Author Topic: "TINY" This time a water cooled side shaft version  (Read 4727 times)

Offline gbritnell

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"TINY" This time a water cooled side shaft version
« on: March 12, 2018, 07:24:27 PM »
Gentlemen,
Having got caught up on the model engine repair work I am doing for a friend I thought it about time to start a new project.

 I had posted a thread awhile back asking for some information on how the governor works on a Domestic side shaft engine and thanks to the responses I resolved those issues.

 As with the other "Tiny" engines this one will use the basic dimensions along with some of the same components. I have the drawings finished for all  the conversion parts and the first order of business was to make the helical gears to drive the side shaft/cam disc. Using my helical gear fixture (thanks Chuck) and the Helical gear spread sheet (thanks Don) I made up the cam bushings to cut the gears. My index plates had one row of holes that I could use for the crank gear but I had to drill another row for the shaft gear. To keep the spacing from the crank to the side shaft at a minimum and still have enough meat on the crank gear I came up with 80 DP gears.

 In my vast collection of gear cutters I haven't used this pitch before so I had to make up a gear cutter. I ground a high speed lathe bit to get the needed radius then cut the tooth profile onto a piece of .375 drill rod. This was hardened and tempered due to the tiny size of the teeth.

 The crank gear is 10 teeth with a helical angle of 60 degrees and the side shaft gear is 20 teeth with a helical angle of 30 degrees. The crank gear is steel and the cam gear is brass.
« Last Edit: March 13, 2018, 10:23:16 AM by gbritnell »
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #1 on: March 12, 2018, 07:28:19 PM »
 Cutting the 30 degree gear wasn't a problem with my setup (using the helical fixture in my mill vise) but to cut the 60 degree gear I had to mount the fixture onto my angle plate so that I had enough clearance to index the spindle.
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Offline Kim

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Re: "TINY" This time a water cooled side shaft version
« Reply #2 on: March 13, 2018, 02:17:19 AM »
Nice work as always, George.  Those are the cutest little helical gears!
I see how you do it, but I don't think I'll fully grock how you make these gears till I have to get in there and do one myself.
Kim

Online crueby

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Re: "TINY" This time a water cooled side shaft version
« Reply #3 on: March 13, 2018, 02:38:58 AM »
Those gears are great! Was there another thread about that fixture? Looks like another very interesting topic.


 :popcorn:

Offline b.lindsey

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Re: "TINY" This time a water cooled side shaft version
« Reply #4 on: March 13, 2018, 11:19:11 AM »
Those look great George!!!  This may be the best "Tiny" yet  :)

Bill

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #5 on: March 13, 2018, 02:47:36 PM »
Hi Chris,
Here's the link to the original design of the helical gear cutting fixture.
http://www.homemodelenginemachinist.com/showthread.php?p=105973&highlight=helical+gear+cutting+fixture#post105973
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #6 on: March 13, 2018, 02:56:37 PM »
Hi Kim,
My previous post covers the whole thread on making and using the helical gear cutting fixture. Somewhere in the archives is a posting by Don Darbonne where he made a spread sheet covering all the facets of the calculations. I believe Marv Klotz also has a program for calculating the gear number.
Basically a fixture is made with a block and spindle to hold the gear blank. At the indexing end is a pair of discs, on fixed to the spindle and the other with the indexing holes. Between the discs and the block is a 1.00"  diameter hub that holds a spiral piece of metal that is formed from flat stock using the calculated numbers for whatever pitch and helix you are going to use. The helical piece of metal rubs against a follower arm with a small ball bearing at the end. As the helical template is rotated against the follower it rotates and advances the spindle thereby cutting a helical path on the gear blank.
gbritnell
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #7 on: March 13, 2018, 03:05:51 PM »
 When I built the first "Tiny" I went strictly by the drawing dimensions and after assembly found that the fuel filler tube was cramped by the connecting rod so I extended the crankcase/block to allow more room for the tube. The second thing I changed was more cosmetic and that was to add draft to the water hopper giving it a little more character. On this engine I added a third feature and that is instead of just having a plain flat top on the water hopper I drilled and tapped the corners for 0-80 screws and then made up a cap to simulate a cast water hopper, here again just cosmetic by kind of neat looking.

