Frustrations

[Gordon]

I find it frustrating when the plans I am following have dimensions which are overly specific. That is, when something is dimensioned 27/64 and then it finally comes down to assembly and I find that it could have been +/- 1/8 and been just fine. I think that what is happening is someone is building a model and designing as they go along and when the model is finished someone else or even the original builder quite a while later measures the finished product and makes the drawing fit the piece exactly. Short of recalculating everything as you are building it it is hard to determine if the dimension is critical. When I see some dimension like 27/64 I assume that the dimension is quite critical or it would have just been labeled 7/16.

Another thing which I find frustrating is when the final dimension can only be arrived at by several mathematical calculations. Also when things like the c/c of holes is critical and the dimensions are given from two different points. ie: c/c is 2" which is critical but is given as 1/2" in from each end of a 3" long piece. I say let dimensioning rules be hanged. Give the builder the dimension he needs without a lot of calculations.

Sorry just a frustrating day I guess.

 

[miner49r]

I feel your frustration. In some of Elmer's drawings the measurements are taken from both the edge and the center line.
Alan

 

[Tin Falcon]

I think we have all been there.
learn what measurements are not important and then do not worry about the rest.
redraw all parts in a way that makes sense to you. sketch with pencil and paper cad or 3-D parmeric
change the dimension notation if you want ie fractions to decimals
tin

 

[rake60]

I have seen the worst of that.

We were making parts for a gas well fracturing ball dropper.
All it did was blast steel balls down the drill pipe to block off different size zones
further down stream in the pipe so the new gas well could be hydraulically
fractured in sections.

Anyway, one part called for a .640 +.001/-.000 through bore with a 63 finish.
The young man running the machine on 3rd shift had to make a small boring bar to
bore the hole to size and maintain the finish requirement.

Long story short, the man in charge of that project came to me screaming about the
time we had on those parts. I pointed out the challenges of that critical small bore.
His reaction would best be described as "BALLISTIC!"

Turned out that hole was nothing more than clearance on a 5/8" rod.
It looked like an important thing to the drafts-person so she made it a critical fit on
the print.

That was not only frustrating, it trimmed the profit margin considerably on a quoted job.

Rick

 

[arnoldb]

What Tin said :bow:

It can be difficult - but don't let that deter you. When I started out, I found the most frustrating thing converting plans to suit my mostly metric tooling - and NO! - I don't want to start a Metric vs Imperial discussion Gents & Ladies - it's just what I have available to build engines with.

Once you've built a couple of engines, you'll start to see where and which the important and critical dimensions are for an engine. If you can work through the plans and get to understand exactly how the engine will work before you start machining, you're well away - in fact, then you can start changing measurements to suit your own needs, materials and equipment.

I'm of the opinion that ifone day when I will pay good money for a set of plans, I'd expect sensible dimensions and very few or no errors on those, but for free or old and no-longer-maintained plans, what you see is what you get. At least someone went to the trouble of drawing up those plans; it's darn hard work to draw up a good set of plans.

Many times in our hobby you'll feel frustrated - but don't let that get to you. I can promise you there are extremely few more satisfying and rewarding things to do than going through the frustration, effort, and failures in the process of building a successful engine.

I don't know how others feel about this, but I see each and every one of the engines I've built as a personal winner's trophy, and I hope you'll find the same goes for you and your engines Thm:

Kind regards, Arnold

 

[stevehuckss396]

I'm of the opinion that ifone day when I will pay good money for a set of plans, I'd expect sensible dimensions and very few or no errors on those

That may or may not happen. You have to remember that alot of engine builders are not machinests. When someone like that creates a set of drawings they work hard to relate the important information to others. Doing that can be a challenge when have never seen a professional drawing. But without these "unprofessional" drawing sets, there would be very little to choose from. Just remember that behind every set of drawings, good or bad, is a well intentioned model builder trying to do something to promote the hobby and provide something to build. It's ALOT harder than you would think.

Believe me I know!

Happy Easter!
Steve

 

[doc1955]

It's ALOT harder than you would think.

Believe me I know!

Happy Easter!
Steve

Steve I agree!! This is what I do for a real job for the past 38 years and some think it is a simple task but that is far from the truth. :big:

By the way Steve you did a good job on your drawing NO COMPLAINTS what so ever!!
I have started on some of the parts I've modeled up most all of the engine.

