Author Topic: Introducing ... the "Steel Webster"  (Read 6289 times)

Offline awake

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The "Steel Webster" build log, part 7b
« Reply #30 on: March 29, 2020, 02:14:54 AM »
Part 7 of the build log, the cylinder, continued:

Once the cylinder (or should that be, the cylinder liner??) was finished, I began work on the cylinder fins. I had a small bit of 1.75" diameter aluminum on hand, so I cut it just over length, faced it, flipped it, and faced it to final length. Then I drilled out the center - I don't recall for sure, but probably drilled it using a .75" drill (attachment 1).

Next were the boring operations, first to size the bore of the aluminum to 1.073" diameter for a shrink fit on the 1.075" diameter cylinder (attachment 2), then boring out the 1.25" diameter x .125" deep recess into which the "lip" of the cylinder liner sits (attachment 3).

I heated up the aluminum using my heat gun and dropped it over the cylinder, which was still mounted on the arbor. Once cooled, they were nicely locked together (attachment 4).

I re-mounted and re-skimmed my "machine-in-place" dead center so that it was perfectly true, then mounted the arbor with the cylinder liner and the aluminum part back between centers (attachment 5). I turned the OD of the aluminum just enough to clean it up ... well, to clean most of it up; as I already knew, this chunk of aluminum had had a hard life, and there were several dings in it that I chose to leave, wanting to maximize the diameter of the fins (attachment 6).

Continued one more time below ...
Andy

Offline awake

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The "Steel Webster" build log, part 7c
« Reply #31 on: March 29, 2020, 02:29:11 AM »
Part 7 of the build log, the cylinder, continued:

Once the OD was (mostly) cleaned up, I set up my dial indicator and began to cut the space between the fins (attachment 1). If I do say so myself, the end result was perfect (attachment 2) ...

... or not. Take a closer look at the second picture, and see if you can spot my mistake. The end in the foreground is the part that goes into the head; the .25" thick part of the aluminum that is supposed to receive the screws is supposed to be down on this end, not the other end. Agh! I decided to see if it would work anyway, so I cut another slot to make two fins out of what was the .25" thick part (attachment 3).

I heated up the cylinder+fins with my heat gun until the Loctite bond was loosened, pressed out the arbor, and cleaned up the bore. Then I set the cylinder assembly into the milling vise, found the center, and located for the 4 holes that hold the cylinder to the head. I drilled and tapped each through the first two fins; in the plans I show 8-32 screws, but in fact I wound up drilling and tapping for 6-32 (attachments 4 & 5).

And voila! One not-so-perfect cylinder, complete with an extra fin. The fact that the 6-32 screws that hold the cylinder to the head are going through two thin fins means that I have to be very careful in tightening it up, but it has worked thus far!
Andy

Offline awake

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The "Steel Webster" build log, part 8
« Reply #32 on: April 02, 2020, 07:42:41 PM »
Part 8 of the build log, the head - only a few pictures of this one, starting with the plans (attachments 1 & 2).

After cutting, squaring up, and bringing the blank to size (the latter two operations on my trusty shaper, though the mill would have worked fine as well), I used the DRO on the mill to locate the four cylinder mounting holes and the central hole for the spark plug, and drilled these with the appropriate drill bits and countersinks - no pictures of any of that, I'm afraid.

Next I transferred the blank to the 4-jaw chuck on the lathe, using parallels to stand it off (I need to make one of those spider jigs ...), and using a DTI to center precisely on the center spark-plug hole (attachment 3). I bored out the .502" deep recess for a nice firm slip-fit with the cylinder (attachment 4), then flipped it over, re-centered on the spark plug hole, and bored out the shallow recess for the spark plug.

I then moved over to the mill to complete the drilling and tapping of the various .188", 6-32, 10-24, and 1/4-20 holes as shown on the plans (attachment 5). Of course, no home-machinist project would be complete without a broken tap, right? I got lucky with this one and was able to wiggle it out. I then went on and milled the .2" deep inset in the side, where it mounts to the frame.

