Author Topic: AOG's version of Elmer's No 50 "The Educational"  (Read 5605 times)

Offline AOG

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AOG's version of Elmer's No 50 "The Educational"
« on: December 17, 2016, 08:47:55 AM »
I'm still working on finishing my PM-3A but while I'm in between coats I figured I would get started on my next project before the the painting drove me crazy. I'm going to make Elmer's number 50 "the educational". This is one of those engines you don't see much of on the internet. It's a cam operated long stroke single cylinder engine based on riverboat practice.



This will be the largest engine I have ever built. Right off the bat I made some changes. Elmer calls out using a plank of the brown stuff for the base. I really don't do the brown stuff so I'm making the base from 3/4 inch aluminum. I squared up the block and then unused my new shell mill to flatten the top.



Next I was going to run a ball end mill around the outside but I promptly screwed it up. Without thinking I moved the mill over half the width of the mill instead of running it along the edge. That left me with this.



With full engagement my speeds and feed were all wrong. The mill wandered all over the place. I decided to take a regular end mill around the outside to make it more or a step. Then I ran the shell mill back over the surface to clean it up.



It will take a lot of filing to clean up but I think it will look ok. With that done I flipped the part over and drilled the mounting holes for the uprights.



There are some two vertical supports that hold the frames. I made another change to Elmer's design by increasing the length of the parts so the the flywheel will clear the base without having to cut a groove in the base. Both uprights are made the same way (with different dimensions). After squaring up the stock I drilled the mounting hole in the bottom.



Next the holes were drilled to mount the rails.



Then the recesses for the rails were milled out.



Then over to the tapping tool to tap all the holes.



That leaves us with this.



Till next time.

Tony


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Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #1 on: December 18, 2016, 01:51:14 AM »
Here is a short update. The next parts to be worked on were the side frames for the engine. These parts were much bigger then I'm used to so I had to get a little creative on the work holding. I stacked the to frames into the vice and squared them up. Then I drilled all of the common holes.



Then I carefully removed the lower frame (which is the back frame) and drilled all of the ancillary holes for the front frame.



With that done I assembled the frame.



Till next time.

Tony


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Online b.lindsey

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #2 on: December 18, 2016, 01:18:54 AM »
Nice start Tony. I don't recall ever seeing a build log on this one as it's not one of Elmer's more popular ones as you noted. But its a nice engine!!

Bill

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #3 on: December 18, 2016, 03:29:17 AM »
Thanks Bill, I suspect the reason this isn't more popular is a combination of the size and the the weird shaped cam that I'm not looking forward to.

Tony

Offline philjoe5

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #4 on: December 18, 2016, 06:10:36 PM »
Nice work Tony.  I haven't actually seen this one so I'll be following along.   :popcorn:

Cheers,
Phil
If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man.  - Mark Twain

Offline Mike Bondarczuk

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #5 on: December 19, 2016, 12:11:15 PM »
Hi Tony,

I have been purchasing all the required stock to make this engine and am just about there now, and as previously mentioned, this is not one of Elmer's more popular builds but to me looks very attractive and should be a nice slow runner.

Julius has very recently published a complete set of Elmer's drawings, in metric and scaled up and for this engine he has scaled up 2X but I will be building it in the original size as my stock material was sized for that.

Will be following your build log with interest and hopefully taking lots of pics of my own build and may well publish a log as well, though that is still uncertain.

Looking forward to watching your build, especially of the cam part  :happyreader:.

Mike
"Everything I can't find is in a totally secure place"

Offline Alan Haisley

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #6 on: December 21, 2016, 11:11:51 AM »
I have been looking forward to someone building this one. I always assumed that the funny cam mechanism was meant to simulate steam expansion while using compressed air, but rereading Elmer's introduction it sounds like it has more to do with keeping steam on a very long stroke. Hopefully, someone here can discuss paddle wheel engines a bit and explain this general design.  :headscratch:

Alan
Near Raleigh, NC, USA

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #7 on: December 27, 2016, 11:14:37 PM »
The next parts to be worked on were the valve block and the cylinder. Both parts are made from the same parent stock and are the same dimensions. I squared up both sets of blanks together and then started the valve block. I drilled and reamed valve hole.



Then the mounting holes and transfer ports were drilled.



Then I flipped it over and drilled and tapped the intake.



With the valve block completed I started the cylinder. This part fought me from beginning to end. After setting the blank up in the four jaw I drilled a starter hole in the bore big enough for my boring bar. That's when I hit problem number one. The drill wandered. I bored the hole straight and brought it up to reaming size.



I pretty sure I got it straightened out but we'll find out later. The hole was reamed and lapped.



Then the cylinder was taken over to the mill where I drilled the mounting holes and the transfer ports. I ended up screwing up two of the mounting holes. I drilled the first hole clearance size Instead of tapping size. Then I drilled the last hole in the wrong position. I had to plug the mistakes and redrill.



Then the ends were drilled for the end caps.



Next it was over to the tapping stand where I broke a 2-56 tap in one end. I drilled out the tap and plugged the hole. When the locktite set I milled the plug flat, redrilled and tapped the hole.

