Author Topic: An experimental V-4 wobbler  (Read 28475 times)

Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #50 on: June 02, 2011, 01:24:54 AM »
Nice work, but why  not studs and bolts?  :thumbup:

I'm not to sure exactly where you are meaning about the studs? :scratch: But if you are referring to the fasteners for holding the packing glands in place, I haven't decided if I will just use hex-head screws for their ease, or to make up some acorn-style nuts and install studs. I guess I'll get it running before I decide on that one.

Thanks for following,

Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME

Offline metalmad

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Re: An experimental V-4 wobbler
« Reply #51 on: June 02, 2011, 04:01:22 AM »
Nice going Tim  :clap:
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Offline krv3000

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Re: An experimental V-4 wobbler
« Reply #52 on: June 02, 2011, 06:19:07 AM »
oooooo brill

Offline saw

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Re: An experimental V-4 wobbler
« Reply #53 on: June 02, 2011, 05:53:48 PM »
No I mean the cylinder topp and cylinder botom. I think that your'e engine should look even better then.  :thumbup:
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Offline metalmad

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Re: An experimental V-4 wobbler
« Reply #54 on: June 09, 2011, 03:27:23 AM »
I agree the unbrakos look a little out of place
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Offline raynerd

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Re: An experimental V-4 wobbler
« Reply #55 on: June 09, 2011, 04:07:32 AM »
Ohh you guys mean using studding and then nuts on top like a more traditional engine. They used this to secure the top and bottom cylinder covers on my Stuart 10V and I really never understand the benefit. ... is it purely just looks? In my opinion, they were more of a pain in the arse than anything but I do expect they will look a bit better than the cap heads maybe!? I`m guessing something that could be replaced with no hastle at the end of the build or in the final build.

Any more updates Tim...I`m waiting patiently...now get your finger our  :poke:   :lol:
Chris

Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #56 on: June 09, 2011, 05:32:24 AM »
Ohh you guys mean using studding and then nuts on top like a more traditional engine. They used this to secure the top and bottom cylinder covers on my Stuart 10V and I really never understand the benefit. ... is it purely just looks? In my opinion, they were more of a pain in the arse than anything but I do expect they will look a bit better than the cap heads maybe!? I`m guessing something that could be replaced with no hastle at the end of the build or in the final build.

Yea, they're referring to replacing the socket caps screws with studs and nuts. I do agree that they look a lot better on a steam engine, but they are a lot of hassle. I'm still undecided on whether to do this on this build, I guess if the engine runs without too much trouble I probably will do the studs and nuts route. But if it takes a whole world of fiddling to get it running I may skip any additional hassle.


Quote
Any more updates Tim...I`m waiting patiently...now get your finger our  :poke:   :lol:
Chris

I've been suffering with a bad back this last week and just havent felt up to it this week, however I did think that I had made some progress last week, I made the pistons and got them to a nice tight sliding fit in the cylinders, ready to be lapped in with some T-cut, then realised that to ensure concentricity for getting a good seal through the packing gland, I should have left the piston oversize to be attached to the con-rods and then finished the piston to size gripping them by the con-rod in the ER32 chuck in the lathe. :bang: :doh: :bang: :doh: :bang:

So hopefully at the weekend I will get a bit more progress done.


Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME

Offline raynerd

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Re: An experimental V-4 wobbler
« Reply #57 on: June 09, 2011, 06:18:53 AM »
Yes, good point. Chris

Offline NickG

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Re: An experimental V-4 wobbler
« Reply #58 on: June 09, 2011, 03:55:26 PM »
Missed this one, nice work and very innovative Tim. On the last few oscillators I've done I have  milled the relief as Bogs suggested and it makes a big difference, lets the port faces pull up nicely to each other.

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Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #59 on: June 09, 2011, 04:31:50 PM »
Thanks Nick :thumbup:

I will be milling the relief as suggested by John, but because I have already glued the magnets and pivot rings into the cylinders, I will be making the relief in the main frame itself.

Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME

Offline stirling lad

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Re: An experimental V-4 wobbler
« Reply #60 on: June 10, 2011, 09:57:05 PM »
keep in mind that these magnets drasticly and permanently lose thier pulling power when they get heated to much,, you might be able to use that in your favour if pulling power is an issue later........just a thought...

   ....Mike...

Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #61 on: June 13, 2011, 03:16:09 PM »
keep in mind that these magnets drasticly and permanently lose thier pulling power when they get heated to much,, you might be able to use that in your favour if pulling power is an issue later........just a thought...

