The Geneva .... My first Hit and Miss Engine

[bearcar1]

Thank you Dean, I failed to mention that I did a few trial runs on a small scrap piece in order to get the radius set correctly. The trough is called out to be .125" deep and at a specified radius so I had to experiment just a bit to get everything set correctly. Also, I had never used a flycutter for anything other than flat facing surfaces. This was interesting to set the mill head over and use the cutter in that method. It worked, but I was nonetheless acutely aware of the setup and cutter location.

BC1
Jim

 

[mklotz]

For the benefit of those of you who wish to use this technique and want to avoid experimenting to get the requisite head tilt angle, my program RADIUS implements all the required calculations.

BTW, the curve formed by this technique is a section of an ellipse; it is not truly circular.

 

[bearcar1]

Marv is certainly correct as usual (don't you just loathe guys like that :big in his statement regarding an elipse. Of course had I set the angle of the mill head over more acutely I would have ended up with a more dished cross section but as the only requirement for clearance in this case was .125" in the center, I was lazy cheated and did not follow the drawings exactly. ;D The next most logical parts to be made were the bearing standards and caps. First it was a matter of sizing and squaring the aluminum pieces before proceeding to the lathe as can be seen here. The brass bar is used to assist the movable jaw of the vise to better apply pressure where it is needed most, in the center of the jaws and not toward the base as the jaw has a tendency to tilt when tightening up. I milled both pieces as a set to insure identical sizing.

I really admire the overall lines of this engine as it seems to possess more of a castings based model appearance rather than one made from barstock (even though this one is) but I did not particularly care for the squarish looks of the standards used in the original build and set off on my own to try and rectify that inconsequential problem. A few weeks ago, there was a thread/discussion regarding the usage of cyanoacrylate (super glue) as a means of holding odd shaped parts while machining. This is the method that I used to accomplish what I wanted to do though it was not without its faults and I will caution those that attempt to use these products in this manner to display and exercise extreme care in doing so. Proper eye protection should be worn at all times goes without saying. In my 'extras' box, I had a couple of disc brake, caliper pistons, that I had been wanting to use for a while and figured this would be the time. These pieces of steel are of a very good grade and once the chrome plating was cut through the base metal was a joy to work. This would serve as a known flat surface to which I used the adhesive, which happens to be a Loctite product, to mount the blanks to. I know what some of you are thinking and I have to agree but again, I had this vision and was determined to follow it through to its completion.

I had center popped the location of what would ultimately become the center of the crankshaft and used the dead center in the tailstock to position and hold the blanks to the surface of the caliper puck. A swabbing down with Isopropyl alcohol removed any traces of oil from its surface and I did not apply any activator although I do not think it would hurt anything.

After a 24hr. period had elapsed, which I figured was a good length of time for the adhesive to cure I again incorporated the use of that dead center in the tailstock and a small-ish slug of aluminum to assist in holding the blank firmly in place. The diameter of the slug had been turned to the diameter of the shoulder called out for and was used as a lazy man's guide to final dimension. After roughing out the piece I switched to a .125" cutter that I had ground a radius on and used it to do the final profiling, that is to eliminate the 90* junction that I did not care for.

Now then, I need to pause here a moment and relate to you all the first "OH S**T" :fan: moment that I encountered so far. In taking the next to last final cut to clean up the piece, it came off the backplate. So, I had to start over again by laying out the piece anew and used my wiggler setup (the one I used to center the cylinder bore and water hopper cuts) to realign it back to true and perform the last cut.

OK, no harm, no foul, a minor setback and off I went to do the other side. With that out of the way I was feeling good again and was back in the "so far, so good mode once again. 8)

That is until I went to begin getting them squared up and mounted to the base. Did you catch it?

To myself I was muttering Hey STUPID!!!! There are supposed to be a "L" and "R" part, yeah you know the same piece but MIRRORED. :-[ :-[ th_wtf1 th_bs

Yeah, yeah, one little mistake. You know I was on autopilot, I knew full well about the parts being handed and did the layout with that very thing in mind and I STILL made two of the same piece. What a mahroo! :big:

Here is the replacement piece being final faced and the world was once again back in balance.

