TorontoBuilder
Sapientia et Doctrina Stabilitas
Im of the opinion that it will not affect the grind. But depth adjustments on the split point and web thinning will.
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Tool Vevor Drill Bit Sharpener Improved
- Thread starter TorontoBuilder
- Start date
Tool
I'm not crazy about 'cone' either but that is due to my mental image bias. Just like 'lathe levelling', haha
OTOH, we need to be understanding of the Team Cone. Apparently it doesn't have to be the common flavor with circular base, apex projected perpendicular from the center like we would visualize a sharpened pencil. The base can be any kind of curve with apex at an angle & Team Cone has not defined the orientation. So it could be a cone.
Cone - Wikipedia
A helical geometry can be visualized like a thread - a defined infeed increment per rotation. Some grinder cams work this way, maybe that's the basis of the Vevor? You can see this profile on single edge countersinks. Zero flute countersinks (with the hole) are a different animal I haven't quite figured out. I think they are like this profile sketch but they seem to vary. Anyways with a cam, it could be anything, not necessarily helical.
And then there are the radius or swing arm style or rocker style which are different again because the radius once defined is constant, just projected through the surface at some offset distance & angle
I both love and hate the way you think sometimes.
Team cone eh! I'm killing myself laughing at that! I think I prefer being "some kind of complete loon" as per the Quorn article.
Our helical or eccentric grind is still not the cone in your diagrams. Your second cone is really just a regular cone sitting at an angle on a base. Said differently, the base is a section of the cone that is at any angle to its axis. Viewed from anyplace on the axis itself, it's still a regular mathematically perfect cone.
Maybe we should try to develop a math formula to describe what you and I have been calling eccentric and helical grinds and then give it a more appropriate name.
Every time I hear the term standard conical grind or any of its varients, my hackles vibrate. Obviously, I'll never be a member of team cone. You would have to kill me first. But I am perfectly comfortable calling it an eccentric or helical grind. I could also live with something like precessing grind. I wonder if an engineer at a drill manufacturer has a term we could swipe?
How about eccentric helical grind? LMAO!
Dan Dubeau
Ultra Member
Engineers......
Has anybody sharpened a drill and drilled a hole with it yet?
Has anybody sharpened a drill and drilled a hole with it yet?
Engineers......
Has anybody sharpened a drill and drilled a hole with it yet?
Yup. I did. It works perfectly.
Thinking of changing my user name to "TheLoonyEngineer".
See here for photos and proof that it works.
Here is a photo of a dull 1/4 drill
Sharpened by drill doctor 250
Sharpened by Drill Doctor 750
Sharpened by Vevor 13B
With back relief by Vevor 13B
I suppose with some adjustment, the back relief could be improved.
Comments:
Setting the drill bit properly in the collet is not a straightforward process. With time, I think we could collectively develop a better procedure than Vevor did.
The back relief could probably use a scooch more depth. As it is, I set the depth by eye. I am sure it can be improved, but I think...
Sharpened by drill doctor 250
Sharpened by Drill Doctor 750
Sharpened by Vevor 13B
With back relief by Vevor 13B
I suppose with some adjustment, the back relief could be improved.
Comments:
Setting the drill bit properly in the collet is not a straightforward process. With time, I think we could collectively develop a better procedure than Vevor did.
The back relief could probably use a scooch more depth. As it is, I set the depth by eye. I am sure it can be improved, but I think...
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Dan Dubeau
Ultra Member
Yup. I did. It works perfectly. See here.
Here is a photo of a dull 1/4 drill
Sharpened by drill doctor 250
Sharpened by Drill Doctor 750
Sharpened by Vevor 13B
With back relief by Vevor 13B
I suppose with some adjustment, the back relief could be improved.
Comments:
Setting the drill bit properly in the collet is not a straightforward process. With time, I think we could collectively develop a better procedure than Vevor did.
The back relief could probably use a scooch more depth. As it is, I set the depth by eye. I am sure it can be improved, but I think...
And the hole.....?
And the hole.....?
Now who is the loony machinist......
I'll take a picture later today just for you. Tough crowd...... Sheesh......
Dan Dubeau
Ultra Member
lol, just poking some (light hearted) fun across the table at my highly analytical Engineer friends......I meant no offense
I am no longer a Machinist. Just a lowly Millbilly apprentice now. I only get an angle grinder to sharpen drill these days, if that. I had to do that on a job last month, guys first thought I was crazy, then thought I was some kind of a wizard when two perfect curls came out from each side.
I am no longer a Machinist. Just a lowly Millbilly apprentice now. I only get an angle grinder to sharpen drill these days, if that. I had to do that on a job last month, guys first thought I was crazy, then thought I was some kind of a wizard when two perfect curls came out from each side
.
thought I was some kind of a wizard when two perfect curls came out from each side
No worries. I didn't take offense at all.