   ....Mike...

Good point Mike, and one I will file away just in case I have too much attraction ( a problem I have never personally suffered from in the past  :lol: )


At the weekend I managed to get a little time to play, erm work done.  :lol: Just a small update this time, hopefully get more done next time.


I started with some brass bar that was a bit oversize, and then drilled a 1.7mm hole in the center, to as deep a depth as I dare.




Then I blacked up the brass bar, marked off a 5.5mm length, and then tapped the hole M2 for the conrod.




Then part off at the previously marked line, and repeat the tapping, marking and parting off until you have 4. Then I cut 4 lengths of 2mm stainless steel for the conrods.




Then mount the 2mm rods in the lathe to thread each end M2. I put a little spot of tapping lube on the tip of the stainless rod ( after putting a little chamfer on the rod with a file ) and then threaded it with my tailstock die-holder.




Then I cleaned the threads, added a drop of locktite and then assembled the conrods to the pistons.




Next will be bringing the pistons down to final size to match the cylinders, and then starting on the crank-webs and crankshafts.


Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME

Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #62 on: June 15, 2011, 02:28:31 PM »
On to truing up and matching the pistons to the cylinders.

I started by mounting a piston-conrod assembly in the ER32 Chuck, but with a couple of washers to space it out from the chuck.




Then I cleaned up the end of the piston and reduced it until it was about 0.1mm oversize, then I put 2 oil-grooves in using the edge of a half-round file, just held by hand to create a shallow groove. ( very important note, any files being used on the lathe MUST have handles installed ) Then I reduced the diameter until the piston just begins to fit into the cylinder bore. ( I was advancing the cross-slide by 0.01mm  each pass ) then I used some 800grit wet&dry to just polish the piston until it fitted snugly in the bore.




Repeat that another 3 times and there you go,



as each piston is matched to a cylinder, I now will try to keep them paired up, each in their own compartment.


It looks like I will have to shorten the conrods a bit, I have another part to make that will screw onto the conrod end that links to the crankpins. So until I have those parts made, and the crankshaft assembly too, the shortening will have to wait.


In view of that I thought I would make a start on the crankwebs. I chucked a piece of 20mm brass into the lathe.




Then I was rudely interrupted by my better half returning home, and so I had to go inside for some lunch. ( just think of all the things we could get done if we didnt have to eat. Would save a fortune too  :lol: ) So the rest of the crankwebs will be for the next update.


Tim
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Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #63 on: June 25, 2011, 04:09:33 PM »
I've been itching to get back into the workshop for over a week now, but I believe that you can get tablets from the doctors to help with that :lol:

I also must give credit for the design and machining order of the crankdiscs to John (Bogs) :bow: :bow: as it is pretty much an exact copy from John's Paddleducks plans, just made a little smaller.

I got a couple of hours more in the workshop today, and carried on from where I left off in the previous post.

I reduced the brass bar down to 15mm diameter.




Then parted off four 4mm thick discs.




Then I chucked each of them in a 15mm er32 chuck and drilled a 3mm hole in the centre.



I could've just drilled them all before parting off, but the drill could well have deflected during the 25mm depth, and I really wanted to make sure that the holes would be central, so I drilled them all separately.


Then I made up a little jig to hold the crankdisc blanks in order to drill the crankpin holes all in exactly the same distance from the crankshaft centre.




It has to be the easiest jig to make, just drill a 2.9mm hole, press a short length of 3mm rod into the hole, then move the mill table over by 6mm ( half the stroke length ) and lock it in place. Then pop a crankdisc on it and then drill it with a 2mm bit.




Do that 3 more times, and then it is on to machining them into somewhat balanced cranks. I put a 3mm drillbit into the central holes and a 2mm rod into the 2mm holes  :doh: then using some 0.5mm shims ( some feeler gauges ) to bring the 2mm rod up a tad. Press the whole lot down onto the vice and tighten.




Then I let loose with a 14mm endmill and nibbled down to what seemed to look ok, zeroing the DRO at the bottom cut. Then turn over and repeat.




Then it was a case of removing any burrs raised, then it was on to cutting the compression slot, this is done on each crankdisc individually, so I used a vice stop. Using the same shims and 3mm and 2mm rods to align before clamping. Then I aligned the slitting saw by eye.




Then I removed the rods and slitted the slot.





Stay tuned for more updates.