 The first series of pictures show the block with all the features machined. On the front bottom corner of the cylinder area I have added a boss for the side shaft bearing block.
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #8 on: March 13, 2018, 03:10:31 PM »
The next set of pics shows the machined cap, the cap sitting on the block and the cap with the screws in place. The flat head screws were made from aluminum and left on the bar they were turned from. They were then screwed in place and hand tightened. I then used a jewelers saw to cut the screws free from the bar.
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #9 on: March 13, 2018, 03:11:52 PM »
This photo shows the screw heads filed flush with the cap.
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #10 on: March 13, 2018, 03:13:42 PM »
This set of pics shows all the corners radiused and everything sanded and polished.
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Offline b.lindsey

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Re: "TINY" This time a water cooled side shaft version
« Reply #11 on: March 13, 2018, 04:38:23 PM »
Except for the hopper it all looks very familiar :). The hopper does add a very nice touch to it though as does the cast on head "look." Your are moving along quickly George.

Bill

Offline PJPickard

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Re: "TINY" This time a water cooled side shaft version
« Reply #12 on: March 14, 2018, 12:43:52 AM »
Following this one! I have "Tiny" on my build list, but I think I'm going to prefer this!

Love the top of the hopper!

Offline Kim

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Re: "TINY" This time a water cooled side shaft version
« Reply #13 on: March 14, 2018, 04:54:00 AM »
Hi Kim,
My previous post covers the whole thread on making and using the helical gear cutting fixture. Somewhere in the archives is a posting by Don Darbonne where he made a spread sheet covering all the facets of the calculations. I believe Marv Klotz also has a program for calculating the gear number.
Basically a fixture is made with a block and spindle to hold the gear blank. At the indexing end is a pair of discs, on fixed to the spindle and the other with the indexing holes. Between the discs and the block is a 1.00"  diameter hub that holds a spiral piece of metal that is formed from flat stock using the calculated numbers for whatever pitch and helix you are going to use. The helical piece of metal rubs against a follower arm with a small ball bearing at the end. As the helical template is rotated against the follower it rotates and advances the spindle thereby cutting a helical path on the gear blank.
gbritnell
Thanks for the excellent summary George.  I do appreciate it.  I believe I 'mostly' follow it, but I'm just going to have to go through it before I fully get my mind around it.  Thank you for your explanation here!

And your engine is looking great!
Kim

Online Dave Otto

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Re: "TINY" This time a water cooled side shaft version
« Reply #14 on: March 14, 2018, 11:20:23 PM »
That's really cool George, a little tiny side shaft!
I'm looking forward to seeing more of this little beauty.

Dave

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #15 on: March 15, 2018, 11:22:56 PM »
Another deviation from the original drawings was to add ball bearings instead of plain bearing. These things don't put out a lot of power so any friction that can be eliminated won't hurt.
The caps were made and bolted in place. The crankcase was then set up in the mill for drilling and boring. I prefer boring when I have to span an open space. Sometimes using a reamer gets the holes out of alignment.
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #16 on: March 15, 2018, 11:26:31 PM »
The bottom half of the crankcase is called out at the fuel tank, which it actually is. A simple job, squaring up a piece of aluminum then cutting the cavity out of the center. The mounting holes are 2-56. I also put two 8-32 holes in the bottom for mounting to whatever base plate is used.
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Offline b.lindsey

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Re: "TINY" This time a water cooled side shaft version
« Reply #17 on: March 15, 2018, 11:38:09 PM »
Things are moving along quickly George. So this is the third Tiny right? The hit and miss, the vertical, and now this one as I recall.

