Rina and T&K drawings

[Norman VantParticipant @normanvant32224]

Jim,

 

Getting a bit ahead of myself here but I’m rather taken by the idea of a points system. I know, I know, clunky and unreliable but cheap and somehow appropriate. No idea how to accommodate it yet, though. I’ll have to see what space is available, and where, as the assembly progresses. Taking it off the crankshaft and having a wasted spark seems OK. It’s got a long history. Though, being a long-time custodian of a Velocette with a mag. by the Prince of Darkness, I’m more familiar with the “completely lost spark” system!

 

For a carb, I am thinking along the lines of a non-throttled, model aero engine type, though I’m aware of the Jan Ridders’ variety. That seems a very long way into the future.

 

 

Regards,

 

Norman.

[Anonymous]

Posted by Jim Greethead on 08/01/2012 03:26:28:

 

Sorry I can’t show you on this forum because I can only upload jpg files and Alibre CAD produces pdf. Maybe if we used HMEM we could do it.

 

 

That’s odd, because I can generate JPG files from Alibre, albeit not of terribly high resolution. Like this:

 

Regards,

 

Andrew

[Jim GreetheadParticipant @jimgreethead]

Hi Norman,

 

I wondered about your preference for points and coils until I came to the word “Velocette”. That explained it. A lovely machine for the afficionado or masochist.

 

So how about a photo or at least some details.

 

My Rina took one step backwards this morning. I have not been happy silver soldering crankshafts so I copied one that Metal Butcher did with Loctite on his Upshurs here: http://www.homemodelenginemachinist.com/index.php?topic=11257.30 but when I put it in the lathe to clean it up, it came loose. So I either have to silver solder one or try again on the assumption that my Loctite was a bit old or had been too cold (I keep them in a fridge but I have just found that storage below 8C can affect the performance).

 

Andrew: I think the reason you can create .jpg and I can’t is that I am using the PE version. But I like your mechanism, what is it?

 

Jim

 

[Anonymous]

Hi Jim,

 

Ah, I expect you’re right. I’m using Alibre Design Expert, which comes with all sorts of export options. Having said that, I normally use PDFs for sending general views to items to clients, as you can rotate, pan and zoom the PDF. The JPG files are ok, but are quite low resolution.

 

The machanism represents the hornplates and drive train for the 4″ Burrell SCC traction engine I am building. The assembly is sectioned through the rear axle. I’ve had to do a re-design of the differential, and I don’t trust the drawings anyway, so I modelled the whole assembly to make sure everything fits together before cutting metal. Sadly I made the second shaft according to the drawings before I did the drive train assembly. According to the assembly the shaft is 13 thou too short. We’ll have to see how it looks when I get the whole lot assembled.

 

Regards,

 

Andrew

[Norman VantParticipant @normanvant32224]

Jim,

 

The Velo is buried at the back of the workshop. Haven’t used it in years now. Can’t get rid of it though. It will form part of my estate! It’s a 1957 Venom in nice condition because I rebuilt it twice with 20 years in between. Initially, it was given to me as a basket case. There is no such thing.

 

The only masochist items are starting it when you first get it. It will break the leg of the neophite in the blink of an eye. You soon learn. The second is the clutch. This is only a problem if you live in a traffic-infested area. It simply wasn’t designed for that. It will jest drag more and more until there is no option but to stop the engine every time you stop the bike. I lived in London then. No problem now, living in a rural area.

 

The first model engine I built , I silver soldered the crank. It just needed some very careful cleaning up of the fillet. Subsequently, I have used Loctite without problems, except on the Rina. Had exactly the same problem as you. It moved during clean-up. I managed to true it up again and it’s solid now. I think that I was just too impatient. Leave it somewhere warm for a day or two.

 

As for producing a jpeg, you could always use the “print screen” key on your keyboard, then just paste it into your imaging programme. That will save it as a jpeg or bmp and you can crop it to taste.

 

I’ve now got to go and figure out how to position and lock the flywheels onto the crank to give clearance for everything, particularly the governor, to work. I’ve got the keyways, but that’s only half the story.

 

 

Regards,

 

Norman.

[Jim GreetheadParticipant @jimgreethead]

Hi Andrew, the Burrell looks like the sort of project that would keep an ordinary person occupied for quite a while but the list of machines in your workshop leads me to believe that you are not the usual sort of “ordinary” person.

