Stuart Beam Engine

[Orrin]

I suspect it is a matter of spelling. I assumed "entablature" was what was intended.

Orrin

 

[Kludge]

That is called a parallel motion link, a Stevenson's patent I think.

Cool. Thanks, John. I'd never seen it before and it truly did puzzle me.

Another reason I love this place!

Best regards,

Kludge

 

[mklotz]

I suspect it is a matter of spelling. I assumed "entablature" was what was intended.

Orrin

I thought they were referring to this...

[ame]http://www.youtube.com/watch?v=lBp5ag6SJH4&mode=related&search=[/ame]

or, perhaps, due to a single letter misspelling, the world famous turbo encabulator...

http://en.wikipedia.org/wiki/Turboencabulator

 

[chuck foster]

and he said all that with a straight face........ :big: ;D ??? :

chuck :-[ :-X :-\ :-* :'( :bow:

 

[Bogstandard]

Marv,

Sounds a little like what your country's leader would come out with, when he forgets his lines.

John

 

[mklotz]

Now, Bogs, you stop making fun of our Prez. How can one not be proud of someone who makes such insightful statements as:

We look forward to hearing your vision, so we can more better do our job. That's what I'm telling you.

One of the common denominators I have found is that expectations rise above that which is expected.

We are ready for any unforeseen event which may or may not happen.

Natural gas is hemispheric. I like to call it hemispheric in nature because it is a product that we can find in our neighborhoods.

Saw a bumper sticker the other day that read, "Somewhere in Texas, a village is missing its idiot."

 

[Kludge]

Sounds a little like what your country's leader would come out with, when he forgets his lines.

He doesn't even have to forget them, just "explain" them. ;D

Kludge

 

[tel]

Kludge,

That is called a parallel motion link, a Stevenson's patent I think.

It allows the linear motion of the cylinder stroke to join onto the rotary motion of the beam end, without putting any bending force onto the cylinder piston rod.

John

Watts Boggy - them fluffy bunnies getting at yer memory banks?

 

[Bogstandard]

Tel,

Notice the disclaimer.

Stevenson's patent I think.

The reason is, I forget to think most times.

Thanks for the correction.

Bogs

 

[tel]

Noted mate, and thanks for not picking up on the 'Watts' rather than the 'Watt's'

 

[NickG]

I'd agree with Bogs re the comment on stuart castings. I have been considering doing a stuart engine purely because the castings and drawings (I assumed) would be very good, clear and concise. As Bogs said, a company such as stuart turner should be producing excellent stuff, and I'm shocked by there response that the drawings are there as a guide only. In my opinion I think a company like Stuart should be thinking of going a step further and actually putting tolerances on their drawings.

This thread has now put me right off buying very expensive Stuart castings as a fill in project. I'd rather spend the time designing something myself and making it from bar stock, then I know it will fit together, I'll have more satisfaction making it and if it didn't work I'd only have myself to blame!

Nick

 

[tel]

Unless they have improved in recent times, Stuarts aren't what they used to be. In 1979 I built a 10V and the castings were a delight, the castings for the Beam I built several years later ranged from OK to, frankly, 'orrible. And the prices? Nowadays I can buy a 5hp Briggs engine for what the 10V castings cost.

 

[Orrin]

The quality of the Stuart castings is very good; but, many are undersized, not allowing enough meat for cleanup. Take the beam, for instance, in places the flange width was less than the finished width called for on the drawings. Granted, it is not a critical dimension; but, it from a cosmetic point of view it is huge.

IMHO, here in the USA a person can get more bang for the buck by buying US products. Granted, some types of engine castings cannot be found on this side of the pond; but, it pays to shop around, anyhow. I heartily recommend this site to you your browsing for supplies:

http://www.antiquengines.com/Davis_Model_Suppliers_List_.htm

Here's another supplier. I've not checked to see if Davis lists it, yet, so forgive me if this is redundant:

http://www.lonestarengineworks.com/Products.html

Best regards,

Orrin

 

[Mcgyver]

I'd agree with Bogs re the comment on stuart castings. I have been considering doing a stuart engine purely because the castings and drawings (I assumed) would be very good, clear and concise.

I've built a couple of stuarts and imo the castings were in a word excellent. I haven't seen bette and that is 99% of it, drawings 1%. imo Stuart drawings are technically there but leave a lot to be desired in usability - they're from the school that says if there any conceivable way the builder can calculate a dimension from upteen others, lets not print it on the drawing. Other drawings i've worked have been much nicer, but end of the day they do give you what you need.

