Elia

Steve thanks.
 
I finished up the rough shaping and polished the long form then cut the sections down to the root diameter.The lift ended up being .021" I can live with that.
 

 

 
the root sections are machined to  .156" diameter
 

 
bored reamed to .125" and parted off ready for pin holes in the root sections
 

 
slipped onto the .125 shaft.
 
Michael
 
 

thanks evreyone for the encouragements.
 
The cam cutting is working well a little slow but I am pleased with the way it is shaping up.
 
I made a small indent pin for the Myford this morning before starting on the shaping.
 

 

 

 
the wheel was progressively marked with the teeth that would be left out until I got to the 1/2 way mark from both sides of the lobe apex
 

 
the cutter was rounded a bit more after this cut

 

 

 
Still .008" to go before the final clean up.
 
Michael

Druxey,Nigel, and Mark, thanks for looking in yes ouch indeed. 
I did a test cut this evening with the sharp nosed bit sideways and am going to cut the cam form as a single piece about 1 inch long.
 

 
  I am going to use the main gear that is normally used to set the headstock in back gear because it is a 60 tooth gear so I will set up an indent so as to lock the spindle in the 6 degree increments, the height of the cam is .022" from the cylindrical body so mapping out the 22 cuts using the gear to index I will be able to form the lobe then clean it up with files and wet and dry polish the hole thing then drill and ream for the 1/8th shaft
 
part off the cams and then locate them and set up a dial to position them drill for the pins then when doing the final assembly use some loctite as well as the pins
 

 
cams made on lathe.pdf
 
Thanks for all the likes
 
Michael

Ouch! At least there was no personal damage beyond pride.

MarkT, Steve, Nils, Ed, Mark, Druxey, Matt, Bob, Jack, Row , Denis, and Remco. thanks for your kind remarks


 
Mark I thought I was on track to make these in pairs  112 degrees rotated from each other. First turning up a trial piece to   the major diameter of the lobes, then using the taper pins I fitted the piece to some 1/8th diameter drill rod rough filed them at 90 degrees like this. My thinking was that I could then use the rotary table and the mill to finish each lobe by following a table of offsets and rotating the piece.
I drew the rotary table to how the process would work.
 

 

 
camshaft template.pdf
 
The part was then set up in the mill
 

 
The first lobe worked well and after removing the pin and flipping it over end for end I was ready to cut the second lobe.
After making the initial cuts to remove the bulk of the material for the second lobe i was getting ready to make the final circular cut around the back side of the lobe when I realized I had cut the wrong side of the rough block of material basically leaving both lobes in the same plane. In order to satisfy myself that this was actually the case I went to rotate the table to get a better look. the cutter was still rotating and I grabbed the wrong handle because I had not pulled it off which I normally do when working the rotary. I gave the lower handle a full turn and instantly uttered a censored word!
 

 
not only dit the cutter eat into the work bending the shaft but also snapped off a bit of the cutter.
 

 
the result
 

 
So now I need to rethink the whole operation.
 
Next I am going to make a long single lobe and then part off the individual cams and pin them separately, I can salvage the rest of the cutter it will need a bit of regrinding on the end but that is not much more trick that sharpening a drill bit.
 
A long winded answer to you question.
 
 
Mark  the buttons are some drill rod turned to the diameter that I want the finished curve to be, the smaller diameter slides into the hole and the larger diameter pushes up to the material that will be shaped
 
Once the two diameters are made I part it off and then heat it to cherry red and quench in water the button is then to hard to be affected by the file.
 
Matt I think that the splashing will do the work.
 
Row, Hmm the pressure is on, the original notion was not to add them, But I am thinking it might be better to add some.
 
Off for a swim at the local pool to warm up and console myself it was chilly in the shop this morning -2 degrees Celcius, -30 outside  probably cooled my brain down and that is why I forgot to remove the mill handle.
 
Oh well these test are there for us to learn from, no point in getting too cranked about it.
 