I don't have pictures of it, but there was one more important step with this head. After all the milling was complete, I took the side where the valve cage connects (the side showing in the picture above) and worked it smooth and flat against some wet/dry paper on a piece of glass. I did the same with the valve cage after screwing the three pieces together. This gave me a tight seal with good compression without having to use any gasket.

In case the question arises - why do the boring on the lathe, when it is already centered up on the mill? The reason is that I don't have a boring head with a facing function, so it was easier to get nice flat faces on each side using the lathe.
« Last Edit: April 02, 2020, 07:45:44 PM by awake »
Andy

Offline awake

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The "Steel Webster" build log, part 9a
« Reply #33 on: April 02, 2020, 08:30:44 PM »
Part 9 of the build log, the valve block (attachments 1 & 2).

For the valve block, I tweaked the design to give me a bit more room to use slightly larger fasteners than called for in Joe's original plans; I also wanted to have each of the three parts of the valve block be the same thickness. The reason for that was so that I could machine all three parts from one blank, which I prepared on the mill (attachments 3 & 4).

If you have been following along this build log, I know you were expecting me to say that I prepared the blank on the shaper. Why the mill, this time? Because, while I love the satin finish that comes off the shaper, for this part I really needed the shiny-smooth finish that I get from the carbide face mill.

You'll notice in the pictures that the blank is large enough to accommodate all three pieces, all of which are almost, but not quite, the same - one, the center piece, has a smaller central hole, and one, the bottom piece, is drilled and tapped for 6-32 threads while the others are drilled for 6-32 through holes (attachment 5). What may not be obvious in attachment 5 is that, in the process of drilling and tapping the 6-32 holes in what will become the bottom piece, I managed to break, not one, but TWO 6-32 taps (attachment 6).

Along with the broken tap in the head, this now makes 3 broken 6-32 taps. Clearly I am doing something wrong ... or else, 6-32 is a size invented by the devil to make life miserable for home machinists. These two broken taps had to be milled out with a 2mm carbide end mill - no pictures of that, but it was successful, and was able to save the part.

Part 9 of the build log continues below ...
Andy

Offline awake

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The "Steel Webster" build log, part 9b
« Reply #34 on: April 02, 2020, 08:34:46 PM »
Part 9 of the build log, the valve block, continued:

Once all the holes were drilled, but before cutting the three pieces apart, I began working on the faces to get them smooth and flat. This process began with a not-so-great diamond sharpening block (attachment 1), followed by increasingly fine grits of wet-dry paper on a flat glass surface (attachment 2).

Frustratingly, the camera makes the final results look far less smooth than they actually were. Attachment 3 shows the three parts after cutting them apart; in the picture it looks like they are all scratched up, but in reality they are smooth enough that, when screwed together, they sealed to provide good compression with no gasket needed.

The next step was to fasten the blocks together and mill the edges to size (attachment 4); then I drilled the holes that go in the side of the middle block (attachment 5).

The remaining steps had to wait until the valve guides were made, which will be part 10 of the build log.
Andy

Offline Admiral_dk

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Re: Introducing ... the "Steel Webster"
« Reply #35 on: April 02, 2020, 09:05:04 PM »
Nice progress - even with the tap problems ...!

There are a number of threads here about how to successfully do tiny diameter threads.

Quote
Frustratingly, the camera makes the final results look far less smooth than they actually were.

That is the name of the game with cameras - unless you really know how to light etc. - they really brings forward the tiny details of light reflected ....

Offline awake

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Re: Introducing ... the "Steel Webster"
« Reply #36 on: April 02, 2020, 09:11:04 PM »
Thanks! In the case of this part, it was ham-fisted operator error more than anything else. After these, I did not break any more 6-32 taps. Note carefully the qualification; I did not say that I didn't break any more taps ... !
Andy

Offline Craig DeShong

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Re: Introducing ... the "Steel Webster"
« Reply #37 on: April 03, 2020, 12:26:45 AM »
Nice work Andy.  I probably would have used a solid chunk for the flywheel... of course I don't weld.  I worked for Babcock & Wilcox in Wilmington, NC years ago.  They built industrial boilers so the guys in the shop knew how to weld.  I could have learned, for FREE, if I'd desired, but at that time I was a wood worker and had no interest...  Just another opportunity I squandered.
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline awake

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Re: Introducing ... the "Steel Webster"
« Reply #38 on: April 03, 2020, 06:20:34 PM »
Thanks, Craig. A solid chunk would certainly have been better/easier, but as with so much else in this build, the controlling factor was the available stock on hand.

