Bouch's workshop - 1.5 x 3.5 horizontal steam engine

Discussion in 'A Work In Progress' started by bouch, Nov 1, 2014.

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  1. Dec 11, 2017 #21

    bouch

    bouch

    bouch

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    It seems like I only update my thread every year or so. I guess that says a lot about how quickly I get work done...

    I have done some more work on this big engine. I've managed to build the steam chest, piston rod, piston, and a bunch of the studs needed to hold everything together.

    The steam chest was cut from solid, using only a drill press and a shaper. No milling machine. (combination of my home shop's milling machine is out of commision for various reasons, so I need to drive up to my father's shop, an attempt to get those nice square corners no one will ever see, and also just to be able to say that I did it that way)

    Barker steam chest.jpg

    "4 corners, neat and square" (bonus points if you get the reference!)

    I've also built the steam chest cover, but that's pretty boring so no photo. You can also see the valve rod gland has been made.

    The piston and rod are built as designed, The taper worked like a charm, everything is nice and concentric. The slots are cut to fit some 1.5" cast iron rings I acquired. Not sure if I'll install them, as I don't expect to need to do any real work with this engine.

    Barker Piston & Rod 1.jpg

    Barker Piston & Rod 2.jpg

    Barker Piston & Rod 3.jpg

    If you look at the 3rd photo, you can see where the hole in the piston is a little larger than the rod. That's because I cut the tapered section a little "overlength" to make sure that it engaged fully. You can also see the piston rod gland has been made.

    Finally, a bunch of studs. These are for the cylinder heads and the steam chest.

    Barker studs.jpg

    Unfortunately, I'm out of material for more studs, and I have a bunch more to make (cylinder mounting studs, crosshead guide mounting studs, crankshaft bearing studs. Anyone know where I could get some steel rod appropriately sized for 10-32 studs? (.190 dia)

    No photos yet, but I've also started work on the porting of the cylinder. I have the ports cut in the valve face, and the "steam line" from one port to one end drilled. Still need to do the other side and the exhaust port. I'm hoping to have the cylinder finished by the end of the year, and then I'll start working on the crosshead

    And for a different project, I did download FreeCad and start working on 3D cad. Here's the first part I printed (at shapeways).

    1st 3d printed pedestal.jpg

    Its the pedestal for a 3/4" gauge caboose truck. Had a reasonably steep learning curve, but once I figured out the concepts, it went pretty well. I still did a bunch of stuff "trial and error" (mostly error), but I got it done. I've designed a few other pieces, need to get them printed and cast...
     
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  2. Dec 12, 2017 #22

    akitene

    akitene

    akitene

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    Great thread, Bouch. This is going to be a great engine.

    "4 corners, neat and square" (bonus points if you get the reference!)
    -> Not sure to get the right reference, but it seems you're talking about "Mike Mulligan and His Steam Shovel."
     
  3. Dec 12, 2017 #23

    bouch

    bouch

    bouch

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    Yup. You get the bonus points. :thumbup:
     
  4. Dec 12, 2017 #24

    Herbiev

    Herbiev

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    Looking great so far. Don't worry about the time factor. We have politicians down here that are ten times slower. :hDe:
     
  5. Dec 21, 2017 #25

    bouch

    bouch

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    Made some progress on the cylinder.

    I have the valve ports cut, but had to do some "correcting". When I cut the edge of the port, the end mill I was using flexed, so I didn't get a straight cut. I don't know how it did it, but it actually flexed so it cut "deeper" than I indended. Somehow, the exhaust port wound up longer than indended, with "bowed" edges.

    I got a shorter, stiffer endmill, and proceeded to fix the issue, making the edges nice and straight. But now I had an exhaust port about .032 wider than expected. So, I moved the inlet ports out .032, so I would leave the same lap between the two ports.

    Now I have to a) adjust the dimensions of the valve face and b) adjust the throw of the eccentric to increase the valve travel. Need to do a little calculating.

    I've also drilled the steam passages from the cylinder edge to the ports. I put the drill in the chuck such that the chuck would just about be hitting the cylinder when the drill broke thru, as a "safety" to keep from drilling too deep.

