An experimental V-4 wobbler

[j45on]

Great pictures 
I'm looking forward to seeing more of this engine 

[spuddevans]

Thanks Arnold and Jason  

I did a little experimentation with the magnets today, if anything, I've found that the magnets may give more attraction than needed, creating extra friction on the "wobbling" motion. But I have an idea of how to adjust the strength by using a different size of disc of steel in the recess on the main frame, thus giving some adjustability.


Tim

[saw]

Looking good 

[raynerd]

Nice one Tim, I think I get what those magnets are doing now.

Chris

[BiggerHammer]

I never would have thought to use magnets... Brilliant. Also looking very nice, hope it runs as good as it looks so far.

[spuddevans]

Thanks for the comments Saw, Chris and BiggerHammer  

Tim

[doubleboost]

The magnet idea is very clever
A friend of mine playes around with magic tricks
I bored out some coins for him and glued magnets in to them i was amazed at the strength of the little things
Great build log by the way
John

[spuddevans]

Thanks John


I got a little more done today, namely the drilling and tapping the 32 holes in the cylinders for the packing glands and endcaps.

Having a DRO with a bolt hole function does make the drilling a lot easier, combine that with a vice-stop for repeatable workpiece positioning makes for a relatively easy time.

I got a little carried away with that and forgot to take any in-progress shots of the drilling, Oops


Then I mounted all 4 cylinders in a vice placed on my tapping stand, and I was really glad to have it. Tapping 32 holes with both M2 taps ( 2nd and bottom ) by hand would've been a nightmare.




As it was, I was able to tap a hole every 20secs, which I thought wasnt to bad. But after tapping 16 holes on the top, then turning them all over and tapping the bottom 16, I started to think if there could be a way to speed the process up a little.

One thing I noticed was that withdrawing the tap seemed to take longer and caused more ache in my arm. Then inspiration hit ( or perhaps it was a particularly bad case of wind  ) and brandishing a hacksaw I made this little mod to the top of the shaft on my tapping stand.




Then I put a slot screwdriver bit in my cordless drill and selected reverse. Then I would wind the tap into the hole by hand until it reached full depth (just before the squeek) then back it out a quarter turn, then it was just a case of slotting the screwgun onto the newly made slot and 2secs later the tap was out, much easier on the arm!!


So at the end of that I have 4 (hopefully) finished cylinders.



Then I had to retire back to the pc to redo some of my plans to adjust some dimentions on the main frame.


Tim

[spuddevans]

I got a little more progress today, not much to show, just some preperation work really.


I started off by making a little angle plate, this is needed for milling and drilling the internal steam passages in the "V" section. I have got some angled parallels (now there's a funny thing), but I didnt want to stack up 8 of them to make 45 degrees !!!

So I marked up a scrap of 10mm ali plate and rough cut it on the bandsaw, then mounted it on the mill table using a V-block to align it for finishing it.

I 1st up aligned the V-block,


this is taken before milling, and yes I did notice that one edge is not fully fitted into the V-block, I adjusted it and re-tightened it before milling.



Here's the result. I know that it is a little rough looking, but it will do just fine, it will only be used 2 or 4 times, and each time will only be for aligning the frame in the vice, the angle itself will have no pressure applied to it.



Then I turned to preparing the Ali for the main frame. I cut off a piece of 1/2" thick Ali' in the bandsaw, then cleaned up and squared the 4 edges. This just left the front and rear faces to clean up and bring to 12mm. My present flycutter has about a 30mm sweep, so it was not enough for this, so I sharpened up a new piece of hss and mounted it in the larger flycutter ( I have a set of 3 flycutters, up til this point I have only used the mid-sized one )

Tooling ready I took a couple of shallow cuts off each side (0.25mm doc), then checking with mic I reduced the thickness to 12mm. The last pass took off 0.1mm and left a really reflective finish.



Then I spent a while marking out the positions for all the holes to be drilled in the face.




