Author Topic: AOG's version of Elmer's No 50 "The Educational"  (Read 8167 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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Offline 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
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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
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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

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
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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
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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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Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #15 on: January 20, 2017, 03:06:30 PM »
I have recovered some more pictures from my camera. The next part to be made was the camshaft drive rod. I turned down a piece of square stock to dimension.



Then it was over to the mill where I drilled a hole and Locktited the drive pin into the hole.



The cam shaft itself was built up. I started with the driven end and drilled and Locktited in the shaft.



After the Locktite had cured I cross drilled the driven end to take the drive rod.



I was going to do the cam next but I was missing the required material so I moved onto the crankshaft. I started by marking out and drilling the blank.



Then the angles were milled on both sides.



Then it was over to the rotary table where the ends were rounded over.



Next the crank was drilled and tapped for. A setscrew.



The crank pin was pressed in and match drilled to the existing collar.



With that done I made the required crankshaft bearings but I couldn't find any pictures of that process. After that, I tried to see I could clean up the flywheel casting on my mill and made a complete hash of the job. I had made the necessary repairs and was waiting for material for my cam and a new flywheel casting. With that I think I'm caught up to where I was before the outage.

Tony


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Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #16 on: January 21, 2017, 10:55:52 PM »
Here it is. The post that people have been waiting for (or so I'd like to imagine) it's time to make the cam. If ever there was a part on Elmer's engines that could use some CNC love it's this one... but since I don't do CNC I had to bust out my inner Chris from clickspring for this one. The first thing to be made was the template. Elmer recommends some 1/16 brass for the template but I didn't have any big enough for the job so I squared up a chunk of aluminum to make it from. I made three attempts to lay out the template per Elmer's instructions but I never could get it right. That's when I remembered something I had seen on clickspring. I drew up the part in fusion360 and printed out full size. Then I glued the blank onto the paper. When the glue was dried I cut away the excess paper and moved it to the mill. I picked up the center point of the hole and drilled it out.



I don't have a scroll saw so I used my jeweler's saw to cut away most of the waste stock.



I used the belt sander to get closer to the lines and then I finished by filing.. and more filing and (you get the picture) the end result was this template.



Next up was to make the cam itself. I made what turned out to be a fortuitous mistake. Elmer tells you to make the part from 1.5 inches of 3/4 diameter stock. I went dyslexic and ordered 1.5 inch diameter stock instead of 3/4. This turned out to be a good thing. Elmer wants you to offset the 3/4 stock in the four jaw before you turn the boss. With the larger stock I had enough room to make the part with the stock centered in the three jaw. I don't know about anyone else but if I can avoid the hassles of a four jaw I will. First I turned the part to the larger diameter.



Then I turned down the boss until I got a good fit on the template.



Then the center hole was drilled and reamed.



The part was moved to the mill while still attached to the parent stock. Then the outline of the template was traced onto the stock. Next I milled away most of the excess stock.



The part was returned to the lathe and parted off. Then it was flipped and the back face cleaned up.



Next the shape was cleaned up on the belt sander and finished out by filing. After that the hole for the grub screw was drilled and tapped.



That leaves us with the final cam.



That leaves just the flywheel left. Till next time.

Tony



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Offline b.lindsey

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #17 on: January 22, 2017, 12:43:37 AM »
Great Tony and not as bad as you had imagined I am betting. As to the 4 jaw chuck, it can be your friend in many situations, don't be afraid to give it a try and I think you will find it very useful.

Bill

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #18 on: January 22, 2017, 12:59:46 AM »
Thanks Bill, my hand work and my soldering are the two biggest things I need to work on in this hobby. This build sure gave the former a workout. As to the four jaw, I used to despise using it (and my face plate) because they took so long to set up. My set up skills have improved dramatically to the point that dialing in a four jaw is nearly as fast as a scroll chuck but I still don't enjoy the process. If I can avoid it I will.

Tony

Offline Flyboy Jim

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #19 on: January 22, 2017, 02:54:49 AM »
The cam looks good Tony.

