Open Source electric conversion information

[bennelson]

Hey everyone!

I am having a machinist build a transmission adapter plate for my Metro, so I can attach an electric motor to it.

Since the machining will be done on a computer controlled machine, why not save the information as a file which I can upload for other people to use?

Once I have my plate done, I am going to ask the machinist the save out the file for me as a .DXF file. Then I can post it for anyone else who wants to make a Metro adapter plate.

Granted, everyone is going to use a different motor, but the transmission information will still be good.

Maybe there is other information that we can freely share with each other to help make other people's conversions easier.

-Ben

[88CRX]

How much do you think everything will cost?

[bennelson]

I am not sure how much the machining will cost.

The machinist is a super-nice guy. I have a feeling he will be giving me a really good deal.

I mentioned the idea to him of saving out a file to be able to share with other people, and he said it would be no problem.

He is a hot-rod guy, and I think he is just really excited to be working on an electric project.

I will be able to ask him how much time he put into it and at least be able to provide that time estimate to others. Or, better yet, save other people a lot of time by providing them with a file of "the shape" of a Geo Metro transmission housing.

[MetroMPG]

Great idea, Ben. FYI, our machinist charged us about half what we would have paid, had we not known the guy. And we paid about $250 for him to assemble our coupler (from supplied parts - machining and welding) and drill the precision holes in our supplied "blank" adapter plate.

[bennelson]

Hey everyone!

As my gift to the world, I am going "open-source" on my work on the Electro-Metro.

I recently had a request from a guy in Tasmania for the file that was used to make the adapter plate between my electric motor and transmission.

I was able to get that file today, although I do need to mention I did modify the plate after it was made.

I am uploading the file here, with the hopes that you good folks can help me modify the DXF file slightly, watermark it with both my web address and ecomodder.com, and give it to the world!

[bennelson]

This file is able to be read by machining programs and many 3D design and animation programs.

In this file, the center circle and six holes around it are specific to the particular motor I used.

The outside holes and general shape of the plate are specific to the Geo Metro/Suzuki Swift 5-speed manual transmission.

Mine was from a '96 car. The second transmission I used was from an unknown year, but was exactly the same. I don't know if they ever made any changes to the transmission, and thus would need to mark this plate as for 19XX-19XX model years.

This drawing needs to be modified so that the concave notch (for the passenger-side wheel driveaxle) is about 3/8th inch bigger - that is to say that I later had to cut off about 3/8ths more later from the plate because there wasn't enough room to fit the axle back in when I tried to hook it all up in the car!

It would also be nice to mark the center of the inside circle on this drawing. The center of that circle is the location of the transmission driven shaft. That's good to know, because the tranny shaft is NOT centered in the transmission!!!

[bennelson]

Here's a JPG version of that file so everyone who isn't into CAD or 3D can see it.

[captainslug]

Here it is in Alibre Xpress Part file format (minus the bolt holes you added for your specific motor).
With Alibre Xpress you can open and edit it to add the hole pattern for your specific motor.

Mechanical 3D CAD for Everyone. Powerful. Easy. Affordable.

Here's how to take CAD drawings from Alibre or Autocad and turn them into printable machining templates.

Making precise machining templates
(with a cheap inkjet printer.)

One of the more irritating hurdles to making your plan become a reality involves converting your plan to actual dimensions to work from on your raw materials. I used to do this markup process using a mechanical pencil and a schematic to work from. This took alot of time and only produced precise results part of the time (due to scribing errors). Machinists use scribing all the time, but they have far more accurate measuring tools than I have at my disposal.
After a recent project I realized I could use my printed to eliminate the need for scribing measurements on my part. This method is meant for any part that is 10" x 8" or smaller. Anything larger and you will have to combine sheets or find a local print shop that can print much larger labels or decals.

Software
There are so many options for software, and most of the more common titles cost more than the average person can afford. I've tried every free trial there is available and I've found one to be the easiest to learn and the most useful since it's an unlimited free trial.
Alibre Xpress is the free version of the full package and will allow you to design simple assemblies and part templates for whatever use you want. It's configured similarly to other Solid CAD programs in that you simply make a sketch on a plane then use one of several methods to extrude the sketch into a solid shape.

Step One: Measure & Sketch
Obviously if you're going to make a part you need measurements to work from. Whatever part you're making Alibre will allow you to sketch in the details you want. For hole placements relative to a corner simply start a line from the center (x0y0z0) by clicking there and then right click and select "Direct Coordinate Entry" which will allow you to place the other end of the line relative to the start of it.
Just continue sketching until you have a finished part.

Step Two: PrntScrn
Screen capture the sketch from Alibre with the sketching grid turned off. In a graphics program paste the screen shot and crop the image around the sketch. Select only the sketch lines and sketch nodes and copy then paste into a new image. Use brightness/contrast to turn the sketch black and then flatten the image.
Step Three: Page layout & Printing
Save as a temporary image and load as Clip Art from File (or just paste) in Microsoft Word (or similar suite). Right click the image and select properties to change the image dimensions to match the dimensions of the sketch in Alibre.

For smaller parts you can fit multiple sketches on a single page. It may also help to save your sketch images as .PNG files with an Alpha Channel layer. That image type seems to scale more cleanly in Microsoft Word for some reason.
Put one full-sheet label in the printer face down and then print your template page at the "Best" quality setting in your printing options so that you are printing at a quality level of atleast 600dpi. A lower DPI will result in extremely pixelated and difficult to use templates.

Step Four: Application
Now simply use some sharp scissors to cut out your individual cutting template labels and apply them to your sheets. It's best to apply them onto the protective film that comes on the sheet because cleaning the label adhesive off of the sheet after doing all of your cutting and drilling can be a time-consuming process.

Step Five: Assembly
Now that all of your individual parts are cut and drilled you can put them together as planned using whatever method you intended.

[bennelson]

OK - here is an updated image:


The round notch on the bottom left needs to be a little bigger for the passenger-side CV joint. Also, up isn't up. I marked in a red line showing the approximate direction of up. The red line on the right shows extra metal that could be trimmed off to make a little more room for long batteries in the radiator area.