Author Topic: "TINY" This time a water cooled side shaft version  (Read 6440 times)

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.
Talent unshared is talent wasted.

Online 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
"The beautiful thing about learning is that no one can take it away from you" B.B. King

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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Offline 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
Talent unshared is talent wasted.

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.
Talent unshared is talent wasted.

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.
Talent unshared is talent wasted.

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