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Old Sep 20, 2014, 07:09 PM
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Open Source Toriodal Core Winder for Open Source CDI Ignition 12F1840

It is assumed that the reader has first familiarized himself/herself with the workings of a toroidal coil winder. YouTube is a great place to start. There, you will find two types of machines, one which uses a shuttle and another that uses a piston (not of interest.) You need to understand how a shuttle is used to stage the wire within the core and how it then winds the wire onto the core.

History
First, a bit of history… I became interested in the Open Source Programmable CDI Ignition 12F1840 project, here, on this forum. Part of the process of making the ignition involves winding a toroid core, a magnetic “donut,” with wire, to certain specifications. The process of doing that by hand seemed tedious.

What we needed is not readily available for purchase. So, I started looking around for a DIY machine, or method by which, to do the work… because I knew that machines had to be winding the coils that you can buy.

Most every design that I could find used a “shuttle,” a circular track, to stage the wire within the core and facilitate making the wire loops around the core. The shuttle did not look to be DIY friendly, nor easy to source for purchase. So, I looked for a machine that did not use one…

I came across an old thread, dated in 2006, regarding a Shuttleless Toroidal Core Winder invented by Mr. Clifford Potthoff and its adaptation for building it DIY. That project was never brought to fruition. Mr. Pottoff’s design appeared to be straightforward enough for a DIY design and I set about making it so.

Mr. Potthoff’s design is ingenious and incorporates a magic trick, which, once its solution is known, is simple. I equate it to those bent-nail and two-horseshoes- linked-together puzzles that I would find at roadside attractions, when I was a boy.
I have, just today, meet Mr. Potthoff, himself! He is a fine person, even offering his help. I hope that our efforts will do him proud and his invention justice.

Our stated objectives are:
- To create a set of plans and protocols for assembling Mr. Potthoff’s Winder
- To add improvements, where they may be found
- To have the instructions simplified for DIY construction from cheap and readily-available, locally sourced materials, to the greatest extent.
- The ability to fashion the parts with simple hand tools, if that is all that is available.
- Adding an UP/Down counting circuit to accurately count the number of winds.
Selected Prototype Materials
- MDF Board
- A Nylon Cutting Board from Wal-Mart
- A Nylon Cutting Pad from Dollar Tree
- Nylon Spacers
- Roller Skate Bearings
- Common Hardware and Fasteners

Development To-Date
I have developed a set of plans using Open Office – Draw. While making the drawings, I realized that, if a scaled set of drawings were given, the parts’ designs could be directly transferred for manufacture, without the need for measurements, or measuring. Therefore, the present set of plans does not include this extraneous information. This is a great boon in simplification for the less skilled DIYer and in time-savings for the expert.

Open Office – Draw is free, but its file format cannot be used with other programs. It may be sufficient, as it will export to the pdf file format. However, our group will need to choose a drawing program for our mutual use. I know that Sketch Up and Gimp are free. But I do not know what parameters need to be considered. I look forward to your input for this matter.

The challenge is now to create a method for transferring the designs directly to the materials. I attempted to use the ironing method of transfer, as is used in etching PCB circuits. I used transparency film for the benefit of being able to see through it to line it up. Ironing results were mixed:
- The transparency film crinkled from the heat. This changed the relationship of the reference lines, to a small extent. But, this was significant enough to require that it be addressed.
- The lines transferred from the film to the MDF, but not readily and not heavily.
- The Nylon Cutting Board cupped significantly from the heat. It did not accept any lines.
- The Nylon Cutting Pad melted to a good extent. It did not accept the lines.

Other options might be using high gloss paper, if removal from the MDF board can be facilitated without water, or silk screening, though less DIY friendly. I have been looking for an ink that is waxed based, instead of the plastic based inkjet ink. Something of that type would transfer even at low temperatures. The easiest approach would likely be to just use rubber cement to attach a paper template to the materials and cut out the pieces with the paper attached. Having given this some thought, I am rather settled on using it. I will give that a go for the nylon parts and report back.

The Magic Trick
Please read the full text of the patent. It is written in legalese and, therefore, it is challenging to understand the workings. But, here a few points to help you along:
- The Potthoff winder does not use a shuttle to create the loop necessary to stage the wire within the core. It uses a “C” shaped conveyor belt to create the bundled loop of wire. The gap in the “C” allows the wire to be sent through the core.
- The magic of the design is similar to a shuttle design. A shuttle disembarks its wire by slipping it off its track. Potthoff’s does, also, however, the line is sent through the middle of two plates with mating faces, to control backlash of the wire. The wire runs around the face of the “Escape Plate.”
- The anti-backlash plates are not joined. They are supported by independent structures.
I look forward to our adventure!

