CENTER POINT MARKER DEVICE
In 2005 I invented and patented the Center Point Marker Device (US Patent No. 7,082,694). After spending $10,000 plus in attempting to market this tool device without success I gave up. I had two promising companies interested in it until the economy went south. My first prototype, which I still use today, was made on a commercial 3D printer. I have abandoned the patent and am herewith making the device public.
The following link is a video using the Center Point Marker Device.
The following link is to the patent in Google Patents. (View this to see additional options)
The Center Point Marker Device is a simple tool for marking the center of an object quickly. It can mark the center of four different shapes: square, circular, rectangular and octangular. By placing a rubber band around the Control Knobs the device will hold to the object. My YouTube video shows marking four different parts. The accuracy is dependent on how well the parts are assembled. My commercially printed prototype had an accuracy of between 0.005 and 0.010 of an inch Note: Not all squares are square and not all cylinders or dowels are truly round, which can affect the accuracy tolerances.
REQUIRED TOOLS AND HARDWARE:
3d Printer and Filament
Sanding sticks, files or/and emery boards
(4) #3 x 3/8â€ Flat Head Sheet Metal Screws
Download the stl files. You can also download the dxf file created in AutoCAD if you wish to make changes or improvements. The PDF file has all the instructions, drawings and photoâ€™s for downloading. The expanded view of the device shows how the parts fit together.
You will need two of each part except the 4 Arm Base which one is required.
Print the parts with the finest resolution you can. I had to do some sanding of the rough faces to have a smoother sliding motion. The fit of the pins and the knobs is critical. Other options can be used for the pins (cutlery rivets or?) if desired. The included design has been enlarged 20% over my original prototype and converted to metri. The size just fits my printer.
I attached the Rotating Jaws with #4 screws. The Male and Female pins also attach with #4 screws.
You can use your choice of a punch. I machined one from steel so I could add a spring. However, I also use an aluminum blind rivet for softer materials. Again the hole should be machined for snug sliding fit as this is critical to the accuracy. The point on the punch must also be at the true center.
Dress the parts as needed. M
achine the punch hole in the 4 Arm Base part so your punch is snug and slides without falling out. The hole must be truly perpendicular for accuracy.
Assemble the Right Angle Jaws to the 4 Arm Base using the Control Knobs. Remember they have to slide freely. The top faces of the Right Angle Jaws face each other. I use hot melt glue to secure the Control Knobs, that way I could remove if needed.
Attach the 4 Arm Base and the Right Angle Jaws together using the Male and Female Pins as shown in the expanded drawing. Use #4 screws to attach the Pins together. Countersink the parts that receive the #3 screws.
Attach the Rotating Jaws to the Right Angle Jaws with #4 screws. Tighten only enough so the Rotating Jaws rotate freely
If you are like me you may have to remake some parts. I have made two of this size and they work fine.
I am happy to answer any question by email: firstname.lastname@example.org
Also I would accept a small donation through PayPal: email@example.com
Thanks for looking and good luck.