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Rina and T&K drawings

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Jim Greethead10/01/2012 22:06:56
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131 forum posts
8 photos
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 Olsen11/01/2012 01:23:44
1039 forum posts
91 photos
1 articles
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 Olsen11/01/2012 01:26:45
1039 forum posts
91 photos
1 articles
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
Andrew Johnston11/01/2012 13:13:04
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5499 forum posts
647 photos
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 Greethead12/01/2012 21:02:39
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131 forum posts
8 photos
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
 
 
 
Andrew Johnston15/01/2012 11:36:04
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5499 forum posts
647 photos
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 Vant21/01/2012 00:08:56
50 forum posts
6 photos
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 Dayman21/01/2012 01:01:30
1818 forum posts
45 photos
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 Vant21/01/2012 12:43:43
50 forum posts
6 photos
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 Dayman21/01/2012 13:48:22
1818 forum posts
45 photos
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 Vant21/01/2012 16:02:55
50 forum posts
6 photos
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 Greethead21/01/2012 19:19:47
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131 forum posts
8 photos
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 Dayman21/01/2012 19:29:00
1818 forum posts
45 photos
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 Vant21/01/2012 22:45:35
50 forum posts
6 photos
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 Vant22/01/2012 16:41:15
50 forum posts
6 photos
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 Dayman22/01/2012 17:54:57
1818 forum posts
45 photos
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 Greethead22/01/2012 20:01:18
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131 forum posts
8 photos
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 Dayman22/01/2012 20:29:17
1818 forum posts
45 photos
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 Vant23/01/2012 00:02:52
50 forum posts
6 photos
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.
Jim Greethead23/01/2012 01:33:49
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131 forum posts
8 photos
Aaah! Not you too Norman? John Somers (www.start-model-engineering.co.uk) gives me a hard time about the DVD player going backwards. We had a conversation one evening in which we each checked to see which way the water went down the plug hole. The result was inconclusive.
 
But I made him an Elmers Tiny upside down as a gift on one of my visits.
 
I like the phrase "abused the privilege" for tidying up after the glue has set. And I will also be more kind to the next one.
 
I don't suppose there is any chance that I will see you at the Harrogate ME Exhibition?
 
Jim
 

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