In terms of welding, it is never too late to learn. :) I don't do a lot of it (as is evident from the quality of my welds!), but I find it to be a satisfying pursuit in and of itself. If you'd like to give it a try, I'm just down the road ... after the current pandemic has settled down, of course!

Meanwhile, my confession is that I have never learned to hard-solder. I've only attempted it once or twice, with highly dubious results. One of these days I need to make a serious effort to learn ... but until then, I guess I'll keep tweaking designs to allow TIG welding!
Andy

Offline awake

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The "Steel Webster" build log, part 10a
« Reply #39 on: April 11, 2020, 02:19:40 AM »
Part 10 of the build log includes the valves, valve guides, and springs (attachments 1 & 2).

I began by working on the guides. First I machined the inside of the guides, including the valve seat (attachment 3). I thought I had a great idea for how I would machine the outside of the guides to be perfectly concentric with the insides - I machined a jig with a body over which the valve guide fit snugly, including a .094" stem that ended in a 2mm thread (attachment 4). This let me set the valve guide in place and secure it with a 2mm nut (attachment 5).

Well, it seemed like a good idea at the time ... but in order to hold the valve guide securely, I had to screw down the nut rather firmly ... and the tiny 2mm thread broke off. :( So I machined the .094" stem away, leaving just the .219" section. Note that all this time I had not removed the jig from the lathe, so it was still perfectly true. I loctited one of the guides in place, let it set, and then machined the outside profile (attachment 6). Still without removing the jig, I used my heat gun to break the bond and remove the finished guide (attachment 7), then loctited the other guide in place and repeated the procedure. I wound up with two guides with which I was pretty happy; attachment 8 shows one of the two, along with the part of the valve block into which it goes, just before I loctited it into place.

Part 10 of the build log continues below ...
Andy

Offline awake

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The "Steel Webster" build log, part 10b
« Reply #40 on: April 11, 2020, 02:50:56 AM »
Part 10 of the build log, the valves/guides/springs, continued:

Next I made the valves. I elected to do this with the stem secured by a live center in the tail stock, with the compound adjusted so that I could cut the 45° head of the valve in the same setup as turning the stem (attachment 1). To let me cut right up to the live center but also be able to cut the head of the valve, I needed to be able to cut both LH and RH, so I used a round-nosed cutting tool (attachment 2). Of course, I left the stem extra-long and made use of emery paper to get the stems to exact size (well, within .0002" or so), testing using a valve guide. (I kept the valve guide and the valve as a matched set, to allow for any variations between the valve guides.)

I chose not to try to part the valves off, but rather cut them off using the bandsaw, then trimmed the bottoms of the valves in my 7x14 lathe (attachment 3). Finally I had two valves that fit smoothly in two valve guides (attachment 4). Except that the next bit went sideways - I did not have a very good .040" drill bit to drill the cross hole that I originally planned to hold the spring and its keeper in place, and I mucked up one of the valves. Sigh ... I remade the valves, this time according to the revised plans shown in the previous post.

The valve spring keeper was next, and it began by machining a bit of CRS to the outside diameter and drilling the .094" hole through the center (attachment 5). I machined the shallow cavity that holds the c-clip (attachment 6), then using a ground HSS parting tool, I machined the .188" diameter section over which the spring fits (attachment 7).

I used the same parting tool to part it off, and made the second keeper in the same fashion. Voila! Two valve spring keepers (attachment 8). Of course, I should have made three ... because down the road, when I was getting ready for the final assembly, I lost one, and had to make another. :(

Part 10 of the build log concludes in the next post ...
Andy

Offline awake

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The "Steel Webster" build log, part 10c
« Reply #41 on: April 11, 2020, 03:22:58 AM »
Part 10 of the build log, the valves/guides/springs, concludes with this post:

Since I redesigned the valves to use c-clips, I had to make the c-clips. The first bit was easy enough - machine the OD, drill a 2mm (0.079") hole, and part off to the desired thickness (attachment 1). That, of course, gave me an "O" rather than a "C"; the hard part was how to cut out the opening. I set a piece of scrap in the vise on the mill and milled a slot just wide enough to hold the O's that I had parted off (attachment 2). I used medium strength (blue) loctite to secure the blanks in the slot; in retrospect I should have used superglue or red loctite. However this time I had made an extra blank just in case (attachment 3).

