Its Been Such a Long Time

It is Dec 26th 2021 at the time of this post.  Boxing Day.  It has been a very long time since my last post.  It feels like an even longer time since the Covid 19 pandemic started. All is well here as I wish it is with you out there.

Since my last posting, I have ventured into G Scale garden trains.  I must say this is an 'all-up' hobby that can use and consume all of one's skills and interests.  Further it is great motivation to get back into blogging!

Here is a bit of a 'catch-up' on activities.  Yes, I did say it was a G-Scale garden train and yes this is my garage, not my garden. But I also said it is December - and it is raining - and my garage is warmer.  nuff-said.

Here is a bit of a 'catch-up' on activities.  Yes, I did say it was a G-Scale garden train and yes this is my garage, not my garden. But I also said it is December - and it is raining - and my garage is warmer.

I have built a test track in sections that allow for modular assembly and disassembly.  So far it is a basic loop. Straight sections are just over 4 feet long and use two sections of LGB 10600 Straight Track, which are each 23-5/8" long. 

The 90 degree curved sections are made with three pieces of  LGB 11000 Curved Track, R1, 30 Degree.

Each section stands on a wooden support which simulates a trestle bent. 

The wood sections are aligned with the dowel and hole setup as shown. When the sections come together I use a short track segment to join the rails. That way when apart the attached track does not over-hang the wood. The shorts are LGB 10080 Straight Track, which are 3-1/4" long.

Power to the track comes from a DIY controller based on the CommandStation-EX project using the open-source software DCC++EX .  Look here for details. This is a very well done open-source project.. The hardware is based on an Arduino MEGA and two high current motor controllers boards. One Motor controller powers the Main track, the other is available for the Program track.  I run my rails on +24V and I can deliver over 10 amps to the track if need be.

Digital Command Control or DCC is the technology used to send power and commands to the locomotives. It has loads of capabilities. If you are interested the actual specifications for DCC are controlled by the National Model Railroad Association and are located here.

The following pictures show stages of the command station build.

Presently I use a web based Throttle called exWebThrottle to run the Loco.  This program is a app that runs on Chrome and communicates the control station.  The app allows for controlling the speed and functions on the Loco. 

                         

 

At the moment I have only one Loco on DCC. I accomplished that in a two-decoder method. I have an off-the-shelf DigiTraxx decoder running the motor and lights. For the horn, I have an Arduino and an SD card MP3 player 'listening' for the loco's addressed horn command. I can load multiple sounds on the SD card for other commands like 'Bell'.

Alright then, you can see I am deep into the electronics of DCC. My next project is a current detector for track occupancy.  This will allow the command station to know where a loco is on the track.  Further I am also looking into LCC which is the track control protocol for controlling lights, switches and other items.  Details on LCC can be found here.

Clearly more posts to come

3D Printer Workout

Without a doubt 3D printing has populated the press as a technology innovation to watch for its impact on just about every industry from baking,biology, to manufacturing.  Have a look at this post given in IEEE Spectrum regarding 3D Printing at CES 2014. It would seem inevitable that the world would progress from being able to print flat two dimensional  images to actual three dimensional objects.

If you have seen any of my other posts you will see that a 'project' is always underway in the shop.  Some of these have been for pure education on how to use shop tools, others have been to make something really cool. This project has been to build a really cool tool that is foremost in the technology watch these days. Pictured here is the 3D printer 'built in the shop' over the fall of 2013 and finished this month.  

Here is a very basic intro to 3D printers.  This tool is part of machine class that is called additive manufacturing.  It 'prints' objects by adding material in layers as opposed to my milling machine that shaves material away.  In particular this project uses Fused filament fabrication to build up layers of an object.  It uses a plastic material called PLA (Polylactic_acid) and an extruder heated to 200 degrees C to produce a 0.4 mm filament that is traced around the outline of each layer of the object being printed.  The printer is capable of producing an object that fits in an XYZ space of 150mm x150mm x 200mm.

The design comes from much open source inspiration.  The Cartesian XY motion is motivated from open source project COREXY with some changes.  NEMA17 stepper motors drive the belt for the XY motion in what is known as an HBOT method.  The metal working of the slides is the same as the COREXY project but the belt is run like the H Bot style.  This avoided the extra pulleys and belt cross over that COREXY uses.  What I like about this design is that neither the X or Y motors are in motion.  Think of this like an etch-a-sketch system where the 'knobs' control where the center plate goes.

