Introducing ... the "Steel Webster"

[stragenmitsuko]

A wel documented build with a lot of pictures is always a pleasure to follow .

pat

 

[awake]

Thanks!

 

[a41capt]

Awake,

I don’t see where you locked your clapper down for the internal keyway, or am I mistaken? If you didn’t lock it down, we’re there any problems with the return stoke, or was there enough clearance for your tool in the early stages of the cut for clearance?

I need to do a similar operation, but a little deeper, and I’m wondering if my tool holder will be rigid enough to not chatter in the cut groove.

Also, I’m thinking as you did in that I could possibly get away with grinding the cutter to create a tight fit for my key rather than “sneaking up on” the width as you did. I too save ALL my broken HSS end mills just for moments like these, so sign me up as a pack rat too!

I’m using a tight and great running Atlas-Craftsman 7B.

Thanks in advance for any wisdom you can pass along!

John W

 

[awake]

Hi John,

You are right - I did not lock the clapper down. I had read that that was the thing to do, and had contemplated how I would need to drill and tap for set screws on either side of the clapper. But something else I read or saw somewhere suggested that it might be possible to do the job without locking, so I tried it, and it worked just fine, with a couple of caveats below. Yes, there was enough clearance - part of why I had to grind the cutter I did, since some of the other options I considered would not have cleared!

A few small bits of experience - more working observations and caveats on my experience to date than any true wisdom, since I have only cut a grand total of 4 key ways on the shaper (no, as I was writing this I remembered that, in addition to having to remake a gear, I also wound up remaking the ignition cam to incorporate a starter spud, and then I remembered that I also cut a key way in a small pulley a while back, though using a different cutter, so actually it has been a grand total of 6 key ways!):

I did cut one part (can't remember off hand if it was one of the gears or one of the ignition cams) with the tool turned the other way around, i.e., cutting at the top rather than the bottom. That may be where it would have really be helpful to lock the clapper - you can quickly visualize that in this configuration, if the clapper moves, it will bring the cutter up into the work, rather than away from it. I got away with it, but it was clear that this was not the best way to do it.

A second observation / caveat, which may be obvious, but just in case - each time that I increased the depth of cut, even though only 2-3 thou at a time, it helped to let the shaper take at least two or three strokes - this may again be where a locked clapper would have helped, because it clearly took 2-3 strokes before it was finished cutting. Of course, it may also be a matter of the shape of the cutter - I am still not sure what the optimal rake might be for this operation.

Third observation - clearance IS an issue, not only for the cutter (which wasn't actually a problem since I had sized that to leave clearance), but rather for all the other bits. The tool has to reach a good ways out to get into and through the bore - and it has to do so without running the screw for the tool holder into the part. One solution would be to extend the "leg" of the holder a lot farther down than I did on the holder I made / show above; another would be to make the body of the cutter holder (or the tool itself) extend further outward, so that less of it is "overshadowed" by the tool holder. Thus the use of only one split cotter clamp - I had to pull the tool further out to allow it to complete the cut without hitting the tool holder. I also had to find a shorter tool holder clamp screw, and in fact on the last key way I cut, just the other day, I substituted a set screw to reduce it even further.

There is a corollary to the last observation - with the tool having to stick a ways out, you may have to find a way to move the part back further in the vice or on the table. The very first key way that I cut, which I just now remembered, was a small pulley for a wood working tool; for that one, I mounted a right-angle fixture to the table and clamped the part to that. But you will see at least one picture above that I had a "duh!" moment when I realized I could move the part further back in the vice simply by putting a scrap piece in front of it.

Hope this helps - I look forward to hearing how you get on, and any improvements you come up with on the process - there is clearly room for improvement!

 

[awake]

Part 5 of the build log is the rod:

Once again this will have to be a multi-part post, as I took quite a few pictures - despite being a relatively small part, the rod took quite a lot of setup and machining, including figuring out how to use my Christmas gift - a 6" rotary table.

The process began with machining a 5/16" thick blank from which the rod would be cut - once again using my trusty shaper to get it flat, parallel, and to size:

Next was boring the hole for the big end, sized to accept a pair of F686 flanged bearings with a light press fit. (I also drilled the hole to accept the plain bearings for the small end - nominally .250", but the exact size didn't matter, since I later made the bearings to fit):

The next operation may look rather strange in the picture, but hopefully will make sense when you look at the plans - I drilled 4 holes, carefully located using the DRO and started using a center drill, which will define the transitions between the rounded ends and the slightly tapered body of the rod:

The next step was to make a mounting plate with "buttons," each tapped and drilled at the top :

The buttons were sized and positioned precisely to accept the rod blank, and a screw and washer in each button held it securely in place. The plate is enough larger than the rod blank to allow clamping onto the rotary table, and it also acts as sacrificial material for the milling process:

Part 5 continues below ...

