How To Easily and Accurately Calibrate a Grain Drill 

If you remove the cover from the right end of the drill and make a hand crank to fit in the rectangle hole you can turn the metering shaft while stationary and can calibrate before going to the field.

Why not just measure the seed and use a computer program?

Yeah I don’t think the factory settings are even a good starting point. I’ve never found them to be close. You might want to reset your feed cups so they’re all even. Close your gates all the way and loosen the bolts on the seed cups to make sure the fluted part is even with the seed cup. If you haven’t done that before I’ll almost guarantee there’s 5-10 lbs/acre difference between different rows.

We’ve got scales on our seed tender which helps us confirm our calibration.

Just beware I’m not sure if this formula works if you’re on a different row spacing than 7.5”. I haven’t been able to reverse engineer the formula to figure out how the 153.65 number comes into play yet.

@@griggsfarmsllc That’s what I’m running, 7.5”.

@@griggsfarmsllc Does drill width matter or just row spacing? Is that where the 153.65 comes in play? I run a 24’ drill.

@@chrisbruffett3270 drill width does not matter

I’m not exactly sure. I’m not the one that came up with the formula. I’m sure it probably has something to do with a conversion considering the equation uses both metric and English measurements. Could also have something to do with row spacing too.

I’m sure the constant is what does the converting from metric to English. Weighing in grams gives a lot higher accuracy because it takes 28.3 grams to make one ounce

I assume it would

As long as drill is on 7.5” spacing drill width doesn’t matter. You measure at the seed tube. You are measuring how many pounds per acre comes out of an individual seed tube. As long as the rest of the seed tubes are putting out the same amount the result will be accurate. The formula takes into account the area that that one single unit covered, not the entire width of the drill

@@griggsfarmsllc So as my 72" Tar River with 10 tubes as an example, the equation should be: ((weight captured 1 tube/distance travelled) x 153.65) x 10 tubes = lbs/acre (in a perfect equal system), correct?

@@sgto_o7118 no. You don’t multiply the final number by 10 tubes

@@griggsfarmsllc thanks for the reply, Ok, I'm confused then, so your equation calculates per tube, but I don't account for the number of tubes? Just clarifying, as I would think the number of tubes has to have some sort of baring on it all, with my drill having 10 tubes, and others having more? I think I'm missing something here

@@sgto_o7118 I don’t know how to make it any simpler. You are measuring the output of one unit. You’re also measuring the distance that one unit covers. The formula calculates the rate based on the output of that ONE unit and also the area that that ONE unit covers, not the entire drill. If you’re measuring plant stand in corn, you measure off the distance of 1/1000th of an acre for ONE row and count the number of plants in that row only and multiply by 1000 to find out how many plants/acre you have. You don’t take into account how many rows your planter is. The same principle applies here.

Width of drill does not matter as long as the row spacing is 7.5”

Not sure. I didn’t come up with the formula

I don’t know. I’m not the one that came up with the formula

Yes

🤔

@@griggsfarmsllc Looks like a possibility of a sponsorship from Tide or Fabreeze.