Totally jealous of your abilities.
Dan Dubeau
Ultra Member
Don't be, it was honestly more luck than anything on that one, but it happened at the right time with a couple guys watching so I'll take it
. I was new to this crew, so I always had an audience (and comment section.....) for everything I did.......Almost all other subsequent sharpenings didn't produce the same near perfect results, but they were acceptable to get through the job at hand. Which was drilling holes, not producing perfect drill points. All I really ask for from a drill sharpening really. Something in the 70-90% (maybe 95% if I take my time, and try hard...) of perfect range will usually do the job. Shoot for one end or the other depending on what you have to work with, what you're goals for the hole are (tolerance), and how time sensitive the task is. In this case it was mag drilling 21mm holes though 4'x8'x 1/2" HR steel plates stacked 7-8 high. 12 holes per plate, and I did 10 stacks. "Good" sharpenings I could get 9-10 holes before performance drop off was noticeable, and could make my way through the rest of the plate usually before sharpening again. "Bad" sharpenings were around 4-6. I did find another drill in the sea can near the end of the job, so I could sharpen both at the same time, and just swap when performance dropped off, instead of pounding through because I just wanted to finish the plate......That sped things up a great deal as It's easier to touch up a slightly worn drill, than one that's totally knackered by a ham fisted idiot that has get'r doneitis (me).....
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TorontoBuilder
Sapientia et Doctrina Stabilitas
Now who is the loony machinist......
I'll take a picture later today just for you. Tough crowd...... Sheesh......
see this is why I didn't mention when I sharpened a drill bit and drilled a hole.
that's not the point. the point is more tools. DUH
TorontoBuilder
Sapientia et Doctrina Stabilitas
Just so ya'll know, IF ya'll really really want a 4 facet grind, you can mod this grinding to provide one. Similar to how they modified the machine to grind end mills.
Tom O
Ultra Member
You just have to draw in the waist arms and head then we can see what she looks like.
And the hole.....?
Just for you Dan...... And only because I trust you to find the hole......
Dan Dubeau
Ultra Member
Nice looking hole......Looks off center though......
Nice looking hole......Looks off center though......
That's deliberately in deference to the cone team......
I think it is important to say a few things about cones. Cones are 3d shapes that have bases that are 'round' and rise to an apex.
A 'standard' cone, is the regular, right, circular cone (what comes in the kid's set of blocks). But a 3d shape can still be a cone if it looks like it came out of the wrong end of a dog. It still has a 'round' base and an apex, but you would never want to use that shape as a drill point on purpose.
I also think it is wrong to say that these shapes are helical. The tool path to create the desired shape is a helix. And probably a special kind of helix called a clothoidal helix where the 'slope' changes proportionately with the length along the path, but the resultant shape is still some kind of cone. If there is a precise name for that kind of shape, I don't know it
And then I think come the complex parts of the cut. I think your pictures show more about what a good shape is than anything I could say. And others have also added important information. But in this one area of nomenclature, I think I can help with why there is such confusion - even if i can't really help to dispel it
Here is a good article on drill bit geometry,
That was a great read Stel. Waaaay better than YouTube video.
Although the author is not an academic, it reads a bit like he is. And if you believe the claims he makes, it sounds like he has frequent academic interactions.
All in all, I find that most of what he writes is not appropriate for us hobbiests. I don't really care if my drill will last for 22,000 operations or just 10,000. Nor do I care if each individual operation is 5% faster or slower, or even if the grind is best for Stainless or for a given Plastic.
If only his comments about outside corner improvements could be reasonably implimented in my shop. Exactly as he noted, that is my most frequent failure mode. Unfortunately, the complexity of the recommended grind is clearly WAAAAAY beyond what I could ever reasonably do in my shop.
This was also the first time I've ever read that split point geometry is not practical at sizes larger than roughly 1/2 inch. He didn't explain that to my satisfaction, so I'll have to explore that at some later date.
After all tbat, I am back to the same point (PNI) I keep making. This project is not about grinding a superior drill. It is about modifying an economical drill grinder to do both variable web thinning and spilt points without breaking the bank.
Perhaps once that is done, it might make some sense to look at what it would take to do 4 facet sharpening. But that is about the extent of what I am willing to do. For anything more than that, I'm back to buying better drills and either discarding or repurposing them when they get damaged or worn out.
I did look to see what was available at Neuman Machining (it's good to remember that's why he wrote the article in first place..... LOL!), and guess what? If they sell his fancy drill point, I couldn't find them! It felt like the typical bait and switch deal to me.