Drill sharpening

[Kittyhawk]

I'm ok at sharpening twist bits - not great, but ok.
But it seems to me that if you want to drill a hole with precision then the point of the drill has to be exactly déad centre to enable the drill to run true. There is plenty of stuff online about cut angles and so on but nothing about centering the point. Most of the drills I use are under 6mm and I don't know how to easily get the point precisely centered, especially on the small ones.

 

[Distinterior]

When I need to do really accurate drilling in metal, for example, I pre drill the hole with one of these https://www.ebay.co.uk/itm/285556908284

 

[deema]

To drill true you need the drill centre in the centre, the cutting edges at the same angle, relief, and length. In other words perfectly symmetrical. I believe that this can only be achieved by a proper drill sharpener if you’re wanting the best accuracy. However, for drills under 6mm I wouldn’t bother and when you need the best accuracy use a brand new drill. You will need to ream to size afterwards.

 

[Jacob]

They can be filed or ground into a spur bit. Not difficult.
https://www.ukworkshop.co.uk/threads/tip-and-spur-and-brad-point-drill-bits.54853/

 

[Inspector]

I agree with Deema. The company I worked for had a guy that did nothing else but sharpen milling and drill bits. He was quick and could freehand sharpen, it was more economical to by new bits under 1/4".

I prefer 120º spotting drill bits over the centre drills recommended by Distinterior. With the starting hole made by a spotting drill the entire flute of the next drill bit engages and centres better. The only centre drills in the plant were for the manual lathe they used for repairs. Make sure you get the 120º and not the 90º spotting drills. Our machinists also used them to make a bigger hole than the drill size to have a chamfer after the drilling. Some examples in NZ you can look into if interested. There are Asian ones that would be cheaper through whatever online sellers you have.

https://suttontools.co.nz/products/spotting-drills-120/

https://www.sowatool.com/p/116354

https://webshop.iscar.co.nz/catalogue/product/1000003459

Pete

 

[Kittyhawk]

Thanks for the replies.
In retrospect I think I will just forget about trying to become a master drill sharpener.
Like probably everyone else I have a box full of well used drill bits and I will continue to sharpen these as best I can and used then on the non critical stuff, and buy a drill set of something like 1mm to 10mm sizes and set them aside just for the precision work. The stress of applying to the Child Bride for the release of funds for tool expenditure will be more than offset by not having the aggravation of trying to sharpen a drill bit properly anymore.

 

[Fergie 307]

I'm with Pete, small ones just aren't worth the bother. I keep a set of good ones in tapping sizes, and for accurate stuff, and loads of others for general use.
My eyes aren't what they were so no lomger sharpen free hand. I have a drill doctor which is really good once you get the hang of it.

 

[MorrisWoodman12]

I think I've sharpened about 3 drills in my life and have a plethora of stuff which needs touching up. This includes a virtually new set that was given me. Can anyone recommend a jig (do please sit down again Jacob ) because I can't be ar**d to learn to do it freehand.

 

[deema]

I think the first question is how good a sharpen you need. Sounds a bit odd doesn’t it, but if your drilling wood and just want a hole that cuts cleanly which means if it’s up to 0.5mm larger it’s not an issue then any of the cheap jigs you see on eBay and Amazon will work. If you’re after something that’s accurate, dead on centre. Almost exactly the drill size with a long edge retention for drilling metal, then your into a different league. Jigs for this that claim to make a reasonable job are probably £500 and going up to thousands depending on what you are trying to achieve.

The level of cost depends on whether your looking for a standard grind, four facet, six facet, point spilling etc etc.

There is a lot of technical stuff in drill sharpening, I’ve probably scratched the surface myself on the subject, and know I have only a basic understanding of the various attributes of each type of grind versus the material, accuracy and longevity of a dill. It’s a big issue if you running CNC machine tools on expensive materials / parts.

 

[ChaiLatte]

Can anyone recommend a jig...

Could you give an idea of how much you wish to spend please.

The cheapest 'good' one, for 13mm-4mm (and down to 2.5mm with care and magnification) is the Proxxon one (BSG220), but it is spendy and is best used for light touching up rather than restoring damaged edges. Occasionally you find one on eBay at a more manageable price. Note that it only does 118 degree standard twist drill points. No fancy spur bits.

If I had money to spare, I would try one of this style:

https://www.amazon.co.uk/Sharpener-MR-13A-Adjustable-Re-Sharpener-Sharpening/dp/B0D9B6KKG1

They are a more affordable clone of the Vertex one and the original Vertex machine works very well. The risk is that the copy does not...

