Bob Shores Eagle Hit/Miss Engine Build Thread

Day 9: 10 A BIG Steps backwards...

So, today started where yesterday ended, needing to put the frame on its side to drill the bearing and camshaft holes! So first, I pulled my vise and stoned it. This is the first time stoning it, so I was pretty surprised to see how much this old table has for nicks :)
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The mail also came with the die for 1/4-28, so I threaded the end of the crankshaft on both ends. Quick and easy :)
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It took a bit to dial in and indicate (plus setting it up backwards once!) but I was able to get it flat and straight, then flat and straight again!
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I realized it was backwards, and flipped it and reindicated :) Not much needed to be moved:
IMG_20200428_144619.jpg

I indicated off the bolts to find the 'center', and then calculated the offset from for the center of the bearings. I also used the indicator to find the 'flat' to get my Y zero.
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It is at this point that I noticed something 'off'. The bearing caps are on the wrong way. The short leg is supposed to go to the back! At the point, I probably could have reversed them back and been alright (and just shortened the rod to make up for it) however the rear 'overhang' was all wrong. I decided that I didn't like the look of it, and figured I could just shorten the rod a bunch more and be fine. SO, I continued on. First, I center drilled the top.

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Then I drilled up to 1/2" through and center-drilled the bottom:
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After that, the boring part! I started working on it with about 300 thou to take out, which was going to take a while. I slowly increased the cut by ~20 thou at a time and just kept going. However, here is where I noticed the problem (and you barely can as well!). That spot on the far face at the joint between the bearing cap and the casting is the threaded hole for the camshaft retaining screw. I had based the camshaft location off of the cylinder-side bolt rather than off the center line, so it is too close! Additionally, with this flipped around it just so happens that the setscrew hole would be 1/2 overlapped with the bearing cap bolt.

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At the point, I decided enough was enough. I kind of hated everything about this frame casting. It has been a monster to try to find straight sides on any part of it, and it is bowed in a couple of places. My list of 'things to live with' was already pretty high because of this part, so I opted to just start over. Fortunately, I have this giant brick of aluminum that I found at a scrap bin somewhere a few years ago. Dimensions wise, it is a little more than an inch too large in each axis, which seemed perfect. I even was able to saw off about an inch in 1 dimension to use for the bearing caps:
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Today, I went to town and attacked it with the fly cutter to get it square in all dimensions. I also finished the 'length'. My next step will be to make the cube the correct dimensions in the other two directions.

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1 more from today :) I spent some time after dinner, I took a bit off the the width to get my width. I'm changing the dimensions of the base a bit to be whole quarters of an inch to be easier to reason about.

I took ~1" off the top with the bandsaw, then milled it flat to the height of the bearing block surface. Using the fly cutter, I then 'stepped' down the diagonal for the cylinder and got that to height. At that point, the night was over :)

I am already happier with this version of the frame, I'm looking forward to being able to count on surfaces being square here :)

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Day 10: Continuing on the frame.
I had to work a bit late today, so I only got about an hour in the shop, and most of it was stuck tramming the head :) At the end of yesterday, I'd got the top surfaces cut and got the proper sized block. Today I continued the process.

First, I tipped the head and cut the 'angled' part as you can see below. I just tipped the head over and went to town, doing it by eye. If I were to do it again, I'd have left a little more material on the small ledge, but I'm otherwise pretty happy. The cylinder will have a slight (~10 thou) overhang on its base, but I can file that flat later:
IMG_20200429_152730.jpg

The stock casting has this 'ledge' around it that I really liked as a detail. Since my fly cutter blade has a nice radius, I opted to use it and feed downward to create a nice transition. I guestimated the distance from the rear jaw, then just kept it at that Y axis position. So all my cuts were left/right. I fed downward until I was at .375 or so on the short edges, and .500 on the long (so that the center 'island' is about the right size!).

I cut the short edges first, since I wanted to make sure I had the most material to hold in the vice at the time, but thinking back now, that was foolish since the parts I was removing later are in the air as well!

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Here is the two short edges done.
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And a progress picture cutting the side. When I flipped it over, I put a parallel under this surface to make sure I indexed off of this face:
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And done!
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I'll probably spend the next steps making the rough shape of the bearing caps (thickness about right, length/height correct). I have some radius bits that I'll use to make the top radius when it comes time. I still have to cut the threaded/through holes on the frame, and hog out the middle material. Once I'm sure I like the bolt hole locations, I'll just do that in 1 go, so probably after the screw holes.
 