    Barker Drilling Port 1.jpg

    Barker Drilling Port 2.jpg

    If you look closely at the picture, you can see the tip of the drill through the port. You can also see how I made the ports themselves. I started by drilling to depth, then I used an end mill to make the slots. This puts a lot less side-pressure on a small endmill, so it's much less likely to break. Once I got a reasonable depth, I stopped cutting all the way to the edge, stopped .032" short in each dimension, to prevent any other possible issues with the port edges. They're not very pretty when you look down into them, but the edges are sharp and straight, they're functional, and no one will see this when the engine is on display.

    As you can also see, the steam passages are parallel to the cylinder. I had enough "meat" in the casting to do so, and I've built other cylinders with parallel steam passages. Its an easier setup, and I don't see any significant downside.

    To complete the steam passages, I drilled 3 .156" diameter holes, each with centers .158" apart. Even with that, I got a little break-through (not a problem at all), and all 3 holes came out nice. I then used an end mill to cut a .125" deep relief to make sure steam can get in the cylinder when the cylinder heads are on. The cylinder heads have a .062" deep relief to center them on the cylinder.

    Barker Drilling Port 3.jpg

    Getting close to having the cylinder done. Next up, the exhaust port and holes for drain cocks.
     
  6. Dec 30, 2017 #26

    bouch

    bouch

    bouch

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    The final steam passage for the cylinder is the exhaust. However, the original (hand-drawn) drawings show the passage leaving the cylinder in a location which interferes with the base casting. The designer says to just cut away part of the base where it interferes.

    When I re-drew everything in Draftsight, this was confirmed. So, I'm thinking I may move everything to hopefully eliminate this, or at least minimize it. So, before doing anything on the cylinder, I decided to drill/tap the mounting holes in the base casting.

    This is where things got interesting. The casting is a) rough and b) longer than the travel on the table on my Bridgeport. So, indicating in over the length just isn't going to happen. What I did to square the base to the table was simply use a combination square on each end. I figure that is close enough, as long as all the holes for the cylinder and crosshead are parallel to each other.

    Here's setting up both ends with the combination square, top photo is the cylinder end, bottom is the crank end.

    Base Cylinder End mill table.jpg

    Base Crank End mill table.jpg

    When I took the combination square and looked in the middle, I found that the base casting has a pretty decent bow in it. Looks about 1/16" to me. Somehow, I didn't notice this when I drilled the mounting holes on the underside of the base to attach it to the aluminum display table I've made.

    Base Middle Bowed mill table.jpg

    After some pondering, and discussion with my father, I decided that it doesn't really matter, As long as I set it up and drill the holes for the cylinder and crosshead so they're in alignment with each other, it doesn't matter if the holes aren't perfectly centered on the base. With a 1/16" bow, it'll be noticeable, but there's not much I can do about it. I'm not about to try straightening a 2 foot long casting.

    So, I've drilled the holes, and now to make the studs to hold everything down. Then I can measure where the exhaust can be to have it clear the bed casting, go back to Draftsight and make sure I can drill the holes without breaking thru the cylinder wall, and adjust things as necessary...

    My current goal is to have everything able to be bolted down on the base (and display stand) and the cylinder machining complete, and the crosshead guides done in time for the annual NEMES show. This year, its on Feb 17 2018, from 10:00 AM to 4:00 PM, at the Charles River Museum of Industry in Waltham, MA. If you're in the area, stop on by and say hello! The engine won't be running, but it'll look like an engine as opposed to the pile of parts I displayed last year!
     
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  7. Jan 8, 2018 #27

    bouch

    bouch

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    More progress on the cylinder today. The last steam passage to drill is for the exhaust, and then the cylinder will be "complete enough" to assemble and test-run the engine (not that I'm even close to that)

    The original, hand drawn, plans called for the exhaust passage to exit the bottom of the cylinder in such a position that a relief would need to be cut in the inside of the base to clear the exhaust pipe. That is, as-designed, the base casting blocks the exhaust outlet. Can't say I was happy with that.

    I spent some time on Draftsight trying to figure out a location where it would clear the base, but I would be able to drill the exhaust passage at an angle to meet up with the exhaust port. I couldn't find a location where the outlet would be square to the cylinder bottom and still be able to drill the passage.