I used a 2mm endmill, taking very light cuts, to cut out the openings (attachment 4). Good thing I made the extra blank - as I noted above, the blue loctite was not quite adequate, and one of the 3 blanks shifted loose, preventing me from completing the machining on it. Fortunately, the others stayed in place, allowing me to complete the 2 c-clips I needed (attachment 5).

The last bit in this part of the build was to make the valve springs. This was the first time I have attempted to make springs, and I have to say that I was pleased by how it went.

Before making springs, I had to make two accessories. First I made a "gripper" - not a very elegant piece, and I don't have any pictures or design to show - just a couple of pieces of scrap steel with a small slot between, such that I could clamp down using the tool holder screws to get the desired grip on the wire. Second, I made an arbor of the appropriate size - or at least, what I hoped was the appropriate size; I had trouble finding a table in Machinery's Handbook that quite gave me what I needed, so I had to extrapolate. (It seemed to work.) I drilled a .040" cross hole though it as a way to hold  the start of the music wire.

Finally I could make the springs. I calculated and set the thread pitch that would give me the desired number of turns over the length called for in the plans, put the wire through the gripper and through the hole in the arbor, and adjusted the grip tension (attachment 6). On the slowest speed of my lathe (30 rpm), I let it build a few starter turns, then engaged the half nuts to create the body of the spring, then disengaged and let it make a couple of finishing turns (attachment 7). After snipping the wire, it sprang open a bit, just as the book said it would (attachment 8). I trimmed down the start and finish turns, and tried it out - and it worked beautifully. My first spring (and the second that followed it) were a success!

This concludes part 10 of the build log. Next up will be a relatively simple part, the rocker arm.
Andy

Offline awake

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The "Steel Webster" build log, part 11
« Reply #42 on: April 12, 2020, 09:40:30 PM »
Part 11 of the build log, the rocker arm (attachments 1 & 2):

Only took a few pictures of this part - it was relatively quick and simple. I cut a blank out, milled it to size, and started drilling the holes, first for the the M3 screw that holds the follower bearing in place, and the .219" hole (shown as .250" on the plan - I changed it when I built it, but haven't yet updated the plans) for the bronze bushings (attachment 3). I turned the piece 90° so that I could drill a hole to locate the bottom of the slot for the bearing (attachment 4), and then milled the slot (attachment 5) until it fit the bearing (attachment 6). Finally I milled to size the end where the tappet adjustment screw goes (attachment 7).

And that's all the pictures I have of this part. Not shown was tapping for the M3 screw, drilling and tapping for the 10-32 tappet adjustment screw, drilling the oiling hole, and filing to finish the slot so that the bearing could move freely. I also failed to take any pictures of making the bushings which get loctited into the rocker arm, or of making the pin which gets loctited into the frame and on which the rocker arm bushings ride. Those bits were probably more exciting than the part I've shown above ... oh, well.
Andy

Offline Roger B

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Re: Introducing ... the "Steel Webster"
« Reply #43 on: April 17, 2020, 11:26:42 AM »
Always interesting to see how other people do things  :ThumbsUp:  :ThumbsUp:  :wine1: I use commercial 'E' clips as valve retainers so I don't mind if the swarf Gnomes get 1 or 2.

The springs came out well  :praise2: Up till now I have always used commercial springs for repeatability.
Best regards

Roger

Offline awake

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Re: Introducing ... the "Steel Webster"
« Reply #44 on: April 17, 2020, 03:02:06 PM »
Thanks! I was pleasantly surprised on how well the springs came out. I've made a couple more since then, and again good results with minimal effort. The key may be the "gripper" that provides the friction - mine is rather crude, but it works effectively to let me get just the amount of friction I need for a given size of wire.
Andy

 

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