Author Topic: building the Frisco Standard Model  (Read 13799 times)

Offline Brian Rupnow

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Re: building the Frisco Standard Model
« Reply #135 on: February 21, 2019, 02:26:05 PM »
Either piston will work. The piston has rings on it, so the piston can be made .001 to.002" undersized to account for differential heat expansion between the aluminum piston and cast iron sleeve.

Offline Craig DeShong

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Re: building the Frisco Standard Model
« Reply #136 on: February 22, 2019, 10:41:45 PM »
Pete, Roger, Brian; thanks for your comments and input.  Thanks for those silently following along also.

I decided to make the pistons out of aluminum.  I have the stock and this way I donít need to silver solder them together (have I mentioned that I ABHOR silver soldering.. basically because I canít do it well?).

Any hoo, here I am, gleefully turning a blank of aluminum to the OD of the piston.



Cutting the ring groves.  I have a friend who was walking with me around the Cabin Fever Expo a few years ago.  Heís a great modeler, so when he talks I tend to listen.  As we were walking by the Arthur Warner booth he pointed out a set of slitting tools and said ďYou need thoseĒ.  At the time I couldnít really see a use for them but Iíve learned to listen.  He was right they REALLY do come in handy from time to time, like for cutting these piston ring groves.



Now with the piece parted from the stock and turned around in the lathe, Iím facing the piston to the correct length.



In this photo Iím forming the skirt.



Time to move to the mill and drill and ream the hole for the wrist pin


Iím hoping I will wrap up these pistons tomorrow.
Craig

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Re: building the Frisco Standard Model
« Reply #137 on: February 22, 2019, 11:53:41 PM »
Looks Awesome Craig!

Dave
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Damned ijjit!

Offline Craig DeShong

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Re: building the Frisco Standard Model
« Reply #138 on: February 23, 2019, 09:44:49 PM »
Thanks for the comment Dave.


Got the connecting rods, rings, and pistons installed.  Everything goes up and down and round and round as it should.   :whoohoo:
Craig

Offline Ye-Ole Steam Dude

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Re: building the Frisco Standard Model
« Reply #139 on: February 23, 2019, 10:17:24 PM »
Hello Craig,

Looking beautiful and it is coming along quite well. Great to see all the parts together and in motion on your video.

Have a great day,
Thomas


Offline 10KPete

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Re: building the Frisco Standard Model
« Reply #140 on: February 23, 2019, 11:31:28 PM »
Nice!  :ThumbsUp:
 :popcorn:

Pete
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Online Art K

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Re: building the Frisco Standard Model
« Reply #141 on: February 24, 2019, 04:14:27 AM »
Craig,
Looks great, everything goes round and round and up and down. :DrinkPint: I'll drink to that.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Craig DeShong

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Re: building the Frisco Standard Model
« Reply #142 on: February 25, 2019, 11:31:41 PM »
Thomas, Pete, Art; thanks for your comments.  Thanks also for those silently following along.

I started working on the heads today.  These are irregular shaped castings with no really good way to hold them.  I decided to file some flats to give me some purchase on the casting and then milled a flat surface on the bottom (that mates the top of the cylinders).  Once this was attained I outside bored the cylinder protrusion.  I would have preferred to do this on the lathe, however I couldnít really figure out how to hold the casting and align it properly.  On the mill I could run my indicator back and forth and get a reasonable alignment of this irregular surface.



The two heads are mirror images of each other; hereís the same operation on the other head.



With a flat surface to align the casting, I scribed a line through the center of the cylinder bore and in a straight line with the front-back orientation of the casting.  This allowed me to mill the flat for the intake but more importantly, one of the two datum references for all the future measurements for machining this casting.



With the two datum references established I could locate the cylinder center from the top of the casting.   This allows me to locate and drill the head mount bolt holes.  The drawings indicate these should be drilled at the center of boss.  I wanted to verify that these holes wouldnít pierce the cylinder liner.  I decided I wanted each hole center should be at least .950 inches from the cylinder centerline.  This allowed the cylinder bolt to be located well within the aluminum casting so it would not interfere with the cylinder liner.  I did have to offset a few bolt holes away from center of casting to achieve this.