    Then I had a "light bulb" moment. Why does the exhaust outlet need to be square to the bottom of the cylinder? Its hidden, and its easy enough to put a bend in the pipe which will take the exhaust out under the display base the whole engine sits on.

    I found that if I drilled a 5/16th hole, centered 13/16th from the valve face, at a 30 degree angle, it would a) hit the cavity for the exhaust port right about at the corner and b) not break through the cylinder wall and c) not interfere with the base. By "at the corner", the hole intersects at where the side of the port meet the bottom. (a photo will make what I mean obvious, its coming below)

    The reason I'm using 5/16" diameter for the exhaust passage is because the exhaust passage needs to be at least the same volume as the inlet passages, or more steam can get into the cylinder than can get out, which will cause back-pressure and possibly lift the D valve off the valve chest. The inlet passages are 3 holes 5/32" diameter, If my math is right, that's an area of .057 square inches. The area of a 5/16" hole is .076 square inches (once again, assuming my math is right!). The area of the exhaust passage is 133% of the inlet passage, so I should be good.

    I set the cylinder up in the mill at 30 degrees. First, I used an endmill to make a flat spot square to the hole I was about to drill, as its very hard to drill straight into an angled surface. Then I made a pilot hole with a 1/8" drill.

    Barker Exhaust Passage - Drilling.jpg

    You can see the flat spot in this photo. (You can also see where I used a sharpie to mark the inner edge of the base casting while doing the design work).

    Once this was done, I used a combination of larger endmills and larger drills to open the passage to the 5/16" diameter. Once done, I used a Q drill and drilled 7/32" deep, and tapped for 3/8-24 5 threads deep.

    Barker Exhaust Passage - Bottom.jpg

    When you look into the exhaust passage, you can see that the exhaust passage is pretty much where Draftsight said it should be, right at the corner.

    Barker Exhaust Passage - Valve Face.jpg

    Finally, I did some cleanup on the exterior of the cylinder. If you look at some of the earlier photos, you'll see some "steps" on the outside surface on either side of the valve surface. (E.G. - the photo on my previous post where I'm drilling the inlet passages)

    As cast, the cylinder casting had two things I didn't like. First, the steam chest was integral with the cylinder. That is, the steam chest would need to be milled out 1" deep (there was no core for the steam chest), and then the ports added to the bottom of this cavity. (LOT of work, wasted cast iron, and no good way to remove machining marks from the valve surface. Second, the steam chest was the same length as the cylinder, which seemed unnecessarily long as well as didn't look particularly good. It also meant that to mount the cylinder, the design called from a flat piece of steel to be slotted into the bottom of the base, and then long studs threaded into the bottom of the cylinder to hold the cylinder to the base. That seemed like a bad way to mount a cylinder.

    On the other side, there were "feet" for mounting holes, but they went all the way up to the center line of the cylinder bore. Way too tall, didn't look very good. (hopefully I explained that well, wish I had photos of the as-cast cylinder)

    Way back when I first started work on this engine, I cut off the iron for the steam chest. I also shortened the valve face to 3", to open up space for "feet" to bolt down the cylinder from the top and improve the looks (IMHO). I milled these steps, while cutting away the "extra" iron. On the other side, I shortened the "feet", and did a little terracing there as well.

    I put a 40:1 dividing head on the mill and put a 1-1/2" slug in the chuck. I then slid the cylinder on this slug and used a 1/4" bolt and washers to tighten the cylinder up against the chuck jaws. For the work I was doing, the friction of the cylinder end against the chuck jaws was sufficient to hold it in place, but I couldn't take particularly heavy cuts (.020 at a time)

    The 40:1 head gave me enough control that I could rotate the cylinder slowly under the endmill and stop right where I needed to so it wouldn't cut into the part of the cylinder the inlet ports run through. This was "machining by feel", no calculated dimensions to machine to.

    When done, I found that a few "terracing" cuts were a little too deep, but I can fill this in with JB weld or something similar. (or, this might just get hidden by lagging, not sure on that yet...)

    Barker Cylinder Cleanup 1.jpg

    Barker Cylinder Cleanup 2.jpg

    After all this, there's only 1 machining step left to be done on the cylinder. Drill holes for drain cocks. I have a couple from P.M. Research, but they look too small for the size of the cylinder. The ones on my Stuart #1 look the part much better, so I have to buy a couple from them.
     