Cheers Michael
 
 

Today I finished the bushings for the con rods
 
The first picture is showing the soldered rod ready to be machined
 

 
the next is showing the bushing ready to be de-soldered.
 

 
ready to be installed in the big end of the rod.
 

 
filing to shape with the hardened button
 

 
ready to be assembled
 

 
test fitting
 

 

 
 
and finally here is a video of the engine to date.
 
That is a big milestone out of the way now I can move on to the camshaft and valves.
 
michael

Bob the privilege is mine having the luxury of good health,  time and materials to be able to follow my hobby. There are those much less fortunate because of many factors beyond their control, where life and the environment  intervenes.
 
Bob,Yes I will be going with straight brass for this engine. There was very little solder left, it was only the small sections of the wall on either side, the soldering iron was clean and held on the end of the composite until the heat melted that connection then the small bit of spring that was in the tweezers was enough to pop them apart.
 
I did not take a picture when doing the first one I will for the second.
 
Thanks Pete.
 
And to all who added likes.
 
Michael

This is, literally, a privilege to watch.
When you de-soldered the bearings, did you leave some tinning on the surface for babbiting effect, or are you going w/ straight brass?

Nigel thanks for your kind comments I am happy that you are enjoying the journey.
 
Druxey, thanks.
 
Mark, in a word Yes. I'm pleased you have found some of these processes useful.
 
Steve and Mark, that make at least three of us
 
Thanks for all the likes
 
Pressing on with the con rods today the first task was to split and solder the brass for the big end bushing, I decided to make these individually so that I could check that it was going to work.
slitting the rod

 

 
soldered ready for machining
 

 
turning down to the flange diameter
 

 
The final bore was done with a 1/8th end mill after first using a centre drill then a 3/64th drill.
 

 
Turning the central part was very tedious with very light cuts and double checking the diameter after each pass of the tool.The bush was then parted off. 
Tthe bore is .125" and the body diameter is .156" so the thickness of the bearing wall is only .0155" and that made me very cautious.
 

 
I used a soldering iron and a pair of tweezers inside the bore to unsolder the bushing, it popped apart very cleanly.
 

 
I turned and hardened a new button for the bottom of the big end of the con rod.
 

 
when everything was cleaned up the moment of truth,...... it fit Yea...a little stiff but not much
 

 
Then I wanted to check the height inside the cylinder and was very pleased with the outcome, I did notice that I plopped the top part of the crankcase on backwards after uploading the photographs... excitement I guess.
 
 
Now I have to repeat the process all over again tomorrow and I also have to relieve the bottoms of the cylinder liners to clear the con rods. I had drawn this in the details but have not done it yet, once that is done tomorrow the the piston with be able to move up and down in a complete cycle
 
 
Michael
 
 
 
 

This was the sequence for the top end shaping.
 
the first shots showing the rotational shaping in the lathe using the chuck as a vice while moving the cutter back and forth.
 

 

 

 

 
Next using a rat tail file to finish off the shape
 

 
after filing but before final clean up.
 

 
ready to assemble
 

 
Michael

Thank you all for you kind comments regarding the notes on the way I go about drilling holes. and thanks for all the folk who liked it.
 
Pressing on with the con-rods the first order of business was to make a brass split holder for some of the following operations this was made from 2 pieces of 1/4 x 3/4 inch bar stock before I drilled and reamed the 1/8th hole through the joint I added two small slivers of .0015 shim stock to spread the bars so that when the con rod which  is 1/8th is placed between them the allen head cap screws will have that .0015 missing so that the bars squeeze the shaft of the con rod holding it firmly.
 
The first three picture show the stage 2 of shaping the rods the round ends have now been reduced to the correct width.
 