Bill

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #18 on: March 15, 2018, 11:42:05 PM »
The cylinder head on this engine is quite complex with the porting having to be drilled at right angles rather than straight in. Shape wise it could be made much simpler but I wanted it to resemble a casting so that involved a multitude of small cuts. I turned the blank on the lathe then transferred it to the mill. While still part of the original stock I had something to hold onto for the drilling and machining.
When the shapes and head bolt holes were finished the piece was put back in the lathe and parted off, leaving a few thou. for cleanup.
I then made a fixture using the end of a piece of round stock. I drilled and tapped the corresponding head bolt holes then mounted the head using spacers to support it clear of the projection that goes into the cylinder. The part was mounted in my dividing head and the right angle porting was put in. The final step was to tilt the dividing head to 70 degrees to put in the spark plug hole.
Using my CAD drawing I calculated the distance from the centerline of the valve holes to the center line of the spark plug hole. I then made a small plug to go into one of the valve guide hole. This was filed to half the diameter to give me the center of the valve guide hole. I then wiggled the plug to establish my dimension.
At this point with all the machine work finished you just have to trust your numbers, otherwise it's start all over again.
As can be seen from the pictures the spark plug port exited the cylinder boss right where it was supposed to.
Using small burrs, mounted stones and files I radiused all the edges to make it look more like a casting.
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #19 on: March 15, 2018, 11:44:32 PM »
Hi Bill,
Actually this will be 4. I built the original engine then modified it a true hit and miss style. Next was the air cooled version. The third was the vertical water cooled engine and now the water cooled side shaft.
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Offline Art K

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Re: "TINY" This time a water cooled side shaft version
« Reply #20 on: March 16, 2018, 02:44:33 AM »
George,
I have been punching the air cooled Tiny drawings into cad and am planning to make the air cooled version. Thanks for all that you teach us as you build an engine like this.
Art

Offline b.lindsey

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Re: "TINY" This time a water cooled side shaft version
« Reply #21 on: March 16, 2018, 11:00:14 AM »
Ah I missed one. The head for this one is beautiful and does indeed have that casting look!! Amazing as always George.

Bill

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #22 on: March 20, 2018, 10:32:12 PM »
I have a few more parts made so here's the update.
First is the crankshaft. It's made from 1144 stressproof steel although in this size there's probably not going to be much warpage so 12L14 could have been use but it rusts too easily.
The process for making the crank is to turn the stock (.748 dia.) to fit the offset holder I have from the other engines. The blank is mounted in a four jaw chuck and indicated true, then center drilled with a #1.
The blank is rotated, indicated and center drilled. At this time the main journal diameter is taken down to .195 (.007 heavy) The fixture block is then mounted in the four jaw chuck with the crank blank secured with a set screw. Using a 1.00 dial indicator the crank is offset .50. After the offset is done the block is centered in the other direction.
The rod journal is then turned to size.
The fixture is removed from the chuck and the chuck is replaced with the collet holder. The unturned end is stuck out and the other main journal is also taken down to .195.
I have a home-made set true chuck for ER11 collets to use in my 6" Atlas lathe. I can dial the part in to -0- with it. Holding just enough of one end I put the live center in the other end and turn the shaft to .187. The crank is reversed and the other main is finished.
As you can see from the pictures I have the counterweights cut and .062 key slots milled into the shaft.
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #23 on: March 20, 2018, 10:40:37 PM »
My procedure in building an engine is to finish all the big multi-operation parts first and then finish up with the simple small parts so the last big, well you can't really call them big (2.00 diameter) parts are the flywheels. I tried something a little different this time. I turned the hub, spoke area and a little of the outer rim from aluminum. I then turned the outer rim from steel for the weight. I allowed .002 for an interference fit. I then heated the rim with the propane torch and the center hub dropped right in, no muss no fuss. I left each piece a little heavy for cleanup.
The first picture shows the spokes just after milling and the second show the radii on all the spokes.
All that's left to do is to make a keyway broach to cut the internal slot in the flywheels.
gbritnell
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Online Brian Rupnow

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Re: "TINY" This time a water cooled side shaft version
« Reply #24 on: March 20, 2018, 10:58:05 PM »
Ahhh George--You do such beautiful work. You are a true master with a Dremel tool and a number of different stones. I do fairly well on the parts which can be machined and don't require the artistic touch for the final work. However, put any kind of grinder, large or small into my hands, and I can ruin a lovely piece of machining in nothing flat.--Brian

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #25 on: March 21, 2018, 10:56:40 AM »
Thanks Brian,
It's nice to hear from a fellow Canuk.
gbritnell
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Offline toolznthings

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Re: "TINY" This time a water cooled side shaft version
« Reply #26 on: March 21, 2018, 07:14:13 PM »
Hi George,

Amazing work as always !

