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UKandy

Pre calculating lead weight?

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Hi all, this may be a daft question, as I'm quite good at them :D.

Okay so I would like to ask if anyone has a recorded table of pre drilled hole diameters & depths, to gauge the weight of which a poured lead slug would weigh?

So if I have a bait that say needs 45g of lead for my desired action, what hole diameters would be needed to pour/drip the correct 45g of lead in to the bait body? Obviously I'm assuming we keep the depth of the holes to a minimum for our lures.

I was going to do some testing by drilling different sizes holes & depths Into some wood, so as an example take a 10mm drill bit drilled to a depth of 20mm then fill with lead and weigh, but then i thought someone may have already done such a task or has information that explains this much easier than I've probably asked it :yay:

Many thanks for your input.

Andy.

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Fairly straight forward equation and several online calculators or if you have an experience with excel can whip it out.

Volume of the hole (cylinder) is needed  then you multiply by density.

picture-formula-volume-of-cylinder.webp

So the weight would be:

Wt=[πr2h]⋅ d

So all you need to do is substitute in your known variables.  We know pi, r2  is equal to the diameter (simply the drill bit size used), h would be the height or in our case the depth of the hole, and finally d is the density of the material used to fill the hole.   

 

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There is no precision pouring lead into a hole. No matter how accurately you calculate the hole depth, you will be lucky to get withing 2 grams of your target weight. In addition, the hole surfaces are charred, there is no adhesion, just a loose slug of lead.

I pour my lead cylinders in a wood mold, and then trim to achieve the exact weight that I require.

If you want a spreadsheet, then write down a specification of what inputs you want to make and outputs you expect, pm me and I will construct the sheet for you.

Dave

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10 hours ago, kakuip said:

Just a minor correction -- r is the radius, which is half the diameter.

r2 would equal (d/2)2 or d2/4, where d is the diameter (not the hole depth).

 

Didn't even notice when I was typing it out.  My youngest will get a kick out of it as about every night I am telling him to check his work as easy to make stupid mistakes.

 

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Good comments by all here. I do what @Vodkamandoes. Clamp two pieces of equally sized hardwood together, then mark equally distanced spots along the long edge where the two pieces meet. Drill holes along these marks using different diameters of bits (10mm, 8mm, and 6mm work for me) down to whatever depth you would like your lead blank to be and then pour your lead. I make mine longer and then use a box cutter to cut them down to whatever size I need. Sounds strange but just place your box cutter on the blank and apply pressure while rolling the box cutter towards and away from you. You’ll cut through the lead in no time. 

582A4C43-9EC2-4700-8EDD-87EC55867167.jpeg

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Another thumps for Mark's idea. Mark, I know you posted this tip a while ago. It has made my lure making easier. You can get a near perfect cylinder that fits the ballast hole tightly. It will reduce the margin of error in Travis' formula caused by irregular ballast weights made with wood molds or ballast poured in a drilled ballast hole.

In a pinch, if Bass Pro is out of the coil lead, you can use the XPS finesse weights as a substitute . They do have a hole through the middle that can be filled with wire.

The 1/2 oz finesse weights are 1-1/16" long and have a diameter of 5/16". They have a hole that can be filled with .051 wire. I don't know the dimensions of the other sizes.

https://www.basspro.com/shop/en/bass-pro-shops-xps-finesse-weights

The finesse weights also make cheap bodies for inline spinners.

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Great input guys!

The pouring of lead did put me off a bit with it been quite dangerous, I have been looking at a Lee production pot, that by the looks of things keeps everything as tidy as possible.

Didn't know about the lead wire, that's a good idea that is :yay:

Andy.

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