  8. Jan 12, 2018 #28

    bouch

    bouch

    bouch

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    Now that the cylinder is all but done, I made the studs to bolt the cylinder to the base. After making 16 short studs for the cylinder heads, making these 4 seemed trivial. But, when I went to test-fit the cylinder, I found an issue. One of the holes for the studs was located wrong. When I removed that stud, the cylinder fit, with it in place, nope. Did some re-measuring and found that I somehow missed the actual location by .062".

    So, here's what I did to fix the issue. I put the frame back on the mill and located the hole. I then moved the table the .062 to the right location. I used a 1/4 endmill to drill a pilot hole the same depth as the existing hole. This overlapped most of the improperly located hole, so using and end mill eliminated the chance of it wandering into the existing hole. (a drill might do that) Then I opened it out with the tap drill for 5/16"-24, and threaded the hole. I left the base mounted on the mill table.

    Turning to the lathe, I took a peice of scrap durabar (about 3/4" square) and turned one end to 5/16 and threaded it 5/16-24.

    I then screwed the plug into the hole, and snugged it up tight. Using a hacksaw held horizontally, I cut off the plug a little proud of the base, and then used a mill to clean everything up. Then I drilled and tapped a new hole 10-32 for the stud.

    Barker 9a - Cylinder mount hole moved.jpg

    The end mill marks are decieving. It looks REALLY obvious because of the layout dye, but its maybe .0005" difference there, I can't even feel it with my fingernail.

    And now the cylinder drops right onto the base.

    Barker 9b - Cylinder Test Fit.jpg

    Looks like I need to make custom mounting nuts, as the storebought ones are almost too large to tighten. (something I was afraid of)

    In the photo, you can also see that I took a shot at removing the machining marks from the valve face. I put some 320 grit sandpaper on my surface plate, and sanded the valve face using a figure 8 pattern. Got most of the marks off, but it still needs a little more work to fully remove them. Not sure if I would ever get them completely gone without using a surface grinder, so I might just declare done on that process...

    Next step is a) finish the cylinder and b) make the crosshead guide.
     
  9. Jan 17, 2018 #29

    bouch

    bouch

    bouch

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    One thing missing on the original cylinder plans was a location for cylinder drain cocks. A cylinder this size is certainly going to have quite a bit of condensation when steam hits it, so I think drain cocks are a requirement.

    I bought the largest available from PM Research, and they just don't look right, they look horribly undersized for the cylinder. I built a Stuart Turner #1, and I decided that I needed the same drain cocks as on that. These are available from Stuart, and they're threaded 1/4"-32.

    The "rims" on the cylinder ends don't have enough meat to them to have drain cocks this large on them and not have part of the drain cock overlapping the ends. The Stuart engine has bosses cast into the cylinder exactly for this purpose.

    Barker 10a - ST#1 Bosses .jpg

    Obviously, I would need to add some bosses to the Barker cylinder. This is what I decided to do. I decided to make some "plugs" which would screw into the cylinder to form these bosses

    First, was to measure the bosses on the ST #1. They're about 5/8" across. Then I did some work on Draftsight to figure a location based on the actual cylinder dimensions, and what I would need to build.

    I also measured the hole through the ST drain cock, this is 5/64" (.078 ) I decided I would drill through the cylinder wall with this size drill (no sense making a larger hole in the cylinder wall than necessary)

    The bosses would screw into smaller holes in the cylinder side, and then "above the surface" would be 5/8" diameter. I decided that the tapped holes in the cylinder would also be 1/4-32 for a few reasons.
    1) The hole in the cylinder side would only about about .218" deep, and I wanted to maximize the number of threads in that short distance.
    2) Figured I would be less prone to mess something up if I only had one tap drill/tap/die to work with, no accidentally drilling the wrong size hole in something.

    I took some small cutoffs of durabar and turned them down. Here are the two bosses

    Barker 10b - Drain Cock Bosses .jpg

    The 1/4-32 hole the drain cock screws into is fairly shallow as well, but if I made them any deeper it would break through. I'll probably have to file a few threads off the ST parts to have them seat flat against the cylinder.