 

 

 

 
The next operation was to drill the holes for the split big end these are clearance for 0x80 bolts
 

 
After the holes were drilled the assembly was taken back to the lathe for the slitting saw to cut the big end into the two parts. they are temporarily held together for drilling out to .156" for the bushing. here they have been drilled and the hole for the wrist pin followed by indexing 1.004" (I'm not sure how it got to be 1.004" I'm just following the drawings)
 

 
The area marked in blue is to remind me that I will need to shape the keeper later and remove that areas marked with some files using a hard button to ensure that the curvature is maintained. I also need to turn up some steel bolts for the big end, and make the split bush, I will do this by soft soldering a couple of bars together then turn the bushing in the lathe then unsolder them ready to fit the rods.
 

 
removed from the jig so that I can get the second one to the same stage.
 
I'm tired time for a nap.
 
Michael
 

 
 

Micheal,
 
Thanks for the tutorial on drilling.  I particularly appreciate the comments on indexing to locate holes.  I am doing a lot of small hole drilling in wood right now on Young America's planking.  Tight holes to hold the planks with pins when glued are #74 and holes for the treenails #73.  There are literally thousands of these on the model.  I always - always - center mark the wood with a sharp scriber and use a hand-held, pencil sized (Wecheer) rotary tool with either steel or carbide bits in a zero opening (Dremel) collet.  As I write this I am fiercely knocking on wood but I have not broken either of the two bits I am using in several months.  The usual cause of breakage for me is dropping the tool or whacking something with it.  I believe the keys are those you mentioned - center-marking, high speed, keeping bits clear - also, a very light touch with the tool helps.
 
I too, will be keeping a copy of your note.  Thanks.
 
Ed 

Thanks Nils and Row for your kind remarks, and to all who added likes.
 
Mark these are the drill bits I have purchased they are good quality general purpose from Acklands Granger The 1/8th shank bits came as a box of mixed sizes,  I got them from Lee Valley and that they got them from Drill bit city but I am only guessing on that one My centre drills are like this one ,in these sizes 0, 1, 2, 3.
 
Mostly I sharpen my drill bits as they get dull.  the ones I use the most are # 50-59 #'s 20, 43, 33, 36, 12, 8, 11, 29, 25,
and most of the fractional from 1/16 to 1/2 in the 1/64th inch increments I have a few metric drills specific to metric taps.
 
The smaller bits I sharpen with a small slip-stone holding both the drill and slip-stone in my hands for the bigger ones I use the big diamond wheel that I got from an optician as a discard when they purchased new equipment.
 
With the bits that I use a lot for brass and plex I use the slip-stone to put a flat on the cutting edge so that it does not grab but scrapes
 
Michael

Jud this is what surprised me the most as well, I am following the same practice as many of the model engines that have been built by the model engine builders and the most important thing is to make sure that the cylinder liner is well polished when using the O rings which is opposite to using cast iron rings. There are a number of tutorials for making cast iron rings down to 3/8th diameter but it takes a bit of practice and some really good cast iron bar stock to be able to make them successfully.  
 
JKLee and Omega
Yes it is a different area of modelwork but basically one only needs to focus on the task at hand and break it down into incremental chunks small chunks I admit. The way I see it is that each time we change materials or scales we encounter new challenges and have to consider using different tools for some tasks.
 
Remco the short answer is no, that said I think that the basic issue with drilling small holes is one of sequences.
 
1)  When drilling into wood with very small drills 1/32 and down to the small #'s 60-80 the wood is not a consistent homogenous material, it is organic and full of subtly different hardness's and textures and this is I believe the main reason for breaking the bits when using a drill press or milling machine, the other issue is the speed of rotation of the bit, the smaller the bit the higher the speed the machine needs to run, this is counter intuitive to the way we use them by hand in pin vices which is technically a snails pace by comparison. I think the difference is that when using a hand held pin vise we use much less pressure and can "feel" the drill cutting, remember our fingertips are one of the most sensitive parts of our bodies with the possibly the most nerve endings. 
 
2) When drilling metal the key is to ensure that the start is exactly centered, and I mean exactly, this can only be accomplished by using a centre drill to spot the centre first my centre drill for the small drills cost me $27 for a tiny 1/8 shank centre drill this means the for every hole I have to do a number of things first decide on where the hole is going to be, this entails laying out the position on the material and fixing the material solidly to the drill press or mill, I tend to use the numbers and not a centre punched divot, by that I mean indexing from two or more sides depending on the shape, the centre drill takes the place of the punched divot.
 
