Fast vs. Effective. There is a Difference!

This post originally appeared on my LinkedIn profile, it proved to be a far more popular post than I could have guessed, so I decided to share it here as a post.  

Lessons of "Fast vs. Efficient". A lesson learned from a new tool, and an old tool

Old school versus new. The speed handle (left),
and the electric screwdriver

While removing and installing inspection panels on an aircraft, I found I love the electric screwdriver for running out the screws.

An example of inspection panels on the wing of a
North American B-25 Mitchel. The quantity required is "P" for plenty.

But I've found for stubborn screws, held in by"Nature's Threadlock" (aka corrosion), or with a boogered up screw-head throws a wrench in the works, you can't beat an old school speed handle.

Why? it has its own advantages.

I have placed the tail end of the speed handle and leaned into a stubborn fastener like a mob enforcer "balancing the books".

I've also have found I prefer the speed handle to install screws.

Why? I can better feel when the screws is run down, and I don't strip out the fasteners

Is the speed handle, with its 100 year old, muscle powered tech as fast as the lithium-ion powered, electric counterpart?

In a word? No.

Do i find that the old speed handle, with its better feel, resulting in fewer stripped screw heads and making quicker work for the next guy?

Arguably. Yes.

The thought it leaves me considering... That job might have been completed fast, to the joy of many who "made the number" this quarter.

But if a year down the road, hours are wasted undoing the minutes saved "getting it done quick".

Was it efficient?

When building a CAD model, there is quick. That means slapping the shape together, and can include:

Under-constraining sketches

Building features on top of features instead of editing the feature (think filling a hole with an extrusion instead of deleting the hole feature)

Creating uber complicated sketches that are difficult to edit. 

Over-complicated sketch. I don't like 'em!

Many times, this can allow us to "spank a shape" quickly. But when that shape needs to change? Oh. The horror. 

What can help make a model easy to edit? Here are some of my thoughts:

Fully constrain features. It makes model updates much more predictable.

Don't create unnecessary features. By that, I mean if a hole is going away, delete the hole. Don't "plug" it with an extrusion. Don't create a new extrusion on top of another if you can edit the feature and make it longer.

Keep sketches simple. I'll take more simple sketches over one that requires 283 constraints.

And finally, try (as much as possible), to build parts and assemblies in ways that mimic how they'll be made. One place I worked at strived (again as much as possible) to dimension their sketches in the same way as the part would be dimensioned on the drawing. 

Are we always able to do this? No. Sometimes, the realities of deadlines force us into a corner. Can we get away with it if it's a "one and done" model that won't change in the future? 

Trying to build models efficiently, may not be fast out of the gate, but as the edits, revisions and updates can become much easier.

Future you might be grateful. 

Observations of a clever 1940s Design - The Trunnion Nut Socket

One thing I find fascinating, is looking at old designs and seeing how the designers of the past tackled a problem. 

I love vintage aircraft and as part of that passion I like to look at vintage prints for these aircraft. 

A drawing that caught my attention was for a "Main Landing Gear Trunnion Nut" for a P-51 Mustang. 

A P-51 Mustang at Chino Airport in Southern Californai

In short, it's a big socket that tightens a big nut that holds the landing gear on the airplaane But what I found most interesting was how it was made. 

The socket was made in two halves and welded together. The side intended to accept the ratchet is one piece, and the side intended to drive the nut is another piece. 

An image of the two separate socket halves

The square drive and 12-point drive geometry are made by broaching. And by making each half separately, it allows the tool clearance to create the geometry. (Not familiar with broaching? Here's a video that shows an example!)

The Welded Socket

Given what I know of 1940s manufacturing, it was a clever way to tackle the problem and design for manufacturing. 

Today, the part could be made by using EDM (Electro Discharge Machining), but I can see how the same process could be used to make the part. 

3D Printed Parts for an Aircraft Restoration - An Update

I think it's about time to update on my project 3d printing "faux gun barrels" for the restoration on a Bell P39 Airacobra non-flying display.

A restored P-39 Airacobra

The P-39 Airacobra I'm helping restore.

There's been some progress since my previous post!

The black PETG I was waiting for arrived, and I printed the new barrels using black instead of the gray I used for a test fit. 

