Author Topic: Elmer's # 13 2X Larger than original ......  (Read 5815 times)

Online toolznthings

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Elmer's # 13 2X Larger than original ......
« on: January 25, 2018, 05:06:26 PM »
Hello All !

Just finished my build of Elmer's #13 Vertical Poppet Engine, double size. Thanks to Julius and his drawings I used his assembly views and modeled
the cams similar to his metric version. I used the original English dimensioned drawings and doubled the sizes. I also made different versions of the connecting
rods and other modifications that I will point out as I post the build progress.

My friend and fellow forum member Yogi also found out what turned out to be a design flaw, at least in the double size of this engine. This proved to be true at the
end of the build when trying to run the engine. That's when he told me, he's still my friend ! :stickpoke: Since there is only a intake valve and no way to release compression on the piston up stoke the engine locks up and will not move until the trapped air bleeds off then locks up again. We came up with a couple of solutions that I will show later. There is a YouTube video of a regular size engine running so this may only apply to the double size. Looser tolerances on the pistons and cylinders or their volume may be the difference.

The engine has 1.750" diameter pistons with a 1.750" stroke. My crankshaft is about 11" overall long. Engine width 5 1/2" x 6 3/4" long x 10" high.

I'll start with the crank build on my next post. A whole story by itself.  ::)

Online b.lindsey

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Re: Elmer's # 13 2X Larger than original ......
« Reply #1 on: January 25, 2018, 06:04:52 PM »
Will be looking forward to it!  Just looked up the original plans...yours at 2X scale will be a sizable model given the dimensions you stated.

Bill

Online toolznthings

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Re: Elmer's # 13 2X Larger than original ......
« Reply #2 on: January 27, 2018, 03:08:41 PM »
Building the crankshaft .......

I started by making the steel blanks for the throws to size and square on the mill and surface grinder. The center throw was made in a rectangle .875" thick x 2.750" high
and 1.594" wide. End throws are .625" thick .875" wide x 1.875" long.

With a mill stop in place and the hole location established on the center throw I spot drilled, rough drilled and used a under size end mill to flat bottom the bores. I decided to use blind holes in the throw rather than through bores as shown in the original plans. Flipping the part against the stop for each hole.

Using ground .500" diameter 12L14 round stock for the journals the bores were sized to allow a bare slip fit with no " wobble " to the mating part.

Similar operations were made to the end throws. These bores are through the part.

The center throw profile was next. A layout was made and the excess stock was band sawed from the blank. Set up on a sine bar to mill the remaining stock within a few thousands of the the layout line. At the surface grinder the final size and finish was completed.

Another setup was made at the grinder to add the 45 degree chamfers where needed on the throws.

Some finish bench work and the journals cut to length the parts were ready for assembly. A " U " shaped spacer was made to establish the distance between the throws where the connecting rods fit. A slight groove was file in the bores to allow air to escape when using Loctite. All parts were primed with Loctite primer and the crank was assembled in stages. The final assembly was done on a small granite plate to insure everything was in alignment.

The end results were excellent with the crank running true.  :)  All done, well not quite ! Later on in the build the joints slipped and threw the crank all out of alignment.  :facepalm:

After two separate attempts and some time later I finally was able to save the crank without starting all over. Might have been easier !
The " new " crank shown later in the build has .562" output ends made from W1 drill rod due to resizing the end bores during the fix and I thought would be a little stronger, too.

Online toolznthings

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Re: Elmer's # 13 2X Larger than original ......
« Reply #3 on: January 27, 2018, 03:10:49 PM »
More crank build pictures .......

Online toolznthings

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Re: Elmer's # 13 2X Larger than original ......
« Reply #4 on: January 27, 2018, 03:12:58 PM »
Some more pictures ............

Online toolznthings

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Re: Elmer's # 13 2X Larger than original ......
« Reply #5 on: January 27, 2018, 03:13:42 PM »
The last ones ............

Offline Dave Otto

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Re: Elmer's # 13 2X Larger than original ......
« Reply #6 on: January 27, 2018, 03:38:01 PM »
Lots of nice work there! I like seeing the use of the sine bar and tall jaws.

Dave

Online b.lindsey

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Re: Elmer's # 13 2X Larger than original ......
« Reply #7 on: January 27, 2018, 05:04:35 PM »
What caused the joints to slip? Was the Loctite now fully set yet or other reasons?

Bill

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Re: Elmer's # 13 2X Larger than original ......
« Reply #8 on: January 28, 2018, 01:04:30 AM »
Hi Bill,

Not totally sure what happened. I applied some air to the engine to see if I could get some idea about movement when it happened. Maybe to much force at the wrong position of the crank or my Loctite was to old. Did not move it much, but a little was the end of the alignment. Difficult working backwards to fix.

Offline yogi

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Re: Elmer's # 13 2X Larger than original ......
« Reply #9 on: January 28, 2018, 07:20:56 PM »
I'm glad we are still friends Brian!  :stickpoke:  :Argue:  :hammerbash:  :lolb:

Great write up, with lots of pictures. I'm looking forward to the build.

Yogi


Offline Plani

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Re: Elmer's # 13 2X Larger than original ......
« Reply #10 on: January 28, 2018, 07:55:24 PM »
Nice work on the crankshaft! Too bad it didn't hold up...

From what I've seen, this engine is a uniflow steam engine. These have some compression by nature. One way to deal with that is to make some dead volume in the cylinder. I'm curious to see what you did and looking forward for the next post.
Keep the pictures coming  :popcorn:

Plani

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Re: Elmer's # 13 2X Larger than original ......
« Reply #11 on: January 29, 2018, 01:54:13 AM »
I'm glad we are still friends Brian!  :stickpoke:  :Argue:  :hammerbash:  :lolb:

Great write up, with lots of pictures. I'm looking forward to the build.

Yogi

Thanks ! Just barely  :lolb:

Online toolznthings

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Re: Elmer's # 13 2X Larger than original ......
« Reply #12 on: January 29, 2018, 01:56:52 AM »
Nice work on the crankshaft! Too bad it didn't hold up...

From what I've seen, this engine is a uniflow steam engine. These have some compression by nature. One way to deal with that is to make some dead volume in the cylinder. I'm curious to see what you did and looking forward for the next post.
Keep the pictures coming  :popcorn:

Plani

Thanks ! The reworked crank actually came out better. Became a career project !  :)

Online toolznthings

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Re: Elmer's # 13 2X Larger than original ......
« Reply #13 on: February 01, 2018, 07:52:25 PM »
Making the base plate for the engine from a piece of mild steel stock I had left from another job. Milled the outside dimensions to size. The plate is about 5/8" thick  and the overall size is 6" x 8". Used a corner rounding end mill to put a 1/4" radius on all the corners. The plate had a blanchard ground surface and was not quite flat so a quick grind of one face was done for flatness and it removed the rough finish. This part will be painted before final assembly.

Four 1/4-28 tapped holes was the last operation. These holes are for the engines " feet ".

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Re: Elmer's # 13 2X Larger than original ......
« Reply #14 on: February 03, 2018, 11:30:07 PM »
Machining the engine feet and bearing blocks for the crank ......

These parts are made from cast aluminum jig plate.

Doing the bearing blocks first and in pairs the width is finished to size of 2.500" and the overall height left long for later operations. The material is .750" thick.
The steps for the mounting holes were mill next with a final width of 1.500" centered on the blank.

The engine feet were done in pairs also and measure .750" thick x 1.500" high x 5.500" long.
The steps for mounting were done to a final width of 4.000" and centered.

Next operations will be drilling, tapping and boring.