Drill sharpeners

In thin sections and sheet metal, especially where the breakout side of the hole needed to be burr-free, I found it paid to use a point angle more obtuse than the standard 118-120 degrees, hoping to get the whole diameter cutting and supported on the cylindrical land before point breakout. Whatever worked for brass seemed to work much the same for alli. Don't remember coming across sheet steel or tube much in that situation.

At the time a lot of work was other than sheet metal,but special rivets needed different angles for 18g ,16g and no burns on the back when drilled.

Bob

I use a Spiralux drill sharpener. It can be abused, especially if I'm "messing about", shall we say, but with care it works well for drill bits between 3mm and 12mm, although to be fair, at 3mm, the drill bits are too small for the tool to handle them easily, whilst at 12mm, the drill bits are rather too long to be easily handled.

As a result, 3mm and below are scrapped, indeed I have taken to buying the smaller drills in multiples of 5 (Arc Euro Trade, I think). I don't use the larger drills all that much so the 12mm, or to be strictly accurate, 3/8" up to 1/2" are generally used as they come regardless of hole accuracy. (Usually they are either clearance holes, or preparatory before boring.)

The biggest problem I have is that I tend to leave drill bit sharpening until absolutely necessary, and then I have a good "set to" which means that the grinder, a 5"/125mm machine without any cooling, starts to overheat, consequently resharpening can take a long time due to having to wait for the grinder to cool down.

However, I am well pleased with my Spiralux, especially as it seems to incorporate all the necessary angles as have been explained before in this forum. (I have a suspicion that Graham Meek might have had a lot to say about this. My apologies to Graham if I'm wrong.)

Peter G. Shaw

This something I've recently tried to learn having failed in the past. After stumbling across a short YouTube video last week I've had some success with the technique shown in it. My cheap Aldi grinder has a tool rest I made myself and I've scribed a line so I can attempt to keep at the right angle. So far I've tried with a 10mm and an 8mm and both drills have come back to cutting decent holes. I figured larger sizes would be easier to start with. I appreciate he shows a very simple grind but I'm hoping if I can perfect it then I can try altering the technique to suit. Link below.

Sharpening video

Question for JohnP. I also have a Christen drill grinder that I picked up for a song at our local scrapyard. Unfortunately, it only came with one collet- you get very poor service at some scrapyards these days!

the collets are quite strange - split at both ends with a cone also at both ends, presumably to grip the drill shank evenly.

does anyone have any spares lying around or know of a source for these - I have toyed with the idea of using an ER11 collet chuck on an 8mm spindle- dead cheap from China, but the originals would be better.

sandy

As others have said, practice grinding by hand on some old bits. It can be quite satisfying. Get familiar with the tip geometry and you never know. Equal cutting lip lengths are important, otherwise you can drill oversized holes. A useful tip however, if you want a slightly larger hole than you have a bit for. It needs some experimentation though.

I'm not a big fan of cheap drill bit sharpeners, they rarely produce a good profile, and I really don't like those that use the side of the wheel.

Less than perfect eyesight does make the sharpening of small bits difficult, if not impossible, so with the smaller sizes, I just buy new ones a few at a time.

I was taught in a tool room at a factory where I worked as a maintenance electrician. The old guy in there Cyril taught me over a period of time & I am so glad he did. Took a while to get the wrist movement correct. But recently have not done too well sharpening large drills. Would be nice to have a good sharpener for the workshop.

Steve.

I have always used 118°

When would I need to use 135° please

have said before.......

buy 2 cheapo drill sets....... Lidil etc.....keep 1 as a pattern and practice on the other.......

after each attemp at sharpening try it on a peice of angle etc.....

u'll soon learn what works.......

no cheapo drill's when I was a lad tho......horrendus waste of good Brit drill's.......still, gotta learn......

Well remeber the 2Ft Grinder that my Dad had used to run this in a wet bath and crank this wile dad sharpen whatever he neded to sharpen Seem to remember being told place 2 hexagon nuts side by side when your drill fits into the V slot this looks good and will cut OK

Brian Morehen

Alexander Smith1 I have a Christen 05-10 and uses the collets you describe, they are still available as are all bits for the Christens, the company you need to google is Anglo Swiss tools, they are based in London. Sit down before you ask the prices though,as with all Swiss stuff they are eye watering expensive!

When you're drilling thin section material and you want minimum burr on the far side. The drill bit acts a little more like a punch in the last few thou. But 135 is just one of a spectrum of values. The idea is to get the cylindrical land into the material before breakthough.

Also the so-called 'crankshaft point' for deep holes in tough materials - but that name seems to be unfashionable nowadays. The point resembles some variants of the 4-facet, which is very much in fashion.

Thanks very much.

Not sure about "four facet" being "in fashion".

Having once experienced drills sharpened in this way, do not want to use any other method.

Mine are sharpened on my Worden cutter grinder, using an ER20 holder of my own design, with a setting jig to ensure that the cutting edge is vertical, (assumes just a minor trim up, not a major recovery from broken )

The last couple of MEW issues contain articles about making up a simple jig to four facet grind drills.

Might be well worth reading and making up the simple sloping table and two wedges.

Howard

Well - fine, each to their own. But there's no doubt in my mind that a 4-facet point requires more time plus more dedicated tooling to achieve. Back when I was machining for pay, nobody I knew ever talked of 4-facet points - the only known variant was the rarely-seen crankshaft point, used as said above for deep holes in difficult material. 4-facet grinds on standard drill seem to have become more available lately - I have some from Lidl that work nicely - and IMO that's what has increased the level of interest, perhaps beyond the real improvement they offer as compared to the extra resource need to produce them.

I agree that the 4-facet design has benefits, but at least some of them can be obtained by careful web-thinning on a standard drill, which requires only a sharp eye and a steady hand plus a few tens of seconds extra at the bench grinder. There's very little work in my usual spectrum of model engineering that needs anything better.

I'd see it chiefly as a matter of how you want to use your time.

Hi Guys,

Four facet ground drills tend to be self centring and take less force to drill a hole ! In mild steel anyway.

As far as tip angles go, I learnt a long time ago that the so called crankshaft point was good for stainless steels but you still have to keep them cutting to avoid work hardening.

I also use brad point drills for sheet metal, the raised lip cuts the outer just before the centre punches through.