    Now to the work on the cylinder. I drilled the 5/64" hole first, locating it 21/64" in from the cylinder edge, that's 1/64" more than half the 5/8" diameter of the boss. This way the boss wouldn't break through the cylinder end.

    Then I took a 5/8" end mill and made a flat surface for the boss to sit against. As you can see, there's a small section of the original cylinder end still there.

    Barker 10c - Cylinder Drain Cock Boss hole 1.jpg

    I then drilled and tapped the 1/4-32 hole, being careful not to break through the cylinder wall.

    Barker 10d - Cylinder Drain Cock  Boss hole 2.jpg

    I then put a little loctite on the threads of the bosses and screwed them in tight up against the flat spot. Since the made the bosses taller than neccessary by about a 1/16", I used an endmill to bring it close to the right height.

    I then mounted it in the lathe and manually rotated the chuck only about 30* to round off the top of the boss down to the diameter of the cylinder end, and then filed it smooth. Still needs some sanding/cleanup, will probably use a touch of JB Weld to try to hide the small but visible gap.

    Barker 10e - Cylinder Drain Cock Boss 1.jpg

    There was something I was afraid of because of the distance I located the drain cocks in from the cylinder end. Looking inside the cylinder, and with a little math, I believe the 5/64" hole will be covered by the piston at dead center. That is, the distance between the two drain cocks is less than the stroke + piston length. So I needed to mill a relief in the cylinder wall so any water in the cylinder can still get out the drain cock.

    I didn't have a 5/64" endmill, so I went up a little bit to a 1/8" endmill and cut a semi-circular slot from the cylinder to the drain cock hole.

    Barker 10f - Cylinder Relief.jpg

    One last picture, here's what the boss looks like with the drain cock in position. To my eye, the proportions between the boss and the drain cock look right. (note: I need to buy new drain cocks from Stuart, this one is "on loan" from the ST #1)

    Barker 10g - Cylinder Drain Cock Boss 2.jpg

    And now, machining work on the cylinder is complete. On to other parts!
     
  10. Jan 18, 2018 #30

    bouch

    bouch

    bouch

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    In between major work on the cylinder, I've been building a few pieces for the crosshead guide, and now that the cylinder is done, so is the crosshead guide.

    The guides themselves are 1/8" x 1" flat ground steel, and the supports are 1/2" pieces of brass turned with a slight taper.

    Barker 11a - Crosshead Guide 1.jpg

    Barker 11b - Crosshead Guide 2.jpg

    A few posts ago, I mentioned that the base has a slight bend to it. I didn't think this would be a problem as long as I drilled the holes to mount the cylinder and crosshead guides are all in line. Well, it might be a slight problem, at least visually.

    Barker 11c - Crosshead Guide 3.jpg

    Barker 11d - Crosshead Guide 4.jpg

    As you can see, the crosshead guide supports overhang the edge of the base slightly. On the other side, not so much.

    Barker 11e - Crosshead Guide 5.jpg

    So, the question is do I ignore this, or do I do something to fix it. The easiest thing is to make the supports smaller so they don't overhang. But I worry that then they'll look out of proportion.

    Right now, I'm strongly leaning towards leaving it alone. Its only cosmetic, and you do have to look closely to see the overhang. As long as everything works, I'm good with it. If someone comments on it, I can explain why. If they don't like it, well, its not their engine...

    I also note that I need to add a couple threads to the mounting studs, and then shorten them a little. That'll be relatively trivial work.

    Next part, the crosshead itself, which I've already started some work on...
     
  11. Jan 22, 2018 #31

    bouch

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    With the crosshead guides done and the cylinder machining done, Its time to do the first "test assembly".

    Back when I first started building the engine, I machined the flywheel, crankshaft, the bearing blocks for the crankshaft, and the outer bearing support block (previously only seen in the initial posting). All I needed to do was make the studs for the connecting rod bearing blocks, which was fairly trivial.

    Now its loosely bolted together, only a few studs for each part. The cylinder heads are on, the piston is in the cylinder, and I've bolted the steam chest to the cylinder. My goal was to get to this point by the February 17th NEMES show in Waltham, MA, so I'm happy about reaching this point. I left the steam chest cover off so people looking at the engine can see the valve porting.