Brian in Ohio
Thanks for the visit !
Brian

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #27 on: March 22, 2018, 09:57:37 PM »
Although the twisting forces on the flywheels of these tiny engines is minimal and in the other versions I just used a set screw tight against a flat filed on the shaft I thought with this one I would use keys in the crankshaft. I had made a .062 wide cutter for another project so I cut the keys in the crankshaft with it but my .062 broach will only go into a .312 hole so I had to make a broach to cut the flywheels.
I drew it up allowing only .01 clearance between the cutting edge and the back of the broach to make sure it was strong enough. I made if from drill rod then filed clearance on all sides before hardening it. Once hardened I honed each edge with a diamond honing stick.
The hard part was going to be how to make sure 1. that the cutter was square to the axis of the lathe and 2. that the cutter was exactly on center. For the square part I mounted the tool in one of my QCTHolders and set it on my layout plate. Using a square and magnifying glass I got it as close as possible. I then mounted the holder in the tool post and I used a tool that I had made years ago for centering something in my rotary table. I have a piece of aluminum turned with an enlarged diameter on one end. The enlarged area has a flat milled right to center. I put this in my chuck and ran an indicator over it until it was perfectly flat. I then adjusted the broach until the top edge indicated the same as the plug. I then adjusted the tool holder with a dial indicator until it went up .031.
The flywheel was put into the chuck and the lathe was put in back gear and rotated by hand until the cutter was centered on one of the spokes.
I inserted the cutter into the bore of the flywheel and advancing it .002 at a time broached out the key slot.
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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #28 on: March 22, 2018, 10:00:52 PM »
The next step was to make keys for each wheel. Using a piece of round stock in the dividing head I cut the keys leaving a shoulder at the inboard end to facilitate key removal.
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Offline Craig DeShong

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Re: "TINY" This time a water cooled side shaft version
« Reply #29 on: March 22, 2018, 10:10:20 PM »
Hi George.  Nice job  :ThumbsUp: with the helical gears.  Sure hope mine turn out as nice !
Craig

Offline 90LX_Notch

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Re: "TINY" This time a water cooled side shaft version
« Reply #30 on: March 24, 2018, 05:45:19 PM »
George, the head is an amazing piece of work. 

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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #31 on: March 29, 2018, 12:38:52 AM »
With all the 'big parts' done it's time to start on all the really tiny pieces. I wanted to get the side shaft mounted because all the other governor parts associate to it. I made up two trunnions (bearing blocks) for the shaft and when I fitted the gears they went together very nicely. Probably one of the more complex parts is the bracket that holds the rocker arm, the front of the side shaft where the cam is mounted and the lock-out lever. The best way I could see making the parts was to carve it on the end of a brass bar. The holes were drilled first and then the profile was cut. The block then had to be turned to all four sides to produce the little pad for the lock-out lever on the back side.
The part was then cut away from the block and all the corner radii were filed and sanded smooth. As with the full sized engine spacer bushing were needed to put the bracket at the correct height relative to the head surface.
(sorry for the poor pictures, I think the old camera is starting to give up the ghost)
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Offline b.lindsey

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Re: "TINY" This time a water cooled side shaft version
« Reply #32 on: March 29, 2018, 12:52:24 AM »
Coming along beautifully George. As always look forward to your updates.

Bill

Offline Craig DeShong

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Re: "TINY" This time a water cooled side shaft version
« Reply #33 on: March 29, 2018, 02:29:35 PM »
Exquisite work know George, looks great!
Craig

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #34 on: March 30, 2018, 03:07:16 PM »
 The next part, the rocker arm, although it looks simple became quite a project in machining. The first operations was to clamp a piece of round stock between small v-blocks in my mill vise. The part was indicated to center. A depth cut was made to allow material for the thickness of the arm plus a little to eventually cut off with a slitting saw. The X and Y cuts were made leaving a couple of thousands for the step-off profiling cuts. Two holes were drilled, one for the roller location (0-80 thread) and one for the pivot (.062 dia.) Using my Cad layout I stepped off the shapes and the radius on the roller end.
The round stock was then moved to the dividing head and indicated concentric. The flat surface on the arm was indicated horizontal and the dividing head set to -0-. The hole for the valve adjustment screw was put in (0-80 thread). The part was then put back in the mill vise for the next operation. The thickness of the arm is .062 but the boss on the valve adjusting end is .110 diam. To minimize filing I set the slitting saw to make the initial cut to created the .062 thickness. I moved the saw into the stock laterally only deep enough to allow for the boss on the end. The saw was then repositioned (Z) and the part was cut from the parent stock.
The holes were tapped and the step-offs filed and polished.