Tim
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Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #64 on: June 26, 2011, 12:55:59 PM »
Got the crankwebs finished off today, not that there was much to do  :lol:

I started by drilling and tapping the hole for the tightening screw. Then I took some 4mm stainless rod and turned a section down to 3mm to use for the central part of the crankshaft that goes through the main frame, and a section of 2mm stainless rod for the crankpin.

Then I couldnt resist assembling some bit together, and came up with this,







Next up will be the little "L" shaped pieces to connect the conrods to the crankpins. Then a little final modifying of the length of the conrods. Then the outer frames and connecting pieces. Then just a few hundred more operations and it'll be all done  :lol: :lol:


Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME

Offline raynerd

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Re: An experimental V-4 wobbler
« Reply #65 on: June 26, 2011, 05:35:32 PM »
Now I know what your making next, will you please get a wriggle on.  :whip: :whip: :poke: :whip:

Only kidding, looking good Tim. I can really see how it is all fitting together now. It stupidly took me a while to understand how these magnets are working/what they are doing but now I fully understand, great idea!!

Chris

Offline saw

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Re: An experimental V-4 wobbler
« Reply #66 on: June 26, 2011, 05:47:53 PM »
Nice progress here, looking very good.  :clap: :clap:
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Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #67 on: July 26, 2011, 10:08:03 AM »
I can't believe that it has been so long since my last update, domestic duties and a week of visiting my better half in hospital have taken my attention til now.

Today I got started on the little "L" pieces that will connect the piston to the crank-pin. I found a piece of brass approx 18mm x 3.3mm x 300mm, made a rough sketch of what I wanted to achieve, and set to it.




I set it up in my vice on a parallel which was slightly thicker than the brass, so I had to use a second parallel to flesh out the brass to be gripped by the vice. Then I set up a temporary vice-stop and zeroed off the rear of the brass and the end next to the vice stop.

Then I moved to the centre of the 3.3mm width, advanced on the x-axis by 2mm and center drilled, then moved over 5mm and drilled again, repeat until 5 holes were started. Then I swapped over to drill for M2 tapping.




Once all those holes were drilled I opened the vice up and turned the brass onto it's side, pushed up against the vice-stop and tightened it up. Then I removed the vice-stop as it was in the way, and moved to the right coords and drilled 2mm holes.




Then I swapped the drill for a 4mm end mill and milled slightly more than half the thickness away.




Then I tapped the top holes M2.




and then carefully hacksawed,




then I gently hacksawed in the other direction to release them. But prior to releasing them, I cleaned them up as much as possible with a small fine file.

Then I gripped each tiny "L" in the vice and rounded over the bottom end with a file. I made 5 as I thought that would give me one to lose/spoil/have-as-a-trophy, and sure enough I did spoil one.




Here they are in place,







And that's as far as I got. I think next up will be making the outer support frames and some form of a base.


Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME

Offline DaveH

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Re: An experimental V-4 wobbler
« Reply #68 on: July 26, 2011, 01:05:51 PM »
Tim,

That was very well done, :clap: :clap:
goodness they are tiny.

It's comming on very nice :thumbup: :thumbup:

DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline NickG

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Re: An experimental V-4 wobbler
« Reply #69 on: July 26, 2011, 03:09:16 PM »
Nice work there Tim and great photos as always. Going to be quite a powerful, compact engine this one.  :thumbup:
Location: County Durham (North East England)

Offline doubleboost

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Re: An experimental V-4 wobbler
« Reply #70 on: July 26, 2011, 05:30:26 PM »
Very nice
Should be a very smooth revvy little engine
John

Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #71 on: August 19, 2011, 02:35:36 PM »
Well, I thought I would get my finger out and get on with this build  :lol: Having finished with another time-sensitive project I got back on track with this, I made a start on the two outer frames that fit either side of the main frame.

After hacksawing, squaring, and then flycutting to thickness, some 6mm ali plate down to just over 5.5mm thick, then I marked out for drilling for the crankshaft and 4 mounting posts.




After drilling the holes I then put all 3 frames together, held in alignment by as couple of 3mm drillbits, and clamped them in the vice in order to drill and tap holes M2.5 for attaching the frames to a base.




After drilling for the M2.5 holes I flycut across the bottom as they were very slight diferences between them and while they were aligned with the drillbits I thought it would be an ideal time to skim a tiny cut to level them.




Then I moved them over to my tapping stand and tapped them.




Then I moved on to shaping the outsides of the frames, 1st up was the outer frames. I have to confess, I did have full intentions of machining them manually using a base-plate jig and the rotary table, but as I had managed to get most of the bugs ironed out of my CNC system I decided to use that method instead.