    Barker 12a - Assembled Engine 1.jpg

    Barker 12b - Assembled Engine 2.jpg

    Barker 12c - Assembled Engine 3.jpg

    Barker 12d - Assembled Engine 4.jpg

    For scale, the flywheel is 10 1/2" diameter, the entire aluminum display base is 25 1/2 x 13 1/2, and the B&M frieght car sitting in the background is an O scale model.

    I've also started working on the crosshead, I'm now hoping to have this in reasonable shape by the show. If you jump back to post #16, you can see the engine I'm patterning the crosshead after, and the initial 2D drawing. Since then, I've made a few small modifications, but you'll get the basic idea.

    First step was to turn down the round end which screws to the piston rod. I used my shaper to remove a good chunk of the metal, I didn't want to deal with a huge interrupted cut on the lathe, trimmed about 1/2" off each side about 9/16 deep from the end.

    Then I centered the piece in the 4-jaw, finding the center with my "Kozo style" center wobbler tool. See https://littlemachineshop.com/Instructions/CenterWobble Instructions.pdf to see what I'm talking about (I call it Kozo style since the first time I saw one was in Kozo Hiraoka's articles in Live Steam, probably the Heisler) After turning to dimension, drilling and tapping for the piston rod, here's what I had.

    Barker 12e - Crosshead 1.jpg

    I then laid out the remaining holes and center punched all of them. The 6 holes on the outside edges are for oil cups and takeup screws to adjust the crosshead on the crosshead guides. The 10 in the center are for holes to make it easier to cut out where the connecting rod goes. The full slot is marked out as well. Not visible are two locations for set screws to lock the connecting rod pin in position, so it doesn't rotate in the crosshead. Not marked out are the horizontal slots in the sides.

    The first hole I drilled was the horizontal one that the connecting rod pin goes in, you can see this in this photos

    Barker 12f - Crosshead 2.jpg

    The next step will be to drill and clean out the center. I'll use my shaper for this, not a mill.
     
  12. Feb 6, 2018 #32

    bouch

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    More work on the crosshead. In my last post, I had turned and threaded the round section which the piston rod gets screwed into. Now do cut some slots and drill/tap some more holes.

    The first slot I cut was the one for the connecting rod. I drilled a series of holes and used a saw to cut out the rough shape of this slot. I then mounted the piece vertially in my shaper and cut away each side to dimension. There's something about using the shaper that is somehow relaxing, don't know how to describe it, maybe its the slow pace at which metal is removed.

    [ame]https://www.youtube.com/watch?v=wG7btpDqDPk&t=40s[/ame]

    And a slightly closer view...

    Barker 13a - Machining crosshead in shaper.jpg

    Once the sides were cleaned up, the bottom of the slot needs machining. To do this, I used a "double sided" cutting tool which I ground when I made a crankshaft for another project. A picture is worth 1000 words...

    Barker 13b - Shaper tooling.jpg

    Its the one on the left. Its not prettty, but each "corner" is a cutting edge. The relief in the middle is to reduce the cutting surface to reduce chatter. The trick is to set it up so both edges are in contact with the surface to be cut. This is done with a piece of paper.

    Barker 13c - Setting up Shaper tooling.jpg

    You adjust until there's an equal amount of pressure on both edges, If one edge grabs the paper more, then you have to shift it slightly towards that edge. This is much more critical with a crank that this, but I still got it level.

    Then find both sides of the slot and simply move the tool back and forth until you get the depth dimension correct.

    Barker 13d - Crosshead 3.jpg

    I followed a similar approach to cut the slots in the sides, where the crosshead rides on the crosshead guide.

    Finally, I drilled and tapped the holes for oil cups and adjustment screws.

    Barker 13e - Crosshead finished 1.jpg

    And, of course, I had a "crash" with the final operation. The crosshead is made from a piece of steel of unknown type. It hasn't exactly been free machining, but its not as bad as stainless, so I've kept going. And somehow, I broke a #43 drill on the last hole I was drilling for the adjustment screws. It seems to have caught as it broke through, and that snapped the drill.