One of the finished barrels

I found the PEtG I used worked well, but it was a little "stringy", and the finish wasn't quite as good as PLA or ABS. But it's nothing that a little sanding can't fix. It also helps that the barrels will be buried inside the flash suppressors, so a lot of them won't be seen. 

One of the guns temporarily placed in its the suppressor

What's left now is a final sanding to knock of the layer lines and a weathering to make the barrels look a little more weathered. 

Overall, it's been a pretty good first attempt!

 

3D Printed Parts for an Aircraft Restoration

Recently, I had an opportunity to mix some modern technology with the restoration of an 80 year old airplane.

The project is a Bell P-39 Airacobra, which is being restored to be a non-flying display at Planes of Fame Air Museum. One of the tasks I was given was to come up with four faux .030 caliber machine gun barrels for the wing mounts. 

An example of a restored P-39 Airacobra
By San Diego Air and Space Museum ArchivesUploaded by Bzuk at en.wikipedia - Source, Public Domain, https://commons.wikimedia.org/w/index.php?curid=24375991

The P-39 I'm helping with has a little ways to go before its finished!

All that was needed was a short length four to six inches so it looked like there was a barrel inside the flash suppressor. 

Given the tools I had available to me, I opted to 3D print the barrels. 

The first step was to get some measurements. Fortunately, Planes of Fame has an SNJ Texan that has a fake 30 caliber machine gun barrel I could use for measurements.

The SNJ and the barrel I could use for measurements.

With measurements sketched on a piece of paper,, I headed home andI created the model I needed in Autodesk Fusion. It wasn't a difficult model. I had it in about an hour or so. 

The 3D Model in Autodesk Fusion

The next step was to print it out. My plan was to print in black PETG, but it didn't arrive before the weekend, so I printed in gray PLA so I would have something to test fit. 

The PLA Print in Progress

Once Saturday rolled around, I had a chance to see how the test barrel fit. 

I was pleasantly surprised to see it fit well! It fit perfectly in one flash suppressor, and should go into the other three with a little light sanding. 

The 3D printed test part next to its "sample

The 3D printed part placed in its tube. 
Its not fully seated here.

The 3D printed barrel recessed in the tube. 
This will be its final position.

The next step? Print in the PETG I intended to, perform another test fit, and make preparations for permanent attachment.

In conclusion, it was a unique experience to be able to be able to use Fusion to create a model that could be 3D printed for the restoration. I'm grateful for the opportunity.  

But my part was indeed small, and I'm not the only one creating models that are turning into parts for this restoration. 

To see some amazing Inventor work that has turned into real parts for this restoration, check out Aviation CAD Technotes here! 

One last bit of "Legal Talk".

Any opinions expressed here are my own, and not necessarily those of Planes of Fame Air Museum. 

Barstool Philosophy - When Did I Become the Expert!

Every once in a while, I responsibly enjoy an "adult beverage" and ponder life. 

I call it "barstool philosophy".  

The beverage over which much
wistom is shared

Recently,  I celebrated my 51st time riding a giant rock around a "gianter" ball of fire floating in the vast expanse of space. 

Only a few days after that, I found myself helping seal the fabric envelope on a 1940s vintage  Taylorcraft. 

The Taylorcraft with fabric
over its steel tube frame

But this time "helping" meant handing the brush to someone half my age and saying, "you're up, kid".  

Somehow, when someone said, "he's the expert", and we looked around for that guy, I realized the eyes were looking at me. 

It didn't seem right. There's so much I don't know, so much I haven't done yet. 

I learned, or rather re-learned, teaching is a different mindset.

It's watching, guiding, stepping in, but not too much. It's saying, "if you do that, this bad thing will happen. Ask me how I know."

But we reached the finish-line in that milestone. The end product was pretty good 

The kids looked at me and said , "I hope we did good. "

Little do they know, the thought going through my mind was...

"I hope I did good."

So what lessons did I learn from this anecdote? \ "old guy with experience". I'm not sure when that happened. 

But happened it did. And I realized I had something to offer. While I don't know it all, the years had taught me more than I realized. Things that had become second nature by me were new, valuable lessons to those just starting out. 

Somewhere, without my realizing it happened, I became a mentor. 