Building the Z supports

Platen Support added

Fabricating Platen Support

XYZ Motors and belts in place

Extruder being added

The electronic that is in the box

After much tweeking and fussing the first object that I printed is a bunny....ok so my wife liked it....The object is known as the Stanford Bunny and has significance as a test pattern for 3D rendering.  The object is a traditional 'test pattern' generated by Stanford University which for 3D printing can be found on a very cool website call thingiverse.  Once you have a 3D printer operating you can download or upload 3D object files for sharing with the community at large.

Keep a look out for more posts on the printer and the workout it took to build it.  This may hold the record for the most complicated project to come out of the shop.  The goal now is to refine its operation and use it to produce pieces for projects yet to come.

Bench Workout

After many years of collecting tools I have finally decided to build the tool that all craftsmen need to own; a solid work bench.

Considering that I work in one side of a two garage, bench size means everything.  I wanted solid, sturdy with storage space.  There are lots of plans on the web but I settled on the-not-so-big-workbench by Ed Pirnik in Fine Woodworking Magazine. 

Roughing out the lumber

The on-line plans are nicely detailed and contain a Sketchup Model.  I went for the video as well.

The parts are cut from red oak.  The tenons were cut on a table saw, while the mortises gave me good cause to go buy a 3/4 inch Robert Sorby mortising chisel.  The mortises are pre-drilled to remove waste wood then squared up with the chisel.

Dry fitting the parts to ensure all mates well.

Once all the parts were cut a dry fit ensured that all went together just fine.  I tend to like my mortise and tenons to fit fairly close when they are this size.  Once glue is added the pieces need to be tapped together with the rubber mallet.

Pinning the tenons with dowels

There are no screws so far in the construction.  The tenons are pinned with dowels and then trimmed flush.  I use a copper shim to act as protection as I trimmed the down.  I did this when the glue was slightly wet so that saw dust would 'stick' in any gaps between the holes and dowels.

Base all complete

Here is the base all assembled.  The maple planks stacked on top give a rough idea of the thickness of the top yet to come.

The Table Design Continues ..

The work on the table started in earnest in August of 2011. The summer saw many rapid days of progress with George and I working on many pieces. As the project continued it became more and more evident that this will be a work that is around for many years. As a result the design began to mature as an adventure in pushing our woodworking skills.  The functionality of the table requires it has a span that covers 4 people standing side by side. The height needs to allow for an easy reach of the communion and offering plates placed in front of them.  For convenience the side facing away from the congregation should allow for storage.

The front side of the table is to have the words "This Do In Remembrance of Me" from Luke 22.19 

 

The design clearly needed to be solid to support the weight of all the pieces considering the span will be 8 feet. It also needed to allow for disassembling for transport to the church. The table would need to be movable around the church. Of all the projects I have tackled this is the most involved for materials, tools, size, woodworking, and purpose.

The design internals is based on an article "Arts and Crafts Library Table" from May/June 2001 of Fine Woodworking.  That is the method of how the drawer case, aprons, and sides come together is similar to the magazine article.  The fronts and sides of the communion table are to be solid with panels.  See my picture from an earlier post.   Yes there is the idea book again.  I have lost track of how many sketches we have done to prove to our selves the options on the design being considered.

As for the woodworking fine details; I am looking to use as few mechanical fasteners as possible.  That is I am trying to limit the number of screws - which puts a great deal of pressure on using solid woodworking joints.  That choice does allow for biscuits, as was used to align the top and bottom sections of the drawer case.  It also gave a chance to try out a double tenon construction to join the drawer case top and bottom.  This joint has plenty of surface area for glue and makes for a rigid construction.

More to come ... 

Back to the Furniture - Transforming Lumber thought Table Sketches to Finished Work!

After a long hiatus on furniture making, this summer was a chance to get back into the project that has been in my garage the longest, awaiting to be completed.
. 
The project of a Communion table for the Woodinville Church of Christ had started in thought a few years ago, but stalled for a time with a load of other activities taking my time.

100 BF rough cut Black Walnut

This project has become something special to work on as much of the tools and material used have a history.

The lumber comes from an elder 'George' in our church who has had this Black Walnut lumber drying in his garage for many years.  It was cut down in Washington maybe 30 years ago by his father. 
Roughly 200 board feet of Black Walnut was waiting for inspiration so as to be transformed into a table.  Shown to the left is about 100 BF measured and sorted.  It is ready for dimensioning.

I'll show more of that later, but needless to say this is rough cut 4/4 and 8/4 Black Walnut of a quality that I seldom see in such quantity in my humble shop.

George and I spent many days this summer cutting, sanding and scratching our heads trying to think carefully of what next.
  