    Barker 13f - Crosshead drill broken.jpg

    So, I have 7 of the 8 adjustment screws drilled and tapped, and one that has a broken drill embedded in it, in an all but inaccessible location. I'll have to drill/tap a new hole. It won't be symmetrical, but fortunately, this is on "the bottom", so it won't be visible.

    I've also machined the connecting rod pin. This was as simple as cleaning up a 1/4" diameter rod and cutting it to about 20 thou under 1" total length.

    Next step is the "adjustment sliders" for the crosshead. Hoping to get those done in time for the NEMES show on Feb 17th...
     
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  13. Mar 1, 2018 #33

    bouch

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    Hi folks,

    I was successful in "finishing" the crosshead for the NEMES show a few weeks ago, but haven't posted since before then.

    Here's the crosshead, in most of its finished glory...

    Barker 14a - Crosshead finished.jpg

    As you can see, I've built 4 brass "wear adjustment plates", I've put in the pin for the connecting rod (and you can see the set screws which lock it place sticking out the back, need to trim them) and I've installed the oil cups. I still need to make the small 4-40 takeup screws to be able to tighten those adjustment plates). Everything seems reasonably in line, the piston/rod/crosshead slides back and forth.

    That leaves the only things left to be done on the engine are the connecting rod and the simple eccentric valve gear. The length of the connecting rod (and eccentric rod) are "build to fit"

    Looking at the engine, it seems that, as it currently sits, the connecting rod is quite short. I estimate that is will only be about 6 1/2" long. The stroke of the engine is 3 1/2", so the connecting rod is less than 2x the stroke (a number I've heard kicked around as a minimum design consideration.).
    Taking the offset of the crank, and the projected length of the connecting rod into consideration, when the crank is at the top of its rotation the angle between the piston rod/crosshead and the connecting rod will be about 15.5 degrees.

    Talking to a few people at the NEMES show, and looking some of the vintage engines on display, having the front cylinder head hang out over the edge of the base isn't that uncommon. Here's one example:

    Lepoulis vintage engine 1.jpg

    One member pointed out that I could move the cylinder up almost exactly the distance between two of the crosshead guide supports, and that'll save me having to redrill every hole.

    I've mocked this and he's right, and that'll give me a connecting rod length of about 8", which will reduce the max angle of the connecting rod to about 12 degrees. 3.5 degrees may not sound like much, but its about a 20% reduction. But, 15 degrees doesn't seem too bad when you consider that this engine will never do any "real work".
    If you look up at post #31, you can see where the cylinder sits now. Here's what it'll look like with the cylinder moved:

    Barker 14b - Cyl Reposition 1.jpg

    Barker 14c - Cyl Reposition 2.jpg

    You can see that I've moved the crosshead support up "1 hole", and the crosshead is still on the guide when moving the piston the full stroke. So, I'm thinking of taking the engine apart and re-drilling the holes for the cylinder mounting studs, one of the crosshead mounting studs, and then filling any un-neccesary holes. Fortunately, I haven't drilled the holes for the valve rod support.

    I'm not sure I like the "look" of having the cylinder overhang there, but I'm thinking that the longer connecting rod trumps the aesthetics there (both in function and looks)

    Anyone have any thoughts/comments/things I haven't considered?
     
  14. Jun 27, 2018 #34

    bouch

    bouch

    bouch

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    I've done a little work lately on the Barker engine.

    In the last post, I mocked up moving the cylinder ahead by about 2" to give more length to the connecting rod.

    I took everything apart, put the bed on the milling machine, and drilled some new holes.
    - 2 for the new "forward" crosshead guide supports
    - 4 new cylinder mounting sutds

    This left a few holes in the base which are no longer necessary. Rather than leaving them sitting out in the open, I decided to fill them. For the first step, I took a piece of "scrap" cast iron and made in into a 3/8" square x 3.5" long blank, using the shaper. (it started as a piece about 1/2" square, but it was hand-cut in a bandsaw so nothing was flat/square). This I then put in a square collet. I made short "flat head screws", threaded 10-32 (to fit the holes). But, I didn't cut them off in the lathe, I made them 1 at a time and left the 3/8" square attached.

    I countersunk the holes to be plugged, and one at a time I screwed in the plugs, using a 3/8" wrench to just tighten. Then I used a hacksaw to cut off the plug, being careful to not mark up the top of the base.

