I've made a start on drawing this one up with a view to fabrication and cutting from solid rather than using the no longer available castings that the drawings are based on.

This image shows the Trace function being used in Alibre where an imported image, in this case a snip from the drawing file, can be shown on the screen and drawn over. The holes and bosses were located first to the dimensions shown and extruded equally either side of the central plane that the drawing was placed on.

The next image is where the trace comes into it's own as you can draw your lines and curves to follow the usually undimensioned "cast" parts of the casting. I've added a couple of features from the photos of original engines and may even go for a completely separate crankshaft bearing caps as it would make it easy for taking the engine apart.

Lastly the start of an assembly, the jacket with be fabricated from 10mm thick steel plate stop and bottom with a length of 3" ERW tube between. The two shapely brackets will come out of 16mm 6082 plate and be cut on the KX3.

I'm going to do this one the same size as the drawings which are for a 42mm bore engine, still quite small for Heinrici engines, this would be the second size up

I've not seen many engines with the claim the design is to help line things up and not sure it was actually a feature of the full size as a lot seem to show a separate cap.

Let the swarf making begin

While waiting for some materials for the current engine under construction I thought I may as well get on with a couple of parts for the Heinrici as I had all the material in stock and the CNC had not been fired up for a couple of weeks so decided to do the levers that transfer the movement of the eccentric boss on the flywheel to the top of the pistons. To help with balance I went with 6082 Aluminium rather than have the weight of a heavier metal needing to be lifted along with that of the pistons.

After drawing out in Alibre the exported files were opened up in F360 and the paths worked out. These were the first 3D parts since my old licence expired so I was limited in not having the "steep & Shallow" that I usually like to use but a combination of "scallop" for the upper curved surfaces and "ramp" for the steeper ones and vertical faces worked out quite well. I also did not have any rapids, not much of an issue with the two previously mentioned paths as the tool mainly stays down and in contact with the work, the Adaptive clearing probably took about 5mins longer than it would have with rapids enabled but that was not a problem. Hopefully all the info is in the video captions

The finished items after a quick "shoe shine" with a strip of Emery Cloth. I've already sleeved the middle one and will do the same to the forked end as unlike other versions I'm not keen on running the pivots in bare aluminium

I have also made a start on some of the components that will become the fabricated water jacket, the tube is 3" ERW tube with the wall thinned down to 2.5mm by boring it out.

The 3 step pulley and brake adjusting knob were just straightforward turning jobs.

They are actually iron Ron, I had a couple of offcuts from some block that were the right sort of size so used them instead, original arms were iron castings.

A bit of manual machining this weekend starting with the end plates that will form the top and bottom of the water jacket. After pickling the 10mm black bar was bored out as I felt this would be easier now than 100mm down inside the jacket plus it reduced the bulk of metal needed to be heated for soldering.

After soldering and another dunking in the pickle the jacket was brought down to overall length having allowed 0.5mm either end for a clean up pass.

Then onto the mill to trim around the top flange which I had left 1mm all round should it not line up perfectly with the bottom after soldering. Also drilled and tapped various holes for the main bearing brackets and brake adjuster bracket.

Then with it held between a pair of angle plates worked my way round milling the bosses back to length then drilling and tapping as required.

The black mill scale can be a bit abrasive so even if milling it off you will get more cutter wear than if it were bright bar so the pickle removes it without affecting tools.

I use Feb "Brickclean" which is basically a 10 %hydrochloric acid and after about 1/2hr the scale just falls off. Use it outside, rinse well after use, dry part and give a quick spray of WD40 to stop it rusting. Also don't forget you have something in the pickle as it can start to eat into it if left for several hours.

Have a look at John Stevenson's couple of posts on this page

Edited By JasonB on 24/12/2020 17:15:23

Back to a bit more swarf production on the CNC today.

The two brackets that support the crankshaft and rocker shaft were exported to F360 and the various adaptive roughing and finishing paths worked out for both sides. Rather than waste too much metal I printed out two profiles and laid these on some 16mm thick 6082 plate and nested then as close as possible then cut them out on the vertical bandsaw. The bottom and end of the foot were machined on the manual mill to give me a reference corner and the mounting holes added at the same time. I then drilled and tapped three M3 holes to be used to holed the part to my well used machining plate, the plate was setup and then drilled on the CNC so easy to line things up. 6mm 3-Flute carbide cutter uncoated and with a helix angle to suit aluminium loaded up and here it is ready to go.

This shot is at the end of the first 5mm high stepdown of the adaptive, the 5000rpm and 500mm/min feed producing decent chips without stressing the machine and within what I could blow/brush away manually.

This is at the end of the adaptive (roughing) which was set to leave 0.5mm to be removed by the finishing cuts.

I then changed to a 4-flute 4mm dia cutter with 1mm radius corner (convex) to do the rest of the work.

The second side was done in much the same way but with the tool not going around the outside of the work as that had been cut to full depth on the first setting.

I tend to judge how productive the day has been by the amount of swarf produced, F360 tells me that had I started with rectangular blocks then 84% would have been turned to swarf, as I nested them it was probably in the region of 65-70%. Some of the waste lumps will be used to make the caps from.

Once the caps have been made tomorrow I will bore the two shaft holes before softening all the edges and surfaces to get things looking a little more "cast"

After turning the second black I decided drill six 1" holes to remove some of the initial waste material as it's a bit more fun than watching the CNC do it with the added bonus that the swarf can drop down rather than need clearing out of deep pockets. While set up like this I also held a scriber point in the chuck and marked the edge of the disc so I could get in the correct position on the other mill.

As I had two flywheels to do and they would need setting up twice so that each side could be done I put a piece of the crankshaft material in a flange mount ER32 collet and clocked that in to 0,0 so the parts would always be centred. 1,2,3 and 20, 40, 80 blocks packed the work up to just clear the top of the collet nut.

It was then just a case of placing a flywheel on the pin, rotating until the mark lined up with a pointer in the chuck and clamping down tight. The basic shape was roughed out with an adaptive path using a 6nn 3-flute cutter at 4500rpm, 300mm/min feed, 5mm vertical DOC with 1mm stepover to leave it looking like this

I've actually just started the finishing "scallop" cut in the above photo using a 6mm 4-flute ball ended cutter at 4500rpm, 500mm/min feed and a stepover of 0.25mm which slowly worked its way around the rim and then down around each spoke to leave a finished half looking like this.

It was then just a case of flipping the part over and running similar cuts for the other side though the boss is round on the inside where as the outside had the boss for the crank pin.

The few odd ridges and steps look a lot worse than they feel and were quickly removed with needle files and a bit of Emery.

I also got round to setting up an air lower for the second side and wish I had done it sooner as I was able to leave the machine to it's own devices rather than having to keep clearing swarf like I did on the first side during the roughing cuts, not so bad on the finish cuts as very little is being removed. Will show some photos of this in the Further Adventures thread at some time.