How would you deal with drill bits having the tip off center ?

I used to sharpen the drills by eye and with different gauges. Collected 2 big coffee cans of drills over 40 years. Bought a Drill Doctor and never looked back. I use 1or 2 of a size. If they don't drill the way I want, I do a quick touch up and keep going.
 
compact8 said:
The bit is new and cuts extremely well, chips are long, continuous curls but the hole is slightly larger. the error is more than acceptable. The diameter of the fluted part is found to be accurate suggesting that the tip is not centered. I believe this is not uncommon and wonder how you guys deal with it. Toss it ? re-grind ?
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Drills are easy to sharpen if you have a fixture or machine to do it. The least expensive way is to use a fixture like this on a bench or pedestal grinder.

Just about any big box home improvement store has them, or they an be ordered online. They usually cost between $20.00 and $30.00 depending on where you purchase it. They're good for occasional use, but a but time consuming to use if you have multiple sizes and lengths to sharpen. I started with one like this, but quickly found I needed something that could sharpen a larger variety and volume in less time.

A step up would be a Drill Doctor like this:

Drill Doctor Drill Bit Sharpener for Split-Point Bits 3/32in. Dia. to 3/4in. Dia. Bits, Model# DD750X | Northern Tool

The Drill Doctor® DD750X is a professional-level drill bit sharpener that is ideal for sharpening HSS, carbide, cobalt, titanium a...
www.northerntool.com www.northerntool.com

Much easier and quicker to use than the previous style. I have an older model that I used for many years before it wore out. I would estimate I sharpened 50 drills a month for over 10 years before the machine wore to the point it wasn't accurate. Drill doctor makes several models. The smaller ones go from 3/32" to 1/2". The larger ones go up to 3/4". They generally sell for between $50.00 and $150.00 depending on the model

If you're looking for an industrial or commercial grade machine you might consider something like this.
https://www.blackdiamondgrinder.com/95series.html

These are top of the line machines that can sharpen just about any style drill you can throw at it. They are quick and easy to use, but extremely costly if purchased new. I have a model 65 which was originally built for the military. It's a 3-phase machine and can sharpen number drills from $1 to #60, fractionals from 1/16" to 3/4", and letter drills from A to Z. They occasionally show up used on eBay for a reasonable price. New they cost between $7,500.00 and $9,000.00 depending on the model and accessories. I purchased mine from a local machine shop for less than #350.00. I pull it out of the corner about once a month and sharpen 30 to 50 drills.
 
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compact8 said:
I am not aware of that. Just measured a quality 7.5 mm drill bit, the diameter at the tip is exactly 7.5 and reduces to 7.44 near the upper end of the flute. Very interesting. Thanks for the knowledge !


In fact that's what I have been doing but it seems that it's not a very popular practice. I dont have a grinder so regrinding is not an option for me. To use the off-center drill, I drill a slight smaller hole first and finish off with the off-center one. When used in that way, the hole will not be centering around the tip and the diameter is determined by that of the body of the drill hence accurate. The only risk is having the drill grab and wander causing the hole position to be off.
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You’ll probably want to buy a grinder.
 
Harry required us to be able to hand sharpen a damaged drill in under 2 minutes. It's a skill I use all the time and something you should be able to do, even if you have a drill grinder.
 
As a rule in my shop (noncommercial) I keep in mind that a drill makes a triangular hole. If the hole is not important, just a bolt hole, I don't worry about it. If it is important, I use a reamer. When a drill is a "fuzz" off center, it usually doesn't show up on something larger than 1/4 inch. I use "step drilling" most of the time. If the drill is off center, it doesn't matter, cutting only on the flutes.

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Don't buy china tools.
Drill bits from USA
,Poland, Germany, Japan, Spain and other countries will be ground correctly.
 
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