I concur with Bill about a 4 jaw chuck. It's really useful and is easy set up since I made a fixture to mount a dedicated dial indicator on the back part of the cross slide of my lathe.

Jim

PS: I'm still on the same page as you when it comes to soldering. I just need to take the time to develop the skill.
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Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #20 on: January 24, 2017, 03:44:01 PM »
Time to finish out the machining on this project. There is one part left, the flywheel. After my last debacle I decided to do this one on the lathe. Useing my three jaw and a bump tool to get it running relatively true, I cleaned up the center boss on both sides of the casting.



Then the center was drilled and reamed.



Next it was time to clean up the rim. I initially tried to do it with the three jaw and then I tried turning it on a mandril. In both cases I got awful ringing and abysmal surface finish. In the end I had to break out my faceplate in order to get enough rigidity to get a decent surface finish. Since the center hole was reamed out the part wasn't to bad to get dialed in using the live center.



With that completed I took the flywheel to the mill and drilled for a setscrew.



Here is the final family shot.



Time to polish, paint and fit it together. Hopefully next time you see it will be running in the showcase.

Tony


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Offline Don1966

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #21 on: January 24, 2017, 05:11:24 PM »
Nice work Tony and some great photos. Still with you....... :ThumbsUp:

Don

Offline Mike Bondarczuk

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #22 on: January 24, 2017, 05:35:16 PM »
Tony,

Very nice family shot and looking forward to seeing it finally painted and assembled and then the video of the running engine.

Great pictures and detailed write-up and I just have the crank, cam and flywheel to make and will be ready to assemble and tune mine for a video so a couple of weeks behind perhaps.

What colour are you thinking off and my inclination for mine is to go with a red colour as near to the Dykem red as possible for the aluminium and steel parts and the brass will be left as brass.

Mike
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Offline mklotz

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #23 on: January 24, 2017, 06:03:15 PM »
That's a big flywheel to be secured with only a setscrew.  I know the engine is low speed but, with a slightly jerky start, you run the risk of the crankshaft turning inside the flywheel.  If that happens you'll have a tough time getting the flywheel off the scarred crankshaft.

At least put a flat on the crankshaft for the setscrew to bear; I notice the plans don't call for one.
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Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #24 on: January 24, 2017, 06:17:43 PM »
Marv, I normally file a flat on my crankshafts but I don't do it until assembly. I will put the flywheel where I want it and then crank down on the setscrew. Then I pull the flywheel off and file a flat where the dimple is. Mike, since I used a flywheel casting I plan on painting it red. I will then lightly polish the aluminum and brass. Then I'll Nitre blue the steel parts.

Tony

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #25 on: January 28, 2017, 08:21:43 PM »
Today is one of those days. I've painted the flywheel and polished all of the aluminum. I was into that final fit and fettle stage. I went to mount the flywheel and it's .050 to big.  :cussing: :Mad: :cussing: :cussing:. I am going to have to turn it down to fit the frame. I should have checked before I painted the thing  :hammerbash: . So much for finishing this weekend.

Tony

Offline b.lindsey

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #26 on: January 28, 2017, 09:06:05 PM »
Tony, you could always shim under the pedestals, or cut a recess in the base for flywheel clearance. Just a couple of options to consider.

Bill

Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #27 on: January 28, 2017, 09:17:08 PM »
I experimented with shiming but I didn't like the look. Elmer's original design had a recess in the base. It bothered my sense of symatry so I raised the pedestals instead. When I switched to a cast flywheel I forgot to annotate the dimension change on the flywheel diameter. In any case I already turned the flywheel and primed it. Hopefully I can get color on it before it gets dark.

Tony

Offline zeeprogrammer

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #28 on: January 28, 2017, 11:05:56 PM »
Looking forward to seeing the cam work! Details please.  :stickpoke:
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Offline Mike Bondarczuk

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #29 on: February 01, 2017, 12:40:27 PM »
Zee,

I found that the cam work was actually relatively easy, and hope that Tony agrees, as I used his idea of an oversize stock piece which meant that I could work with a three jaw initially and then switch to my 5C collets for holding and not have to worry about offsets.

