Drill sharpening?

[Bo’sunParticipant @bosun58570]

[Bo’sunParticipant @bosun58570]

Good morning All,

Yes, I know I should learn to do it by hand, but it's one of those things, if you don't re-sharpen drills that often, it's difficult to master. The smaller sizes I just replace when required

I've got a "Picador" style drill sharpener, but I'm not keen on using the side of the wheel, plus, I will inevitably need to re-dress the side of the wheel at some stage.. Any recommendations for a reasonably priced alternative?

[BC ProfParticipant @bcprof]

Tried various versions . Had some success with them all but finally settled on Drill Doctor. Not cheap but only a couple of failures that were sorted by butting them back in and re setting the drill in the holder . I know that I should be able to sharpen them by hand but the Drill Doctor makes it so easy and quickly sorted out my badly sharpened / damaged Morse taper drill purchases from junk markets . up to 3/4"

Brian

[larry phelan 1Participant @larryphelan1]

Still trying hard50 years later, so dont give up !

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I to have the Picador style sharpener and find it took me a time to get it to grind the correct angles, my faults. I grind my drills by hand and have got very good results so the Picador sharpener is not used, so I recommend you get some old drills and practice and you will soon get good results. I am at a stage where I am making the grinding rest by Harrold Hall, but my grinder at the moment has two adjustable plates bolted on the grinder so I can get different angles to grind up HSS blanks also you can mark with a pen angles on the plates so to get approximate 59 deg for drill sharpening. All this works for me but would like to have a go at sharpening end mills with the advanced grinding rest.

Bob

[BC ProfParticipant @bcprof]

Just looked up the price of a Drill Doctor 750 !!! They are good but not that good . Go with a cheaper alternative unless you break /blunt a heck of a lot of drills a day

Brian

[Howard LewisParticipant @howardlewis46836]

The Picador is not that precise, nor are the various clones, and back numbers of MEW will show the modifications made by various people to overcome the shortcomings, such as inclining the pivot axis.

If only you could access a cutter grinder, you would be able to four facet grind your drills. The results are so much better!

Howard

[Paul LousickParticipant @paullousick59116]

You could keep your Picador sharpener and replace the stone grinding wheel with a diamond impregnated wheel (which can also sharpen carbide tools) or use it with a vertically mounted belt grinder.

Paul

[Bo’sunParticipant @bosun58570]

Thanks Paul,

I take it you're refering to a CBN wheel? Yes, that would address the issue of using the side of the wheel (that's assuming I can find one to replace the 150 x 20 x 20 existing wheel). Even then, the Picador style grinding fixture leaves a little to be desired.

[peak4Participant @peak4]

Posted by Bo'sun on 11/06/2020 11:30:58:

………………..

I've got a "Picador" style drill sharpener, …………………….

Hello Bo'sun, there's a difference between a Picador and a "Picador Style" jig, which is down to more than the quality of the castings etc.
The geometry is different as well; a genuine Picador seems to work reasonably OK out of the box, but search out an article by Graham Meek on improvements to the non-genuine ones.
The Sealey SMS2008 isn't bad after a bit of fine tuning to the wheel position, though I still sometimes struggle with drills smaller than about ¼".
For a swinging jig "Picador" style but made of cast iron, keep an eye open for a Reliance jig on ebay or elsewhere. Similar in operation, though without the location detent for setting the cutting edge.

See also This Thread, and the one linked to in my first post.
Bill

[Mick B1Participant @mickb1]

When I was learning in the 70s everyone was simply expected to learn to offhand-grind their own drills. Tool'n'cutter grinding machines were for toolroom use and shopfloor turners didn't expect to have access to them.

I can't remember whether it cost me 1 day or 3 to learn the technique, but I've never thought a drill grinding jig or machine was worth either the purchase price or the time spent learning it and setting it up – better just to wander over to the bench grinder for a few minutes. Do it decently and the drill will cut to size from solid within a thou or so, and drill many tens or perhaps hundreds of holes before you need to regrind it.

[Clive FosterParticipant @clivefoster55965]

I got pretty good with the Picador device and found the device in older Plasplugs sharpening system to work respectably well and reliably despite the cheap'n nasty plastic construction. But using the Picador was always something done when I had a bunch of drills to do as there is a certain knack involved in getting the drill held correctly.

Then I found a drill sharpening attachment for my Clarkson T&C grinder at a silly low price due to a couple of missing parts. Eventually got round to sorting it out and now its essentially permanently mounted so any drill needing sharpening gets done immediately. Takes about 2 minutes. Results are sharp, really sharp every time.