Tom
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Old Sep 24, 2014, 07:20 PM
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Here is the link discussed in the other thread to get things started...

https://www.physicsforums.com/thread...inding.130135/
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Old Sep 25, 2014, 12:44 PM
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Thanks, Jake... Yep, that link is where I got my original inspiration...
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Old Sep 25, 2014, 01:05 PM
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View Diagrams with BOM are attached for Beta Development...

Scaled PDF Files for Beta Development are attached...
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Old Sep 25, 2014, 02:33 PM
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The General Idea for Construction
- Parts are to be printed from the "Tattoos" pdf and secured with rubber cement for cutting.
- All wooden parts will layout on and come out of a single piece of MDF Board 16"x24." The base board does not have a tattoo. Its dimensions are approximately 16"x8".
- The Dollar Tree Nylon Cutting Pad will be used to make the Bushing Plate and various washers
- The WalMart Nylon Cutting Board will be used to make the Escape Plate and the Anti-Backlash Plate
- The Nylon Spacers will be used to make the Conveyor Rollers
- The Inner Tube will be used to make the Conveyor Belt
Once a successful machine has been developed, we will post construction instructions...

Tom
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Old Sep 25, 2014, 06:05 PM
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Pictures of Board Parts Layout and cooked nylon board and pad
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Old Sep 25, 2014, 07:21 PM
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Rough Draft of Assembly Instructions...
I know that I have forgotten to add the fender washers.

EZ Toroidal Core Winder General Assembly Instructions
All parts are rough cut from the MDF Board, Nylon Board and Pad.

The Escape Plate is cut to final shape, drilled and reamed to receive all hardware (#6 Screws and 5/16” bolt.)

The Drive Drum is cut to final shape, drilled for the 5/16” axle and mortised to receive two lock nuts. It is then given a slight crown, to facilitate belt tracking.

The Drive Pulley is cut to shape, drilled for the 5/16” axle and mortised to receive two lock nuts. It is then shaped to receive your drive belt of choice.

The Right Sidewall is cut to shape, drilled for the 5/16” axle and mortised to receive the two bearings. The bearings are now set. The mortise for the bearings should be a tight fit. Glue the bearings in, being careful to not get glue on the moving parts. You may be tempted to use a Paddle Bit. But I suggest using a Forstner Bit for better accuracy for the width and perpendicular walls with right angles to a flat bottom.

The Right Sidewall Block Support is cut to shape, pre-drilled and reamed for hardware and attached to the Right Sidewall with 1-5/8” Screws.

The Anti-Backlash Plate is cut to shape, drilled for the 1/2” T-Bolt and mortised to receive the head of the bolt.

The Left Sidewall is cut to shape and mortised to receive the Compression Spring.

The Left Sidewall Block Support is cut to shape, pre-drilled and reamed for hardware and attached to the Left Sidewall with 1-5/8” Screws.

The Base Board is cut to shape, pre-drilled and reamed for hardware.

The 5/16” Flathead Axle Bolt is passed through the Escape Plate. A Lock Nut is added to the bolt and placed such as to hold the Drive Drum just off the Escape Plate - to allow it to spin with little play. Epoxy glue is added to the axle and the Drive Drum is slid on. Care is taken to keep glue from spreading to any other parts. The second nut is put in place.

The Bushing Plate is slid onto the axle, taking care to have its cut-out facing forward.

The Right Sidewall is slid onto the axle, taking care to have its cut-out facing forward.

This Escape Plate assemblage is fastened to the Right Sidewall with #6 screws. Nylon spacers are placed over these screws to create the conveyor rollers.

The Right Side Assembly is set aside.

The ” T-Bolt is slid through the Anti-Backlash Plate and its head aligned with the mortise. The Compression Spring is added. The Left Sidewall is slid into place. The Lock Nut is added.

The Right Sidewall Assembly is secured to the Base Board. The Left Assembly is secured, also.

A Drive Pulley Lock Nut is added to the axle and secured such that the pulley can spin free of the Right Sidewall. The Drive Pulley is added to the axle. Epoxy glue and the second lock nut secure the pulley. Care is taken that the glue does not spread.

A ” wide strip is cut from the Inner Tube of sufficient length to run the entire course around the Drive Drum and Belt Rollers. It is looped about the conveyor rollers and drive drum. It is stretched just taught and secured with cement.

A toroid core support, of our own design, will need to be schemed and added. Mr. Potthoff’s wire support and guide are good designs. I have some ideas for the toroid support that will allow it to turn the core during winding.

