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My oldest daughter and I make a craft item that we sell. I have made several different sleds to cut the material but have needed a way to locate a pilot hole for a screw eye exactly in the center with out measuring. The craft item varies greatly in size depending upon what material I am cutting. My first effort worked, somewhat, but with sales increasing I needed something better.
This was made from a wooden hand clamp from Harbor Freight and scraps from the shop. Part of the scraps was a section of maple bowling alley.
The first picture is the finished jig.
The second picture is of the core of the unit. The threaded rod from the hand clamp is held in place so when it is turned the jaws would open. Did you know that you cannot find a left-hand acme nut? To hold the rod in place I made thick washers from some UHMW and held them and the rod in place with a nail acting as a roll pin. The most important part of this was making sure the wood and washers' thickness was so, when the jaws were close, they both were snug against the wood.
The third picture is how I had to modify the clamp jaw. I had to drill a relief, so the washes were not in the way of the jaw closing. By clamping the jaws to the center block I was able to drill holes for guide rods. This was necessary to keep the jaws parallel since I was only using one of the threaded rods to operate the unit.
The fourth picture shows how I had to cut the center block and the jaws for an aluminum track.
The fifth picture shows the completed unit at my drill press. Sorry the picture is up-side down, but I tried to correct it, but nothing worked.
The sixth picture is another view of the jig where you see a black knob to the left. Once the jig is centered and clamped to the drill press table, I need to move the jig to place the bit over the place I want the hole and then tighten it down.
I made a centering block to positioning the jig. I located the center of the block and drilled the hole. I then turned the block 180 degrees to test it. I was off by 1/132" Not bad. That is more than enough for the craft item.

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Make a video as this needs more clarification. I have been thinking about something along this line but I have not thought it thru yet. This might be great - not sure yet.
 

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What part of my description needs clarification? It's sole purpose is that as a self-centering jig. When I place it on my drill press table the jig it is centered under the bit with an indexing block and is locked in place. Now the jaws move equally left and right so an item would be centered when the jaws are tighten. I can, also, move it from front to the back to position the bit from the edge of the item to be drilled.

I could make a video using a scrap piece of wood. The craft item I am not interested in showing. I may try that.
 

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Very creative and an excellent idea!

I think dannmarks confusion probably stems from the fact that you know what you're drilling and we don't. Yes, it self-centers but, only in one direction. And, you would still need to position the first part by laying it out and lining it up by eye to locate the jig on your table, correct?
 

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In the last paragraph of my description I describe making an indexing block for positioning the jig on the drill press table. It is placed in the jig to locate the center point of the jig to the drill bit. Now ANYTHING (round, square, oval or any shape) I put between the jaws will be centered under the drill bit when I tighten the jaws. That takes care of the left and right direction. The base the jig is secured to moves from front to back that allows me to position the hole location from the edge of the object. That is done by eye.

Not sure I can do a video, but I will make some pictures of the step by step process. The item I built this for I cannot show due to some legal issues we are dealing with. The other reason is if I did show to it to this group everyone would copy it since it is easy to make, cheap to make and sales well.

I hope this clears up the confusion. I will try to make some pictures today.

Thanks for the interest. Sometimes we make an item that only fits our need, but the method can help others with an item they may need to build for their self.
 

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In the last paragraph of my description I describe making an indexing block for positioning the jig on the drill press table. It is placed in the jig to locate the center point of the jig to the drill bit. Now ANYTHING (round, square, oval or any shape) I put between the jaws will be centered under the drill bit when I tighten the jaws. That takes care of the left and right direction. The base the jig is secured to moves from front to back that allows me to position the hole location from the edge of the object. That is done by eye.
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- Bearpaw
I missed the indexing hole when I read it originally. That makes sense now. The front to back was the only other thing I was unclear on but now I see that is done by eye. Again, very creative and excellent build. Thanks for sharing!
 

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Took some time but it came out working like a charm. Nice garage engineering!!
 

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This looks intricate! I'd love to see a video of it in action man!
 

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People have asked for a video of this tool in operation, but I cannot do that. However here are step by step descriptions of me using the jig.


The set up block is put into the jaws. When the jaws are tighten, the drill bit is now centered. Located the drill bit in the chuck. Now the jig is centered under the chuck.


Secure the jig to the drill press table. Now you are ready to work.


Replace the set up block with what ever you are wanting to drill a pilot hole into.



You can position the sled from front to back by loosing the black knob.

Finished product.
 

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