I learned patience. I learned to look at a student and say, "You made this mistake. This is what you did wrong." And with a wry smile I'd say, with accurate self-deprecation, "Ask me how I know. I did it too.' 

And finally..

This post is pretty far removed from the Computer Aided Design Posts I've done in the past. My life and career has evolved. I'm not as deep in 3D modeling tools as I once was. The versions I use are old, and I don't use them at the level I did a few years go. 

But the lesson shares common ground.

For those of use who have a little more gray in our hair, and find ourselves squinting a little harder at our screens because "someone made the fonts smaller". 

Look to the fresh faced kids who were born after we graduated high school. 

You might have something to teach them. 

Lessons from a Mentor, a Quarter Century Later

 Sometimes, a lesson learned from long ago comes to pass. 

Recently I was working on a project that required I transfer the location of four threaded holes to a piece of aluminum so clearance holes could be drilled. The question was, how to do it? 

Sure I could measure out the holes, but the threaded holes were t-nuts pressed into plywood, and the holes for the t-nuts were measured using a tape measure. So the hole placement was made to more of a carpentry accuracy than an aerospace tolerance. But I still wanted to keep the clearance holes as tight as practical.

A 3D model of the T-nut that was pressed into Plywood

But I remembered watching an old tool maker when I was a young engineer fresh out of college. And if you haven't guessed by the title of this post, that was about 25 years ago.... Ouch. 

He showed me a "threaded hole transfer punch". It's a small tool that stores threaded screws that look almost like set screws. However they have points in them instead of the hex that one would expect from a set screw. 

I had my solution! I placed an order with McMaster Carr for the punch I needed, and I had it in my hands the next day. 

They're screwed into the holes you need to transfer. You then position the workpiece that requires the holes, give it a quick strike with a hammer. And now you have marks where you need to drill. 

Then it's off to the drill press to drill the holes you need. 

The transfer punch tool and two of its inserts.
The inserts are stored inside the tool. 
The tool also doubles as a wrench for the inserts.

The transfer punch with two punches threaded into the T-nuts

The marks left in the aluminum from the punches.
I'm afraid I didn't get a chance to get a picture of the drilled holes.

Using the tool that old die maker showed me, in the way he showed me how to use it, I had the holes I needed in no time flat. The whole process took about fifteen minutes. And that includes walking to another building where the drill press was kept! 

That's a lot quicker than trying to match the holes by measuring it out.  

And, in a strange case of deja vu, a young intern looked over my shoulder and asked me, "How did you mark those holes?"

So it was my turn to pass along the lesson I learned 25 years ago from an old die maker about the "threaded hole transfer punch". 

Other than sharing a cool story, what's the lesson? 

I would say to look for those small mentoring moments that can sometimes come from the most unexpected places. It might be from someone on the shop floor, an analyst in the corner of that dark office, or a program manager who's "been there and done that". 

A lesson can be learned in a few minutes can take years to pay off. But when it  does, it can be a life saver! 

Wow, that lesson was twenty five years ago.... Thinking of that I'm suddenly overcome by the urge to yell at some kids to get off my lawn....

About the Author:

Jonathan Landeros is a degreed Mechanical Engineer and certified Aircraft Maintenance Techncian. He designs in Autodesk Inventor at work, and Autodesk Fusion 360 for home projects. 

For fun he cycles, snowboards, and turns wrenches on aircraft. 

Why I chose to use Autodesk Fusion 360

Part of a Hydraulic Valve for 
a P-51 Mustang

Recently, I was asked why I used Autodesk Fusion 360 for my side project of modeling vintage aircraft parts. Why not use Autodesk Inventor? Or Dassault Solidworks?

Sitting down one evening, I decided to take a few moments to share my thoughts. These reasons are purely my own, as one guy cranking out models on evenings and weekends. I'm not an evangelist proclaiming my choice is better than yours. It's just that, my choice. 

Also, I do pay for a Fusion 360 subscription. I chose to take advantage of one of the promotions a few years back. I know this is likely still a hot button issue for some, but in my case, I'm glad I did. I thought it was

important that I mention that, in the interests of full disclosure.

 So, why did I chose Fusion 360? 

