[Thad E Ginathom]

More superb work with the hacksaw!

I've been seeing pics elsewhere of people skating on Dutch waterways. For Debbie's sake, I am glad that warmer weather is coming your way now

[Jeroen]

Last week Saturday it was -10oC. Today, exactly a week later it is 18oC. Much better, so I spend some time in my garage with Debbie.

I finalised the muffler mounting block. It was quite a complex part, requiring a lot of thinking, measuring, and endless putting into a clamp in different positions, taking it out again etc.

First draw out the main dimensions;



Next in the mini mill and mill away excess material to get the basic shape in place:



Producing a nice angled finish on the corners:



The drawing called for this mounting block to be attached with M2 bolts to the cilinder. However, I thought that would be a bit risky. The last thing I need now, is to break a tap on the cilinder. So I decided to play it safe and upgrade to M3.

Threading with my trusted tap follower tool



Quite pleased with the end result:





Mounted it straight away on the cilinder. Looking good, I think!





Only a few more parts to be produced, then I will star soldering and next I can start building up the engine on the main base plate.

Jeroen

[Jeroen]

Another productive Sunday morning. I produced the two little base supports for the carburator.

First I cut and machined two pieces of brass into the correct rectangular shapes.
Next, into my mini mill with my special little fly cutter.

Speed set at 280rpm as this thing is set up to cut a 35mm diameter!. I took passes of 0,3mm, which went really nice.





I was very pleased how this went. I wasn’t sure at first on how to do this, but my model engine forum friends told me the fly cutter would be doing fine.



Really good fit too!



I milled a slight indent on the short side of the base support, drilled holes in the bottom and threaded them M3x0,5



Again, pleased how they turned out





Still a few more small bits to produce.

Jeroen

[Jeroen]

Over the weekend I attempted to produce the cam. On this engine the cam only moves the microswitch for the ignition spark. That is how it is set up on the original design.

As I have shown earlier I have a fully electronic ignition, based on a Hall sensor ready to be installed. In all honesty, it still remains to be seen if that will work, but for now that is what I am aiming for. So I don’t really need the cam as such. But I have never machined a cam, I think it looks cool on the engine. Also I do need something to attach the magnet that triggers the Hall sensor. So I will be using the side of the cam for that.

First thing is to produce the main shape. I had a piece of brass round bar left over from earlier. Well more a slice of round bar, but should be possible to produce the cam from this.

The boss I produced earlier came in handy again!



The cam shaft has a slight (1mm) indent on the back so it attached properly on the hub of the fly wheel. Easy peasy for me to machine these days!



Fits like thus:



next step is to make this circular slice into a cam. I decided to use the same technique as I had used to produce the drive rod earlier.

So the boss with the brass slice into the mini mill







But when I had this all set up, I was not quite happy with it. When I was machining the drive rod, that was an easy piece to hold and turn around the boss. This is a completely circular object. And you need to be able to hold it very firmly, or it will start spinning as soon as you move it to the cutter.

So I decided to make a simple tool to help me hold it. Which also meant drilling the three holes, used to bolt the cam to the fly wheel. To copy the position of these holes I use this very simple paper template technique. In the merchant navy we used this similar technique to produce DIY packings.

Just put the paper on the subject at hand and tap every so slightly along all edges, including any and all (bolt) holes.







Centre punch and drill the holes



And once again, Bob is your uncle!



Next produced a little handle from a piece of aluminium and bolted in place








Much better I thought!



Well, I thought it was better and it looked and felt better. Still, for some reason the cutter dug in on one side of the cam. Not sure why.



I checked everything, allgingment etc. Could not find anything. But I decided to set up everything again, but a bit more sturdy, bigger clamp, tighten down to cam some more etc:



That did the trick! I proudly present my very first cam!



Looks good on the flywheel too!



In between business calls yesterday I also cycled over to our local camping shop. I bought a 1litre bottle of Coleman Fuel. This little engine should run on regular fuel too. But especially with this evaporating type of carburator, the Coleman fuel should allow it to start easier.

Two more brass bits to go and then I can start the soldering I think!

Jeroen

[Jeroen]

Some more progress on Debbie

I have made my first attempt on the soldering. I am only partly pleased with it, I might want to redo some of this.





This morning I decided to see how the various parts look when put onto the base plate.



Pretty impressive, even if I say so myself. So I decided that I wanted to get at least all the running gear finished today. First thing I needed was a small spacer.



The pulley still needed three holes drilled and threaded so it can be fixated on the shaft





Some very carefully measuring and adjusting. The shaft needs to align to the piston rod, but also when turning the piston needs to be in certain position in relation to the various openings in the cilinder.



Measuring, adjusting, measuring, adjusting, measuring, adjusting



Drill, thread and bolt down!





More importantly, lets see how it runs:

https://www.youtube.com/watch?v=I65NCkCmlxU

Looks pretty slick. It does easily three full rotations with one hand swing. Which is within spec if I go by Jan Ridder’s design. I did not have the piston rod O-ring installed yet.