So far as I can see the basic geometry is the same as any other swing across the wheel system albeit swinging vertically rather than horizontally. But the construction is industrial style massive and the drill is held in a good quality 6 jaw chuck making setting the correct stick out ,1/2", and cutting edge angle, horizontal),very easy. The chuck is on a hollow spindle, to accommodate main length of the drills, with an indexing collar on the back so flipping 180° to do the second edge is easy and accurate. Having the T&C screw adjustment and lever travel slides does make setting up the correct grind really easy.

The inherent issues swing across the wheel sharpeners of Picador or Spiralux / General et al clone seem to relate mostly to the Vee block style carrier. Inexpensive but it does need a practiced hand to repeat well. The instructions are always inadequate. Although they more or less tell you what to do they are little help when things go wrong. Very easy to lock into a bad technique without realising it. When it comes to the import clones it really doesn't help that many are made with fundamentally incorrect geometry.

Now respectable quality drill chucks can be got at reasonable prices it seems to me that the time is ripe for a good DIY device design using Clarkson or Kaindl **LINK** geometry with a bored out drill chuck to carry the drill and a suitable index plate for flipping. Kaindl being possibly more practical geometry as it runs over the periphery of the wheel so you don't need a cup wheel and dressing back flat is easier. A screw driven grind depth adjustment system is of course essential.

Clive

Edited By Clive Foster on 11/06/2020 13:51:53

Edited By Clive Foster on 11/06/2020 13:52:26

[robjon44Participant @robjon44]

Hi Bo'sun, if you don't have time to waste do not waste any learning to off hand grind twist drills, your time is too valuable! I myself can grind a passable drill point by hand but that will not be acceptable most of the time, it seems that most of the Picador swing type jobs are distinctly hit & miss judging by the many articles about trying to get them to function correctly in MEW & Model Engineer. So, I have a Drill Doctor purchased a long time ago at a knock down drag out price from a car boot & if I had a pound for every 135 degree split point it sharpened during my working life I would be a very rich man, it is a little known fact that when setting & operating 2 small CNC bar machines where most of the holes are drilled with TiN coated HSS drills having access to 56mm U drills are no help at all. So it is quite possible to grind a 4 facet point where the facets are flat ie not curved using the toolrest designed by Mr Harold Hall incorporating rear stop, micrometer (ish) forward feed & 2 position indexing capability. I have on one of my bench grinders 2 metal bodied diamond wheels, 1 six inch & 1 two & a half inch still capable of lapping carbide tipped masonry drills et al, on the face. To address the final misgiving, that is grinding on the side of the wheel, purchase the stout type of wheel used on tool & cutter grinders specifically designed for grinding on the face not the periphery.

BobH

[Ady1Participant @ady1]

Tried my picador for about 10 mins

…then went back to doing it by eye

If you have a good drill that really does the biz then eyeball it, or put it to one side as a permanent reference

[GeorgineerParticipant @georgineer]

When I was an apprentice in the late sixties we were taught how to grind drills freehand, and we then had to show them to our instructor.

"How's that Mr Roberts?"

"Hmm… hmm… hmmm…" as he checked it against his gauge, "Not bad." Then he'd flatten the whole point off against the wheel and say "Now do it again."

I have my father's Picador jig which hasn't been out of its box since the seventies. He bought it, tried it, and found it was no better than his Portsmouth Dockyard apprenticeship had taught him in the 1920s.

George B.

[John BaronParticipant @johnbaron31275]

Hi Guys,

I can recommend having a look at

http://www.gadgetbuilder.com/

Under drill grinders. I built the Four Facet drill grinder and can vouch for its ability to produce accurate repeatable sharp drills.

[SamsarandaParticipant @samsaranda]

As an airframe tradesman in the Air Force in the 60’s we were expected to learn freehand drill sharpening, we didn’t have access to fancy drill sharpening equipment, we soon acquired the necessary skills and this was mostly on 1/8 drills. We had to produce accurate size holes for riveting in aircraft structures, oversize holes were definitely out. I have tried various gadgets for drill sharpening since then but can’t get on with them, once you have taught yourself to sharpen drills freehand it stays with you, although in my 70’s now and eyesight is definitely a problem with small drills.
Dave W

[Brian HParticipant @brianh50089]

Like Mick B1 above, I was taught to offhand grind drills as an apprentice. I was easy to learn using large drills where you could easily check your work. Once you have mastered grinding large drills it is easy to use the same principles on smaller drills.