Accessibility

 A hydraulic housing in the
Fusion 360 mobile viewer

 The first reason I chose Fusion 360 it's easy for me to get. Yes. It's as simple as that.

Even if I chose not to subscribe, there's a free version that covers most of what I would choose to do. Sure, there's a cost associated with my subscription. But my cost for a yearly subscription is less than I'd spend on a weekend snowboarding. So for me, it's worth the expense to indulge my hobby.

Sure, there are probably ways I could get an educational copy of Inventor or Solidworks. Some are probably above board, others, more "gray market". 

At least in this case, I don't have to worry about stepping on anyone's

EULA (End User license Agreement). 

Capability

As far as bang for the buck. Fusion 360 does everything I need to do, plus more.

Most of what I do is currently limited to the parts, assemblies, and drawings. I haven't delved into the manufacturing or simulation space. But it's good to know I can do it should the time come!

I have used Fusion 360 to create *stl files for 3D printing and dxf files for a waterjet (see that post here), and overall, I've been happy with the results.

One thing I really like is the way Fusion 360 models threads. More than once I've been able to 3D print a usable thread out of Fusion 360.

A 3D print created with Fusion 360.
The fitting is threaded into 3D printed threads.

Ease of Administration

I've configured installations for Autodesk Inventor, Autodesk Vault, and to a lesser degree, Solidworks. All these tools are incredibly powerful. But with that, comes a great deal of setup and configuation. Where are the templates placed? How are you configuring your data management system? When you upgrade, what's your migration strategy? What are you using for a server?

For Fusion 360, the server is on the cloud, so there's no data to move when it's time to update hardware. 

When I purchased a new laptop, I installed Fusion 360 on my new computer, logged into my account, and had instant access to all my designs.

There was no need to migrate files or remap file locations. It was already there. In about an hour's time, I was up and running.

In Summary

In conclusion there isn't much, really. 

My big reasons why I chose Fusion 360. It works for me! Does that mean it would work for you on whatever projects you're working on? Maybe, maybe not! That's for you to decide. And whichever way you decided to go, happy 3D modeling!

Using Fusion 360 to Create Parts for a B-17 Restoration

A portion of the original print used to 
create the model.

 For many years, I've created models in Fusion 360. On occasion, I've 3D printed a few of my Fusion 360 models as "desk ornaments". 

But a few weeks ago, I had a fantastic opportunity to create a model that would be used to make a part for the restoration of a B-17 Flying Fortress. 

The part was a "friction washer" for use in the throttle quadrant. And the team needed geometry that could be cut on a water jet.

It started with a reproduction of the original Boeing print. Having the original dimensions made the modeling easy. It was interesting to note that even though standards have changed in the nearly 80 years since that print was created, it's not too different from the prints I work with today. 

The model of the friction washer, created in 
Fusion 360

Next, was to place the view on a drawing. The first goal was to dimension the drawing as a way of verifying all the dimensions were correct. Second, the drawing is what creates the 2D DXF file for the water jet. 

Once the drawing is created, delete any information that isn't required for the waterjet. This includes borders, title blocks, dimensions, centerlines and centermarks, etc. You might even consider creating a second page in the drawing for this purpose. 

Also, make sure to save the drawing before you export. I learned the hard way when I realized that the first file I exported still had all that extra geometry. Save the file before export!

The dxf geometry sent to the waterjet

Once I recovered from my snag. I sent the files off to my colleague for cutting. 

A few days later, we had our part and it fit perfectly, making for a very satisfying little journey. 

And while this little project was well worth a victory lap, there were three minor challenges that are worth mentioning. 

1) Drawing standards have changed over the decades, and while the drawing wasn't hard to interpret, some information wasn't where I'd expect it to be. Modern 3D modelers have spoiled us. We can "slap down" a new view in seconds. For the drafters of old? Adding the simplest view would take minutes. A more complicated one? Hours. 

The number of views was kept to a minimum. A part of single thickness, such as this one, will likely have the thickness dimension called out in a note. 

2) Not only have drawing standards changed, industry standards have changed. That material specification called out in 1943? It's been long superseded by a new standard. It's even possible that the standard that superseded the 1943 standard has, in turn, been superseded itself. 

Be prepared to spend a few minutes Googling the updated standards. Thank goodness for the internet! 