3) The way I index is to use an  edge finder or centre finder to set the datum on at least two edges then I can simply set the dials on the table to 0 and them index them to the two coordinates x and y that is the centre of the hole, I do this regardless of the size of the piece I am drilling, it is a habit. The quill of the mill also has a dial so that I can set the tip of the drill to 0 at the surface that way I know how deep my hole will be if I am not going all the way through. if I am going all the way through I sometime use some wast material as a support so that the drill does not catch and snag on exit one of the biggest causes of broken drills in the smaller sizes, the other is the drill bending because the start was off centre from the centre axis of the rotation of the drill as it gets deeper the bending forces increase often snapping the drill.
 
4) The next important thing regarding wood or metal is ensuring that the drill flutes do not get clogged with the material what you are removing out of the hole, it has to go somewhere so raising the drill out of the hole frequently allows it to escape (this is usually centrifugal force that throws it off the drill) sometime the material is "gummy" some brass and some aluminum can be this way and so a lubricant (Varsol or Paraffin works well) is needed to keep the bit slippery, a cutting oil for steel. Obviously one doesn't need the lubricant on wood but it can clog the bit even more quickly than metal, so small "pecks" (frequent raising of the drill to clear the wood off the drill) a small fine stiff brush can be very helpful to clear this debris out of the flutes.
 
The last thing to remember is the depth to diameter ration of the hole deep holes are more difficult to drill for all the above reasons
Finally use the best quality drills you can afford and I always use a centre drill to spot the hole, this means that if I am drilling a number of holes I can drill all the centre spots first (following all the numbers on the index map drawing) then go back and follow all the numbers again with the drill this is the fastest way when I an drilling multiple holes to the same depth. Or I can change the drill from the centre drill to the hole size drill with each cut, it depends on what I am drilling and for what purpose I choose which way to go.
 
I hope this answers your question.
 
All of what I just said applies to using a drill press mainly, and also ensuring that the work is rigid (clamped in some way is also very important) when working freehand or using a hand held drilling devise drill or Dremel type tool similar conditions apply but they are not quite the same, and I take my hat off to all the steady hands out there, drilling treenail holes. I cringe when I read of using a # 70+ drill bit by hand.
 
 
Omega actually this really applies to your Ingomar yacht model 
 
 
Michael

Steve and Bob thanks for your nice comments, and to all who have added likes.
 
I ended up making a new holder and some new pistons (it would be nice to only have to make something once for a change)
The new collet really does help a great deal being able to see clearly what I am doing. the new holder also is a bit stronger, the firdt pic show drilling the 1/16th hole for the wrist pin.
 

 
the finished pistons with the rectangular cavity and the wrist pins temporarily in place.
 

 
I have turned down the blanks for the con rods,
 

 

 
The next operation on the con rods will be to machine the large diameters into flats, then bore the hole for the crank , and drill and tap the crank end before splitting it with the slitting saw. then the big end will be re assembled and rebored for the big end bearings
 

 
piston and con rod.pdf
 
Michael

Thanks Denis.
 
Not a great deal of progress over the Christmas, too much food intake and family visiting all very enjoyable of course.
 
I spent a little time today mostly building a special collet for the 1/8th shaft mills and drills which I would normally use in a drill chuck, but using a drill chuck for milling is to court disaster. I used some free machining 3/8 mild steel for the collet, this tool will only be used for light work.
First I turned it down to 1/4 and threaded the locking end 1/4 x20 to fit into the 1/4 collet in the Clarkson collet holder for the mill then it was drilled with a #31 drill and reamed 1/8th for the 1/8 diameter shank drills and mills.
 
the end was threaded 5/16 x 24 and the end 1/2 inch was cross slotted with a .014 slitting saw and a 41 degree taper was turned to match the 82 degree 1/4 diameter countersink that I have. A locking nut was machined out of a scrap of 1/2 inch diameter mild steel and a couple of flats filed onto it for a wrench
 
All this was done so that I could actually see what I am doing because with the small diameter end mills the Clarkson collet holder is too big a diameter and really restricts the view when using the small diameter mills.
 

