LHL-14: A horizontal long-stroke

[b.lindsey]

Very nice project Nick, i will be following along with great interest. Doing the patterns and castings yourself certainly adds a lot to it also!!

Bill

[MuellerNick]

So I made the cores. And there is still time left for today's casting … 


#1: Water jacket for the upper half with the pattern behind
#2: Same for lower half
#3: Core for water jacket on the tube (AKA cylinder barrel).
#4: Core for the piston


The water jacket is only 5mm in thickness. I didn't want the cylinder to be clumsy. But that didn't make things much easier. I had a few failures ramming the core sand into the core box (with the tube as part of the box). But that's normal, tricky cores take a few trials to find out where and how to ram. And where and how to rattle on the core box to get the core back out.

Edit:
The pattern for the piston looks a bit strange to some, I guess. The useless round on the right is for clamping. Clamp on the piston and turn the clamping round smooth, then clamp on the clamping round and finish all the OD work, bore, cut piston ring groove. And then part off to length.



Nick

[steamer]

Looking forward to some chips!

Dave

[MuellerNick]

Looking forward to some chips!

Dave, first you need to learn how to spell "patience" and what that is.
It's Sunday, sun is shining and I had a walk. Then glued together the cores. Then made and drilled the alignment pins for the patterns. And cut the thread for pulling them out.


Nick

[steamer]

I don't recall being impatient Nick...
Just that I am interested in the subject and your build of it.

Dave

[MuellerNick]

So this is todays harvest:
Piston, camshaft-bracket and the three bearing covers.


The cylinder head was a failure, I almost expected that. Shrinkage! I already was casting it quite cool at 660 °C. Next time, even cooler at 650 °C And a raiser, maybe even an exothermic one.


The cylinder didn't want to stay in the cope and always fell out, ruining the mold. I had the same problem with a similar casting and I have a solution for it. But not today.
So tomorrow, three castings to go.
And a bigger crucible to be welded. Not enough volume for the base. And I don't want to fire up the furnace outside with the big crucible.




Nick

[MuellerNick]

So I have the cylinder head!
Pouring temp lowered to 650 °C, two risers added and added some exothermic powder on top of the riser (on the left in the picture).


And the cylinder!
First try went quite bad. In gate was too small. When pouring, the melt went directly into a venting hole (my fault) and the melt was too cool (680 °C).
So, next try 690 °C, better in gate, paying more attention to the venting hole. When the melt came out of the hole, I've put a load of exothermic powder on it to keep that part liquid . A lot of bubbles escape from there. That venting thing can be seen on the right of the second picture. Also had a cold run in one portion where wall-thickness was minimal and the melt had contact with the steel tube. Isolated that region with a wash, worked like a charm. 
Had some sand breakage, but that's nothing to be upset. Can be repaired on the casting and avoided with the next pour.


Now to the crucible …


Nick

[MuellerNick]

And here is the base:
It is 370 mm long. Casting went quite well. There's a fault in one of the crankshaft's bearing blocks, but it is within the finishing allowance and where the ball bearing sits.
Only thing was, that I decided to have a few beer afterwards.  But these went well too!


So tomorrow, I can start making chips. Just have to decide where to start. I guess it will be the base.


Nick

[b.lindsey]

Nick, sorry to hear about the few false starts, but those are really some fine looking castings. Someday i hope to try some casting, but for now i'll settle for admiring your impressive work!!

Bil

[MuellerNick]

Nick, sorry to hear about the few false starts,

The cylinder head was just a mishap, as I already expected that.
The cylinder was a great success. Even with the first fail. The water jacked has no connection to the outside, so every caster will tell you that this won't work. The core sand will start to gas, no matter what you do. There just needs to be a way for the gas to escape. It worked, I'm happy.
Yesterday, I had so many victories (with other things too), that it was a really great day!


I'll put the cylinder and cylinder head in the furnace to bake out the sand binder, while milling the bearing caps and the base. Pictures this evening …


Nick

[gbritnell]

Great looking castings Nick. I can't wait to see some machining progress.
gbritnell

[ths]

Very nice castings, especially the base, which has come up well.

Hugh.

[MuellerNick]

I just went to the temperature-controlled oven, where the cylinder head and the cylinder were in to bake out the binder of the core sand. Display said 480 °C, that's what I programmed.
Opened the furnace and … a sea of molten aluminium! I guess the sensor went kaputt. 


I quite feel like having to cry.




Nick

[b.lindsey]

Oh wow Nick....how discouraging after those parts turning out so nicely. Man...I feel bad for you...what a bummer!!!!

Bill

[steamer]

Sorry to hear that!.....

Dave