1910 Sears Motor Buggy

[kenlwest]

20 hours ago, Bugatti Fan said:

Was unaware until later in the this thread that the model is both 1/8th scale and drawn up in 3D CAD and then 3D Printed.

Must have access to quite a large printer to make the chassis and seat etc. Interesting project and subject. 3D CAD and printing have revolutionised the model making process for many these days whether private individuals or a cottage industry.

In the case of the cottage industry, no more master and mould making, mixing of resin and limited to when the moulds give up. No more wastage when parts come out with blow holes or distortion etc. To a certain extent for the private individual or industry you are designing and producing your own kit or parts that can be repeated ad infinitum with consistency.

I have been into 3d printing for a few years now, and the technology, cost, and accuracy just gets better and better over time.  It will be awhile before 3d printing could compete with injection molded plastic kits.  For now, 3d printing is really great for hobbyists wanting to design and build low volume, not available subjects.  

Here is a shot of the frame with engine mounts and fasteners added.  The leaf springs are nice and detailed, however, they are not very stiff, and will need to be reinforced.  I have a plan for addressing that later on.

[kenlwest]

I printed the wheels using 2 different types of printing (filament vs resin) as a comparison. The dark wheel is resin, and light gray is filament.  Both methods have their pros and cons.  Obviously, resin is the better method for the wheels.

[bobthehobbyguy]

Very cool project.  Another cool project using 3d printing.

[kenlwest]

The front suspension is printed in one piece.  Temporarily tacked to the front wheels.

[kenlwest]

Might be a little hard to see, but here is a picture of the brake system.  The vertical lever is pulled by a steel cable (by pressing the center pedal).  As the lever is pulled, it turns a metal cam between the upper and lower brake shoes.  The turning cam spreads the shoes to make contact with the drum assembly.  The vertical spring pulls the shoes together and away from the drum when the pedal is not pressed.  I was able to recreate this from parts shown in the service parts manual, and photos on the internet.

[kenlwest]

The rear springs in place as well as the frame-mounted spring stops.

[kenlwest]

All four springs in place on the frame, shown upside down.

[kenlwest]

Axles attached to the springs.  Note the small wires used to support the weight of the model.  My hope is that they won't be too visible.

[kenlwest]

Last picture for a Friday night...  the wheels placed on axles to illustrate the size of the model.  Added a quarter for reference.

[kenlwest]

I lied... one more!  I wanted to see how the well the spring wires are supporting the weight.  Seems to work great, and at this scale, they are hard to see.  

[Big John]

Fantastic eye for detail Ken, and skilled draftsmanship.  Love the break mechanism, springs are  bear in CAD.

Thanks for sharing your project with us, looking forward to getting color on this cutie.

[kenlwest]

Ready to print the brake drums, drive chains, differential parts, and drive wheel.

[kenlwest]

Just pulled from the printer.  Happy that the chains came out nice.

[kenlwest]

I felt like I was performing eye surgery on a house fly as I was removing the chain from the print supports!  The brake drums fit through the large sprocket, then the wheel bolts to the brake drums.

After everything is fit to the chassis, I will explain how the mechanical speed control, and differentials work.

[Bainford]

Very cool project. The drive parts and chain look fantastic.

[Big John]

great work on the drive line and chains!  Scale roller link chain can also be had at MFH and Micro-Mark railroad accessories.  Not everyone wants to invest their time and big bucks in machining equipment just to join the "Real" world.

[kenlwest]

The Sears MB was available in 3 color configurations:

Chassis and Wheels were either - Brewster Green, Black, or Carmine Red.

All bodies were Black.

My version will be Brewster Green.

 

The motor is attached to the frame with 2 pins; one on each side.  The center frame bracket is attached to the back of the engine.

 

[kenlwest]

The drive gears, brake drums and wheel attachments, temporarily placed over the brake shoes.  Also a picture of the drive wheel, to be installed later.  This wheel serves as a clutch, and is the main component that controls vehicle speed.  I will explain this in more detail when the rest of the system is in place.

[Richard Bartrop]

So, we're looking at the granddaddy of all CVTs.

 

[Big John]

Outstanding, can't wait to see the transaxle/gearbox.

[Bugatti Fan]

Proficiency in 3D CAD (computer aided design) is a must for projects like this as basically it is designing your own plastic kit, and the CNC (computer numerically controlled) 3D printing machine making them for you. 3D printing allows for hollows and undercuts to be made that are Impossible by normal methods to be done in one go. The drawback is the learning curve one has to go through to get proficient with any 3D CAD program. Naturally those who use it full time on industry have a flying start having got proficient and their company covering their initial training costs

Strength will probably be a real trade off compared to an engineered scratch built model made by more traditional machining and hand skills in metal and wood etc.I

Either method can produce really lovely models however. Just different skills needed!

Edited August 21, 2023 by Bugatti Fan

[kenlwest]

6 hours ago, Bugatti Fan said:

Proficiency in 3D CAD (computer aided design) is a must for projects like this as basically it is designing your own plastic kit, and the CNC (computer numerically controlled) 3D printing machine making them for you. 3D printing allows for hollows and undercuts to be made that are Impossible by normal methods to be done in one go. The drawback is the learning curve one has to go through to get proficient with any 3D CAD program. Naturally those who use it full time on industry have a flying start having got proficient and their company covering their initial training costs

Strength will probably be a real trade off compared to an engineered scratch built model made by more traditional machining and hand skills in metal and wood etc.I

Either method can produce really lovely models however. Just different skills needed!

Another point to make concerning CAD & 3D printing vs scratch using natural materials:  the work I have seen in this forum using brass, soldering, wood and many other things, is impressive.  Based on the accuracy of this work, I can see that it requires magnification, patience, and alot of fitting, trial and error, and time.  In the end, I believe scratch building would be considered superior from a structural perspective, and creates a model that more reflects what the original subject was built from.  Time is another important factor.  The car I am building will take approximately 2 months from start to finish.  That would need to be translated into hours in order to compare the time required to build the same car using traditional methods.  I would be interested to know estimates of required time by those with experience in scratch building.

[kenlwest]

The term "dash" comes from the horse and buggy days.  Dash has different meanings in the dictionary, but the one that is pertinate here is:  "she was dashed with mud".  The word "dash" was the name given to the shield that prevented dust, dirt, and horse exhaust and droppings from flinging up onto the passengers in the buggy.  The term "dash" was carried over from the horse and buggy Era.

Here is a picture of the dash for the Sears buggy.

[Big John]

Hi Ken, going back to your third reference pic I see now how the transmission of power gets transferred to the drive axle.  It is the friction drive between the engine flywheel and the small spoked friction wheel.  No gearbox required. Dash It All!

[kenlwest]

9 hours ago, Big John said:

Hi Ken, going back to your third reference pic I see now how the transmission of power gets transferred to the drive axle.  It is the friction drive between the engine flywheel and the small spoked friction wheel.  No gearbox required. Dash It All!

Exactly.  Looking at the same reference picture, you will notice an "L" shaped lever directly behind the friction wheel.  The lever is controlled by a vertical handle next to the seat. As the handle is pushed or pulled, the friction wheel moves side to side against the flywheel.  The more outward the friction wheel moves, the faster the car goes.  As the friction wheel moves toward the center of the flywheel, the car slows down.  And, as the friction wheel crosses over the center of the flywheel, the car moves in reverse.  The motor maintains a steady low rpm.