 

Modelling the assembly is fun. Even so, I still miss things but that is one of the limitations of PE – not having the checks available in expert. The other drawback (for me) is that I keep getting good ideas that I try on the model. It is still good fun, and that is what I am doing this for. But it does slow the production of the finished article.

 

It was the clutch Norman, that was the bit I thought was a bit masochistic. Not from personal experience, just from hearing others in the Club discussing it quietly amongst themselves. They would never openly admit that Velos are anything but perfect. I can understand why a 1957 Venom remains in your possession. It is a work of art, particularly as you built it yourself. People who collect statues and paintings (done by others) don’t understand but that is because they are ignorant.

 

And “printscreen”!!! Never thought of that. It works a treat. I will put up the photo shortly.

 

Jim

 

[Jim GreetheadParticipant @jimgreethead]

Back again; I was just about to put up the jpeg when visitors arrived. So I will do it now.

 

I am going to try the crankshaft again, this time with fresh Loctite. Reading all the specifications for Loctite (read the manual?) it seems to me that 638 is the strongest so that is what I will try. And although Metal Butcher used parallel pins, I intend to use taper pins. I have ordered the reamer, now just need to find somewhere that will sell me the pins in sensible quantities.

 

So here goes for the jpeg

 

Jim

 

 

[John OlsenParticipant @johnolsen79199]

Hi Guys,

 

Nice to see some kind remarks about my conversion of the drawings to Alibre, and it is good to see that Jim is getting some use out of them too. As you will see if you look at my album, I converted the drawings to jpg, the way that I did this was to open the pdf version in Photoshop and then save it as jpg. This is a nicer way than the screengrab approach, which will also work. I only have a fairly old version of Photoshop, Version 6, which is at least ten years old. However the printscreen approach also has its uses when the pdf is protected, I was able to grab some data the other day that I was not supposed to be able to print. Since it was my own medical data I have no qualms about doing that.

 

One nice thing you can do with Alibre is save the file as a 3D pdf file, this means that others could view the object from any angle, except of course this site does not allow users to post such things. With an assembly being viewed in this way, you can hide parts to allow seeing internal bits that might be obscured….you can imagine how this helps in seeing what the actual part looks like, and how they all go together.

 

I haven’t been to this site much lately, I gave up nearly a year ago when I also stopped submitting articles to ME. I had sent in four or five articles with drawings done with Alibre, and hence including some useful isometric views, but it appears that the editorial requirement is more towards articles with no drawings so I abandoned the others I was working on and got on with my projects.

 

regards

John

[John OlsenParticipant @johnolsen79199]

Incidently I have always preferred to make crankshafts from solid, by milling them between centres to remove the bulk of the material, then turning to get the finish. That way I know that they are not likely to move.

 

regards

John

[Anonymous]

Hi Jim,

 

Thanks for your kind words. Sorry to disappoint you, but I am just an ordinary sort of person. I’m building two Burrells, on the grounds that it doesn’t take twice as long to build two, as well as a hit ‘n’ miss engine, for which I’m designing my own ignition system. Come to think of it, may that’s evidence that I’m not ordinary, but just plain batty.

 

I agree that it does take time to model parts and assemblies, but I enjoy it and find it useful. The traction engine drawings are incomplete, and in some cases inaccurate. In addition some of the castings are subtly different to the drawings, so holes need moving for instance. I prefer to sort this out at the computer, rather than in the workshop! It also helps me to think about machining options and sequences. I’m not sure that the modelling does slow things down; ideally, I make parts once, and they fit together first time. And if you believe that you’ll believe anything.

 

Regards,

 

Andrew

[Jim GreetheadParticipant @jimgreethead]

Hi John, I wondered where you had got to. I really must thank you for introducing me to Alibre which is just magic.

 

 

And also, of course, to the Rina files that you sent me. They gave me a good starting point and a reference. In typical fashion, I drew everything from scratch when converting from imperial Rina to metric Rino but there were many occasions on which I referred to your files to see how you did something.

 

In regard to submissions and postings, you might get more joy from the MadModder or HMEM websites. Have a look.

 

And as for “ordinary Andrew”: Two Burrells and a H&M sounds about right. Like you, I reasoned that building two or more is simple since the setup time is shared. So I set out to build four of PutPutMan’s Tiny four stroke engines. Despite using jigs and stops and Alibre modelling, I generated scrap at an alarming rate. Heads in particular were mounting up to the point where I considered fishing as an alternative so I could use the sinkers.