 

[chuck foster]

another frustrating thing is to make all the parts according to the drawings only to find out the drawings are wrong

myself and a few other guys on here know all about the galloway drawings :

chuck

 

[stevehuckss396]

another frustrating thing is to make all the parts according to the drawings only to find out the drawings are wrong

myself and a few other guys on here know all about the galloway drawings :

chuck

I have heard rumor that there are 3 sizes of the galloway. One was built and the drawings are good. The other 2 were scaled down or up from the original and not checked very good. That was the source of the troubles.

The new owner had Gbritnell build the engines and edit the drawings as he went. I'm not sure where he is at, but I would think the drawings are in fine shape by now.

That's one of the reasons I decided to go the Paypal route to purchase my drawings. This way when an error is reported to me, I can email everybody the changes or omissions before they run into trouble like that.

 

[kuhncw]

No matter whose drawings you have, I think it pays to study ahead on the drawings to make sure you understand the critical dimensions, catch any errors, or note things you might want to change. To me that is part of the fun as I usually end up changing the design a bit anyway.

I built the 1/4 scale Galloway, found a few bugs in the drawings, changed a few things, became good friends with three other fellows building the same engine, and generally had a heck of a good time. Despite a few drawing errors, Richard Shelly is a nice fellow and deserves a lot of credit for the contribution he and his wife have made to our hobby.

The Chanticleer I built had a few quirks in the drawings as well. The only engine I've built that, as far as I know, had no errors in the drawings was the 0.3 scale Deere developed by Jerry Frisbie and now sold by Gary Martin.

Those are my thoughts. Just look out ahead as you build and don't let a few errors in the prints get you down.

Like Steve said, getting a perfect set of drawings out is not easy.

Regards,

Chuck Kuhn

 

[Tin Falcon]

As rick pointed out the designers often do not know what is needed or how to communicate it.
I worked in a shop that expected people to be mind readers.
the blue prints were drawn by the owner his dad was an architect. dimensions were in fractions. I was taut that fractional dimensions wer close counts make quick +- 1/64 of an inch. so I make the parts only to find the forman remaking them because my parts were out of spec and they may me out to look like the dummy . I only stayed on that job for a few months the owner was a....... . I say nothing if it is not nice ;D
In model work there is flexibility if you understand what is needed. You are the machinist , QC, accounting,and the customer. One of my engines has a part that is a half inch too long . I just did not take the time to cut off the extra but it is my engine and I never had a person at a show complain LOL.
Like it or not part of machining is checking the drawings.
Tin

 

[Tin Falcon]

Producing good quality provisional looking drawings that are error free is indeed no an easy task. and there are several conventions that can be used and different folks are used to different styles and conventions.
what are the best units of measure decimal inches , fractions . millimeters? And should the dimensions reference on corner or the center. what is the best corner to reference.
Rudy kuhoupt managed to make a comfortable living at this . He may have had some income from retirement from previous jobs do not know.
little locos tried to make it a business and never made a profit. like others have said people do there best . and you take what is there.
We are fortunate to have Brian Rupnow here. his plans are professional quality he is a pro.
If I practice enough at Alibre maybe one day I maybe able to produce good plan sets.
Tin

 

[stevehuckss396]

If I practice enough at Alibre maybe one day I maybe able to produce good plan sets.

That's what I used to make my set. Problem with Alibre is, it will only do what you ask it. You have to actually know what a good drawing looks like. In my case I don't know what a real drawing looks like. I just fudged my way thru puting numbers on what I thought was important. I did'nt use tolerance because I dont know exactly what they should be. I just put a note when 2 pieces should be press fit. Size really isn't as important as how they fit. I would guess that most hobby designers do the same as I do and I'm glad they were brave enough to do it. It's a little nerve racking having your work judged by thousands of internet onlookers.

Think about this. The average price for a set of drawings for a model engine is $0 - $100. For a professional to design and build a nice engine and then create a perfect set of drawings I would imagine that price would go up 10 times. We buy cheap machines and tools because having to purchase Pro stuff is out of the budget for the hobbiest. We accept the machines and it's many flaws as good enough and we work with what we have. Drawings are the same way. In many cases they are affordable and with a little work on our part, the project can be completed to a high degree of quality.If everybody only excepted the highest quality everything, there would be about 100 people left who could afford to do this.