Please let me know of any needed editing.

Thanks,
Tom
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Old Sep 25, 2014, 10:27 PM
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Wow, looks like you're well on your way to having this thing working!

I've got unlimited MDF scrap here at the shop. So anything you want milled just let me know.

Once the design is worked out well I can cut enough parts for everybody who's interested. A 4'x8' sheet of 3/4" MDF only costs us around ~$15, and I've got plenty of scrap that we're paying to dispose of on a regular basis.
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Old Sep 26, 2014, 12:20 PM
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Thanks, Jake! I appreciate your offer to help. Very kind of you...
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Old Sep 26, 2014, 12:43 PM
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I want to take a minute to talk about MDF verses Particle Board, for those that aren't familiar with the two. MDF is made from fine wood dust. Particle Board is made from small wood chips. MDF is dense and the particles are so small that they are not individually identifiable. With Particle Board you can see the chips. Look at the cut edge of the board to make the comparison.

Though Particle Board is less expensive, I highly suggest using MDF. The reason is that the project has fast-spinning, moving parts and friction surfaces. MDF should hold up better.

Home Depot does offer MDF in their project board selection. However, what I bought was a 16"x4' piece of shelving material, found with their shelving boards. I think it was around $12US.

My Lowes did not offer MDF in their project board section. I did not check in their shelving section, but I rather think that you could find it there.

Both stores offer full sheets of MDF for around $32US. You can get two machines out of one 16"x4' shelving board. Get a friend in on it... You can split the cost and enjoy building the project together.
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Old Sep 26, 2014, 08:51 PM
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I was able to get the square parts cut out of the MDF, today. I realized two measuring mistakes on the drawings. I have them corrected and posted the new drawings.

I saw one place for improvement. The front and back face plates are to be held on with Velcro tabs. I have extended the Base Blocks to protrude beyond the edges of the Sidewall Plates. This will allow the Base Blocks to align and hold the Front and Rear Face Plates.

Here are pictures of the casework. The parts have not been attached, but I got a sense of how things will go together.

Tom
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Old Sep 26, 2014, 10:33 PM
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Why not wind these cores manual? A whisper of a penny, Old School.
Or are you starting a factory? Than it has nothing to do with modeling in general and I would publici in another forum!

Taurus Flyer
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Old Sep 27, 2014, 08:14 AM
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Taurus Flyer,

What method of manual winding do you use?
I have tried winding wire around dowel and the passing the dowel through the hole of the toroid. It was a mess: wire on the dowel would become loose, wire on the toroid would unwind and spread, not enough wire on the dowel (to pass through the hole) to get the number of turns I wanted, etc.

I'm not so interested in an automatic winder as I am in some device that maintains control of the process.

Alan

PS just found the patent (downloadable pdf) at http://www.freepatentsonline.com/4127238.html . It can be a manual winder
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Old Sep 28, 2014, 09:00 PM
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When I mocked up the design with the parts I had cut out, I found some more things that I wanted to change, mostly to widen the case. I made the changes and I have updated the pdf file.

I originally used the Transparency/Iron-On method for the first cutouts. This method poorly transferred the lines to the MDF board and the heat melted the Nylon parts. So, I changed the template method to use plain paper copies secured with spray adhesive.

The link below shows the type of spray cement I used. It gave superior results... great holding power and no bleed-through of the glue. I highly recommend it. Changing to this method means that I will have to update the drawings to be non-mirrored and post them again... Coming soon, but not tonight

http://elmers.com/product/detail/E451
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Old Sep 29, 2014, 03:46 PM
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Quote:
Originally Posted by Tee One Dee View Post
- The magic of the design is similar to a shuttle design. A shuttle disembarks its wire by slipping it off its track. Potthoff’s does, also, however, the line is sent through the middle of two plates with mating faces, to control backlash of the wire. The wire runs around the face of the “Escape Plate.”
- The anti-backlash plates are not joined. They are supported by independent structures.
thank you......i was trying to figure out how the wire was played out when there is a crank on one side and a spring doohickey on the other side....i hate trying to read patents.

now i can also understand why the escape plate is rounded and of a slightly larger diameter than the "C" belt.

on the belt fed winders with no slider the wire is usually run between a flat metal plate and a "hair pad"....don't really know the correct term but it's the same as the painting pads that have angled hairs or bristles. in one shop i was in i actually spotted a cut up adhesive backed painting pad on the bench

and what are your plans for the belt? i would think a small poly-V would work nicely. pulleys are cheap and easy to find or even make and all the wire you need for a core would easily fit in one of the small V grooves.
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