Next time things should get a little more interesting, I will be drilling all the thru holes and then boring on each face the 10mm bore's that the cylinders pivot on, plus some bores for the crankshaft ballraces, then will be drilling the long internal air/steam passages (longest is 46mm)


Tim

[saw]

You are doing good Tim 

[spuddevans]

Thanks Benni


I've got a little more progress made of the frame.

I mounted the frame in the vice on the mill on some parallels and then using an edge-finder I zeroed on the bottom of the frame (actually I zeroed off the jaw of the vice) and then zeroed off one side of the frame blank. I then moved in to the center of the frame and zeroed there. This is because of the way I have marked the dimensions on the plans, working from the center of the frame rather than from one edge.

Then I put a little center drill ( I really must get some proper spotting drills ) in the chuck and center drilled all the holes using the coords off my plans.




Then I set about drilling all the thru holes, and all was going well until a little "plink" sound. Grrrrr, I broke a 1.5mm drill halfway thru leaving a small segment of drlllbit stuck fast.





I finished off drilling the rest of the thru holes with a fresh bit, and bored out the larger blind bores for the cylinder pivots and for the ball-races for the crankshaft. Then I turned the blank over and bored out the larger blind bores on that side, then very carefully drilled the failed 1.5mm hole from the other side until I heard and felt the drillbit start to catch the stuck fragment.

I then spent an hour or more digging it out using various methods with not much success until I tried using a pointed V carbide burr. I then very gradually fed the burr into the stuck drillbit until I had bored most of the way through the stuck bit, then I took the remainder of the broken drillbit, ground the broken end flat and then I applied a little persuasion with a hammer and the stuck bit popped right out.


Then I took a couple of pieces of 6mm steel rod for the next step.




These 6mm rods fit into the blind bores for the ballraces, and are used along with the 45degree angle I made earlier to mount the frame vertically in the mill vice as shown, the two HSS lathe bits are there to raise the frame up enough to allow me to get the right angle




Then (once the vice was tightened up) I touched off the 6mm rod with a 16mm endmill, zeroed the DRO and then raised up the Z-axis by 38.87mm (according to my plans the distance from the center of the crankshaft to this edge of the frame is 41.87mm, subtract half of the 6mm rod brings you to 38.87mm) and zeroed again.




Then it was just a case of raising the cutter up and then nibbling my way back down to zero. Then I loosened the vice, rotate the frame and align using the 45degree angle and tighten the vice. Then nibble away the 2nd corner.




I did think about shaping more of these upper arms while having it in this position, but I have some long holes to drill, and want to do that before spending any more efforts, just in case I totally mess up the long boring. The shaping of the outsides of these arms are not critical, so the shaping can wait til later.


Next up will be boring these 4 long steam passages between 38-46mm approx deep, then if nothing snaps or gets stuck, I will be shaping the outer edges of the frame.


One handy tip I have learnt from snapping the 1.5mm drillbit, when I started using the new bit I began rubbing a pencil up the flutes. This seemed to stop the ali welding itself into the flutes, and I re-applied the pencil a couple more times per 12mm deep hole, this seemed to work really well, good old carbon lubrication.


Tim

[spuddevans]

It's amazing just how things go, when I was designing this engine, the part that puckered my cheeks the most was thinking about drilling the long narrow internal air/steam passages, close to 50mm long with just a 2.2mm bit, drilled into Ali' which I know from experience just loves to gum up a drillbit, break it and weld the broken bit deep in the workpiece.

But what do you know, the deep drilling went without a hitch, no breakages, no gumming up, and no breaking through where it shouldnt.

Here's a picture when I'd drilled the last of the 4 deep holes, and I've drawn on it to show where the internal passages meet. Because the passages are offset from each other the passage on the front (green) is not connected to the rear passage (purple) (I just know someone is going to make a joke about that !!! Get your minds out of the sewer and into the gutter with the rest of us  )

I drilled the first 30mm of each hole with a 2.5mm drill, then finished the hole off with a 2.2mm bit. The reason was not only for ensuring the bit wouldnt break, but also made sure that these long holes would break through into the 1.5mm cross drilled cylinder ports. Then by switching to a slightly smaller bit gives a little more room for error on drilling without breaking into the central crankshaft bore.