Sketch Book of Table End

Personally I find it hard to create unless I can 'see' the end result. That is why I use sketch books (Yes and Google Sketchup) to capture ideas and passion.   I like to use the paperback size books as they are easy to sit with and hold while sketching.

A good mechanical pencil, a cup of coffee, a comfortable chair and the tools are in place to capture ideas as they come.

For this table I wanted to highlight the wood as much as possible.  The style I was looking for needed to be simple, not ornate, but capture some essence of its theological function.

The use of the pointed arches on each of the three side panels is what I decided upon as the theme catching element.  Three panels on each side to capture the essence of the Trinity.

Table End - Ready for final

There is much to post on this project but here is a glimpse of what is taking form.

The sides have been done very close to the sketch.  Design is a constant revisit of form and function.  The tapers where kept as the inverse taper.  But I opted not to have through tenons as it kept the look and work simpler.

This wood is far too nice to cover-up with standard finishes!

There will be no stain and poly urethane process here. It will be an oil finish. "George" likes the Danish oils as it pulls out the wood tone real nicely.


Much more to come....

Van de Graaff in the Garage

Sparks will fly!

Happiness is an excuse to build a Van de Graaff generator because your son needs one for a physics assignment. OK so he didn't need that big of one, but why not teach the next generation to dream and plan big.  If you are going to make an electrostatic discharge to impress your friends it had better be real long and snap real loud!    Ok here we go, this entry is a montage of our latest built in the shop project.



Let the Sparks Fly!

 The deal is garage science projects need to be done on a budget, and on time.  The project must teach something (skills in construction or science ) and it absolutely must be over-the-top fun!

A Van de Graaff (VDG) generator generates static electricity in large potentials. Generating 100kV is in itself cool. Discharging it to produce 3 to 4 inch sparks is way cool.  Since there is no current it is relatively safe - at least in the size we built.  NOTE there is already shop talk of VDG2 and how to make it better!


That's using your head!



There are many many sites on the Internet that show general plans for a VDG.  We took a look at a few and came up with our own ideas to fit tools available in our shop.  Most of the materials used are surplus items or low cost purchases from a local hardware store.  The domes used are stainless steel salad bowls we found at Fred Meyers.  Although they work the rim causes some unwanted discharge.  Very late in the build we found rimless bowls at our local Ikea store - hence the idea of VDG 2.

The tower is 4 inch PVC that is held in place with a PVC pipe-stand piece we found at Lowes.

Rubber belt cut from sheet shown with top pulley mount.

The belt material was the single most expensive purchase - but we wanted enough material in case things did not work out in the first attempt.  I found rubber sheet sold by the foot at Hardwick and Son's Hardware in the Seattle U district.  At first we thought joining the belt would require lacing.  It turns out the rubber glues very well with cyanoacrylates.  To join the edges we scarfed the rubber at 45 degrees.  A little glue on the bevel, press fit the edges, and clamping it down to hold in alignment and the belt was done.  Note our first belt was 2.5 inches wide but turned out to be too big.  We settled for a 2 inch wide belt in the end.  It was cut from 4 feet long rubber sheeting.

The static potential is generated by the belt carrying charge from a bottom (metal) pulley to a pulley (nylon) located on top of the PVC tower and inside the bowls (err domes).  A copper comb near the bottom pulley sprays charges onto the belt.  In our case this comb is electrically grounded.  Another comb on the top side transfers the charge from the belt to the dome.  By Faraday's law the charge should accumulate on the outside of the dome.  The picture below shows the mechanism used to hold the bowls to the tower and align the top pulley in place.  The position of the top comb can be seen just above the peak of the belt's travel.

Dome bottom with pulley and comb assembly


The top mechanism became quite involved but it works great.  Everything is built from plastic and nylon except for the copper combs.  Once assembled (with he belt through the pulley) the entire assembly rests on top of the PVC tower.  Notice that the charge is carried from the comb to the bottom bowl by the copper strap seen on the lower right. 





Making the top pulley bearing mount



Cutting hole in dome bottom

 



Bottom comb with grounding wire



Wood base, motor mount and bottom pulley
(obscured by the copper comb)




Center drilling the aluminum bottom pulley



Center drilling the top nylon pulley







 


Close up of plastic ring assembly used
to hold and align the bowls/pulley

   

Machining the rings to hold the
bottom bowl /top pulley to the PVC tower



More details to follow - stay posted!