As Bogs said, a company such as stuart turner should be producing excellent stuff, and I'm shocked by there response that the drawings are there as a guide only. In my opinion I think a company like Stuart should be thinking of going a step further and actually putting tolerances on their drawings.

On this I completely disagree with you. I'll rant a bit, not so much at you ….but at the notion someone familiar with industrial practice comes to the hobby and in ignorance is critical of things they haven't fully thought though....

If you are in industry, tolerances are critical and the drawing defines everything leaving nothing to chance. Parts suppliers on different sides of the globe make their respective bits and pieces, the all come together, fit and the assembly works. yippy.

BUT, parts suppliers are only chosen who can satisfy the tolerance requirements of the drawing. They don't redesign the whole thing because some bidder says "hey, I don't have a thread grinder, can we come at this a different way". No, they get guys with thread grinders (or whatever) to bid.

This isn't how model engineering works. We don't by rote follow plans and tolerances; we take them as a guide to interpret in the context of our abilities and machines. There are big difference between us and industry, is 1) the variance in available equipment, 2) that everything included final assembly is done by one participant, 4) we’re not mass producing and 3) the objective is to make it accessible for as many as possible- not just a couple of bidders who have specialized equipment.

Let me give you an example. Let’s say we’re making an internal combustion engine where the nominal bore is 1". Industry would spec a tolerance, say .0005 +- on the cylinder and say the piston .998 +- .0005. The cylinder will be a maximum of 2 thou and a minimum of 1 thou larger than the piston. Well, maybe I don't have a micrometer. I can still build that engine and have it work perfectly with the piston 1.5 thou smaller than the bore because i know how to fit a piston to a bore. However the bore may be 1.010" because I don't have a micrometer. Specifying a tolerance wouldn’t accomplish anything because for one of's made and assembled by the same person there is no need. The hobby is model engineering - the builder has to develop engineer skills to figure out how to make it in the context of what they have available - if the hobby was by rote machining to drawings it would be rather dull.

You’re critical of Stuart – but take a broader perspective - I've got 1000's of model engineers going back to the 30's. In these or Live Steam or Engineering in Miniature or Home Shop Machinists I can’t remember ever seeing drawings presented as they are in industry with tolerances– are they all wrong? Anyone familiar with the content that has graced the pages of ME for last 70 years would hardly categorize those brilliant engineers as not knowing what they are doing; no the omission of tolerances is intentional and logical in the context of how they are used by us hobbyist and comparison to industrial drawings practice is not warranted or sensible.

End of the day, I have to agree with Stuart; drawings for ME's are a guide and its up to us as amateur engineers to determine fits and tolerance and construction techniques in the context of our abilities and resources. Now wether there is value is a personal decision, they are getting bloody expensive.

 

[tel]

I agree with what you say McG, my bone(s) of contention are with the declining quality of the castings, and the price.

 

[NickG]

I'd go along with all of what you have said Mcgyver, I wasn't suggesting that all model engineering drawings should have tolerances, as you said, it would be dull and would take most of the fun out of the hobby for the majority. However, I was picking up on something that Bogs said and just thought it would be a nice option for the beginner, he / she wouldn't have to follow them, but it would be a good guide and it would also get the beginner thinking about limits and fits.

As John said, without a good set of drawings a beginner could easily mess up a set of expensive castings (S50, 10V, 10H etc) that they say are for the beginner purely because their drawings are sub-standard, this could leave a beginner quite upset and they would have no comeback if that's the sort of reply stuart are giving.

So I just think a company like stuart should be putting out top notch drawings and a comprehensive set of building instructions if they want to charge the prices they do. The tolerancing comment was a bit of a throw away one, nevertheless, I still think it would be a big improvement to have that option.

Perhaps though, I should try a set of stuart castings before I comment any further.

 

[Mcgyver]

hey Nick, like i said wasn't directed at you but I've heard this lack of tolerance criticism a few times and while its not like i'm hot about it, the reasons this criticism is unfounded takes a bit of explaining so it takes the form of a rant

I do agree the drawings are far from the the nicest i've worked from, but they are i think technically competent

 

[compound driver 2]

Im in the middle of machining two sets of S50 castings for a customer that were bought last month and the drawings and castings are fine. Irons nice and clean to machine with no hard spots and all the dimms on the drawings are ok.