An experimental V-4 wobbler

[spuddevans]

Some time ago I started designing a little V4 wobbler in Alibre and made a 3d rendering in pdf format to give some idea what I hope it will look like when built.

Click here for interactive pdf rendering

Anyway, over the last few days I have been finalising some of the details and also printing out some plans, and today I have made a little start on this little engine.

The design is to have a V4 configuration, 8mm bore 12-14mm stroke (cant remember which ), double acting wobbler.


I hope to keep a good record of the build with plenty of pics of all the processes, cos I know you all like pics    

Actually, todays progress is pretty boring, just some sizing of stock.


Normally, as many other builders, I would have liked to have started on the most complicated part 1st, which on this build is the main frame, but I am awaiting the arrival of some materials for the frame, so I made a start on the cylinders.

I started by putting the ER32 chuck on the lathe, and gripped a length of 20mm round brass bar in it, squaring the end up, then using my patent-pending method of marking up, I traced a mark at 21.5mm from the end.







I then used a thin parting tool to put a cut in at the mark to a depth of around 3-4mm, it's not important what depth, just so long as it is deep enough to be still there when I reduce the bar down to 16mm.




Then I swopped over to a 6mm round profiling tool ( as recommended by Bogs ages ago, and well worth getting ) and reduced to required size, just needing a quick swipe with some emery to clean up.





Then I swopped back to the parting tool and finished parting off. Then loosen the chuck, extend the bar out a little more, tighten, mark up and measure off another 21.5mm, make the initial parting cut, reduce to 16mm, part off and repeat another 2 times, or perhaps 3 times to give you a spare. (as I did knowing that it will be needed   )





The reason for making the initial shallow cut with the parting tool was just to give me an indication of how far to reduce the diameter of the 20mm brass bar to each time, and to therefore hopefully stop me from trying to cut too long a section down to 16mm. You might have a firm enough lathe to turn down much longer sections, but on my (as yet, completely unmodified, straight out of the box condition) rubber lathe, I have learnt to keep the minimum stock sticking out of the chuck when trying to keep to dimension, and so the visual reminder that putting on a partial parting cut gives is a helpful reminder to me to only turn down one piece at a time. Plus the parting tool is already in the QC changer from parting off the previous blank, so it only takes a moment to do.


These cylinders are not totally straight-forward in themselves, as, just to be difficult, I have designed the bore to be offset by 1mm from the center of the cylinder blank, so I spent the rest of my time in the workshop figuring out just how I am going to machine all the features and also in what sequence to machine it, and of course, how to hold it for machining.

Next up will be machining all the cylinder blanks to the same length (hopefully 20mm), and then machining a pivot on the side of each cylinder before boring out the bore

Anyway, that is as far as I got today, more updates to follow.


Tim

[sbwhart]

Sounds a real nice project Tim.

Tried opening the interactive pdf and got a blank page 

Stew

[spuddevans]

Tried opening the interactive pdf and got a blank page 

  Funny, it works on this end, try the attached file.


Tim


Edit, Dang it, managed to upload the same file twice, sorry Eric, just delete one as I cant seem to delete it myself.

[lordedmond]

Those links are blank as well

but I am using a beta OS called Lion ( mac )




Stuart

[sbwhart]

Yes I got blanks

You always start a project with a blank page 

Stew

[spuddevans]

I've just tried it on IE and it works ok, and on firefox too 

What version of Adobe Acrobat reader are you using? I think it needs v9.4 to open.


I also downloaded it on my phone using Opera, and it opened on adobe acrobat reader LE 2.5 (from 2009)


So I am completely stumped. I am sorry that you cant open any of the 3d renderings, as the real thing will probably not look anything like the model 


Tim

[arnoldb]

Nice design Tim  

I'm really curious how your porting will work and how you want to keep the cylinders on the port faces  ; Guess I will have to wait and see  

(I can see the engine using Linux - but not interactive - Don't know about the Macs. Stew, do you have a fairly new version of Acrobat ? - you need one of the newer interactive 3D compatible ones)

Kind regards, Arnold

[dickda1]

I opened it in Adobe Reader and was able to rotate it - cool.  I don't know about other people.  But, although I can read engineering drawings/blueprints just fine, a 3D representation is worth its weight in gold.  We'll be following your progress.
-Dick

[Rob.Wilson]

Interesting Design Tim 


Opens fine in Google Chrome and my Adobe   

Rob

[dsquire]

Tim

Works fine on this side of the pond with Mozilla. Looks like it will be an interesting little engine. I'll be watching.   