Here is the final family shot.



Hopefully This next session will go better than the last one.

Tony


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Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #8 on: January 02, 2017, 01:11:14 AM »
Here is the next update. The next parts to be worked were the cylinder covers. I started by milling some brass 3/4 square bar to 5/8 x 3/4. The bar was set up in the four jaw and the locating boss turned for the front cover.



Then it was parted off cleaned up and put aside. Next I turned the piston rod boss on the other cover.



After it was parted off, it was placed in the collet chuck. Then the back face was cleaned up and the locating boss was turned.



Following that, the hole for the piston rod was drilled and reamed.



Both covers were taken to the mill and the mounting holes were drilled.



Next up was the piston. I am planning to use an o ring so I turned the piston 4 thousand undersized.



I am using 00X series rings so they are 1/16 in diameter. That is the same size as my grooving tool so it made it easy to cut the ring groove.



Then the end of the piston was drilled, tapped and parted off.



Next I turned and threaded the piston rod from some brass stock.



The piston was mounted on the piston rod and the end was cleaned up.



Next up was the connecting rod. The blank was squared up and the part laid out. The holes were then drilled and reamed.



The profile was then cut by milling to the lines.



After rounding over the ends, I turned up the required bushings.



Next up is the piston valve. The part was built up by bonding the valve spools onto a 3/32 brass rod.



Then the end was threaded to fit the crosshead.



Next the flats were milled into the valve assembly.



To finish the part, I cut a screwdriver slot in the end.



The last thing I did was to make some studs and test mount the cylinder and valve block.



Till next time

Tony



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Offline Mike Bondarczuk

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #9 on: January 04, 2017, 12:15:28 PM »
Hi Tony,

Following along and noting your excellent progress  :happyreader:and hoping to start my own build within the next week or so.

Mike
"Everything I can't find is in a totally secure place"

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #10 on: January 04, 2017, 02:09:01 PM »
Thanks Mike. This is easily the largest engine I've made to date. That's made for some interesting work holding challenges in areas I didn't expect. Other than the size, it's been Elmer's standard practices so far. If you've done one of his more advanced engines you shouldn't have any issues with the majority of the build. The only thing I'm not looking forward to is the cam. We'll see how that goes when I get there.

Tony

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #11 on: January 05, 2017, 09:16:42 PM »
I made some more progress this week. The first part I made is the support shelf for the crosshead guide. I squared up the blank and milled the required cut out.



Then the part was tilted vertically and I used a long end mill to square up the bottom and clean up the sides of the cut.



Next the mounting holes were drilled and tapped.



With that done, I started on the crosshead guides. I took two pieces of tool steel and superglued them together. The combined parts were squared up and milled to dimension.



The mounting holes were drilled and the parts separated using my mini torch.



I made the four spacers by drilling some brass rod and parting them to length.



The last piece made was the crosshead itself. After squaring up the blank, I drilled and tapped the hole for the piston rod.



Then the part was flipped and the hole for the connecting rod pin was drilled. Next I milled out a slot in the side. The part was reversed and the other slot drilled.



The part was then turned and the connecting rod slot was cut.



I installed the crosshead assembly and filed the components to correct some binding issues.



That's it for this update.

Tony




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Offline Mike Bondarczuk

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #12 on: January 10, 2017, 06:12:34 PM »
Hi Tony,

Watching your build and have started my own but will not hijack this log.

I am building the imperial version as designed by Elmer with the exception that I have changed the fixings sizes to metric as the UNC and UNF versions are proving hard to find as nuts and bolts.

I do have a question in that I have made the frames and stands and also the valve block and looking at the drawings I cannot find the exhaust port for the cylinder  :happyreader:.

Is something missing from the drawings and have you any ideas of the exhaust cycle  :help:.

Many thanks,

Mike
"Everything I can't find is in a totally secure place"

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #13 on: January 10, 2017, 05:50:55 PM »
What happens is that when the piston valve is at the end of it's stroke the other end passes over the transfer port. This allows it to vent directly to the valve bore and out of the ends.

Tony

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #14 on: January 20, 2017, 05:13:04 AM »
Ok it looks like I only lost two major posts covering the cam guide, follower and camshaft. Let's see what we can do to recreate those from my picture archive. First up was the cam frame. After squaring up a blank I turned the boss that fits in the frame.



Then it was drilled and reamed to take the cam shaft.



The mounting holes where drilled and tapped.



Next the recess for the cam follower was milled out.



Then I milled out the guide recesses.



Finally I made the retainers and drilled and tapped the mounting holes for them.



The next part is the cam follower. The verticals were drilled for a locating recess and the ends were drill to take the studs. On side tap drilled and tapped and the other side clearance drilled.



Then the parts were milled to the correct width.



A locating spigot was then turned onto the end of the guide bars.



Then the frames were Locktited together and the screws Locktited in.



On side was drilled and tapped to take the valve rod.



Here is a picture of the cam guide and frame fitted.



That recreated the first missing post. I don't have the pics for the camshaft on this iPad. I think I have a copy still on the camera so I'll make another post when I get them downloaded.

Tony


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