Day 11: The frame is back to where I was before I ruined it!

I know, a tough title :) I didn't grab pictures, but I made the bearing caps out of a ruined project I'd previously done. It was only about 75 thou too thick, I was able to cut another dimension, and then bandsawed in half to make a pair of rectangles. I did rough shaping on the mill, and drilled the mounting holes.

THEN, I started drilling/tapping the holes in the frame itself. The cylinder mount went without a hitch (no broken #32 this time!), however when tapping my very list hole, the tap snapped off. It was JUST proud of the top, but as soon as I touched it pliers it shattered below the surface.

SO, I hit it with a 1/16" carbide endmill. That broke. So I used the only other 1/16" carbide endmill I had. That broke. SO, I tried a 1/8th endmill. That dulled and started making funny nosies.

My final try was to use a 3/16" endmill and just hog out a bunch of material over-sided. It seemed to have made it all the way through! I then threaded the hole for 1/4-28, about a 1/2" deep. I went to my lathe (again no pictures :/) and turned down some 3/8 aluminum down to 1/4", threaded with a die for 1/4-28, then center drilled and tapped for the 4-40 I needed. I used some loctite and left it a little long, then used an endmill to cut it reasonably flat. Its... alright. At least it is under the bearing cap.

You can see it in the lower-left of the below picture (and highlighted by the 2nd one):
IMG_20200430_160028.jpg
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Next, I decided to try hogging out the center of the frame. The rod and crankshaft need to 'spin' in this area, plus you can mount a fuel tank under the cylinder here, so I figured it would be a nice to have.

I have a 5/8" 3 flute roughing endmill that did most of the work:
IMG_20200430_161255.jpg

THEN, an 18mm radius endmill (2 flute) from my 1911 project. It hated this job, but it rounded over the sides fairly well and kept the bottom reasonably flat.:

IMG_20200430_163130.jpg

I then flipped it over and made the mounting holes again, this time the correct (for me!) 1/4-20. Instructions say a #8, but I have a ton of 1/4-20 bolts , and it seems just as well. The instructions also suggest 4 holes, I chose 2 a set distance apart (5.5") to make sure the holes in the wood base are easier to do.

Here she is all assembled with what fits so far!:
IMG_20200430_165214.jpg

I then used a 3/16" radius bit (inside angle? whatever they call them) to clean up the caps a little:

IMG_20200430_165832.jpg



I didn't get a picture, but I decided to setup the bearing holes before dinner. Since all my faces are 'flat' now, I was able to use the mill vise instead of using the angle brackets. I'm already liking this frame better than the last one :)

So, tomorrow I should be able to cut the bearing holes, then get the crankshaft mounted in the bearings/in the frame! I'm not sure what my next step will be (I have to do the cylinder liner, I have some gears to make, some springs to make, and a ton of other random pieces), but whatever I opt for starts tomorrow!
 

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Great recovery on the frame. It's looking great!
 
Your doing a great job on both the project and this thread , ! You have me looking at engine kits , some are just castings , are there brands that are better then others or have more material ( components & stock ) ? Thanks Al
 
Your doing a great job on both the project and this thread , ! You have me looking at engine kits , some are just castings , are there brands that are better then others or have more material ( components & stock ) ? Thanks Al

I've been very impressed with my PM Research No. 6 engine. I have seen others making the same comments for some of PMR's other models. The iron castings are very clean and accurate. They provide you with all the material including barstock (no extra for screw ups), hardware, and plans. The plans are really detailed. Haven't had any issues with ambiguous dimensions or missing information.

I believe PM will also sell you individual castings if needed.
 
Day 11: The frame is back to where I was before I ruined it!

I know, a tough title :) I didn't grab pictures, but I made the bearing caps out of a ruined project I'd previously done. It was only about 75 thou too thick, I was able to cut another dimension, and then bandsawed in half to make a pair of rectangles. I did rough shaping on the mill, and drilled the mounting holes.

THEN, I started drilling/tapping the holes in the frame itself. The cylinder mount went without a hitch (no broken #32 this time!), however when tapping my very list hole, the tap snapped off. It was JUST proud of the top, but as soon as I touched it pliers it shattered below the surface.

SO, I hit it with a 1/16" carbide endmill. That broke. So I used the only other 1/16" carbide endmill I had. That broke. SO, I tried a 1/8th endmill. That dulled and started making funny nosies.