Cheers 

Don

[DaveH]

Tim,

Opens for me as well in Adobe,

Tim are you using Alibre?

DaveH

[spuddevans]

I'm really curious how your porting will work and how you want to keep the cylinders on the port faces  ; Guess I will have to wait and see  

Me too  

It's not a big secret, just an unknown quantity. The cylinders will ( hopefully ) be held on by recessed rare-earth magnets in both the frame and cylinders, with just a little gap between the two sets of magnets.

The porting is the standard wobbler type, but the air/steam passages are deep drilled through the frame, then the holes are covered brass tips on the ends of the frame.


I'm glad that others are able to open the pdf's, I thought I was the only one who could see them.

Tim are you using Alibre?

DaveH

Sure do Dave , I've found it really useful. Well worth the $99, or £64 when it showed up on the ccard bill


Tim

[Bogstandard]

Very nice design Tim.

I was a bit worried where all the piping was, but as you said, hiding it in the standards is perfectly OK.

Not only am I a ball bearing addict, I also have a fetish for magnets, they are stuck all over my shop if you care to search them out. I even think I have some 1mm diameter neo magnets somewhere, so if you need any, don't be afraid to ask, and if I haven't got the right size, I can send you where they will have, very reasonably priced as well.


John

[saw]

This project looks very intressting, I will be follow... 

[spuddevans]

Thanks John hopefully it'll turn out something like the 3d design

Not only am I a ball bearing addict, I also have a fetish for magnets, they are stuck all over my shop if you care to search them out. I even think I have some 1mm diameter neo magnets somewhere, so if you need any, don't be afraid to ask, and if I haven't got the right size, I can send you where they will have, very reasonably priced as well.

Funny you say that, I too am fascinated with the neo magnets. And I am also including ball bearings on this build, should be 4 of them on the crankshafts.

Thanks for the offer of magnets, I have got some 8mm x 2mm thick neo magnets on their way off flea-bay.

I had been anticipating using much smaller diameter magnets, but I'm not sure if they would have enough pull to hold the cylinders in place, I too got some 1mm magnets, and some 2 and 3mm ones too. So I redesigned the pivot area to use the wider magnets.

Time will tell if they work or not.

I have been temped to make it a V8 by adding a 2nd frame and 4 more cylinders, but for the time being I am resisting that temptation until I have got the V4 running. Potentially you could add as many of the main frames as you want to make V8, V12, V16, up to a V-whatever.

It is quite a small engine, as a V4 it should be able to fit onto a footprint of just 75mm wide by 85mm deep by 60mm high including the reversing/speed control.


Tim

[sbwhart]

I'm trying to see it on a mac,

I'll try on my lap top when I've finished down loading a disc onto its hard drive.

Stew

[spuddevans]

I'm trying to see it on a mac,

Ahh, that's obviously the problem, your mac has detected the slightest hint of microsnot that must've crept in from my pc  


Tim

[arnoldb]

your mac has detected the slightest hint of microsnot that must've crept in from my pc

Brilliant!

 , Arnold

[sbwhart]

I'm trying to see it on a mac,

I'll try on my lap top when I've finished down loading a disc onto its hard drive.

Stew

That did the trick Microsoft rule OK 

Ahh, that's obviously the problem, your mac has detected the slightest hint of microsnot that must've crept in from my pc   

 

Yes bloody mac:- wife got it despite my objections, and I bought my laptop as I refused to relearn to use the mac software knowing Id have to teach her how to use it same as I did with microsoft, that led to a lot of arguments and time down the pub keeping out of her way, I only ever use it for the internet, all the rest I do on the lap top, any mac problems she has, have to be sorted by her sister who convinsed her that macs were the way to go, they stop speaking to each other for weeks at a time

   


 

Back on topic ther's a similar engine on her http://jpduval.free.fr/Plans_moteurs_vapeur_p1.htm that may help you sort things.