3) Finally, how does one interpret the tolerances called out on the drawing? Symmetric, +/-.005 for example, is easy. Model to the nominal. But what about a tolerance such as +.010/-.000? Do you "split the difference"? Do you aim for nominal? 

In my case, I decided to aim for the dimension as it was called out on the print. I figured that was the target dimension, after all. 

And in my case. It worked! Fusion 360 gave me an excellent dxf file that the waterjet used with no issuee, and the part fit perfectly into its intended position.  

It was a wonderful opportunity to contribute to a restoration. And a wonderful learning opportunity!

Acknowledgements

Print Reproduction via my Aircorps Library Subscription

Models and drawings created in Autodesk Fusion 360

A Milestone Creating a Fusion 360 Title Block!

I have completed the task I challenged myself with in my previous post. I finished up my reproduction of a 1940s era North American Aviation title block in Autodesk Fusion 360!

The original, and Fusion 360 Title block together

It was a little tedious at times, it's a lot of repetitive sketching geometry and inserting text and properties. 

But it's completed, and ready for use. I'm sure I'll find a few more things to adjust as I test it out. 

Ultimately, I was able to recreate nearly every feature of the title block. It's not an exact match. I couldn't find a solid fill to block out the box above the part number for example. But it is close, and it will serve it's purpose just fine. 

As more features get added to Fusion 360, I'll update the title block accordingly. 

The North American Aviation tile block finished

So now, it's time to start creating drawings! From there, I'll learn more lessons and make more adjustments!

Credits:

Title Block Sourced from my Aircorps Library subscription.

About the Author:

Jonathan Landeros is a degreed Mechanical Engineer and certified Aircraft Maintenance Techncian. He designs in Autodesk Inventor, Siemens NX, at work, and Autodesk Fusion 360 for home projects. 

For fun he cycles, snowboards, and turns wrenches on aircraft. 

A Trick - Creating Fusion 360 Title Blocks from an Image

 Happy 2022! Here's to hoping for a prosperous loop around the sun. 

One of my latest endeavors has been recreating 1940s aviation prints as 3D models in Fusion 360. The drawings are available via my Aircorps Library subscription, and they're a great look into how parts and assemblies were documented nearly 100 years ago. 

A piston for an actuator on a North American P-51 Mustang.
Model created in Autodesk Fusion 360

The models are the fun part for sure, but I also decided to recreate the drawings themselves too. 

The first part of recreating the drawing, is to recreate the title block of course. 

The title block image, ready for import into Fusion 360

\

It's still a work in progress, but I thought I'd spare a moment to document my progress.

It almost goes without saying, the process can be tedious. Since the original drawings are hand drawn, they have to be recreated from scratch. 

The thought of trying to "eyeball" the title block wasn't very appealing, but finally an idea dawned on me that made the process much less challenging. 

I imported an image of the title block, scaled it to a suitable size, and laid out the geometry on top of the image.

The title block in Fusion 360. The lines sketched in Fusion 360 are highlighted.

Overall, I felt pretty well. But there was one thing I did have to overcome

There's no image opacity setting like there are in other parts of Fusion 360. But I was able to see where my sketched lines were by highlighting them. I also extended the lines beyond the edges of the image. I can always trim them later. 

Finally, I'd also use the good old, "Delete, Inspect, Undo" trick by deleting the image, inspecting, and undoing the delete.

Overall, its working pretty well. I've found the process is much faster, accurate, and less frustrating than trying to scale by using the title block in a separate window. 

As I said earlier, it's a work in progress.  I'll share my final product when I'm done. Give me time, it might be a while! This is an "evening here and there" project! 

One Final Note

The team at Aircorps Library have done a spectacular job collecting, scanning, and sharing these vintage documents. Out of respect for their work, I won't be sharing any documents or models. Please, don't ask me to do so.

If you are really interested in their documentation, feel free to check out their site and investigate a subscription yourself! 

About the Author:

Jonathan Landeros is a degreed Mechanical Engineer and certified Aircraft Maintenance Techncian. He designs in Autodesk Inventor, Siemens NX, at work, and Autodesk Fusion 360 for home projects. 

For fun he cycles, snowboards, and turns wrenches on aircraft.