With the heads drilled for the head bolts, I affixed them to the cylinder casting and spotted the bolt hole locations.



With the bolt hole locations spotted I could drill and thread the cylinder for the head bolts.

« Last Edit: February 26, 2019, 10:17:14 PM by Craig DeShong »
Craig

Online Dave Otto

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Re: building the Frisco Standard Model
« Reply #143 on: February 26, 2019, 12:27:37 AM »
Looks good so far Craig, hopefully the rest of the machine work on the heads goes ok for you.

Dave

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Re: building the Frisco Standard Model
« Reply #144 on: February 26, 2019, 12:33:39 AM »
I was afraid to ask when you posted the up and down and round and round vid.   But the heads DO reach down inside.   pwew!    8)

Dave
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Damned ijjit!

Online crueby

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Re: building the Frisco Standard Model
« Reply #145 on: February 26, 2019, 01:02:41 AM »
Craig, I have never outside bored like that, does it require a cutter with edge on other side, or running the mill backwards?

Offline Jo

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Re: building the Frisco Standard Model
« Reply #146 on: February 26, 2019, 08:17:56 AM »
 :thinking:

Positioning those heads bolt holes looked to be a tricky job to balance things out I bet you are pleased it worked ok  :).

Jo
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Offline Craig DeShong

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Re: building the Frisco Standard Model
« Reply #147 on: February 26, 2019, 11:00:13 PM »
Chris- just ran the mill backwards (and set the down feed to up-feed since the mill was running backwards).
Jo- got to drag out the old Trigonometry and use the Pythagorean Theorem.  I could read the x & y from my DRO and by applying the theorem, as long as I got a hypotenuse of the triangle over .95 inches I knew I was good to go.  As George B. in a post not long ago said ďThe math doesnít lieĒ.

Today I started out locating the hole in each head for the vertical cam shaft.  The building notes instruct the builder to make a pointed shaft (slightly longer than the allowed space) and fit it to the base, then attach the head and ďspotĒ the location for the hole.  Iím doing this in the photo below.



Once the location of the hole was spotted I took measurements on the mill from the two X and Y datum, turned the head over and then re-located the location for the bearing hole.  I then center drilled, drilled and finally reamed the hole.  The drawings call for this steel camshaft to run in the aluminum casting.  Iím again choosing to use a brass bushing so I over bored the hole in preparation for installing the bushing.



An assembly check shows both upper camshaft bearing holes to be located correctly.  WHEW!



There were a plethora of holes to be drilled thru the top of both castings.  Things went pretty well with the front casting, not so well with the rear casting. 
With the rear casting, the holes just didnít seem to locate on the established bosses well, and the two furthest outboard holes were completely off the casting!  I was thinking at first that I was working with another measurement in error, but the same measurements are used for both castings and the castings are supposed to be mirrors of each other.  Had I shifted the casting outboard more, the head bolts would not have hit their bosses.   



I just decided to re-locate the holes for the exhaust valve pivot and the igniter pivot as seen in the drawing below.  This may (will?) require me to do a slight re-design of the rocker and pivot arms, but that probably can be accomplished later. 

Craig

Offline Craig DeShong

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Re: building the Frisco Standard Model
« Reply #148 on: February 27, 2019, 10:15:37 PM »
Work progressed on the heads today.  It was a busy day and I missed taking ďin progressĒ pictures.  I guess I was too busy concentrating on all the steps. 

The clearances between some of the holes is tight and I was concerned I might get some interference, especially since I didnít hold exactly to the drawings in my work yesterday.  Turns out I have only one minor interference in one of the heads; Itís with one of the valve guides and I believe once I install the guides I can touch-up the hole and everything will be ok.  The interference isnít enough to reach the valve stem.
Iíve included a few photos of the completed heads, sans the holes through to the valve guides which Iíll need to drill after I fabricate and install the guides.
Craig

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Re: building the Frisco Standard Model
« Reply #149 on: February 27, 2019, 11:06:05 PM »
Nicely Done Craig!    Very Unusual heads!  The slot is interesting...

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!