 

I am sure that a lot of us would be interested in the build log of your projects. Have you considered sharing the ride?

 

Cheers

JIm

 

 

 

[Anonymous]

Hi Jim,

 

I know the feeling! I’ve just machined the hornplates for my traction engines. Generally fine, but I do have a few holes in the wrong place. One was due to mis-dimensioning the drawing; I didn’t spot that Alibre had picked up the edge of the hole, not the centre. The others were due to stupidity on my part. I had the holes correctly placed but then changed them while machining, as they didn’t seem right. They’ll be hidden on final assembly, but I am planning to weld blanking plugs in before drilling the holes in the correct places.

I can’t say I’d considered a build log. I’ll think about it, but it wouldn’t half be a bumpy ride!

Regards,

Andrew

[Norman VantParticipant @normanvant32224]

Hello again,

 

Making progress. I’ve got the flywheels on and it feels like a major step. The thing looks like an engine now! With those in place, it is now clear how to mount my beloved points ignition system. It will have to go on the non-governor side. Plenty of room there to put them on the crankshaft and have the lost spark on alternate revs., as per Brian Rupnow’s version. A set of Lucas type A Series points should do nicely. I was weaned on those. With a bit of thought, I should be able to make them so that the timing can be varied on the fly.

 

Back in the days when I understood cars (and bikes) it was easy. Battery, coil, distributor (where appropriate) and plug. Simple. All that “antique stuff is still about. The only issue I have is that I would like a far smaller 6V coil, one that I can hide away. Now it gets complicated. I have looked at the thread on this site about ignition systems and now I know less than I did before.

 

I am extremely averse to spending more on the ignition system than on the materials for the rest of the engine put together. All I need is a small, cheap coil (if that’s not a contradiction). At the moment I’m looking on Ebay at the aftermarket coil for a Honda NP50 Mini Melody 6v. Fits my critera – small and cheap!

 

Can any of our more knowledgeable brethren confirm that this would work or, equally valuably, tell me that it won’t. At the moment, I’m havering.

 

I’d be grateful for any advice simple enough that I won’t run away screaming.

 

 

Regards,

 

Norman.

[Jeff DaymanParticipant @jeffdayman43397]

Hi Norman,

 

A used or new coil from a lawnmower or chainsaw or string trimmer will work, as long as you get one that is for use with a points type ignition rather than for a CDI type. They are usually much cheaper than motorbike or car coils. Some CDI coils may work too, depending on internal electrickery being present or not, but if the coil came off a points engine it will surely work and will not have all the fancy junk inside, just wire.

 

Chainsaw and trimmer coils are small. Do use the condensor it came with, if you find such a coil. The points obviously could be used too.

 

Most small engine shops here in North America will likely have something in a used small coil for under $20 / 12 UK Pounds or less but I’m not sure about pricing at, or availability of, small engine shops in UK or elsewhere. If you take your engine or bits of it along, and tell them what you are doing, it sometimes makes what seems like an odd enquiry to a small engine person make sense. Bear in mind they are used to most people coming in asking for a specific part for a specific make model and year of a particular machine.

 

JD

[Norman VantParticipant @normanvant32224]

Jeff,

 

Thank you so much for your reply. It’s a rare delight to get an answer on this subject that I can actually understand. You have made things clear at last.

 

Looking at what’s available here, it appears that an aftermarket coil for a small motorbike is cheaper. No logic there, just rip-off pricing in the UK. Additionally, if I were to go to my local mower/chainsaw shop, I anticipate that their knowledge level will be less than mine – don’t think they have mastered the knife and fork yet.

 

No problem. Now I know what I want, and more importantly, what I don’t want, I can order one off Ebay. Should be here by Tuesday.

 

Thank you once again,

 

Norman.

[Jeff DaymanParticipant @jeffdayman43397]

Hi Norman,

 

You’re welcome. Glad to help if I can.

 

One other thing I forgot to mention is power sources for small model engines. I’ve been successfull lately using ‘wall wart’ power supply adapters as used for battery charging for phones, appliances etc. to power the coils. The ones I mean plug into the mains at the wall receptacles and have a cord and plug which suit the item being charged. For model use, I cut the low voltage output plug off and solder the outlet leads into my ignition circuit. For safety, I wire in a 1A or 2A glass body fuse in a fuseholder, in series with one of the leads to the ignition switch. That way, if the circuit draws too much current, the fuse protects the wall wart and the mains from overload and overheating or fire. I have tried 5, 6 and 12VDC ones rated 1A up to 3A output and they all worked fine. The higher voltage/current ones produced hotter sparks though.

