A Simple Uniflow Engine

[gary.a.ayres]

Onwards and upwards.

Cutting the blanks for the two sides of the frame from 6mm aluminium plate with my Evolution Rage circular saw:





First time in ages that I've used this saw. I'd forgotten how good it is. It sliced through the plate like a knife through butter:



The paper template was used to mark out the rough shape of the frame on one of the blanks:



The two blanks were clamped together, drilled at the four corners and fixed together with M6 cap head screws so that they can be machined together to make the two frame sides identical:



The only critical edge at this point for alignment of the two pieces of plate is the bottom one, facing the camera. I used the surface plate to align the blanks before clamping them together and on running my thumbnail across the two thicknesses it felt like just one piece of metal.

The next stage is drilling holes along the bottom of the blanks so that they can be fixed to the frame mounting bars. The four marks along the edge roughly indicate the positions of these holes. At this stage the only purpose of having the curved shape of the finished frame marked on the blank is to act as a guide for positioning these and other holes. Cutting the frame to shape is still several steps away...

[propforward]

Very cool. That saw made short work of those plates.

[MJM460]

Hi Gary, good to see you able to get back on the job.  Nice to see some progress again.

I like your unique take on the side frame plates.  Did you use a special blade on that saw for the aluminium?  Or is it a whole special saw?  Either way, it would have been noisy!

MJM460

[gary.a.ayres]

Thanks guys.

The Evolution Rage blade easily cuts steel, aluminium, wood, wood with 6 inch (or even 9 inch ) nails through it, plastic.... etc.

Amazingly good saws and not too expensive for what they are. Interestingly, the blade doesn't get hot as it cuts.

They make other types of saws too - I also have their smallest mitre saw which I have used and abused for several years now.

So yes, MJM - it's a whole special saw. But you are right - cutting the plate was a noisy affair!

 

[Admiral_dk]

I have the bigger version - nessesary when building my Sister and Brother in Laws big hal 39x12x11 meters from steel profiles I welded together - and the Manufactor warns that the original blade MUST only cut steel and iron. They do sell another special blade for cutting Aluminium.
It cuts a big steel profile in a few seconds and yes it's rather noisy, but quick and the swarf is cool compared to all other methods

For daily use I wish that I had the smaller one you got, as it only a third of the weight => I rarely use it nowadays ....

[gary.a.ayres]

Per - thanks for looking in.

The one that I have is advertised as being suitable for steel, wood, aluminium... and it cuts steel plate nicely too.

Different blade from yours maybe?

[Admiral_dk]

They might have found a solution to improve how many different materials they support with a single blade - but since I expects many more years of use on the current one, I'm not looking to buy another yet (specially considered the price).
When I bought mine they strongly warned about aluminium would destroy the blade - but it's certainly the same brand and yours looks like a miniature version of mine.

[gary.a.ayres]

Per - yes, I guess they must have developed the blade over time.

After yet another weekend of domestic and automotive obligations (it has been a ridiculous few weeks!), I managed to squeeze in a little bit of shop time, as evidenced by this moody, atmospheric late-night still life of some aluminium, an automatic centre punch and a lens to peer through in the name of accuracy:



Sometimes I find it easier to use traditional manual marking out methods than to spend ages clocking in a workpiece (in this case just to drill four holes). The holes in question are along the bottom of the frame side plates, and the two plates were left fixed together for the drilling op, so it was eight holes for the price of four really. I used a wiggler in the mill to pick up the centre punch marks. No pictures of the drilled plates because all the photos tonight (except for the above) were blurry for some reason.

The next job will be to transfer the holes in the plates to the vertical side of each frame mounting bar, which will be a significant step towards building the main structure of the frame.

[propforward]

Frustrating when you can only get small amounts of shop time in - but hopefully you can get back for extended sessions soon!

[gary.a.ayres]

 Cheers Stuart.

[gary.a.ayres]

The two frame sides and the two frame mounting bars were all clamped together:



Remember that the uneven top edges of the plates don't matter - they will be trimmed off later. The bottom edges are nicely aligned, though, and the two screws at the top corners keep them that way.

The clamped assembly was then held in the milling vice ready for drilling the mounting holes in the support bars:



Since the side  plates were already drilled it was just a matter of spotting through the holes in them and drilling down through the two support bars. Because of this the holes in all four parts are aligned.

The frame sides were temporarily fixed to the support bars using stainless steel M6 cap head screws. This type of screw appeals to me for a contemporary style of engine, but I'll use shorter ones for the finished job:



Finally, a shot of the frames set up on either side of the main engine components:



This engine will be quite wide, but it will be slightly narrower than it looks here because the main bearings will be turned down a bit. Also, the frame sides will be reduced in size, shaped, and drilled with decorative holes. Although this evening's offering is not particularly glamorous, it's a significant stage  of the build because now that the sides can be attached to a temporary base, the next stage will be to drill the holes in the frame for the main bearings, so an initial mockup and perhaps an initial test on air are now on the horizon.

[crueby]

Coming together well!   

[gary.a.ayres]

Thank you Chris.

 

[gary.a.ayres]

Drilled a couple more holes tonight. The ones for the main bearings.

Getting ready:



I wanted to drill the holes 19.5mm and finish them with a reamer. However, my 20mm reamer has a MT2 shank, this mill is R8 and I don't have a suitable adaptor sleeve, so I just swapped to a 20mm drill as the last of four (including the centre drill) progressively increasing in size. The oil can contains some new (to me) cutting fluid called 'Molyslip'. It's a nice dark green colour and it seems to cut really smoothly. It has a nice viscosity to it so you can squirt it on to a spinning cutter and some of it sticks. Again the frame sides were bolted together and both were drilled in one operation.

The idea is that the bearing goes through the hole and the collar slips on to it from the other side of the plate, after which the components will be fixed together by a bolt circle that passes through the plate.



After drilling the 20mm holes tonight I discovered that the bearings are a fraction too big to go through them. Ideally I would have bored the holes a tiny bit wider at the same setting of the mill, but my boring head is also MT2, so same problem as above (I really need to get that sorted out!). Instead, I'll just turn the bearings down in the lathe. Not ideal because it risks a rattly fit between the bearings and the collars (and consequent inaccuracy in the crankshaft alignment). However, the amount that needs to be removed from the bearings is very small so as long as I'm careful it should all stay centred ok.

I couldn't resist a mockup showing the progress to date, despite the fact that the crankshaft is just sitting loosely in the holes without bearings:





To be honest the whole thing is riding a bit high in its frame at this point, but that was deliberate as I don't know yet whether or not I'll have to increase the diameter of these flywheels.

One step at a time...

[propforward]

Good progress Gary! Like you say, one step at a time. Love the test assembly. It’s going to be a super engine.