I firstly turned down my stock to a 13/16" diameter for the 3/8" thickness and then sliced of just oversize at a few thou to leave room for clean up.

Placed the complete piece into a 13/16" 5C collet and turned down the non-cam side to 5/16" and then changed it over to a 5/16" 5C collet so that I could work on the cam face.

Painted with face with Dykem and then spotted the centre. Removed the work and placed it into a 5/16" ER32 collet in a square holder and with a compass marked out the 13/32" radius arc and then where it intersected the edge of the work marked out the two 5/8" radius arcs and finally the 7/32" radius bottom arc which gave me all of the lay lines for the cam.

Back to the lathe and drilled and reamed for the 1/8" centre hole and then off to the file for shaping, still using the ER32 square block holder to rigidly but safely hold the piece.

I am pretty sure that this was the same procedure which Tony used and I can say that it was not difficult at all, and when I post the final video I will show the cam in detail.

Just waiting for the stock for the flywheel and I am changing it to be 1/2" thick with 1/8" rebates each side though still 6" diameter, and Marvin has forwarded me the rotary table co-ordinates and that will be the subject of a separate build log on here hopefully next week.

Mike
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Offline AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #30 on: February 01, 2017, 02:23:44 PM »
Here is a quick update. I got the flywheel turned and painted but I still couldn't put a piece of paper between the flywheel and the base. I ended up making some brass spacers per Bill's suggestion.



I was in the process of setting my throws when the cam frame broke. It turns out the the Locktite wasn't strong enough to take the loads. I went back and silver soldered the frame and after some clean up it appears to be working. To answer zee's question the cam set up so that it holds the valve open for the full length of the stroke. Now for the real question. Anyone have any ideas on how to set the valve timing? Elmer's "adjust cam until the engine runs well" wasn't particularly useful. Because of the shape of the cam, I don't think I can advance the timing 90 degrees like I would for an eccentric.

Tony


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« Last Edit: February 01, 2017, 03:46:06 PM by AOG »

Offline b.lindsey

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #31 on: February 01, 2017, 02:59:03 PM »
The spacers look fine Tony and the contrast of the brass and aluminum add just another focal point as well. This is going to be a large engine based on that last picture. Sorry I can't help with the timing question, but will have a look at the plans and see if anything springs to mind. That flywheel should have plenty of clearance now though.

Bill

Offline Mike Bondarczuk

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #32 on: February 01, 2017, 03:35:35 PM »
Hi Tony,

When I cam to make the cam frames I decided to mill them from a solid piece of brass which resulted in a matched pair of frames with no gluing or brazing to make things go out of shape, and the wastage was quite small, but the end result worth it.

I also had questions about the cam timing as the copies of the drawings I had are very blurred and impossible to make out the comments so Jo, who is on this site as well, was good enough to forward me a photo version of the relevant page and I am assuming that the engine runs anti-clockwise when viewed from the side with the cylinder nearest the viewer.

1: with the con rod fully forwards, meaning piston at the top of the stroke, the widest part of the cam should be up pointing at 12 o'clock and should also be centred in the frames.

2: with the con rid fully backwards, meaning piston at the bottom of the stoke, the narrowest part of the cam should be pointing upwards at 12 o'clock and should also be centred in the frames.

3: when the cam drive rod knuckle is going towards fully up the cam should be turning anti-clockwise and pulling the frame back towards the flywheel.

4: when the cam drive rod knuckle is going towards fully down the cam should be turning anti-clockwise and pushing the frame forwards away from the flywheel.

If anyone else has built this engine and had it running perhaps they could comment on my interpretation of the cam timing so that we can at least try to get these two engines to run.

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 #33 on: February 02, 2017, 10:27:19 PM »
Thanks Mike that's what I needed. She's a runner.  :whoohoo: :pinkelephant: pics and a video in the showcase at the following location:

http://www.modelenginemaker.com/index.php/topic,6851.msg140616/topicseen.html#new

Tony
« Last Edit: February 02, 2017, 10:41:38 PM by AOG »

 

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