 

[awake]

Continuation of part 5 of the build log, the rod:

The next bit took a while as I began trying to figure out the best way to center the new 6" rotary table under the spindle of the mill. I put an MT2 dead center in the center hole of the RT, and started out trying to use a DTI to center it:

I was not getting entirely consistent results this way, so I tried switching to an edge finder, and compared the results; they did not exactly agree, but I got it within .003" or so and got frustrated and quit decided it was good enough:

With the RT centered on the mill spindle as best I could, zeroed the DRO X & Y. Then I clamped the mounting block in place, centering the big end "button" under the spindle using the edge finder - thus it should also be centered to the RT. I also used the edge finder to line up the small end button so that it was exactly 0° along the X-axis, and I zeroed the dial on the RT:

Getting the RT centered AND the part centered on the RT was by far the hardest and most time consuming part of making the rod - is there an easier way to go about it? (I was badly lusting after a Volstro rotary attachment by the time I got done with this!)

Once centered and aligned, however, the actual machining proceeded pretty much according to plan. First I moved the X-axis to position the 0.250" diameter cutter on the OD radius of the big end. I raised the knee until I just grazed the blank, zeroed it, then raised it .031" and rotated the RT 360° to machine the boss around the big end:

I continued to rotate the RT until the cutter was aligned with one of the .250" holes previously drilled to define the transitions, raised the knee another 50 thou or so, and rotated the RT to cut around to the other transition hole on the other side; rinse and repeat until the OD of the boss was completely cut out.

Next I reset the RT to 0°, lowered the knee back to where I was taking a .031" deep cut, and machined away the inset section of the body of the rod:

Once again I reset the RT to 0°, moved the X- and Y- axes to position the cutter at the location of one of the transition holes, rotated the RT 2°, lowered the knee 50 thou or so, and began cutting the tapered flank of the body section, stopping when I reached the transition hole at the small end. Rinse and repeat until the flank is completely cut away:

I lowered the knee again, rotated the RT to 2° on the other side of 0, positioned the X and Y axes to the other transition hole at the big end, and again raised the knee and began cutting the other flank of the rod by 50 thou or so at a time. Finally, the sides of the rod, along with the OD of the big end, were completely machined:

I removed the screws holding the blank in place, flipped the piece over, and took the .031" deep cut around the boss and down the length of the inset section of the body of the rod. Then I reset the X and Y axes back to 0,0 (centered over the RT), removed the blank from the mounting plate, unclamped the mounting plate, and reversed it to center the small end on the RT / under the spindle. This time I tried using the cone side of the edge finder, and I decided that was way better than trying to center the part using the edges:

I followed a similar process to the one described above to cut the boss section on each side of the small end, as well as the OD of the small end. At last, the rod is complete:

Well, almost - we still need bearings! Continued one more time ...

 

[awake]

Final continuation of part 5 of the build log, the rod:

The next step was to make the plain bearings for the small end. Unfortunately I did not have any 660 bronze smaller than .75" in diameter, so I had to turn that down - but these plain bearings are very short, so not too much waste. I turned down a length to the diameter of the flange and drilled out a .125" hole through the middle. Using a dial indicator to get the exact length, I turned down the body of the bearing to .251" diameter and .150" long, then moved over to leave a .020" thick flange and parted it off:

I repeated the last few steps and then I had two plain bearings. Note that the length of these bearings will leave a .013" gap in the middle of the small end of the rod. I drilled through the top side of the small end using my smallest center drill, giving me a "dimple" in the top and a tiny hole through, so that oil can drip through from the cylinder to the piston, from the piston to the small end, and make its way around the .013" gap to lubricate the wrist pin. At least, that's my theory!

You may have noted that these plain bearings were sized at .251", to go into a hole in the small end that is a nominal .250" - in other words, a press (or rather, a shrink) fit. .001" is actually more interference than I thought I really needed, so I actually sized it for about .0005" of interference. I heated up the small end of the rod using my trusty heat gun (a bit of an impulse buy on an extra-cheap sale, but it has proved to be invaluable over the few years I've had it):

With big end heated up nicely, I only had to press very lightly, really just a slip fit, to seat the bearings on either side. Of course, once the rod cooled down, the bearings were going nowhere:

There is nothing much to the wrist pin (the plans for which are actually together with the piston, coming as part 6 of the build log); the main consideration is achieving a rather precise OD of .187":

This precise sizing was intended to fit into an equally rather precise hole of .188" diameter through the small end bushing. Two problems: the first is, how to hold the rod at this point, with all of its rounded and angled surfaces? The answer was to use the mounting block again, this time in the vice. I mounted the big end on the mounting block and screwed it down with the small end hanging over the edge so that I could drill through; this worked way better than it seemed that it should - I was able to drill without movement or chatter:

The other problem was how to get the precise .188" diameter hole when I didn't have a reamer of that size. The answer was an old-timer's trick - I "snuck up" on it by drilling it first with a 5/32" drill (through the undersized hole that I had predrilled in the bearings); then I drilled again with an 11/64" drill; then one last time with a 3/16" drill. The idea is that the 5/32" drill will drill a bit oversize, as is typical for the average twist drill; the 11/64" will mostly just clean that up; and the 3/16" drill will basically act like a reamer. It worked; the result was a very nice sliding fit on my wrist pin:

The final step was the addition of F686 bearings in the big end. These were a light press fit, and I used them that way throughout the first few runs of the engine, but once I took it apart, finalized everything, and reassembled, they were secured with "red" Loctite:

The rod is now complete; on to the piston!

 

[kvom]

With regard to the frame drawing and dimensions, I'd make a few changes for ease of use.

There's no dimension for the height of the lower part of the rail, and the angle cut in the side could be indicated as many builders would probably mill these with the work set at an angle in the vise.

If you use the bottom of the frame as the reference and dimension from there up I think the vertical positioning will end up very consistent.

 

[awake]

kvom, many thanks! I will add those in. Actually, the dimension of the lower part of the rail WAS in the plans - but I made a change in the model, and it confused the part of the software that turns the 3d model into plans, so I had to re-do several of the dimensions. Obviously I missed that one!

On the angle, I confess I left it out because the exact angle is completely non-critical - but it is a trivial matter to add it in for anyone who would like to have it.

Again, many thanks!

 

[awake]

Whew! It has been an insanely busy week. Apparently "work at home" has been translated into, "it's really easy to schedule a virtual meeting, and I'm sure you have nothing else to do, so let's schedule 10 or 20 of them!" Sheesh - glad it's finally the weekend so I can focus on something important!

Here is part 6 of the Steel Webster build log, the piston:

As you will see, I did not take many pictures - this went more easily than I thought it might. The following picture shows the OD of the piston already completed, but not yet parted to size. Here's the most interesting bit of this part of the build log - if you look below the piston in the chuck, you will see a rusty chunk of cast iron, cut off of an old pump housing. This is the other side of the stock from which I made the piston that is mounted in the lathe! I cut a piece down on the bandsaw as best I could, then shaved down the lumpy outside to get something round enough to hold in the chuck. Then I turned it down ... and as you can see, it turned beautifully:

Since the stock that I reclaimed in this way was more than long enough, I decided to try making some cast-iron rings. First I reversed the piston in the chuck and protected it by my highly sophisticated aluminum shim (AKA cut-up Coke can); then I OD I wanted for the rings; then I bored it out to the ID:

I then parted out 5 rings using a narrow parting tool; not shown is the dial indicator clamped to the ways that lets me control the movement of the carriage, and thus the thickness of the rings, very precisely:

The round rod that you see is just a bit of cold-rolled steel that I put in a drill chuck in the tail stock; it is there only to catch the rings as they come off the blank:

Confession: I haven't actually done anything with these ring blanks. Since this was my first engine build, I decided to try going with a viton o-ring, and that seems to be working well - just a single o-ring, but you will note in the first picture above that I cut two grooves for rings - this in case I decide to experiment with the CI rings down the road.

I failed to take any pictures of the next couple of steps: After getting as many rings as I could from the blank, I made the final facing cuts to bring the piston to the desired length. I then mounted it in the mill vise "crosswise," i.e., with the axis of the piston set along the Y-axis, resting on parallels. After finding the center and the end of the pistion, I drilled the wrist-pin hole, using my "sneak-up-on-it" approach described in the build log for the rod.

I could then put the piston in the mill vise using the drill bit through the wrist pin hole to line up the wrist pin parallel to the vise; this let me then mill the oval slot where the small end of the rod will reside at a right angle to the wrist pin:

You may be wondering about the threaded hole that shows up in these pictures - that was part of my original reclaimed cast-iron blank. I had carefully planned how to cut the blank out of the chunk of CI so that I would be roughly centered on that hole - otherwise, I would not have been able to get a big enough blank to work with!

Not shown, but easy to do, was the final step, remounting the piston "crosswise" as described above, and once again using a drill bit through the wrist pin holes to align the wrist pin parallel to the table. Then I found the center and the end, and drilled out the 0.094" hole that allows oil to drip through to the matching hole in the small end of the rod. In Webster's original plans, this should have a brass tube pressed in to carry the oil right up to the small end ... I haven't done that, at least not yet - maybe a later improvement.

