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[bazmak]

Hi just a quick comment.I use s/s rod for most pins and shafts.Normal round
is ground to nom - 1 thou.Its tougher and silver solders well.Corrosion free
no cleaning the fiddly bits and its cheap.Works well on crankshafts
Only downside is its tough to machine.Precission ground M/S is more expensive
Just my twopennef

 

[deverett]

Hi just a quick comment.I use s/s rod for most pins and shafts.Normal round
is ground to nom - 1 thou.Its tougher and silver solders well.Corrosion free
no cleaning the fiddly bits and its cheap.Works well on crankshafts
Only downside is its tough to machine.Precision ground M/S is more expensive
Just my twopennef

Depends on the grade of Stainless. Sounds like you are describing 316. 303 is much easier to machine, but does have less resistance to rusting.

A good source of excellent stainless rods is old printers/photocopiers/scanners. The older the machine, the more useful bits inside. In addition to the rods, there are numerous springs, gears several small motors and really old machines will yield ball bearings and/or bronze bushes. The electronic wizards may be able to make use of some of the electrickery bits as well.

Dave
The Emerald Isle

 

[gus]

I would be happy to have the sweepings off the floor from a spring manufacturer, I'm sure that there would be a lot of small springs lost under benches etc.

Paul.

Its true. Fascinated with their technology with springs flying out .

Whenever Mustad Plant calls for compressor service,my fishy mates were so happy.Only problem was, when hooks are packed and despatched to warehouse,getting choice free hooks not possible.Not even free samples.
But whatever hooks they are making on their hi speed presses,you can take some.Another problem. Either too big or too small. :wall::rant:

 

[gus]

Next trip to TokyuHands.Will buy a series of spring wire and make springs as per Tubal Cain's Book. Harold Hall has drawings on a spring winding machine.

 

[simister]

I have now finished the frame. Now to start on the cylinder. I have ordered a brake cylinder honing tool to finish the bore. I have also managed to get a drill and reamer through ebay. They are second hand but should do the job.

 

[canadianhorsepower]

is it me or if your cyl head is on the wrong side

 

[Swifty]

That's what I thought at first Luc, but I googled some models and the flywheel sits between the uprights and the cylinder is on the outside.

Paul.

 

[Brian Rupnow]

Looks very good so far.--One nice thing about that design--If you want to go to a real killer flywheel to get low rpm, you can drill 2 mew holes in the base and move that outboard bearing support almost an inch to the outside for a much thicker flywheel. There is also enough vertical clearance to go to a 3.950" diameter flywheel without removing any material from the top of the baseplate.-Brian

 

[simister]

I have got onto a guy here that can supply material for the flywheel in cast. Hopefully that should have enough weight in it. I was going to machine the inner diameter to keep the weight to the outside.

 

[Brian Rupnow]

You don't really have to machine away any material. It won't make the engine run any better if you do. The reason most cast flywheels had the center relieved was simply to save material for the manufacturer. It is true, the material machined away (if you do so) doesn't have much positive effect on how well the flywheel works if you leave it in place. 95% of the actual flywheel influence on the engine is all in the outer rim. Relieving the center is mostly a cosmetic thing.---Brian

 

[vederstein]

Some time ago a forum member asked about substituting aluminum for cast iron in a flywheel. After several somewhat ambiguous answers, I replied with an explanation of mass moment of intertia.

You can find the post in this thread:

http://www.homemodelenginemachinist.com/showthread.php?t=23069&highlight=moment+intertia

...Ved.

 

[simister]

Interesting! I wasn't sure about machining the inner of the flywheel. I have often seen the inner machined out and was under the opinion that it was a design requirement. I can see that the larger diameter will give it more inertia. I am going to put the maximum diameter cast iron flywheel that can be fitted. That will be just under 4 " diameter.

 

[simister]

Brian, I have made the crank as per your design with the counter balance. It is all finished and looks fine. However, I never thought at the time but I have made it in Aluminium. I realise now that I can't silver solder it to the crankshaft and will have to loctite it instead.

Do you think this will be a problem or should I make it again in steel?

John

 

[Brian Rupnow]

Aluminum only weighs 1/3 of what steel weighs, so it should never be used for a counterweight. . Aluminum should never be used anywhere on a crankshaft.

 

[Jasonb]

The inner part of the flywheel is often machined away as it improves throttle response as there is less innertia to overcome when the engine changes speed. Thats why you will find lightweight flywheels fitted to improve the performance of car engines.

Not too much of an issue on an engine like this but worth bearing in mind for future projects

 

[simister]

Ok, I thought that might be the case. Anyway good practice - I will make another.

 

[simister]

I finally finished the crank. This is the second one I have made. The first I made in aluminium. I only realised after I finished it that I had used the wrong material. I should of known that it was going to be useless as a counter weight. I have now made this one in steel. Also, as far as I know, I wouldn't have been able to silver solder it to the crankshaft. I used Brian's design as it looked quite good - thanks Brian.

John

 

[Brian Rupnow]

Simister--You're not the first person to be caught by that. ---Brian

 

[simister]

Can anyone give me some ideas where to start looking for the spring steel for the rocker arm?

 

[Jasonb]

Piano wire also known as music wire is available from the local RC model shop or online.

J