Now if I had this to do over and I possessed a rotary table (why don't I own one anyway ???) I would mount the parts on it and use a ball end cutter in the mill to perform this step, it would be a whole lot easier than what I did but I got the job at hand done. One could argue that I could have gripped the part in a four jaw chuck as well but again, I "had a vision". Man I hope I don't get many more of those ;D

BC1
Jim

 

[bearcar1]

It's been a few days now and I had been pondering how to proceed with machining the slant backs on the bearing standards that the drawings call for. Hmmmm. Now I've mentioned before that I am by no means a math prodigy and this problem was no different and only loaned itself to my ignorance and lack of attention in class as a young lad. However, I would like to extend a HUGE thank-you to member, Bob Warfield, for having provided what I have found to be a quite useful program called G-Wizard. With it one merely plugs in the known dimensions and the program does the heavy lifting and calculations and then 'fills in the blanks' of the variables in question. Another nice feature about it is that it displays a graphic representation of the function you are working on, it helps in visualizing what is what. After some down and dirty addition and subtractions to arrive at the basics required, I plugged in the numbers and lo and behold, the program spit out 22.795*. Man, that was so easy, thanks once again Bob. Now all that remained was to come up with a method of holding the parts at that angle accurately. Not having a Sine bar or angled parallels I decided to make a holding fixture. This was done by first squaring up a scrap piece of .375" plate and then milling a square recessed pocket into its surface and finally, using a protractor, set the plate up in the mill vise and used an end mill to surface the edge of the plate flat. I turned the plate over and milled a flat on what was the bottom edge and when completed, the fixture could be repeatedly removed and remounted in a vise as it now had a reference surface in which to do so.

The addition of a drilled and tapped hole allowed for using a hold down clamp to securely capture the pieces for milling as shown below. I milled both of them at the same time so that I would be assured they were both the same. This probably was not necessary but it made me feel better.

I'll work on the caps another day but for now "so far, so good" ;D

BC1
Jim

 

[Deanofid]

"So far, so good". You got that right, buddy. Things are coming along well, even with that pesky "handedness" problem.

Jim, if you want to use the super glue thing again, try putting a number of circular grooves in your work holding piece. Pic below to show what I mean. I've used these things for years, and that works well. They let the glue cure properly. I usually just let mine cure for, maybe 10 minutes, the get to cutting. Done a lot of gear faces that way, and never lost one yet.

Keep up the good work, and thanks for all the pictures!

Dean

 

[bearcar1]

Whatya' say Dean, you know, I saw your post before showing that little tip of using the grooved back plate when using the cyano- adhesives but I forgot all about it till you just mentioned it again. I can see that the grooves would supply more surface area for the adhesive to bite, not to mention the fact that the majority of it would not get pressed out of the joint in the mounting process. I have to try your method next time around, that is *IF* I remember to. ;D The egg holiday is over and today I did not achieve a great deal :'(.

Below are the tools that I use primarily to locate holes for drilling and I would like to take a moment or two to discuss the procedure. I have mentioned before that I do not have DRO capabilities in the shop and having grown up seeing these methods used I find them to be quite satisfying albeit a bit time consuming. from Left to Right are drilling chuck with 00 center drill mounted, 60* center punch, carbide scriber, 1oz. ball peen hammer, 2" magnifying glass, digital height gauge. Of course my bearing standards and the bearing cap blanks that I worked on today. In the backround is the engine base, toolmakers square, and my cheapo dial caliper. ($12USD but they have been every bit as accurate as my Starrett ones and I don't have to sweat bullets about dropping them th_confused0052. During the layout of a part I try to make reasonably deep scribes where the lines intersect for the hole centers ONLY. After I am satisfied that everything is as it should be (except for the occasional th_wtf1 in doing mirrored items :big I use a magnifier and the carbide scribe to find the line intersects by 'feel', the extra fine point will "drop" into the deep lines mentioned previously. Once I am certain I have found the intersect I do a very light tap with the hammer and use the magnifier to inspect the pop mark and make any needed corrections in location at this time. Using the scribe again in the previously made pop mark I tap it just a bit harder and again inspect for location and go on to the next spot requiring this treatment. After all of the centers to be drilled have been found in this manner I switch to the normal center punch and give all of the locations a smart rap to make a deeper mark. For small diameter holes, this is as far as I go before drilling as the smaller drills will be fine starting using the pop marks, but if I require larger holes of say .125" I do one additional step and that is use the center drill in the chuck to begin drilling out the locations by hand before advancing to the drill press. For me this works out the best as my eyesight is not s good as it used to be and I have in the past drilled a hole off-location by not following this process :rant:. When I use this method the accuracy is quite good and I feel like I accomplished something as well.