 

[Gordon]

I agree that making drawings is difficult. I have spent my life designing and building custom industrial machines. To date I have built about 15 model engines. When I have a sketchy set of plane I frequently will redraw them with CAD. The model I am working on at this time has a good looking set of CAD drawings. Even when I figure out what a dimension should be and it is some obscure fraction like 27/64 and I feel it can be anything close I wonder what I am missing. The present drawings have quite a few pieces which are specifies as just slightly over a standard size like 2.040 and 1.520 blank size and when I get the part complete I find that 2" and 1.5 stock size would have worked just fine by making the mating pieces to fit. I suspect that the present drawings may have been converted from metric, thus the odd dimensions. Since this is a new type of engine for me I have not been as familiar with the entire design.Also I may have been lulled into complacency by nice looking drawings. On the other hand that is the joy of this hobby, learning new things and trying to adapt the designs to eq

 

[Tin Falcon]

Steve I think I have a pretty good idea of what is needed for a drawing. I have studied mechanical drawing here and there bits and pieces since Jr high school. took classes in college. USAF Tech school was for machining and welding but included blue print reading and basic part drawing. I have and have studied the drawings of Rudy Kuhoupt and Elmer V.
And I am a machinist so I know from that as well.

the design process takes time and work. come up with an Idea. sketch it drawit machine a prototype find and correct the mistakes then prove it in the field market publish .... correct mistakes found after release. software is in many respects the same way . never finished but sometimes left as is.
Tin

Tin

 

[Mosey]

I just finished 50 years of designing buildings, and the development of drawings to communicate the intended construction to the various people who had to build those structures. I enjoyed training dozens of people over the years to make drawings for others to build from. Some got it, others didn't. We worked in feet, inches, and fractions because the construction of buildings derives from materials and techniques that often were not precise. there were always approximations. Modern structures are now much more precise in materials and making them go together. Having said that, fractions simply do not belong in precise work in my opinion.

Now, machinery is another world from construction, and precision and Clarity in making machines and in the drawings communicating the building of the intended machine is important and necessary. It is possible that one of the attractions of machining for us is just that precision. It is for me. No fractions, please.
I can't talk about clarity in drawings because it is a very difficult area to express in words. Let's just say that there are clear ways to communicate the dimensions and other basic drawing information, rarely seen. For example, the Elmer #25 shows the plan view from the bottom looking up...worm's eye view! Not the best way, folks. I will probably say more about good drawings in a later post.

 

[Tin Falcon]

..worm's eye view! Not the best way, folks.

From what I understand common in European standards. And can be helpful as an auxiliary view. Not of any use for buildings though.

Tin

 

[stevehuckss396]

Steve I think I have a pretty good idea of what is needed for a drawing. I have studied mechanical drawing here and there bits and pieces since Jr high school. took classes in college. USAF Tech school was for machining and welding but included blue print reading and basic part drawing. I have and have studied the drawings of Rudy Kuhoupt and Elmer V.
And I am a machinist so I know from that as well.

the design process takes time and work. come up with an Idea. sketch it drawit machine a prototype find and correct the mistakes then prove it in the field market publish .... correct mistakes found after release. software is in many respects the same way . never finished but sometimes left as is.

Sorry Tin, I'm not trying to make it sound like we are all clueless when it comes to this stuff. I guess I was trying to drum up a little compassion for those who don't and try anyway. Takes gut's and I appreciate every one of them.

 

[Tin Falcon]

No offence taken Steve. There is a lot of amateur stuff out there that deserves kudos. whether in the form of videos, and engine or a drawing. like any other media and in the interest of good communication the outcome depends on the person producing the drawings the method of production and the intended audience.

How much information is the right amount.? not enough and the user has to guess. too much info and the newby may be confused overwhelmed or both. HMMM It is all good Steve.
And I do realize a pretty model in Albre does not guarantee it can be machined. there are thing that can be drawn that may be difficult to impossible to machine.
I am currently trying to redraw some of Elmers stuff with alibre figure a good place to start.
Tin

 

[Kaleb]

I have something to add here about drawings. I'm currently in a metal fabrication course at TAFE, which includes a section on technical drawings. A.S. 1100 is the convention used here in Australia generally. Here, dimensions are nearly always given in millimetres, so units are often only mentioned in a note reading "All dimensions in millimetres". Radii are indicated by an R in front of the dimension, for instance a 4mm radius would be written as R4. Diameters are indicated by the symbol Ø, e.g. a diameter of 8mm would be written as Ø8. General information, like tolerances, surface finish, amendments, author of drawing, date, approval etc. is generally placed in a title block at the bottom. Surface finishes are specified in microns or as an N grade. These range from N12 to N1. Each grade is half the roughness value in microns as you go down. N12 is like a roughish(I've seen much rougher than that) oxy cut at 50 microns. N11 is like the finish on a raw casting at 25 microns. Machining will generally produce a finish between N10 and N6. N5 can be achieved by a very fine grinding operation, N4 is like a honed surface, N3 is like a buffed surface, N2 and N1 are achieved by very fine polishing.

I have attached a drawing for a lathe dog as an example.