Hope this helps

Stew

[raynerd]

Hi Tim, super design! I really like the CAD diagrams ... 3D does it for me   

Not clear how the magnets work but I`m sure I`ll find out soon with all those pictures you are going to post  ....

Can`t wait for an update!   

Chris

[Brass_Machine]

Very cool. Will be watching this one.

Edit, Dang it, managed to upload the same file twice, sorry Eric, just delete one as I cant seem to delete it myself.

I will fix that today

[spuddevans]

I will fix that today

Thanks Eric


I got another couple of hours in the playroom workshop today, and started by mounting my new vice onto the mill, and then clocked it square with a dti, I didnt go crazy, but just got it down to +/- 0.05mm 




I then mounted all 4 cylinder blanks on some parallels and with two pieces of ali at the front and back to compensate for the minor differences of thickness on each cylinder. If you dont put some soft material between the jaws and the workpieces then the slight differences will cause the multiple pieces to not all be gripped the same, which is perfectly fine unless you actually want to machine any of them. The Ali not only protects the brass from the steel vice jaws, but also will squish a little to compensate for the minor differences.

Anyway, I then I worked back and forth with a flycutter to get all 4 to the same length, 20mm.




I then turned the cylinders on their sides, gripped them in the same manner, and made a few more passes with the flycutter. Here's a shot after I cut the flat down until the required thickness ( 14mm ). Others might prefer to switch to an endmill to get the bulk removed, but as there was only 2mm to remove, and on brass I am able to take 0.25mm depth of cuts with this flycutter, it was quicker to keep using the flycutter. Plus it leaves a lovely silky smooth finish. Don't let the curved lines fool you, they cannot be felt by my fingernail.





Not having a lot of time left I started to set up for the next machining processes. The next thing will be to bore out a 2mm deep, 10mm diameter recess in the center of the flat section, and I will probably drill the inlet/exhaust holes at the same time. Because this has to be done on all 4, I'm going to use my sophisticated vice stop system shown below.




And for making sure that the cylinder flat is positioned true and flat I use another patent-pending system...




It wasnt until I had released the vice after flycutting all the flat sections that I realised that I should have kept them in place and just drilled and bored all the relevant holes using my edge finder on each cylinder and then moving to the right coord's for the holes


Oh well, you live and learn.

So next will be a boring post ( oh come come! this post has been boring anyway  ) and then some silver soldering.


Tim

[saw]

Nice work

[spuddevans]

I've made a little more progress on the cylinders.

According to my plans I have to drill the 2 inlet/outlet holes, and also a central 10mm diameter hole. The small inlet holes pose no problem, but the 10mm diameter hole is a little more tricky for me as I found that I do not have a 10mm endmill, and this hole must be flat bottomed. (wasnt that a queen song, "flat bottomed something-or-other"  )

I could've made a 10mm D-bit, but I figured out another way. I do have a 3/8" endmill which is 9.51mm approx in new money, and I also have a boring head that I can set to 10mm.

So here are my tools for this task,




Center drilling the holes,




Boring out the majority with the endmill,




Drilling the 1.5mm steam passages,




Then I swopped the ER32 chuck and mounted the boring head in the mill and then bored out to 10mm, I left the boring head locked at the needed diameter.





Repeat the above steps another 3 times, til you have this.




Then I turned the cylinder upright in order to bore out the bore

Using my expensive vice-stop to position the cylinders to make a little production line, first up after centering up was center drilling all 4 cylinders,




Then following through with drills up to 7.8mm,




Then I reamed all 4 out to 8mm, I was going to bore them with my boring head but I realised I didnt have a slim enough boring bar for it ( something for the shopping list )




Next I turned up 4 little rings of brass, 10mm OD, 8.1mm ID x 3.5mm depth.




And this is where they fit,




And here are the pieces all together with 4 8mm x 2mm neo' magnets sitting in place.




The magnets will be epoxied in place, and I am considering leaving the rings unfixed, they will fit into corresponding 10mm recesses in the main frame, and the magnetic attraction should keep them all in place.


While I have the vice stop set up, I will probably next drill the 4 holes on each end of the cylinders for fixing the endcaps or glands, then that should be all the cylinder machining operations done.


All that and maybe more (or less) on next weeks show.....



Tim

[arnoldb]

Well sir, that was a lot of boring, but not at all boring 
Good progress!

Kind regards, Arnold