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Center Point Marker Device

by hlyman, published

Center Point Marker Device by hlyman Jan 28, 2012
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This tool is useful for marking the center of a square, cylinder and rectangular objects



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.

3d Printer and Filament
Sanding sticks, files or/and emery boards
Drill Press
(1) Punch
(4) #3 x 3/8” Flat Head Sheet Metal Screws
Rubber Band

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 photo’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: [email protected]

Also I would accept a small donation through PayPal: [email protected]

Thanks for looking and good luck.

Hugh Lyman

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I see a mention in the PDF of Drill Bit Bushings and an Extender Arm. Are those files available? I'm currently printing one of these and those extra parts look like they'd complete it quite nicely. This is a great tool and design. Thank you sir for sharing it with us.

Wow! Very elegant smart design that handily solves a common task. Thank you for making this available to the DIY community!

For those who are following this thing, I have the following suggestion:

You can smooth the 3D printed parts by brushing on ABS solvent cement #2354 my Scigrip. Or and, coat the parts with XTC-3D epoxy. This will make the sliding more easy and smooth.

Fantastic work! Thank you so much for sharing.

Have you sold this design to any big companies yet? It seems like a no brainer for a company to pick up, have you tried Stanley Black and Decker? Great job!

Sorry I haven't replied before, too busy replying to other inventions. Originally I did try the big companies, General Tool almost wanted it till they got a new product developer and the economy went bad.

I was reading Jetty's comment about kickstarter and I too think it would be a good idea. If you ever find the energy to do it let us know. You may be able to get some of that investment money back. A lot of the DIY community would probably participate to your kickstarter. They usualy do.

I am too old to start any new ventures. In my life time I have owned and sold several businesses.

The DXF file has been re-uploaded and it now shows 644 kb.

Sorry about that. I only posted once honestly. It got stuck in some kind of rety loop.

Fantastic product idea. A true shame about the trouble marketing. Unfortunately your story is far from unique.

By the way, the dxf file you setup is 0 bytes and errors out when I try to load. Any chance you could look into that?
Thanks and best wishes.

Fantastic product idea. A true shame about the trouble marketing. Unfortunately your story is far from unique.

By the way, the dxf file you setup is 0 bytes and errors out when I try to load. Any chance you could look into that?
Thanks and best wishes.

Fantastic product idea. A true shame about the trouble marketing. Unfortunately your story is far from unique.

By the way, the dxf file you setup is 0 bytes and errors out when I try to load. Any chance you could look into that?
Thanks and best wishes.

Great tool! Thanks for sharing


What you suggest may be viable, however when I designed this thing it was inspired for the need to mark the center of a half inch dowel that I used in making a part for a radio controlled aircraft. Go for it and let me know how it works.

The Right Angle Jaw has been re-uploaded.

Jan 30, 2012

Please fix the right angle jaw file. it is at 0 bytes.

Thank you for posting this design, sorry the product idea didn't work out. By posting this design here, it will be used and help people build new things, instead of buried in the millions of garbage patents.

The two large L shaped parts: couldn't they be replaced with four solid beams that have swivel holes at each end? The end points would still be constrained to run along the X shape. That way you have a four bar linkage and if constructed accurately enough would still provide a center. The possible
disadvantage would be greater inaccuracy when measuring very small stock. However, it should be easier to make an accurate hole than an accurate slot.


Thanks for the comment. I am not interested in trying to sell this thing as I am 82 years old and don't need anymore businesses. As it is now public anyone that wants to make and sell them is OK with me.

maybe take a single print, single sale approach? no investment until someone has bought one.

Thanks Jetty,

I will check them out.

This is neat idea. Not so great that it didn't work out for you, especially as people want it. Have you considered "Kickstarter": http://www.kickstarter.com/http://www.kickstarter.com/

It sounds like an ideal project for them. It would get your dies funded, product made and make your project a reality. If you didn't get enough interest, then theres no financial risk to yourself. At the end of it, you would have a finished product that was ready to roll with other companies or via online sales.

That is a really nice device :-D

Thank you for sharing.