...ouch!

That would be 42CrMo4-QT. Might well be, have turned that already. Or C60 (1060), but he simply didn't know.
Anyhow, nicer surface than leaded steel.


Nick

[ths]

Is that a blasted finish Nick? I wonder what happened to the saw blade that cut the discs?

Hugh.