[SEL] Re: Alamo piston pattern update

[Dave Otto]

Curt Holland wrote:

> I meant the cope side. Yes the cope side of this flask is 5" tall.
> Incidentally the drag side is 4" tall on this flask set. So the riser is
> 1.75" where it hooks on the top of the parting board and tapers to a
> smaller diameter in its' 5" height. The taper is roughly a 1/4"/ft. taper.

I must have been half asleep last night when I asked you about that, for
some reason I was thinking the 1.75 dimension was the height or depth of the
drag side riser. I don't think you indicated what this height was?

Thanks for the flask size drawings; do I need to put the 2" holes in the
parting board? I would assume so. Also I have the Freeman locaters on order,
these will still be used, correct? And am I safe to assume they need to be
placed in side the dotted line?

> Hey I noticed you chucked one end of your block in a 4 jaw chuck. How
> did you assure that the center of rotation was dead on the parting
> centerline? I gave up having sucess and ultimately made a tool that the
> 3 jaw chuck could hold and this tool is screwed to the end of the block
> right on centerline. Even so, with the new tool I was off about .030 on
> this last pattern (the Herc) I made over the weekend. I am going to have
> to mill a little off one side and build up a little on the other to
> compensate. Obviously I've still got work to do making a better tool.

The two pieces that made up the blank were the same size, so I just centered
the blank in the chuck. Then I carefully tapped the other end to line the
paper joint up the center and center drilled it. After the blank was round
and put in the 3 jaw chuck, I had to tap it around a little to line the
center up with the split. 

There were actually three steps, the first to make it round. The second to
turn the part around and put the round part in the three jaw chuck, and
center drill it. At this point the core print end was machined. The third
step the part was turned around again, indicated in and the piston end was
turned to size and length.

One thing I did find out pretty quickly is the blank would not clear the
cross slide of my 13" tool room lathe. So my first cuts had to be deep
enough to make it clear.

> Oh goodness it is a heavy beast! I will HAVE to put it on wheels despite
> it originally being a skid mount. I simply have no way to move it around
> otherwise. Hopefully all that mass will make a slow smooth running
> engine. I have yet to see one at a show so have no clue how they run....

Rob Skinner has a couple of large engines that are on skids, I know he shows
then because I have seen pictures. Maybe he can tell us how he loads and
unloads them. Rob are you there?

It would be fun to see the progress; you are taking pictures aren't you?

Dave Otto
Boise, Id
USA
Dotto at velocitus.net
http://community.webshots.com/user/otto1960