 The cam disc was next. I turned a piece of stock to the O.D. and put a counterbore into it to allow for the cam hump. The stock was drilled and reamed .062. The stock was then moved to the dividing head and indicated true. Using a .062 end mill I cut the material away from the face down to the bottom of the counterbore creating the cam hump. On my drawing a gave the exhaust a duration of 200 degrees which means that the cam hump would have to be shaped for 100 degrees. As the roller hits the hump it needs to hit it squarely and drop off squarely so the hump took the shape of a tiny triangle. While it was still on the end of the rod I filed a small radius on the edges of the hump and then cut it free in the lathe. The part was then Loctited to the end of the shaft.

 A roller wheel was made and a brass mounting screw.

The pictures show the parts assembled. I apologize for not taking pictures while making the parts but these are so tiny that it's hard to get a good shot while machining.

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Offline cfellows

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Re: "TINY" This time a water cooled side shaft version
« Reply #35 on: March 31, 2018, 05:27:01 PM »
Hey George, great work, as usual.  What is the diametral pitch of those helical gears you made?
So many projects, so little time...

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #36 on: March 31, 2018, 05:52:29 PM »
Hi Chuck.
The D.P. is 80. I first picked a diameter that would fit over the crankshaft (.187) plus about .025 metal wall then developed a pitch diameter and pitch that would fit. I tried to keep the spacing between gears as tight as possible so that they would line up with the exaust valve.
gbritnell
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Offline Hugh Currin

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Re: "TINY" This time a water cooled side shaft version
« Reply #37 on: April 01, 2018, 01:25:32 AM »
George:

Very nice design and build. I'd like to try a Tiny and have the basic plans. Likely not the hit and miss, but one of the versions.

Thanks for the build log. Following along, as I can, quietly.

Hugh
Hugh

Offline NickG

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Re: "TINY" This time a water cooled side shaft version
« Reply #38 on: April 01, 2018, 01:25:19 PM »
I like the look of this George , do you know why manufacturers went towards side shaft engines? Were there a lot of advantages? Guess its like an overhead camshaft really.


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Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #39 on: April 01, 2018, 06:40:55 PM »
All of the tiny pieces are coming together. I have the whole governor parts train made and temporarily assembled. I have put small springs in place but won't know exactly what weights to use until I see how they react while running. The lockout shaft coming from the governor mechanism on the flywheel is .047 diameter stainless steel. This diameter corresponds with mm1.2 so the shaft ends were threaded that size. Up at the head end 2 small nuts were made to adjust the lockout lever. These are .078 across the flats.
Nick, I'm not sure why this particular style of valve operation and governing was use. It's possible that at the time there could have been patent infringements, much like when the crankshaft was patented on steam engines so for a while other forms of connecting the piston rod to the crankshaft were devised.
gbritnell
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Offline b.lindsey

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Re: "TINY" This time a water cooled side shaft version
« Reply #40 on: April 01, 2018, 09:12:03 PM »
Really incredible George. The pictures are great but I can well imagine how small many of those parts really are :o

Bill

Offline Admiral_dk

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Re: "TINY" This time a water cooled side shaft version
« Reply #41 on: April 01, 2018, 10:04:08 PM »
Another beauty from you George  :praise2: .... but I must admit that I don't quite get how the movement of weight on the flywheel is transferred to the linear movement towards the cylinder head ... do the weight function as a wedge ...?... :noidea:

Best wishes

Per

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #42 on: April 02, 2018, 01:56:07 PM »
Hi Per,
Here's how this type of governing system works.
In this picture you see the shaft with the brass weight on it. The shaft is screwed into a turned disc which has a hole reamed through it that fits the crankshaft diameter. In making the disc it is turned on the lathe leaving a step for the brass ring that you see. As I said it is drilled and reamed through on center to fit the crankshaft. While the disc is still on the shaft that it is turned from it is taken out of the lathe and put in the mill and indicated on center. A hole of the same diameter as the through hole is offset and cut through the disc. In this case the hole is .187 diameter. (4.76mm) and is offset .03 (.76mm) This forms a slot in the disc. The hole for the shaft was drilled and tapped in the disc. The disc was then cut off in the lathe. So now you have a disc that when slid over the crankshaft can move radially .03 from center. The weight and spring return it to center.
Now over top of the shoulder that is turned on the disc you have a brass ring, much like the eccentric strap on a steam engine. When the disc offsets it allows the governor rod to move .03. At this point you're saying "yes, but it oscillates .03 in both directions so it would move the lockout lever back and forth." The answer is yes it does but the governor rod doesn't have a fixed connection to the lock-out lever but rather slides through the hole.
In the second picture you see the governor rod going through the lock-out lever and has two adjusting nuts to set the position of the lock-out lever.  The lock-out lever is spring loaded so it will return to the unlocked position.
As the engine spins the eccentric disc offsets which moves the governor rod forward and thus moves the lock-out lever into position to hold the exhaust valve open. Now as the flywheel rotates 180 degrees the eccentric pulls the governor rod back .03 but being as it's free to slide through the hole in the lockout lever the lever stays in place being held by the tension of the valve spring against the rocker arm.
When the engine slow down the eccentric disc moved back to center so there is clearance between the adjusting nuts and the lock-out lever. Now as the cam moves the rocker arm it frees the lock-out lever and the return spring pulls the lock-out lever back to the unlocked position.
I hope this makes sense? I had to study it when I was building it because I like you had no idea how it worked.
gbritnell
Talent unshared is talent wasted.

Offline Admiral_dk

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Re: "TINY" This time a water cooled side shaft version
« Reply #43 on: April 02, 2018, 10:41:28 PM »
Thank you very much for explaining the function. I got the part of cylinder head before I asked about the rest - it was the offset of the disk that I hadn't realized, as I thought that it "squeezed" the ring and that didn't make any sense ...  :noidea: ....
But that it oscillates the rod to the head forth and back in the active mode makes sense too now that I got the rest + that this haven't got any influence when it moves away on half the cycle.

I like this, even though it is a brain twister (or maybe just because it is :stir: ).

Offline gbritnell

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Re: "TINY" This time a water cooled side shaft version
« Reply #44 on: April 09, 2018, 07:34:54 PM »
 As with most original design projects there's things along the way that need correcting or modifying. Such was the case with the rocker arm. I always have one drawing that's kind of an assembly sheet. I use this to compare parts while building. When I developed the rocker arm I used two views, the front and top. Well in the top view for some reason I didn't have the valve layer turned on so I just went on my merry way of creating the rocker arm. As I was assembling the parts the other day I realized that the valve length/rocker arm shape collided. Hmmm, back to the layout. I couldn't make the existing rocker arm work as I would have had to shorten the valve stem way too much so I redrew the rocker arm and with the combination of the two was able to get back on track. This was my repair drawing. I then changed the main drawing to a completely set of new dimensions to allow the valve stem to be almost as long as the original.

 I now have all the governor bits made and fitted. I mounted the flywheel and governor eccentric on a dummy shaft and spin it in the lathe, adjusting spring weights until the eccentric moved at about 1200 rpm. I figured this would be a good starting point as these little engines like to run fast no matter what.

 The first 4 pictures show everything assembled. The spring is .008 diameter wired wound on a .04 diameter mandrel. What a son-of-a-gun trying to put the eyes on the ends of the spring.
The 5th picture shows the lock-out lever in position holding the rocker arm in the valve open position.
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Offline b.lindsey

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Re: "TINY" This time a water cooled side shaft version
« Reply #45 on: April 09, 2018, 07:51:03 PM »
The whole head and governor/valve assembly is just phenomenal in this small scale George. So looking forward to seeing this one running. As usual, the pictures are great as well in showing the various details.

Bill

Offline Craig DeShong

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Re: "TINY" This time a water cooled side shaft version
« Reply #46 on: April 20, 2018, 01:27:49 AM »
Bill says it all George, just phenomenal work !
Craig