| Author |
 Topic Search  Topic Options
|
mlpankey 
Orange Level
Joined: 13 Sep 2009
Location: Vols country
Points: 4580
|
 Post Options
 Thanks(0)
 Quote  Reply
 Posted: 30 Nov 2010 at 8:28pm |
|
Andy its a good topic. One which brought out the thinking caps. whats your thoughts?
|
 |
|
Sponsored Links
|
|
|
firebrick43
Orange Level
Joined: 10 Dec 2009
Location: Warren County
Points: 592
|
Post Options
Thanks(0)
Quote Reply
Posted: 30 Nov 2010 at 11:47pm |
 mlpankey wrote:
i ran a piston in a computer with no piston pin offset piston speed at 10 degrees crank angle was 5.664 ftps with 1 mm positive offset piston speed at 10 degrees crank angle was 5.6636. i ran out of time had to leave . the engine in the above is a small engine 90 mm stroke 25 mm rod journal 100 mm rod center to center. |
Where/what program are you running to do these calculations on and where could I possibly get it? I have been reading up on aluminum casting, something my father and I did many years ago and I have several projects that I could use some castings in, so I have been thinking of setting up another foundry. In one of the books I have been reading, by Steve Chastain, he has another book on casting and machining pistons so I may just have to get it and give it a read. It will be a while till I get around to actually doing it however as I just have to many other projects.
|
|
mlpankey
Orange Level
Joined: 13 Sep 2009
Location: Vols country
Points: 4580
|
Post Options
Thanks(0)
Quote Reply
Posted: 01 Dec 2010 at 7:14am |
|
larry meuxs pipe max soft wear or Stan Weiss progams are good reasonable to purchase programs. wallace racing site has some free calculators a person can use but not one for wrist pin offset to my knowledge.
|
|
Gerald J.
Orange Level
Joined: 12 Sep 2009
Location: Hamilton Co, IA
Points: 5636
|
Post Options
Thanks(0)
Quote Reply
Posted: 01 Dec 2010 at 9:22am |
|
Look into lost foam casting, its simpler than sand casting or lost wax and can make some fine results.
Gerald J.
|
|
firebrick43
Orange Level
Joined: 10 Dec 2009
Location: Warren County
Points: 592
|
Post Options
Thanks(0)
Quote Reply
Posted: 01 Dec 2010 at 11:10am |
|
I have done lost foam and lost wax Gerald. It has its advantages, but I would have to make 6 or 8 foam/wax patterns, just to cast enough pistons(with a few extra for machining/scrap allowance. If I was casting just one, I did lost foam, otherwise we always made a pattern and core box if necessary.
|
|
Gerald J.
Orange Level
Joined: 12 Sep 2009
Location: Hamilton Co, IA
Points: 5636
|
Post Options
Thanks(0)
Quote Reply
Posted: 01 Dec 2010 at 11:50am |
|
For production you could make one pattern, and make a rubber mold from that, then create foam patterns in that rubber mold as many as you liked so long as the foam didn't stick to the rubber. And if the surface of that rubber mold is smooth, the cast foam will have that smooth surface better than a carved block of foam.
Gerald J.
|
|
firebrick43
Orange Level
Joined: 10 Dec 2009
Location: Warren County
Points: 592
|
Post Options
Thanks(0)
Quote Reply
Posted: 01 Dec 2010 at 12:06pm |
|
The foams we used were the dow blue board type foams. I recall that there are very few pourable foams that are suitable for lost foam casting. There is one(I have never used) but it was expensive) but using wax is a good solution for the method that you are talking about. But still, dipping multiple times in the plaster slurry, drying the slurry still need sand to back it up, cost of molding rubber and pourable foam/wax, it all adds up. Green sand and molasses baked cores are cheap, wood patterns and core boxes are cheap. Surface finish on cores is easy with a core wash. On the green sand, using a very fine facing sand gives decent finish but most of the outer surface is going to be machined completely anyhow and the interior surface as long is there is not serious defects, surface finish is of little consequence.
Lost wax/foam has its advantages in parts that need excellent surface finish and no/very little machining.
|
|
mlpankey
Orange Level
Joined: 13 Sep 2009
Location: Vols country
Points: 4580
|
Post Options
Thanks(0)
Quote Reply
Posted: 01 Dec 2010 at 1:40pm |
|
i sent it to you firebrick
Edited by mlpankey - 01 Dec 2010 at 1:40pm
|
|