This is a close up of the caps after getting "the treatment".

BC1
Jim

 

[Deanofid]

OH, I need a baby ball pein hammer like that!

On the times I lay out for holes, I do it the same way, letting a sharp scribe or stylus fall into the intersection of the lines. It puts 'em where you want 'em. Or, at least, it puts them where the lines cross... I have a harder time putting the lines where I want them than punching the marks!

Thanks for the update, Jim.

Dean

 

[Maryak]

Jim,

Nice work. :bow: I use the same method except for the hand drilling. I also use a scribing block, (surface gauge), because I don't have a vernier height gauge.

Dean,

A small piece of drill rod weighed, turned and tempered makes a great little punching hammer. Will take a picture of mine next time I find my shop.

Best Regards
Bob

 

[cobra428]

Nice Work Jim,
That's going to turn out to be a very nice engine!

Tony

 

[Deanofid]

Dean,

A small piece of drill rod weighed, turned and tempered makes a great little punching hammer. Will take a picture of mine next time I find my shop.

Best Regards
Bob

Bob, I have a number of small hammers. I was just being a bit covetous of Jim's little number. You know.

Dean

 

[bearcar1]

Bob, Tony, Dean, I thank you for your comments and support, it is reassuring to know that others do some of the same things that give me a feeling like I am a cave man sometimes. That little hammer was a gift from my Dad many years ago, I believe it came off of the Snap On tool truck that used to stop by his shop once a month. I also have a 1/2oz. one made by Craftsman that was my Grandfather's, he used it for the same thing and also for 'cutting' gaskets. (you know, place the gasket material on the part and lightly tap around the edge to cut and/or shape and locate the bolt holes) Mine certainly is *the* thing :-* for what I am using it for . Dean, you are more than welcome to borrow it whenever you feel like it but you'll have to come here to get it. (ROADTRIP!!!!!) :big: Thanks again guys, I'm off to the shop for some quiet time now, after I finally got the caps drilled and studs made for them and the caps secured down. (Sorry, no photos at this time :hDe: Yeah, yeah, I know th_wwp, but you all will just have to wait till the next time around. "so far, so good".


BC1
Jim

 

[bearcar1]

I've been fooling around with getting the bearings and the cylinder block lined up squarely on the base plate as well as aligned with one another and came up with this method. Although it is not a standard practice it seemed to work out for this application. I am pretty confident that the cylinder bore runs true and square through the block so this became my initial datum point. This is due to the fact that extra attention was taken in the layout and setup before the actual boring took place. Now all that was required was to extend and transfer that accuracy from the block to the bearing standards, insuring that they would be parallel to the bore. I found a piece of Acer Saccharum, that's hard maple for all of you brown stuff fanatics :big:, that had been a part of some wine bottle rack that never completely found its way to the trash pile ;D and turned it down to be a snug, press fit it the cylinder bore. the bore was just slightly smaller in diameter than the distance measured between the bearing standards so a step up was made on one end to accommodate that dimension. With this wooden dowel pressed into the bore it essentially was supplying me with a surface that I could use to position the bearings squarely to the bore and if I were to reposition the cylinder block for some reason, the positions of the bearing standards would follow along accordingly. No muss, no fuss, cheap and dirty, and relatively foolproof. Now in order to get the cylinder block aligned with the base to begin with, I clamped the base, on edge, to a large square V-block and used shim stock and cutter bits to pack the side of the cylinder until I had the cylinder at the correct height. A clamp was then used to hold the two parts together and using a transfer punch the locations for the mounting bolts were transferred to the block. Surprisingly enough, the holes came out in the exact same positions as what had been previously scribed in laying out. I just never really trusted myself to drill two parts like this and have everything line up the first time and to have all four holes come out this accurate was quite a pleasant surprise in itself. (now tell me none of you have ever drilled beforehand and found out later that one or two (all) of the holes did not line up. No really ;D) With the cylinder block holes drilled and tapped,and the lump bolted to the base, it was now time to affix the bearing stands and see if my rather barbaric plan would work. I once again inserted the wooden dowel into the bore and with a minor amount of fiddling and fussing was able to get the stands aligned to the base and firmly seated against the dowel to my satisfaction. Again using clamps and a transfer punch, those holes were located and drilled.

