How hard is it to sharpen drill bits freehand on a diamond stone or do you need a drill doctor?

[theastronaut]

I think you missed the point. Don't expect Youtube to give you all the right answers to every problem.

It was a pretty straightforward question..

Can I watch a YouTube on drill bits and do a good job that way or is it too hard to hold the angles?

 

[ez-duzit]

It was a pretty straightforward question..

Nowhere in your original post did you quote that question. So it was taken as a blanket statement.

 

[Whitworth]

First, We are talking about drill bits we can resharpen in this thread. Even the shops with CNC cutter grinders inhouse we didn't grind drills in the number gauge sizes. 6mm gun drills was about the smallest and that was because of the how expensive they were.

Second, If you would have read the link I posted, It talks about precision standards and how they relate to the diameter. I didn't just spout it off, I actually linked pertinent information.

Here is a screen shot of Cleaveland/Chicago Latrobe/walter catalog on drill tolerances. The finished diameter of the drill bit itself(not the diameter of hole it makes) has tolerances as large as you claim before it ever even starts drilling a hole.



Third, Few if any one is going to have a chuck on their drill press or mill that will have .0005" runout or less. Maybe an new Albreicht. But in the CNC world that is going to be a shrink fit tool holder or hydraulic like a Shunk.

Fourth, they make reamers that are wire sizes as well. https://www.mcmaster.com/products/reamers/system-of-measurement~wire-gauge/
If you want an accurate small hole, you start with an even smaller hole and ream it to size.

It's not just the hole diameter and roundness of the hole (which is important), but also the position of the hole and the straightness. An off center grind can cause a drill bit to wander, particularly a long drill bit. Doesn't matter CNC or manual.

 

[Firebrick43]

It's not just the hole diameter and roundness of the hole (which is important), but also the position of the hole and the straightness. An off center grind can cause a drill bit to wander, particularly a long drill bit. Doesn't matter CNC or manual.

Yes, but I was replying to post 28 and the only thing mentioned was diameter. I wasn't going to expand/muddy the conversation to True positioning, perpendicularity, straightness, or ovality.

 

[Tonymanx]

Not sure how velvo(u)r can sharpen drill bits. It’s pretty soft.

Saturate the velour with lapping compound........;-)

 

[Jswain]

Sharpening drill bits on a bench grinder is an art that anyone who drills even a modest amount of steel should learn.

We've all seen guys struggle trying to drill a hole through some metal, sweating. Thinking dang that's tough, and all it is was a dull drill bit.

Watch some YouTube videos, dress your grinding wheel, get a cup of water to dunk the bits in, grab your old dull drill bit index and start on the larger sizes so you can see what you're doing.

Two nuts tacked together as shown above makes a pretty nice guide.

It's not rocket science

 

[PoorUB]

Why? You can thin the web at the end and eventually you end up with a screw machine length which is great on the mill or lathe.

Well, I don't own a mill or lathe, so a shorter drill bit has no value to me. And I don't own a sharpener other than a bench grinder with a fine stone, so once they get to a certain point I toss them as it isn't that easy to thin the web by hand and do a decent job. It isn't like I toss a huge amount of drill bits larger than 1/4". In 40 years I have bought maybe three new drill bit sets up to 1/2". I just bought a new set maybe 5 years ago and tossed the old set. That set was about $100, I won't loose any sleep over it.

 

[PoorUB]

For general fabrication that 90% of people are doing, who cares?

Does the bolt fit in the hole? Yes, mission accomplished. I'll often drill the hole a couple sizes bigger so it's easier to line up.

That is typical in product too. Pretty much nobody in production drills a 1/2" hole for a 1/2" bolt. They drill them a bit over sized, how much depends on use.

 

[Old Man Roger]

I’ve been using one of these for decades, I think it cost me 20 bucks. Pretty sure you can still get them for close to that price.

This and a bench grinder will have you making sharp bits in no time. No real learning curve, no gauge needed, you can cut different size bits, and different angles for different materials.

 

[MushCreek]

When I started in the trade, part of our training was hand sharpening drill bits. They had buckets of dull bits to use as busy work when there was nothing else to do. They'd give us a big chunk of brass to test the results of our efforts. After thousands of drill bits, you get pretty good at it. I'm still pretty darn good at it, even though my eyes aren't what they used to be.

 

[cvairwerks]

Bert: Chicago-Latrobe 11070, #40, 6" HSS, 135 degree, NAS907 Type B spec, 72 of them for $54, including shipping.
Chicago-Latrobe 46710, jobber length, 135 degree, cobalt, NAS907 Type J spec, 48 of them for $49, including shipping.
NAS 907 bits are close tolerance, with the diameter spec going to the 4th decimal. I don't need that accuracy, but they were cheaper than standard 135 degree bits. Chicago-Latrobe and Cleveland are my go to's for anything under a #10. I watch evilbay for someone dumping full packages of the sizes I use and generally try to buy their entire lot, if the price is good.