Manipulating the Future

This project is a home-brew of a parallel manipulator robot known as a Delta-Robot. This robot has 3 degrees of freedom and allows for very fast positioning of it moving platform. The project started as an idea for learning\teaching kinematics. With too much on the go with other activities progress was idle for some time. Although the mechanical work is near done there is a load of software work now to make the robot useful.

The interesting feature of this robot is its design symmetry. There are relativley few different parts. The XYZ movement of the triangular platform (end effector) is accomplished via three angular joint mechanisms that are placed 120 degrees apart on the base.

Note the implementation shown is still missing the mount to hold it upside down from what is pictured.

The joint mechanisms are each controlled by a separate model airplane servo that pivots the fore arm. This arm is attached to a parallelogram seen as the parallel white rods in the photos. The parallelograms pivot on the fore-arm and the end effector. Again, three assemblies of the servo, fore-arm and parallelogram are placed at 120 degree angular spacing.

From the two photos shown next one can see the rather large range of motion the end effector can have with little change in the fore-arm's angular position.

The project is built with black lexan, while delrin and white fiber glass rods. Although it is not as light as it could be the implemention is sturdy and allows for a good deal of force.

The servos are controlled by a serial servo controller. (The small circuit board shown).

The end-effector platform can be seen below as the three-legged black lexan piece. The joints for the parallelograms are also made from black lexan. Some 8-32 nylon screws hold the pieces together.

More on all this later......

Boxing Day

Having newly made tools just lie around on a bench or in a drawer simply isn't right. Here is a weekend fun project of resawing, box-jointing and making a home for a tool from a previous post.

That't right the words are cut on the CNC. I use DeskEngrave to make the G-Code for the working. It is a free-bee PC tool. Try it if yo want to make some quick signs or lettering.

Pinion Jigs and fly cutting

I think I said it earlier that model engineering and in particular clock making is the art of making tools to make tools that make parts. Although there has not been much shop time lately I did take some time at the end of the summer (2010) to build a pinion milling jig. The plans for this came from Model Engineer's Workshop #164. Not having large mild steel on hand I made it from aluminum.

The lesson here came from proper grinding of a fly cutting bit. Have a look at this great site for details on grinding a fly cutter bit. http://start-model-engineering.co.uk/begin-with-bogs/fly-cutting/
This site is an excellent resource and a good list of model engine projects.

Tesla Turbine

The Motivation to Build

Sometime multiple things need to come together to make things happen. Sometimes people need to come together to create the drive for things happen as well. The motivation for this project came about as a father-son lets-build-something-cool in the shop and spend less time in the 'virtual world' of video games. argh..sigh... Dad.... Perhaps motivated by my observation that my son's interests are different than mine, as mine were different from my father's, but realizing all are linked by a common drive for understanding. Or maybe it was just a nice distraction to build something in the shop while talking between generations.

The Project

This project is a high-speed turbine, based Nikola Telsa's idea, as implemented with plans found here:
www.instructables.com/id/Build-a-15%2c000-rpm-Tesla-Turbine-using-hard-drive-/


and also here:
www.blogger.com/www.phys.washington.edu/users/sbtroy/Tesla_Turbine/Tesla_Turbine.html

This project came about after a few things came together
(1) watching a PBS show on Nikola Tesla www.blogger.com/www.pbs.org/tesla/,
(2) a chance surfing-stumble across a related link on the DIY website www.instructables.com/, and
(3) a sudden thought on what to do with a bunch of old hard-drives piling up in the junk-bin.
The first cool part here was taking apart old hard drives. It is amazing the converstation you can have with teenagers when you are busy on a fun project. Needed was the aluminum platters contained in each drive. These serve as the smooth serviced disks that Tesla used in his turbine.


Cutting the Ventalation Slots in Platters
The Hard Drive platters serve as the turbine disks. However they require slots cut in them to allow for the air (fluid) to exit dear the center of rotation. Three arcs were cut with a 0.250" end mill. Rather than use a rotary table, the CNC milling was machine was given some quick GCode.

















This is always fun to watch when the machine is cutting on its own. A simple clamping jig allowed for disks to the aligned on the table repeatedly. These disks are made of aluminum and cut fairly easily. The picture above shows the end result along with the needed spacer.


















Cutting Ventalation slots in the housing
Ow this posting is skipping a lot of steps. Below is a video of the ventalation slots being CNC'd into the side of the housing. Cutting in plexi is real easy. Can't say I know the actual cutting RPM, trial and error gave a nice result. Going too fast melts everything.





Stacking the Disks on the arbor
Below you can see the arbor carrying the disk stack. This build used 8 disks separated by about 0.030"





















More to come....