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Drill bit sharpener - anything out there that actually works? Answered

I have no problem fixing the bigger drills I have once they get blunt from use.
But once we go into the range of 5mm and below it is quite tricky.
The grinding wheel that works well for a 10mm drill can be way too coarse to deal with a 2mm drill...

I looked a quite a few commercially available sharpeners, even tried a few in store but they just don't satisfy :(
Most create a rather rough surface finnish which makes the drill go blunt even fast, although it cuts really well for the first hole LOL
Especially when it comes to producing more than a standard edge this toys seem to be useless.
Ever tried to use a 13mm drill that has no back cut and no center cut angle added? It's a pain...

Last night I went through some now vintage photos and remembered that my grandfather had a metal rig for the drills.
It screwed onto a mount for these stand up and "see through" slotted disk grinders people had in their workshops back then.
The drill was fixed in place by a pin in the flute, so stoppers could ensure you are always grinding at the correct angle.
Not just the angle for the cutting edge but also the angle in relation to the flute.
Once this initial sharpening step was done you clicked the whole thing sideways to get the back cut angle added and a stopper ensured you won't be able to grind off too much.
It was not able to do these fine center cuts that allow you to get away without a pilot hole but the drills were sharp as and kept their bite for a long time.

Does anyone still have one of these things in their toolbox or vintage collection to provide some detailed images?
Would love to design something similar but reall struggle with the mechanical side of things.
The original had the option for three different edge angles to be selected.
The "lenght" was set by letting the drill touch the disk (off), locking it and then by using a clicking screw to drive the drill up in I think 0.1mm increments.
It was very, very easy to get perfectly sharpened drills with it and I would love to be able to use something like it again :(

The only thing getting a bit close to this that I found so far comes from China - of course it does...
A crappy and cheap grinder similar but smaller than an electric chainsaw sharpener.
A grinding disk about twice the size of a dremel one does the cutting.
To make sure all is even the drill is aligned so its center is right on the edge of the grinding disk.
On the free side is a simple stpping plate.
Might work somehow but something tells me tht the center of the drill will never be perfect.


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Best Answer 11 months ago

See Project Farm's video on YT


Answer 11 months ago

Well I got a cheap one without the fancy backcut option.
These drill doctors are not only really expensive but also hard to find for 240V mains supply.
Did not expect too much for a $50 device and I only selected it with the aim of making my own attachments on the 3D printer later on.
As it came suprisingly fast into my letter box I tried it out...
If you want one to see just check fleabuy or similar for "drill knife chisel electric" and you find them in various colors.
Three different attachments for the diamond wheel side...
Can provide a link or pic if need be ;)

What there to say about these crappy toys?
The run at over 6000RPM, so if you use only little pressure the 180 grit wheel will actually do a decent surface finnish with little to complain about.
But in terms of usability and reliablitly....
Nothing has a tight fit, there is play whatever you want to sharpen.
Will be fixed by custom attachment once I find a few hours for the designing to spare...
Let's start with the knife a sissor attachment...
Depending on the handle you already struggle to sharpen the full length of the knife.
With nothing to esure you keep the blade straight it is up to you alone how even the edge will be...
And being a 180 grit diamond wheel at high speed mean you make one mistake and you can ruin over 1mm of your edge quickly...
Similar story for a pair of sissors.
No clue what the fixed angle is supposed to be good for but I had nothing coming even close to a match.
To I only dared with some $2 ones for hobby use.
The resulting edge was not perfect but a few cuts through fine sandpaper fixed it quickly.
The angle works reasonably well on paper, not so good on double layered carboard and really struggles with fine fabrics, jeans however still no problem.
so for everyday use in the kitchen the toy might be good enough, to shrpen your expensive sewing sissors you stick to better ways.

Next the chisel attachment...
At first I failed to understand why I could not get a flat angle of 15%, then I realised all other attachment had to come off their resting places first to give enough room :(
As said, it wobbles up, down and also sideways a bit.
Cheap plastic parts with low manufacturing costs and high tolerance clearings.
But if you hold it all steady you get a nice and even edge - sort of...
Thing is that chisels come in all sorts of sizes and thicknesses.
But you can't adjust the height relative to the grinding wheel, only the angle.
Means, unless you add some extra spacer or a piece or carboard you might have to grind off over 5mm of your chisel to create a new (now rounded) edge :(
These rounded edges are sharp as hell once you used some leather to remove the burr.
But they are also very thin an sensitive.
I already ruined it when I struck a bit of knotted wood too hard.
they also bit into the wood like no tomorrow, one mistake an you go in like an axe.
There is option for a lower speed or water either but no big deal.

The drill attachment, the reason I bought it apart from modifying it LOL
Instruction are of course in very qualified chinglish with extra large images to explain the instructions.
Means you fail to understand most of it and even under a magnifying glass the images are of such poor quality that you struggle to see what is drill and what is plastic.
Found some slightly better instructions online for a very similar model so followed these...
Let's say you have a nice looking drill that is a bit blunt.
You place it into the plastic chuck and then use the guide on the left to set the drill bit properly.
All is good and you push the holder into the grinding position...
then you need to remove about 4mm of the tip of your drill to create the new edge - WTF!?
Turn over to get it even and enjoy.
Only problem is that the supplied attachment seems to be for left handed drill bits.
At least, no matter what and how I try, the cutting edge always ends up lower than the back.
Means the drill bit is just circling on the shoulder of the new edge without doing any cutting at all ROFL
Only way to "fix this" is by manually creating a big back cut, but still you never make to the cutting edge.

So was it worth the 50 bucks?
Considering it comes with a spare grinding wheel already....
No jokes a replacement whel for these costs about 15 bucks, so in reality, motor, housing, attachments and all are only worth about 20 bucks LOL
If you just need a motor with a 50mm diamond grinding wheel on it than it is a good deal.
For doing any serious sharpening jobs just stay away.
The attachments are of simple desing, so making some mods should be quite easy but who else would be a new grinder just with the intention of not really using much of it in the original form?....
For me it will still come in handy for a lot of odd jobs, so I don't mind too much.
Aleadry thinking of an an attachment to finish off glas edges after cutting panes.
Or to put the entire thing into the bench so only the wheel stick out at the correct angle....
Love to tinker...