 

 
Tomorrow I will do some work on the inside of the piston.
 
Michael
 
 
 
 

I have got the gearbox to the point where I can now move on to the driving portion of this engine namely the pistons and associated gubbins.
 

 

 

 
First I needed to machine up some blank pistons these are .311" (7.89mm) in diameter and .372" (9.52mm) high
 
these were then set into a fixture to drill the wrist pin holes and to machine the squarish hole inside.
 

 

 
they are fiddly little things to work with, popping the O ring on is easy getting the ring off is another story.
 

 

 
they slide up and down nicely in the cylinder head.
 

 
 
Merry Christmas everyone
 
michael

michael,
 
Wow....it looks as detailed as full size. Amazing.
 
Mark

Thanks for the likes.
 
I used a trick I employed when filing up connecting rods on my model steam locomotive, and that is to use a hardened button as a filing guide.
 

 

 

 
The top of the handle ended up being hand filed I had originally intended to turn it in the lathe by holding the lever in the four jaw chuck, it caught and bent so after straightening it I used needle files sandpaper and steel wool to clean it up.
 

 
Michael

Greg, Mark, Carl and Mark thanks for your encouraging comments about my work, and again to all who have appreciated it quietly.
 
Moving forward to the control of the clutch I have started to make the forward reverse lever. This lever will need to have some ability to be adjusted.To give just the right amount of pressure to the clutch spring. The geometry of the fulcrum points is critical.
 
The strength of the coil spring is also one of the items that might need a few reworks to get right as well. The whole physics of springs and their construction is no doubt a science, but from my practical point of reference, a trial and error method will have to suffice. So I will see if it works.
 
I rummaged through the scrap box until I found the right bit of brass to cut the lever out of. I used the vernier height gauge to lay out the shape, then pre-drilled all the holes while it was rectangular this makes it much easier to get them square to each other.
 

 
the cutting was done with a fine blade in the jewelers saw. I have already started to file the surfaces to the final shape.
 

 
The keeper rods are now set into the gearbox these were turned up from some free machining 1/8th inch hex stock, at first I left the heads as a hex bolt but they were too big and interfered with the pressure collar. so turned them into cheesehead screws. the spring was wound from some .020 music wire, I used the number drill series of drills as the arbor to find the correct size to finish up with a 3/16th internal bore the third attempt produced the correct diameter, it was a number 21 drill.
 

 
The lower pivot point to which the lever connect to will be mounted on the back wall of the oil pan below the prop shaft, and will be able to be threaded forwards and backwards to give the adjustment.
 

 
There will be a connecting link from the lever to the clamp on top of the clamp ring.
 
Michael
 
 

Bob, Druxey and Nils thank you all for your kind comments, they are very encouraging, makes all the re do's worth while.
And not forgetting all the people who added a like.
 
Nils, Not exactly, I have been making stuff though for a long time, and as a commercial model-builder and designer I had a lot of projects that gave me the opportunity to learn new skills. I have learned from my mistakes what works and what has not. I had good teachers at school, who encouraged a genuine curiosity for learning how to do things for myself.
My woodwork teacher taught me how to sharpen tools.
The first machine that I purchased was a Myford lathe back in 1971, I learn new things about how it works every day it seems.
 
Michael

Ed, and Jack, thank you for your kind comments. and for all who added likes.
 
I had to make a new band clamp because the tabs were not wide enough to bolt it to the pan. the new one was machined from a solid ring and then a lot of fiddling and filing to get it to spring just right.
 

 

 
I also whipped up a flywheel because it is tough on my fingertips turning the 1/8th shaft all the time to test stuff.
 

 

 
Today I worked on the clutch, it was a bit of a design build affair following the general principles, the gearbox and clutch will be underneath the cover so only the top of the linkage and the lever will need to be as accurate as possible to keep the appearance of the engine looking as the full size engine.
 