Then I moved the frame into a vice on the tapping stand to tap the central hole on each arm M2, this is for attaching a cap to cover and seal the ends of the long internal steam passages.




Once that was done I couldn't resist fitting the cylinders and pivot rings to see how it looks.






Next I will be making some steel inserts to fit into the 10mm pivot bores in the frame to give the magnets something to pull onto. There will probably be some experimentation with the sizing of the steel inserts to get the appropriate "pull force". Then I will be moving back to the cylinders, or rather, to the end caps and packing glands and pistons.


Tim

[arnoldb]

Good going Tim 

Drilling those thin deep holes in alli can be a bit daunting

  Glad you did not end up connecting the wrong passages 

Kind regards, Arnold

[saw]

You are doing fine, it looks very good. Nice work. 

[Bogstandard]

Tim,

I designed and made two different running prototypes of tiny V-twins, for minivap boats, and I had to use tiny external tubing to connect up the ports, what a PITA, but the holes would have been just too difficult to drill as you have, the drills would have been about 0.7mm diameter, and almost guaranteed to break down the transfer holes.
I gave HS93 (Peter) all the parts to make about ten of them a little while ago.

If I could just make a suggestion.

On the port faces of your cylinders, run an end mill across the centre of them, or across the centres of the port faces of the main standard, they only need to be about 10 thou (0.25mm) deep, so you have equi distances either side of the port holes unmachined. That will reduce friction no end, and help the faces to bed in much more quickly.

John

[raynerd]

Wow !!     Drilling those holes was impressive    It would have gone horribly wrong had I tried! Nice work!

Chris

[Imagineering]

Hiya Spud,

All this DRO caper - I thought that you had CNC'd this X2 Mill of yours??

Murray.

[spuddevans]

If I could just make a suggestion.

Please do, I appreciate all the help I can get.

On the port faces of your cylinders, run an end mill across the centre of them, or across the centres of the port faces of the main standard, they only need to be about 10 thou (0.25mm) deep, so you have equi distances either side of the port holes unmachined. That will reduce friction no end, and help the faces to bed in much more quickly.

Do you mean like this,


If so maybe using a larger endmill may do the trick, centered on the pivot bore.



Thanks Chris

Hiya Spud,

All this DRO caper - I thought that you had CNC'd this X2 Mill of yours??

Murray.

Hi Murray, you are right, My X2 is CNC'd, but for the purposes of this build log I'm not using it except as a fancy sort of DRO system. One reason for this is that I still have some bugs to iron out in the CNC setup, but the main reason for just using it as a DRO system on this build is that I dont want to give the impression that CNC is needed to build this engine. In fact, you dont even need a DRO, although it does maxe it a lot easier, it is very possible to machine it off the dials and via accurate marking out.

Tim

[spuddevans]

I got started on the Endcaps today, and started by chucking some 20mm brass bar in the lathe, and then turning down a section to 13.8mm (the OD of the endcaps) and then turned a tiny 8mm spigot (to fit the cylinder bore). Then I marked up the bar to show a 1.5mm line.




Then I parted off at the line, then repeated 3 more times.

Then I had to clean up the little pip left on from parting, my plan is to mount them into a 14mm ER32 collet and then skim off about 0.1mm off the face. However, as I have tried to chuck up thin items before in my ER32 chuck and have found that without something the same diameter in the rear of the collet, when you tighten the collet up it tends to pull out of true, so I just used one of the endcaps in the other end,




Then I used a plastic handle to "nudge" the endcap into alignment while the collet is only hand tightened with the lathe rotating slowly, then stop the lathe and tighten up.




All four,




Then I took the ER32 collet off the lathe and mounted it on the mill, and drilled the mounting holes.




Then after drilling all 4 holes in the endcaps I couldnt resist mounting one on a cylinder.




Next up will be the packing glands.