But still, this looks encouraging

Jeroen

[Thad E Ginathom]

Super progress, Jeroen. Looks close to being a working engine now

[Jeroen]

At long last got to spend some time on Debbie. Finished all soldering. Some pretty ok, some not so.

Fixing these little tubes and bits prior to soldering is a bit of fiddle. I used wires to keep everything in place.



First one, not bad!



More to come. I really should not be using just ordinary pebbles to hold the brass parts in place. But it’s all I got. Safety goggles on permanently!!



Not bad:



Not all went well, first time. Had to redo a few, despite my best effort and wires they still ended up crooked!



This is how a piece looks right after cooling down.



I use my little ultrasonic cleaner machine with citron acid. Heated to 80oC, five minutes cleaning gets you this:





Next I use a rotating copper wire brush in my Dremel to polish.



All kinds of odd shapes I had to fit









I did a little pressure/vacuum test on both the carburator and the dampner.

Just filled them with water, closed of the various pipes/holes and blew on it. Tried with soap water too. Had to redo one solder.



A quick fit to see how it holds together, pretty good!!



Tried out the ignition one more time.



I have to make a bracket for the Hall sensor and drill a hole in the cam for the magnet. Hall sensors are sensitive to one magnetic pole only, so I had to try which side worked. 50% chance. But as I will be gluing the magnet into a hole to be drilled into the cam, I better get it right first time.

Jeroen

[Thad E Ginathom]

Super soldering setup!

When it comes to holding parts for soldering, whatever works.... works. I'm aware of, but never seen, a product made for jewellers: Knew Concepts Titanium Soldering Strips. If I were tmaking jewellery again, or soldering any small things, I'd get these.

There is a guy on Instagram who is an incredibly skilled maker of miniatures and collector of antique tools. He recently showed a tiny ship's porthole he had made in brass. He had used gold solder for one process. I asked, why? was it for the colour? Yes, he said, it was a perfect match. Perfection at any cost! For those that don't know, yes, gold solder is gold and costs by weight at least the same as the same standard gold, and the last time I looked, came in minimum 3gr pieces. Three grams may not sound much, but hey, the price of gold. I recall it was rather more than the "profit" I made on the first gold bangle I ever made.

(Instagram: @wmrrobertsonminiatures, web: William R. Robertson

[Jeroen]

Made good progress with Debbie:

First thing, I made a little bracket for the Hall sensor:



Next I drilled a small shallow hole into the cam and glued the magnet in. You need to ensure you get the orientation correct as the Hall sensor will only work on one magnet pole.



Installed the bracket:





Next I assembled all of Debbie!! Looking good, for the first time I filled up her carburator with Coleman Fuel. I tried to start her and got her running for about 4-5 seconds!!



Which is not bad for a few first tries. However, unfortunately my Hal sensor packed up. Not sure what is wrong. I have a different one, and the plug does spark on that one. However, it is a very different model and it would not be easy to mount that on Debbie. So I have ordered some 4 new Hal sensors from Aliexpress. Should arrive in the next 10-14 days.

In the meantime I will add some small touches to Debbie, just keep going!

Jeroen

[Thad E Ginathom]

Originally Posted by Jeroen

Next I assembled all of Debbie!! Looking good, for the first time I filled up her carburator with Coleman Fuel. I tried to start her and got her running for about 4-5 seconds!!

She lives!

Congratulations! That must have been hugely satisfying

[Jeroen]

I also managed to find the identical Hall sensor here in the Netherlands. So i ordered that too. Ordering one from the Netherlands is five times as expensive as ordering one from China!! That does include freight and shipping, believe it or not.

I also ordered a little rubber wheel. I am going to mount it on one of my electric drill, to help Debbie start. Not sure it I can get enough friction, if not I will have to make a special adaptor.

Whilst waiting for parts I build the wooden frame for Debbie.



Still two more coats of paint to go on, but looking nice. The metal base plate fits on top, and I still need to mount four studs on the wooden frame .

[Jeroen]

My new Hall sensors arrived yesterday! So I quickly installed one, adjusted it properly so the ignition commences at exact top dead bottom position of the piston. Checked and double checked.

Next I tried to start Debbie. Using my little rubber wheel in the electric drill. A couple of coughs and nothing. Upon further investigation I found that the Hall sensor broke again. This is very strange. There is no mechanical contact between the sensor and any of the rotating parts.

In order to mount the sensor I have to count/shave of a few bits, I would not think that would make any difference. Maybe it is the vibration?

I posted on my Dutch modelbuilding forum, maybe somebody can come up with a suggestion. I have three more Hall sensors left, but I don’t see the point in just trying again. Need to do something different.

I have found a somewhat different shaped, but probably more robust Hall sensor here in the Netherlands too, ordered that, so maybe that will help. Wished Sutripta was still about. Do we have any electronic specialist on the forum. Why would a Hall sensor work fine whilst testing (spinning the flywheel by hand) and would it fail as soon as the flywheel gets cranked up to higher RPM?