The top of the pile would be a Christen (https://www.ebay.co.uk/itm/256568117079), but that is only a dream.

 

[Distinterior]

I'm fortunate to have a " BestMateMark" model for all my drill bit sharpening needs.....We have been best mates since we started our engineering apprenticeships together back in 1978......He worked as a Tool maker in the Tool Room and I worked in the Electro Mechanical department.
He was taught to hand sharpen drill bits when he first started and was given boxes & boxes of bits that needing sharpening.....Even watching him recently and all these years later its impressive to see the results........I suppose it's like riding a bike.....something you never forget how to do once you've learnt.

 

[Phil Pascoe]

I spoke only last week to a friend about drill sharpening. He's coming up to retirement and has worked in engineering in one form or another all his life, and he sharpens freehand. He told me the younger people coming through the system now are no long taught to do it, they just throw the smaller bits away, sending larger ones elsewhere.

 

[Chief Sawdust Maker]

I was taught as an apprentice back in the early 80's to sharpen free hand on a bench grinder we used to do everything from around 1/16 right up to 3" along with some specials at about 10mm that were 1.2m long
The long ones were to drill a grease hole through the centre of a stainless shaft and we actually ground the off centre so as the cut big to prevent rubbing and grabbing
A dressed wheel is important along with no letting the drill get hot, CBN wheels are a big step forward but come at a price
I think it is like ridding a bike and you dont forget it, I have a couple of friends that i will do it for
Sometimes its useful to keep sharpening stuff i have some very short drill that can get into all sorts of places.
I have just started wood turning and brought a set of Tomek jigs to sharpen gouges etc, but as my turning gets better I will aim to start free handing all my turning tools I just want consistence at the moment

 

[Amplidyne]

If you want to get the point central, then hold the drill up against the sky, or something white so it is in silhouette.
The eye is remarkably accurate at discerning what is centred and what isn't. Drills aren't that accurate anyway, you need to ream the (undersized) hole anyway after for accuracy.

As for small drills for wood, I have seriously just used a small nail with the head cut off in the drill for pilot holes before now. Cheap, and don't break.

 

[Phil Pascoe]

Up to 4.6mm, less than £3 for ten. Why even think about sharpening them?

I bought a 170 piece set for £32 in 2002, over the years I replaced the 3mms and 6mms but most are now blunt so I've just treated myself to another set. £44.50p.

https://www.ukdrills.com/drill-sets...etal/170pc-hss-drill-magazine-titanium-coated

 

[deema]

@ChaiLatte After a lot of research I also came to the conclusion that the Christen drill grinder is probably the best drill sharpener ever built. The Swiss company that made them I believe is sadly just a memory, however spares are still available. The machine shown on eBay doesn’t appear to be complete. You need the cams and finger inserts to truly use it to its full potential. I was lucky recently to find a Christen virtually complete at a price I could just about justify! The manual Im still studying is over 250 pages of A4, with very few diagrams and a lot of theory on how to achieve the various grinds on just about any pointy tool.

https://www.lathes.co.uk/christen-drill-grinders/

The other truly nice sharpening jig that can also do 4 facet grinding as well as traditional is the Clarkson drill grinding jig designed to be used with a Clarkson Tool and cutter grinder. They seem to be rarer than hens teeth though. However there now appears to be ‘clones’ on eBay for around £500. They go up to 16mm drills as well as being able to do end mills and taps. When I finally get my workshop back u0 and running I wall do a side by side comparison. By good fortune, my Clarkson grinder came with the drill jig.

https://www.lathes.co.uk/clarkson/

One of the many listings for what looks to me to be a clone

https://www.ebay.co.uk/itm/35642138...ar=625414949565&widget_ver=artemis&media=COPY

 

[deema]

I had looked at other drill bit sharpeners including the ‘famous’ Drill Doctor’ and the more ‘advanced sharpeners like those suggested by TrPete222. I’ve ‘had a go’ with a Drill Doctor, but wasn’t that impressed, it’s just a traditional grind that can be achieved…..or so I believe. It’s a lot of money for a very basic machine. I haven’t tried the sort of machines MrPete reviews, but there seem to a number all very similar and all seem to want a good chunk of change.



I taught myself to hand sharpen drills, for basic wood and metal work where your just wanting a hole it works well. I have known a lot of extremely talented tool makers who could do it with their eyes closed, but, for all precision work we always had the drills jig sharpened to achieve the absolute accuracy we needed. A drill point gauge I find of great benefit both for learning and also doing it freehand. They are very very inexpensive.

https://www.ebay.co.uk/itm/16727246...8mfAKrtRtW&var=&widget_ver=artemis&media=COPY