Tim

[raynerd]

Nice job, Tim. It is really coming together great!

Chris

[Bogstandard]

That's exactly what I mean Tim. Most times it is done on the standard, but it can also be cut as you have shown and as I said.

The use of magnets is really intriguing me, I can't wait to see how it turns out.

I'm all for experimentation with new ideas.


John

[spuddevans]

That's exactly what I mean Tim. Most times it is done on the standard, but it can also be cut as you have shown and as I said.

I can see how this will reduce the friction, I think I might make the cuts on the frame instead of the cylinders due to holding the frame in the mill being a lot easier than the cylinders, thanks for that suggestion With the strength of these magnets, eliminating as much friction as possible will really help.

The use of magnets is really intriguing me, I can't wait to see how it turns out.

I'm all for experimentation with new ideas.

The idea of using magnets to hold the cylinders on has fascinated me for about a year, but only at the start of this project have I had any chance to try it out. The worst that can happen is that it doesnt work, but having done a few rough-n-ready tests of the strength of pull's of various magnet sizes, and also of magnet to steel strengths, I have come to the conclusion that I will be faced with the problem of too much attraction rather than too little, and that should be solved by adjusting the size of the steel inserts that the magnets attract to, as well as having the option of slightly increasing the operating gap between magnet and steel insert.

At the moment I am still making parts that should not have any adjustments to them, but in a while I will be back to making experimental parts and adjusting them, then updating the plans on Alibre to match, should be fun  


Tim

[spuddevans]

Just a brief update, I found a couple of hours in the 'shop and made a start on the packing glands, or rather, the gland nuts.

I was intending making direct copies of the packing glands as designed by Bog's in the paddleducks build, but as these are quite a bit smaller I had to reconsider.

Therefore I came up with an experimental design ( at least I think it is experimental, I havent seen in used on other builds. Time will tell if there is a very good reason for that )

But just like in the paddleducks plans, I am making the nuts 1st so that they can be mounted on the packing glands for theu drilling to ensure concentricity.


So I started out with some 8mm brass hex in the 3jaw




Then used the round profile tool to form a profile on one end, then centre drilled




Drilled to a depth of 3-3.5mm




Then tapped M4, I had to grind the tips off the taps, you can see an unground tap in the background.




Then part off and repeat 3 more times.

I then spent the rest of the time I had figuring out how I was going to turn the packing gland. I did make just one, just to see how and if I could make it. And just to tease you here's a pic of it with the other nuts.




These packing glands are of an inverted thread design, ie the exterior thread is on the gland, the interior on the nut. I reaslise that this is not standard, and am half expecting that it will not work quite as well as the more standard version. I have very little room for anything else on this engine, plus I expect this engine will be operating on fairly low pressure (about 5-10 psi once ran in) and so should run ok even without any stuffing in the packing glands.


Next time I will show how I turned the glands (or at least the 3 remaining ones )


Tim

[spuddevans]

On to the rest of the Packing glands.

I chucked some 20mm brass bar and reduced a section to 13.8mm ( the required od ) and then reduced a 0.5mm bit to fit the bore on the cylinders (about 8mm)




Then I swapped over for a parting tool and turned a 4mm long section down to 4mm diameter.




Then after parting it off and making the others, I mounted a 14mm collet and reversed the glands in the chuck, then using a tailstock die holder I threaded the 4mm diameter spigot M4 as far as I could get, and then centre drilled the end to form the "V" for the packing.




Then screw on the packing nut made earlier and centre drill it





Follow up with a 2mm drill bit and drill thru both the nut and the packing gland (carefully pecking to prevent drill snappage) and make sure that you keep each nut paired with the gland.

And here all 4 are,




I then unbolted the ER32 chuck from the lathe and gripped it in the mill vice to drill the 4 mounting holes.




And here is the obligitory posed shot with a cylinder (complete with magnet epoxied in place)




Next up will be the pistons and con-rods, crank webs and crankshafts.


Tim

[saw]

Nice work, but why  not studs and bolts?