Brian

[Clive FosterParticipant @clivefoster55965]

I suspect most, if not all, of the folk who claim to "hand sharpen drills as good as new" would have a nasty shock if they took the results through proper inspection or merely put them into an industrial standard sharpener.

I have some that were clearly expertly hand sharpened, indeed I watched an ex toolmaker friend do a few.

Put in the accurate Clarkson device simple observation of the grind shows the expert hand sharpening results to be sadly asymmetric. Confirmed by a quick look through the travelling microscope. Hole size immediately after sharpening doesn't seem to be a particularly good test as both hand and machine ground ones were within all but the most exacting tolerances. I'm a little better equipped than the average bear butcertainly don't have the gear to properly and reliably define the actual differences.

What a did notice is that hand sharpening has much shorter useful, free cutting, life than machine sharpened. Doesn't take many holes before the drill is clearly working a bit harder with one cutting edge doing most of the work. But drills are fairly imprecise devices at the ebst of times.

Clive

[SamsarandaParticipant @samsaranda]

I thought the object of the process was to produce drills that were fit for purpose not to meet a spec that was precisely to size , within micron tolerances. 🤔.
Dave W

[LimpetParticipant @limpet]

Posted by John Baron on 11/06/2020 16:55:25:

Hi Guys,

I can recommend having a look at

http://www.gadgetbuilder.com/

Under drill grinders. I built the Four Facet drill grinder and can vouch for its ability to produce accurate repeatable sharp drills.

Although I can do (sometimes) passible hand grind I am currently building gadget builders incarnation, I have both picador and drill doctor but don't get on with either of them

Lionel

[Neil LickfoldParticipant @neillickfold44316]

In my experience the life of the resharpened drill is seriously effected by the surface finish on the grind itself. Rough out using the standard grade wheel of 40 or 60 grit, and then finish with a fine wheel of 120 or finer. An alternate is to hone the edge. These will last every bit as long a s a new drill, and if sharpened correctly will drill a hole to be better than 0.05mm of the drill size and have a roundness of the hole better than 0.03mm tir. Hand sharpened or fixture sharpened should be giving the same results. Hand sharpening drills is a skill that some can never manage. Although it looks ok, when used won't be. You know when it is right as the swarf comes off fairly evenly from each drill flute. I have seen many new drills that require a touch up to get them to drill proper holes.

[Danny M2ZParticipant @dannym2z]

One of the best attachments that I made for my Picador clone was a Harold Hall inspired attachment to ensure exactly 180° rotatation of the drill bit being sharpened.

Details are contained in this excellent book which should be considered as a useful reference for model engineers. Tool and Cutter Sharpening

No affiliation, just a satisfied customer/reader.

* Danny M *

[Gary WoodingParticipant @garywooding25363]

I use one of ***THESE***

The price was far less than I expected, works really well and is very easy to use.

[John BaronParticipant @johnbaron31275]

Posted by Neil Lickfold on 11/06/2020 20:38:22:

In my experience the life of the resharpened drill is seriously effected by the surface finish on the grind itself. Rough out using the standard grade wheel of 40 or 60 grit, and then finish with a fine wheel of 120 or finer. An alternate is to hone the edge. These will last every bit as long a s a new drill, and if sharpened correctly will drill a hole to be better than 0.05mm of the drill size and have a roundness of the hole better than 0.03mm tir. Hand sharpened or fixture sharpened should be giving the same results. Hand sharpening drills is a skill that some can never manage. Although it looks ok, when used won't be. You know when it is right as the swarf comes off fairly evenly from each drill flute. I have seen many new drills that require a touch up to get them to drill proper holes.

Hi Neil, Guys,

When you have an accurate drill grinder, like the

https://www.gadgetbuilder.com/DrillSharp.html#Facet4 one,

putting a brand new drill into it and marking the facets with a marker. Very lightly touch up the facets and you will be surprised just how often they are way out. Most often one side is longer than the other or the face angles are wrong. Regrinding them makes a world of difference particularly to the larger drills. Also you will find that deeper holes don't wander as much. This I think is because you don't need as much pressure on the drill to keep it cutting, so the drill doesn't flex.

Unfortunately the biggest drill that I can sharpen in the four facet sharpener is 10 mm, so I either do them by hand or use the picador, which once you have set it up properly does a reasonable job.

NOTE: I had to bore out the collet holder to 1/2" to be able to actually get a 10 mm drill in there.

 

Edited By John Baron on 12/06/2020 08:52:45

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