Author Topic: AOG's version of Elmer's number 8 Scotty  (Read 5417 times)

Offline AOG

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AOG's version of Elmer's number 8 Scotty
« on: April 18, 2016, 06:15:10 PM »
It's time for a new engine build. Specifically it's time to build one of Elmer's engines. I have decided to build the Scotty Scotch yoke engine. I consider it one of Elmer's classic engines and I've been meaning to build one for a while. The engine has been in work for a couple of weeks but I've been too lazy to post the build.  It will take a couple of posts to catch up to where I am. Let's get started. I started off with squaring up and face milling a piece of aluminum for the base.



Then the base was marked out and drilled. I also counterbored the mounting holes to take the screw heads.



Next was the frame. I squared up the piece and face milled both sides.



Then the piece was marked out.



Next it was over to the mill where the holes were drilled.



I set up my die filer with a hacksaw blade and cut out the scrap. Then the cuts were cleaned up on the mill.



After rounding over the corner on the die filer I drilled the air passage.

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Along the way I screwed up. This is what happens when you forget to account for the width of you edge finder.



Luckily I caught it before I went to deep. I will plug the holes after I get the bearing mounted and drilled through.

The next step was to drill the mounting holes for the base and the support bracket.



After all the holes were tapped, I ended up with this.

.

That's all I have time to post now. I will continue my catch up later.

Tony

Offline b.lindsey

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #1 on: April 18, 2016, 06:25:30 PM »
Nice to see you get another one underway Tony. The scotch yoke should be a nice addition to the collection too!!

Bill

Offline zeeprogrammer

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #2 on: April 18, 2016, 09:44:48 PM »
Goodie.  :popcorn:
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Offline Tennessee Whiskey

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #3 on: April 18, 2016, 11:34:02 PM »
The way you go after a build,  this one will be running in no time.  I love all of Elmer's engines,  don't think I have seen a build log on this one.  I'm  :popcorn::DrinkPint:, and following along.

Cletus


Offline AOG

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #4 on: April 19, 2016, 02:42:14 PM »
I'm sitting in the doctor's office so it's time for part 2. I'll start off with the cylinder. I squared up a block of aluminum.



Then I drilled and reamed the bore.



Next I flipped the part over and drilled the four mounting holes and the port.



The mounting holes were tapped 2-56.



I used my variable angle block to mill off the corners.



With that the cylinder is complete it's time to make the bearing. This engine uses the same valve setup as the standby. Air goes into the bearing and the shaft has valve flats that direct the air. First the profile was turned.



Next the hole was drilled and reamed



Then it was out of the lathe and into the collet block to drill and counterbore the air passage.



I'll solder a piece of tube to the bearing later. Next part is the crank disk. This piece will be press fit onto the shaft. I always have problems with wobble when I do a pressed crank disk so I turned the part oversized. Then I drilled and reamed the center hole.



Then it was out of the lathe and into a collet block in the mill. I centered up on the shaft with my coaxial indicator.



Then I dialed in the offset and drilled for the crank pin.



Then the disk was parted off and set aside. That's it for now. There is still more to get caught up on so till next time.

Tony




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Offline zeeprogrammer

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #5 on: April 19, 2016, 04:36:38 PM »
Wow, what progress. Looking good.  :ThumbsUp:

I hadn't heard about a variable angle block and looked it up. Neat.
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Offline AOG

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #6 on: April 19, 2016, 05:24:49 PM »
Thanks Zee. It's one of those tools you never knew you needed until you have one. No more hunting for the right combination of angle blocks. No more angle blocks slipping and throwing off the angle. No need to dink around with a sine vise. Just put it in your standard vise, set it and forget it.

Tony

Offline b.lindsey

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #7 on: April 19, 2016, 05:32:12 PM »
Just put it in your standard vise, set it and forget it.

Tony

Hmmmmm....I though that was the Ron Popeil Rotisserie Oven  :lolb:

Bill

Offline Tennessee Whiskey

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #8 on: April 19, 2016, 06:35:04 PM »
I think I have one of those angle blocks that came with a tool makers vice.  I haven't figured out how to use it if the part isn't as wide or wider than it is  :shrug:. Bill, or an employee's alarm clock  :lolb: :lolb:. Dr's office : the only place that takes longer and gets in no bigger hurry than a machine shop  :stir:. I'm following along  :cheers:.