One bit about which I am quite uncertain - my decision on how to keep the wrist-pin from floating out and scoring the cylinder. As you can see in the plans, I chamfered the outside of the wrist-pin holes. For the final installation of the wrist pin, I cleaned it all well and used a bit of red Loctite as the first line of defense. Then after that was set, I came back and lightly staked the ends of the wrist pin so that they protrude a bit into the chamfer. Had I done a better job, that would have been the end of it ... but I didn't get the wrist pin positioned quite right when Loctiting in place, so I had to do some strategic filing to bring the end of the wrist pin back down to where it would not scrape the cylinder. The engine runs nicely, so it did work, but clearly I need to refine my technique ...

 

[a41capt]

One bit about which I am quite uncertain - my decision on how to keep the wrist-pin from floating out and scoring the cylinder. As you can see in the plans, I chamfered the outside of the wrist-pin holes. For the final installation of the wrist pin, I cleaned it all well and used a bit of red Loctite as the first line of defense. Then after that was set, I came back and lightly staked the ends of the wrist pin so that they protrude a bit into the chamfer. Had I done a better job, that would have been the end of it ... but I didn't get the wrist pin positioned quite right when Loctiting in place, so I had to do some strategic filing to bring the end of the wrist pin back down to where it would not scrape the cylinder. The engine runs nicely, so it did work, but clearly I need to refine my technique ...
[/QUOTE]

On my Henry Ford Kitchen Sink Engine, I drilled and tapped two holes at #4-40 in the piston above the wrist pin, and then marked and lightly filed flats in the wrist pin corresponding to the tapped holes. I hold the wrist pin in place with two #4-40 allen head set screws to keep it from walking.

John W

 

[awake]

John, that's actually what the Webster plans call for. I don't have a 4-40 tap, and didn't think there was enough room to use 6-32, so I tried this. Dunno ... the engine is running fine thus far; I ran a tank of gas through it today, playing with various adjustments to see what ignition timing / mixture / throttle settings it liked best. So far so good ... but next time I'm either going with the set screws, or brass rivets on the ends of the wrist pin.

 

[awake]

Part 7 of the Steel Webster build log - the cylinder:

I lucked out in having a scrap piece of DOM tubing with an .875" ID; the exterior was a little rusty, but the interior was pristine. Using this meant having to make the complete cylinder in two parts, with the fins cut from a separate piece of aluminum. That mostly went well ... mostly.

First step was to face it, cut it just over the desired length, and face the other side to the target length of 2.5":

At first I was thinking I would turn this short length "between centers," and I experimented a bit with using the live center in the tailstock as I began to rough it out:

But I just wasn't confident that I could guarantee that the tube would set on the centers perfectly concentrically, since I didn't have a way to cut a center seat that was perfectly concentric to the bore. Well ... I could have swapped in the 4-jaw chuck, centered on the bore, and cut a seat, but I decide to go a different route and made an arbor. I began by facing and center drilling each end of a 4.5" long piece of cold rolled steel. Then I put my "machine-in-place" dead center in the three-jaw, set the compound to cut the 60° included angle, and skimmed it so that I had a perfect dead center to work with:

I mounted the arbor blank between centers and machined it with .75" diameter ends, a little under 1" long, and the center section just over 2.5" long at just under .875" for a nice sliding fit in the nascent cylinder; here is the arbor in process:

I installed the arbor in the cylinder with Loctite; after it set up overnight, I could return to machining the OD of the cylinder. The arbor worked great, letting me flip end for end as needed to machine the details:

Continued below ...

 

[awake]

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:

Next were the boring operations, first boring to 1.073" diameter for a shrink fit on the 1.075" diameter cylinder:

Then I bored out the 1.25" diameter x .125" deep recess into which the "lip" of the cylinder liner sits:

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:

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:

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:

Continued one more time below ...

 

[awake]

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:

If I do say so myself, the end result was perfect:

... or not. Take a closer look at the picture above, 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 - one of them thinner than all the others:

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:

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!

 

[David Willoughby]

An excellent job with precise specs. Thanks for the post

 

[kvom]

"94.000 thou" isn't proper dimensioning. .094 is.

 

[awake]

"94.000 thou" isn't proper dimensioning. .094 is.

You are so right. This is a bug in the software I am using that drove me crazy. Later on I discovered how to over-ride it, and I tried to go back and do so on earlier sheets, but obviously missed some!

 

[awake]

Part 8 of the build log, the head - only a few pictures of this one:

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 bits - 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:

I bored out the .502" deep recess for a nice firm slip-fit with the cylinder:

After flipping it over, re-centering on the spark plug hole, and boring out the shallow recess for the spark plug, I 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. 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.

 

[awake]

Part 9 of the build log, the valve block:

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:

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 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:

What may not be obvious in the picture above 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:

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.

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 began with a cheap diamond sharpening block:

Followed by increasingly fine grits of wet-dry paper on a smooth glass surface:

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

Then I drilled the holes that go in the side of the middle block:

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