Now don't make fun of the extra long stud and the crappy bolts Rof}, they were what I had quickly at hand and will be replaced with proper hardware later. Overall things turned out well again as things go, I just hope it remains that way for the rest of this adventure. I'm certainly open to any and all suggestions and would love to hear of others experiences, this method seems to have worked for me.
"So far, So good"

 

[zeeprogrammer]

I know you mentioned them...but I'm not letting you off the hook...
My only suggestion is to get rid of the crappy nuts.
Anything less than a good nut is rotten. ;D

 

[bearcar1]

You're absolutely right Z', those ARE crappy nuts , but do you have any idea how many crappy nuts I had to dig through just to find those ???, Let me tell you, it wasn't pretty. :big:

BC1
Jim

 

[zeeprogrammer]

Hey, you're the one that brought it up. :big:

But just to be clear...

That was my only suggestion. Meaning...there's nothing I could say to make the rest of the project any better than you're doing. I'm watching with interest and enjoying.

P.S. If you had to dig through a bunch of crappy nuts then it may be time to get some new ones. But, if you're like me, you may not have a choice but to stick with the ones you have. :big:

 

[bearcar1]

Oh yeah, I think that I'll take your suggestion and stick with the crappy nuts I have, I've had them for a good many years now and it would be difficult for me to get rid of them now. th_confused0052 (cold hands) ;D Thanks for your your kind words Z', hopefully this adventure will be successful. :bow:


BC1
Jim

 

[arnoldb]

That's coming along very well Jim. And very interesting methods you're using too!

Regards, Arnold

 

[bearcar1]

Thanks Arnold, yes that could be considered an 'unusual' : method but it seemed effective for what needed to be done. I've been dreading (that is not really looking forward to) boring the hole for the crankshaft as I am scared of it being out-of-line as well, but in preparation to that critical step, I decided to provide for a method that would insure the alignment did not get forced out of square and also to allow for the bearing stands and cylinder to be exactly realigned if/when they would require removal. (I'm certain it will be multiple times before I am finished) ;D I am confident that all is aligned accurately at this point in time so I drilled a series of holes up through the bottom of the base into these two components and pressed in a set of .092" dowel pins to insure everything stayed that way before proceeding with the boring operation.
BC1
Jim

 

[bearcar1]

Well lads, the time that I have been dreading fearing the most finally arrived and I could no longer postpone it nor ignore it . That would be the boring of the hole through the bearing stands/cap assemblies that the crankshaft will reside someday. This is what I came up with. I first clamped an aluminum plate to the backside of the mill table. This would act as my angle plate sans the lower leg. Now having used a dowel rod to align the standards I thought why not use a similar method to assure perpendicular alignment of the crank and after checking to be certain my lathe tailstock was true, I turned down an aluminum rod that was a smooth slip fit in the cylinder and long enough to extend past the front and rear of the base assembly. Next up was the use of a small set of V-blocks and clamps to hold this bar in a parallel horizontal position on the table. With this arrangement, by clamping the bottom of the engine base to that aluminum plate I mentioned previously, I was able to use a wiggler to indicate the center location that I had laid out prior to mounting the lump onto my homebrew mandrel. I first drilled a .250" hole through the stands and the mandrel and then followed that up with a .375" bit and finally used a .500" mill cutter for the semi-final sizing. These photos were taken after all of the excitement was over and I could breathe again. (no calls to 911 were necessary thank goodness :bow. All of the hold downs have been removed. I used an expandable reamer to bring the holes out to final size by creeping up on that dimension a few thousandths at a time Thm:. I also did a bit of profiling to lend a bit more of a scale appearance and will need to do the profiles of the bearing caps next as well as get rid of the crappy nuts :big:. "So far, so good" yeah!

BC1
Jim

 

[zeeprogrammer]

Wow. That's looking great Jim.

As for getting rid of the crappy nuts..."Choose wisely".