That being said, it wouldn't take much to set up on a rotary table, and I still had to make a little jig plate to attach the frames to so that they can be held securely for machining, which is what I did next. Using a scrap piece of 6mm ali plate, I quickly squared it up and then drilled matching holes for the 4 3mm holes that are also in all the frames, then I tapped them M3.




Then I mounted one of the outer frames onto it and was pleasantly surprised to find that the M3 cap screws aligned quite tightly even before tightening them up, then to make sure everything was held square I ran a dti held in the chuck along one edge of the frame, and again was surprised that it was spot on ( well it was 0.05mm out over the length of the base, close enough for me )

Then I unleashed the CNC and let it do it's thing, just watched and brushed the chips away and squirted a bit of cutting fluid on from time to time until I ended up with this,




After doing the other one and a bit of cleaning up I ended up with this,



I know that the upper circular part is not centered on the crankshaft hole, I may redo that, but will probably use a couple of filing buttons and just hand file it to the right shape.


Then I set up the main frame in the jig and, because there is so much more work involved in the main frame, and some very critical distances involved with the long drilled internal steam passages, I double checked that the frame was still held perfectly square.





That's all I got done, so next will be the sphincter-tightening stage of cutting out the shape on the main frame, either you will hear from me with joy as it has gone well, or you will not hear from me for some time as I have to remake it :bang:


Tim
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Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #72 on: August 31, 2011, 03:57:09 PM »
Well, I didnt screw the frame up, but I have slightly mixed feelings as my CAM output that I made for CNC'ing the frame ended up cutting it a bit too close for my comfort. It didnt break through any of the long-drilled holes, but there isnt much left, just enough to smooth the frame.

Anyway, here's a pic of the frame after shaping and then some cleanup with files and sandpaper (yea, my inexperience with CNC is showing, but I've learnt a huge amount on this)




I then marked up the tops of the arms for the frame for drilling the inlet/exhaust pipework that will go to the speed control/reversing valve.




When I attempted to drill the holes for the inlets using a 4mm drillbit, it broke through to the top long-drilled hole in the arm (which is only 1mm or less from the top of the arm) and that pulled the drill off line and made the hole oval. :bang: So instead of having a 4mm hole that the copper feed pipe could fit snugly into (soldered to a flange that screws to the top of the arm) I had to enlarge the hole to 6mm using a 6mm endmill ( I should have used a 4mm endmill to start with to prevent it being pulled offline when it breaks into the long-drilled hole )




Then, while I had the vice stop set up I moved over 4.5mm and drilled for tapping M2, then went 9mm the other way (4.5mm the other side of the inlet) and drilled again, then I swapped over to the other arm and repeated the process. Once all hole were drilled I then tapped them M2.




Then I turned up 2 flanges out of brass, I forgot to take any in progress pics but they are very straight-forward to turn, a section 6mm diameter to fit into the holes I just made in the frame arms, and a 12mm flange with a 4mm thru hole for the copper pipe to be soldered into.

Side profile,





Then I had to make a jig up to drill the fixing holes in the flanges. Just a 6mm hole drilled thru some scrap Ali, a 2mm hole drilled 4.5mm away from the 1st hole, and a little pin I have from another jig.




Then insert a flange into the jig and drill one hole,




Then insert the pin to keep the flange from rotating, and then move over 9mm to drill the other hole.




Then I just used some files to shape the sides of the flanges, and here is one in place on the frame.




The flanges are a nice fit into the frame, which when combined with a smear of liquid gasket it should seal quite nicely.


Next up will be some form of a base.



Thanks for watching,

Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME

Offline raynerd

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Re: An experimental V-4 wobbler
« Reply #73 on: August 31, 2011, 04:14:12 PM »
Looking great Tim and nice job on the CNC frames - your machine works great!

Chris

Offline spuddevans

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Re: An experimental V-4 wobbler
« Reply #74 on: August 31, 2011, 04:22:14 PM »
Looking great Tim and nice job on the CNC frames - your machine works great!

Chris

Thanks Chris, but while the CNC worked great, my programming in CamBam was quite lacking. There was a lot of cleaning up that I had to do. I didnt program a cleanup pass, and so I had to file out all the marks from milling it down 1mm at a time.

Another time I should program it to leave 0.3-0.5mm for a final full-depth pass to clean up.


Tim
Measure with a micrometer, mark with chalk, cut with an axe  -  MI0TME