 

As to cost, I picked up 3 of these wall warts at a surplus store recently for a total of $5 / 3 UK pounds roughly. Your local dollar / pound shop may have them also. Much cheaper than buying large lantern 6V dry cells regularly (or a bunch of AA rechargeable cells at high cost to power ignitions.)

 

Good luck, JD

[Norman VantParticipant @normanvant32224]

Jeff,

 

Now that’s an expression that doesn’t seem to have crossed the Atlantic! What an excellent idea. No need to buy one, I seem to have a drawer full of them from long dead phones.

 

One question arises from your previious reply. The coil I have ordered does not come with a condenser. Will an old fashioned automotive one do? Or can it be omitted as not important? The neighbours won’t realise why they can’t get a TV picture.

 

Regards,

 

Norman.

[Jim GreetheadParticipant @jimgreethead]

Hi Norman,

 

I am still following with interest.

 

You do need a condensor (capacitor) in the circuit; its function is to suppress the spark at the points which would otherwise destroy the points in no time.

 

Keep up the good work, I am looking forward to the photos/video of this engine in full song.

 

Jim

 

[Jeff DaymanParticipant @jeffdayman43397]

Hi Norman,

 

Do check the voltage and current rating of the wall warts in your drawer, some phone ones are rated at 500 mA or less. These may work for model ignition, but might not have quite enough current capacity. If you have one with 1 or 2 amps rating, that will likely work fine.

 

Yes you do need the condensor , any auto or motorbike or small engine one will likely do, again if it comes from a points system. I can’t vouch for any capacitors from a CDI ignition or other fancy electronic gizmos. The main purpose of the condensor in a points ignition is to prevent arcing at the points when they open, to prolong their life, but of course as you mention, a side benefit of the condensor is to reduce radio interference.

 

I’m sure the electron experts will tell us you can also use X capacitor from X radio supply, and that may be true electrically, but the condensors from cars bikes etc are made and rated for the heat vibration and current conditions in engine ignition. This may or may not be true for capacitors from other sources. The environment inside a TV or phone is a lot different than the environment of being bolted to the side of a screaming bike or car engine, hot and shaking, inside an oily cover.

 

Just my $0.02, your mileage may vary.

 

Again good luck, JD

Edited By Jeff Dayman on 21/01/2012 19:31:05

[Norman VantParticipant @normanvant32224]

Jim and Jeff,

 

I was clear that all the old vehicle ignition systems (at least, those that didn’t have a wick) had condensers, my doubt stemmed from the term “universal” used for the coil I have ordered. It occurred to me that there might be one buried away inside. However, I have emailed the vendor just ot be sure. I’ve got one, ready to fit if needed. It is the electronics experts I so fear!

 

As for a video of the beast on full song. There might be a considerable wait. It’s a bit like building a car. Rolling chassis and power train happen fairly quickly. It’s the fitting out and the trimming that go on for ever – and it might be a death rattle from the start.

 

However, if I can get a spark at a reasonably predictable time, I think that will be the last big query dealt with. The rest is just labour and patience.

 

Regards,

 

Norman.

[Norman VantParticipant @normanvant32224]

Jim,

 

Just had a major setback. Having got the flywheels on and fixed, it is now clear tha the crankshaft is not straight. About 1/16″ wobble on the governor side rim. The chances of clocking it up and straightening it seem minimal since it would probably mis-align the main bearings. Bugger!

 

Looks as if the next job is a new crankshaft. I know that some have doubts about using Loctite in this application but I suspect that I just did not let it harden for long enough before trying to clean up the insides of the webs. Never had any trouble before and it’s absolutely rock solid now!

 

For the next go, I think that time and gentle heat might be the answer (standing it on top of the central heating boiler for a week). Don’t really want to silver solder it if it can be avoided. I have a rooted objection to re-making parts but an even deeper one to wobbly flywheels. A new one will have its advantages though. I can make the keyway a little deeper, and of the correct length to give a positive stop against which to screw up the governor-side wheel – a bit of a lash up on Mk. 1.