    Repeat 6 times to plug all the extraneous holes, and file the plugs down to the surface of the base.

    Barker 15a - base holes plugged painted.JPG

    Four of the plugs for the cylinder mounting holes are circled in the above photo. Of course, the two plugs in the most visible locations are also the two which are the most easily seen. Oh well, hopefully when everything's together they won't be as obvious.

    I also turned the base on the side and drilled/tapped 3 holes for the valve rod guide. This will support the valve rod between the steam chest and the joint with the eccentric rod. This completed all the machining needed on the base.

    You can also see that I decided to paint the base. A while back, my local hardware store had a sale on Rustoleum, selling cans of select colors for something like 50% off (I don't know why, the colors are still available) I got a quart of "gloss navy". Two coats of clean metal primer and 2 more coats of navy, and the base is this nice, deep blue. Since the "dry time" for each coat was 24 hours, this took way longer than I expected ;)

    So, the next step is to determine the length of the connecting rod. To do this, I built one of these:

    Barker 15b - adjustable connecting rod.JPG

    A few pictures showing how this work will be easier than trying to explain..

    1) put it on the engine

    Barker 15c - Adj Conn Rod 1.JPG

    flipping the crank between dead centers, adjust the distance between the two blocks so the crosshead is reasonably centered on the crosshead guide.

    Barker 15e - Adj Conn Rod RDC 1.JPG

    Barker 15d - Adj Conn Rod FDC 1.JPG

    (you can really notice the plugged holes in this photo. Hopefully they're not that obvious in "real life", but since I know where they are, I can't un-see them)

    Now lock everything down so the blocks can't move. After removing the adjustible connecting rod from the engine, I can put gauge pins in each block, and measure the lenght. (note that my dial calipers aren't long enough, but my father has 12" vernier calipers that I can use to measure)

    While getting everything set on the crosshead guide, I also can adjust the position of the piston/rod in relation to the crosshead so dead centers have about the same volume. You can see the exposed threads on the piston rod, due to this adjustment, in the above photos. I'll make a lock nut to both "fill the gap" and prevent he piston/rod assembly from rotating when the engine is running.

    Barker 15f - Adj Conn Rod FDC 2.JPG

    Barker 15g - Adj Conn Rod RDC 2 .JPG

    Time to start drawing up the connecting rod. I want to make a "marine style" rod, even though I don't really need split bearings on either end. I just think I'll look cool. I have the book for the beam engine "Mary", and I'm going to use that as a template for the rod ends...

    While drawing/designing, I'll probably have the shaper going making the valve rod guide.
     
  15. Jul 5, 2018 #35

    bouch

    bouch

    bouch

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    And the length of the connecting rod, between centers of the bearings, is 7.843". Actual measurement was 7.851, but I shortened it to the nearest 32nd for two reasons
    1) to have a "nice number" for the length
    2) As you can see in the previous post, at front dead center, the crosshead is right at the end of the guides. At rear dead center, its not quite at the ends. Shortening the rod would help even out this minor asymmetry.

    With a 3.5" stroke, that's over the "length of the connecting rod should be twice the stroke" rule of thumb by almost an inch.
     
  16. Jul 6, 2018 #36

    GWH

    GWH

    GWH

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    Are those casting sets till available? I s what is their contain information?
     
  17. Jul 11, 2018 #37

    bouch

    bouch

    bouch

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    Unfortunately, no. I bought them easily 15-20 years ago. Pretty much no one had seen the seller until recently, when he attended (as a spectator) my club's model engineering show. I talked to him about my engine, and he said that he enjoyed seeing how people built them with their own "interpretation" of the drawings. But he gave no indication that he had any castings still kicking around, nor any plans to make more.

    Kinda a shame. The castings cut like butter, no voids or hard spots. And its shaping up as an impressively sized project. The only downsize was the drawings that came with the castings are pretty poor. But at least that flaw got me to learn Draftsight so I could produce my own drawings.
     
  18. Jul 11, 2018 #38

    GWH

    GWH

    GWH

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    It looks like it would have been a
     
  19. Jul 11, 2018 #39

    GWH

    GWH

    GWH

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    It looks like it would have been a good project!
    Good luck with your building of it.
    Thank you for the response.
     

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