My final try was to use a 3/16" endmill and just hog out a bunch of material over-sided. It seemed to have made it all the way through! I then threaded the hole for 1/4-28, about a 1/2" deep. I went to my lathe (again no pictures :/) and turned down some 3/8 aluminum down to 1/4", threaded with a die for 1/4-28, then center drilled and tapped for the 4-40 I needed. I used some loctite and left it a little long, then used an endmill to cut it reasonably flat. Its... alright. At least it is under the bearing cap.

You can see it in the lower-left of the below picture (and highlighted by the 2nd one):
View attachment 322816
View attachment 322817


Next, I decided to try hogging out the center of the frame. The rod and crankshaft need to 'spin' in this area, plus you can mount a fuel tank under the cylinder here, so I figured it would be a nice to have.

I have a 5/8" 3 flute roughing endmill that did most of the work:
View attachment 322818

THEN, an 18mm radius endmill (2 flute) from my 1911 project. It hated this job, but it rounded over the sides fairly well and kept the bottom reasonably flat.:

View attachment 322819

I then flipped it over and made the mounting holes again, this time the correct (for me!) 1/4-20. Instructions say a #8, but I have a ton of 1/4-20 bolts , and it seems just as well. The instructions also suggest 4 holes, I chose 2 a set distance apart (5.5") to make sure the holes in the wood base are easier to do.

Here she is all assembled with what fits so far!:
View attachment 322821

I then used a 3/16" radius bit (inside angle? whatever they call them) to clean up the caps a little:

View attachment 322822



I didn't get a picture, but I decided to setup the bearing holes before dinner. Since all my faces are 'flat' now, I was able to use the mill vise instead of using the angle brackets. I'm already liking this frame better than the last one :)

So, tomorrow I should be able to cut the bearing holes, then get the crankshaft mounted in the bearings/in the frame! I'm not sure what my next step will be (I have to do the cylinder liner, I have some gears to make, some springs to make, and a ton of other random pieces), but whatever I opt for starts tomorrow!

This is looking great! Awesome work and nice save. A bit of emery cloth to round the edges and it will look just like the original casting (or better).
 
Great recovery on the frame. It's looking great!

Thanks! I was really mad when the tap broke (LITERALLY the last hole) and thought I was going to have to scrap the part! Fortunately I was able to repair it in a way that only _I_ will know about :)

Your doing a great job on both the project and this thread , ! You have me looking at engine kits , some are just castings , are there brands that are better then others or have more material ( components & stock ) ? Thanks Al

Thanks! PM Research kits are the absolute best as @macardoso says. Here are their kits: https://www.pmmodelengines.com/product-tag/unmachined-casting-kits/. They have a few advantages:
1- Their castings are basically perfect. I'm not sure how they manage, but each one is identical and just about perfect dimensionally.
2- Their plans are nicer and leave less to 'guessing'.
3- The kit comes with 'everything'. The materials they give are a little stingy (so you might, for example, want to buy some extra brass!), but it is REALLY great to know you don't have to buy a foot of an expensive material despite needing 3/4 of an inch.

I did a #3 a little while ago which is their most popular one. I found it to be a great intro to casting kits and steam engines! The #2 is an oscillating engine (meaning the valves are controlled by the cylinder tipping back and forth) and is a bit cheaper, so it might be interesting as well.

The #5 and #1 have a more traditional steam chest, so you might like that. The #6 (as macardoso is doing!) and #4 are their largest ones (#4 is the vertical version of the #6), and I'd lpove to do some day!

This is looking great! Awesome work and nice save. A bit of emery cloth to round the edges and it will look just like the original casting (or better).

Thanks! I've got quite a few more steps to do on this (there is a bunch of stuff that mounts to it with very small screws :)), but afterwards I was going to do quite a bit of file/sandpaper work on it. I'm considering using the hammerite paint to give it a casting look, but I'm not sure yet!
 
Watching very closely as I bought this same kit after reading your first post last week. Unfortunately my kit has been stuck in Detroit and USPS says they don't know when it might leave there. Maybe in a week or maybe several weeks. Many people out with the virus and just a big mess there.

Ray
Did you get your kit yet? Any progress made? I'd love to see how you're doing!

Also @Alcap: Stick to steam or solar for the first engine or so. The PM kits have much fewer parts than a hit/miss engine. The gas powered engines have a whole bunch of additional parts that are necessary to run. Steam is just a valve-chest, a cylinder, and the rotating bits. Add a little compressed air, and you're all set!
 
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