Cletus

Offline AOG

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #9 on: April 19, 2016, 07:51:41 PM »
I haven't figured out how to use it if the part isn't as wide or wider than it is  :shrug:.


If it's wider than the block you clamp on the part. The trick comes in when the part is narrower than the block. That's when I put the part against the fixed jaw of the vise. Then I use an adjustable parallel turned on its side as a spacer between the movable jaw and the part.

Tony

Offline tvoght

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #10 on: April 19, 2016, 08:17:31 PM »

If it's wider than the block you clamp on the part. ...

Tony

One point learned from bad experience: If you're clamping on a part wider than the angle block, you have to make sure the block is parallel to the fixed vise jaw, or things can easily go all askew. You can lay a parallel down between the vise jaw and the angle block and hold the angle block while tightening the vise on the part.

--Tim

Offline AOG

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #11 on: April 20, 2016, 06:43:49 PM »
It's time for part three. To continue with the crankshaft I drilled the exhaust hole into the shaft.



Then the end was turned down for a press fit in the crank disk.



Next it was over to the mill and into a collet block. The intake and exhaust slots were milled into the shaft. Sorry about the picture quality.



Then the shaft was pressed into the disk. Next the assembly was trued up and taken to dimension in the lathe and the crank pin was pressed in.



The next part was the piston. I turned a piece of brass to the bore size. Just prior to reaching the final dimension I cut some oil grooves. The final cut also cleaned up the bur from from the oil groove.



The center of the piston was drilled out, parted off and threaded.



To make the rod I cut a thread on the end of a piece of brass rod and threaded it into the piston.



That gets me caught up with where I am In the build. I will finish with a family shot.



Till next time.

Tony

Offline AOG

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #12 on: April 28, 2016, 03:46:54 PM »
I now have enough progress to do another installment of this build log. The next piece to be made was the support bracket that holds the back end of the piston rod. I started by squaring up a small brass off cut. Then I marked out and drilled the holes. (Sorry about the pic quality)



Then the sides were profiled. Looking back at the image I have to say that wasn't the most secure setup I've ever done but it worked.



To round over the end I made a couple of fileing buttons and went to town.



With the bracket done it was time to start the flywheel.

The part was marked out in the lathe.



Next the flywheel was grooved.



The part was drilled and parted off.



Then the part was flipped around and the other side was grooved.



Next the flywheel was mounted on a mandril and trued up.



Then it was over to the mill to drill and tap for the set screw.



The next part was the yoke. The blank was squared up, drilled for the piston rod, and then the main slot was milled out.



The cross slot was then milled into the piece.



Then the part was taken over to the lathe and dialed into my four jaw chuck. For some reason, this is a task that always kicks my rear end. This case was no exception. I ended up putting off making this part because I was dreading the need for the four jaw. In the end I got it done.



The end of the part was profiled.



Then the hole for the set screw was drilled and tapped.



That completes the parts so I started assembly. First I soldered the intake tube onto the bearing. That was a complete horror show. I used way to much solder and it took me forever to file off the excess and clean up the part.



Next I pressed the bearing into the frame.



That allowed me to finish drilling the air passage.



Then the holes were plugged and and the excess was filed off.



Unfortunately I did the job to well. I ended up plugging the side hole to the cylinder. I had to drill out the plug and clear the hole. I put in a replacement and I am waiting for the sealant to cure. All I have left is to do is file down the plug , blue the flywheel and yoke and then hopefully we'll have a runner.

Tony

Offline AOG

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #13 on: May 02, 2016, 04:23:42 AM »
I got the bluing done and tried to assemble the engine. Unfortunately I have a major interference issue with the yoke.  :hammerbash: :facepalm2:. I need to turn down the thickness of the crank disk. It also looks like I'll have to plug the shaft hole in the yoke and redrill.

Tony

Offline b.lindsey

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Re: AOG's version of Elmer's number 8 Scotty
« Reply #14 on: May 02, 2016, 12:24:03 PM »
That's a bummer Tony...but fortunately shouldn't be a difficult fix. Still looking forward to seeing this one run, it's one of Elmer's I haven't made but very much like. Hang in there, today will be better  ;)

Bill

 

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