I was also given the address of a specialist Model hobby shop who might have this sort of equipment too. Maybe they can help.

To be continued

Jeroen

[Jeroen]

Some more fiddling with another Hall sensor and that broke too. No idea what is wrong. The only thing I can think of is that somehow the electronic ignition and the Hall sensors I am using are not compatible? A bit weird.

I have been getting some good suggestions from my friends on my Dutch Modelbuild forum. One suggested just replacing the hall sensor with a micro switch.

But first I wanted to produce the spark plug. As I mentioned earlier; the ready made spark plug protrudes less through the cilinder head as the DIY version. Which means two things; The compression ratio will be negatively impacted and also the actual spark is very high up in the cilinder head.


Producing the steel body for the spark plug was pretty straight forward



One of the two electrode is attached to the body, the other sits in the middle of the insulator. The former needed a tiny 1mm hole right on the edge of the 6mm hole for the insulator. (see drawing below). Drilling a 1mm hole is nerve-racking at the best of times. Getting it in a very specific position is even worse



I wanted the 1mm hole for the electrode to slightly overlap with the 6mm for the insulator. That way the electrode would be nicely held in place.

Used my mini-mill to make two flat sides on the body of the spark plug so a standard 14mm open wrench would fit nicely



Next, turning the teflon insulator. Never turned or milled teflon before. Very easy.
Cutting the thread went very easy.



Beginning to look like a real spark plug already!





Next I got a brass bolt, cut of the head, drilled a 1mm hole top to bottom and inserted another electrode. Soldered it together.



Voila!! I must have handled hundreds of spark plugs over the years. But this is my very first DIY self made one. Gapped it at 0,55mm



Here you see the ready made and the DIY spark plug together:



Next, to replace the Hall sensor with the microswitch.



Yes, yes, I know, looks a bit patchy and iffy. But this is just a try out version. I soldered on some wires so I could hook up a multimeter in parallel. That allows me to adjust the ignition timing, using a simple multimeter



Fairly straightforward. I loosen up the three grub screws on the fly wheel. I push the piston to it top bottom point using the micrometer. At that position I turn the flywheel till the cam (which is attached to the flywheel) closed the microswitch. tighten the grub screws and Bob’s your uncle.

I also made a small adjustment to the little ball valve. It’s opening height was about 0,5mm to big.

Next filled up the carburator with Coleman fuel. This is what happens then:

https://www.youtube.com/watch?v=6xIYvYhY77U

I am ever so pleased!! Very proud of myself. It runs really well. I tried starting it by hand four more time. The fourth time after it had been sitting idle for over an hour. Starts up straight away. Which means that all the fittings, dimension, clearances etc are all pretty much on the mark!!

I will need to make a proper mount for the micro switch, tidy up the wiring, hide the electronics in the wooden base I made earlier. Just pretty her up a bit.

But still, I am very glad I got it to run. Not everybody has managed to do so. In fact there are not that many people that managed to get this little engine to run.

There are couple of very critical components. The piston and cilinder need to be made to near perfection. This piston does not have piston rings. So its clearance in the cilinder has to be around 0,02mm!! Which on my little Sieg lathe is a bit of stretch at the best of times. So I spend many, many hours honing the cilinder to get the piston to fit correctly. Also the piston rod seal needs to 100% concentric and again very small tolerances, or it will not run or seal properly.

Finally, what has been a problem for many model builders is the ball valve. It needs to close 100% or the engine won’t work. You loose compression and or the scavenging will not work either.

So a little bit more work to be done on Debbie. I will also be doing a proper little video on the whole building process.

Time to start thinking about the next project.

Actually, last night I bought a model V8 kit. Just a plastic kit, but at 1:3 scale and see through operation I thought it would be cool!





https://www.louis.nl/artikel/franzis...umber=10015027

No metal working required as far as I can see though.

Jeroen

[Thad E Ginathom]

Superb. Easy to start even. Being easy to start must be the cherry on the cake!

I have not been watching much machining recently (mostly Steve Summers rebuilding his shop) but I see that Joe Pi is making a scale model lathe. Well, he's made it of course, by the time I started to watch.

[Jeroen]

Originally Posted by Thad E Ginathom

Superb. Easy to start even. Being easy to start must be the cherry on the cake!

I have not been watching much machining recently (mostly Steve Summers rebuilding his shop) but I see that Joe Pi is making a scale model lathe. Well, he's made it of course, by the time I started to watch.

Yes, I am very pleased. Having seen/heard so many people struggling. Yes, the hand crank is really the proverbial cherry on the cake! I have seen some of these engine’s running but only by starting them up with a drill.

Hand cranking means all the tolerances are spot on!

I have been following Joe Pie for some time now. Very interesting. But way above my abilities. I still prefer Blondihacks. Much more my thing. Not necessarily my level of competence, still a long way to go.

There is also this guy: adventures with a very small lathe

https://youtu.be/k3yWIkkP8w8

He works on a Proxon lathe and has the same Proxon mini mill as me. But his skill set is about a billion times better than mine. Makes good videos!

Jeroen