I abandoned the cap screw hex and made a hex broach from a 3/16 allen key. first I heated it up and let it cool slowly to take the hardness out of it, then cut a taper on one end of the hex. Next I added the beveled slots to create the cutting faces. I ended up making a second one because I forgot to temper the first one after re hardening it, it cut the first hex through about a half inch length of brass stock, and then I tried a longer piece of brass and it shattered into three.
 

 
Pushing the second one with the vice rather than using the hammer which is how I managed to wreck the first one.
 

 
At the back end of the broach I reduced the diameter before it was hardened so that I could part off the disks one at a time, as the broach was forced through, each time the broach reached the end I put it back in the lathe parted off another disc
 

 
Next I turned a few discs of mild steel off a blank that had been pre drilled for the keeper rods. the steel discs are 5/8 diameter and .020 thick the brass plates are 5/16 diameter and .040 thick. the steel discs will be fixed to the gearbox and rotate about the hex the hex will be pinned to the prop shaft and the brass plated will spin with the hex
 
.
 
Here they are test fitted for size, the wide brass collar is also keyed to the prop shaft and will be the pushing element to squeeze the plates together.
 

 
Time for bed
 
Michael
 
 

I can't add any knew words, Micheal, but the like button just seems completely inadequate.  Beatiful design.  Beautiful workmanship.  Can't wait to see it running.
 
Ed

Remco, Steve, Joe, and Row thanks for your very kind remarks. Thanks to all who pressed the like button as well.
 
I finished up the clamp ring today and made the actuating lever to open and close the ring, it is quite tiny but was manageable. in order to get the widths that I wanted quickly I spun up a disc on the lathe, bored out the centre hole on the lathe then stood up the rod with the disc still attached in the vice on the mill and offset the other hole .156" then took it back to the lathe and parted it off then used the jewelers saw to cut out the crank.
 

 
Then cleaned it up with some files, then polished it up to a rouge finish and beveled the hub to create the cam.
 

 
Here it is set in position with the spring loaded bolt in the open position the width of the flanges at the bolt are .290"
 

 
And here with the lever in the closed position the width of the flange at the bolt is .250" locking the gearbox casing.
 

 
This is how it works
 
next the rear cam locking collar.
 
Michael
 

Thanks everyone for the comments and Likes.
Its been a long couple of days working on the gearboxes, yes I ended up redoing the casing a couple of times over, I also opted to redo the inner stuff as well. Although the micro gears worked they were not as smooth as I wanted. I ended up using some 48DP "pinion wire" it is actually 10 tooth brass pinion, and is exactly 1/4 inch in diameter. this way I was able to go by the numbers and make the proper distances for the gears to mesh'
 

 
Like this Video
 
In order for the gearbox to be able to lock so that the prop rotates forward there is a clutch that is splined, I have been wracking my brains working at finding a way to make a small spline. This morning as I woke up it hit me.
 

 
Yup the trusty old allen head cap screw has a negative hex to accept the hex key, I matched up a 5/16 cap screw with some 1/4 inch hex brass. the steel collar will revolve in the base of the forward/reverse lever and will move about 1/64 to clamp the prop shaft to the gearbox causing the forward motion. the hex part will be pinned to the prop shaft, and a loose clamping collar will be inserted between the hex collar and the casing of the gearbox, when the lever is pulled back the hex collar will move forward clamping the case and loose collar hence locking the case to the prop-shaft
 

 

 
The revers is accomplished by clamping the gearbox inside a steel band which was made from some steel rings turned up and silver soldered together. As the gearbox is clamped the splined collar also releases the loose clamping collar allowing the gears inside to impart the reverse
 

 
The rings were machined to shape using the mill and the lathe.
 

 

 

 
When I cut the slot on the top of the band it automatically sprung to a smaller diameter which works in my favour because in order to open the band a wedge has to slide forward, this wedge is connected to the forward reverse lever.
 
It is getting there.
 
Michael