 

Oh, well.

 

Regards,

 

Norman.

[Jeff DaymanParticipant @jeffdayman43397]

One thing I have found with using Loctite is it is important to make both surfaces perfectly clean before applying the stuff. You can use the (expensive) Loctite primer, but a good wash with clean laquer thinners then a rinse with rubbing/isopropyl alcohol then a half hour air dry is just as effective.

 

Another thing to keep in mind is to leave sufficient clearance for the compound. Some strategically placed centre punch marks at 120 degrees or 4 places at 90 degrees around the bore will ensure a small gap (ie about .002″ a side) for the compound. If the bore is deep, two sets next to each other may help keep the wheel square to the shaft as the compound sets.

 

I have made several crankshafts with Loctite cylindrical retaining compound and later pinned them with 3/32 spring roll pins (the C shape type, not the rolled up ones). I waited a week in warm weather before drilling and pinning for the compound to fully set. No troubles with these cranks, some are under heavy loads. I made sure the opening of the C shape of the pins was aligned in the direction torque would be applied. If the open slot of the C is aligned along the journals, in theory the torque could compress the spring pin and work them loose. I doubt it ever would in the real world though, as it took about a quarter ton of force to install the pins, and a small gas or steam engine doesn’t generate that sort of high forces even when firing. The Loctite alone should be good for several hundred foot pounds of torque resistance.

 

JD

[Jim GreetheadParticipant @jimgreethead]

Norman,

 

That’s really bad luck and I sympathise with you. I have been distracted and have not yet commenced the new crankshaft for my engine. One of the things I have been looking at is methods of mounting the flywheels.

 

Some of the experts over on the HMEM forum favour tapered locking centres of various types because they permit the flywheel to be precisely located and accurately bored to prevent wobble. So I am messing around with designs instead of getting on with the job.

 

Did you try straightening the crankshaft? On a previous engine I found some distortion after silver soldering it so I put it in the lathe and wacked it with a hammer and block of wood until it clocked true.

 

On the current one, I did all the things that Jeff suggests and I left it for about a week to harden in Australian summer temperatures before drilling and pinning. But I might have been a bit premature with the turning after pinning. Perhaps only 3 or 4 days.

 

I have ordered the taper reamers for the taper pins but now I cannot find a supplier of taper pins who is willing to sell me less than a couple of hundred. So I now either have to make my own or change the design to copy Jeff’s example.

 

Jeff: I am really pleased to hear that it is possible to use Loctite. I know that Metal Butcher has used it successfully on his Upshur Farm Engines and you have confirmed that it does work on your engines. Of course, the pins will help.

 

Ah well, we press on.

 

Jim

[Jeff DaymanParticipant @jeffdayman43397]

Are you guys machining the cranks after Loctite assy?

 

I have never done that, as I thought it would be tempting fate to try. I do all the machining on my cranks before assy, other than the drilling for the spring pins. While doing that drilling I make sure all cutting forces are on the web piece only, not the Loctited joints, and when breaking through into the round parts of the shaft, I go very carefully so as not to push anything out of whack.

 

One other thought – Loctite releases with applied heat starting at just over 330 deg C up to red heat, so I am careful to keep everything cool when drilling Loctited assys. Maybe heat buildup during turning affected the crank with problems? In the lathe or mill, you can’t easily tell when stock is getting too hot, until it starts smelling hot or oil on the stock starts smoking.

 

Hope these ideas help.

 

JD

[Norman VantParticipant @normanvant32224]

Jim and Jd,

 

Thanks for the suggestions. I’m fairly certain that the only problem was my impatience. 12 hours almost certainly wasn’t enough for a full cure. This is confirmed somewhat by reading the Loctite Spec. sheets. When all else fails…

 

On previous occasions I have machined after using Loctite and it just behaved like solid metal. That was on smaller diameter cranks too, with far less gluing area. I was so impressed that I think I abused the privilege this time. It won’t happen again, that’s for sure. Also pinning, after a decent interval. sounds like a plan. Certainly, this crank will take more in the way of shock loads than my previous ones for steam.

 

Jim,

 

Not until now did I realise that you were in Oz. It must be so confusing, making everything upside down and having them rotate the wrong way. A little bit envious really, we are in the depths of winter and my workshop seems to be 10 degress colder than the outside world!

 

Regards,

 

Norman.

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