|496 forum posts|
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 Prof||11/06/2020 11:53:55|
|159 forum posts|
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"
|larry phelan 1||11/06/2020 11:56:46|
|1079 forum posts|
Still trying hard50 years later, so dont give up !
|BOB BLACKSHAW||11/06/2020 11:58:52|
|425 forum posts|
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.
|BC Prof||11/06/2020 12:01:06|
|159 forum posts|
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
|Howard Lewis||11/06/2020 12:07:10|
|5237 forum posts|
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!
|Paul Lousick||11/06/2020 12:31:58|
|1844 forum posts|
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.
|496 forum posts|
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.
1469 forum posts
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.
|Mick B1||11/06/2020 13:23:52|
|2005 forum posts|
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 Foster||11/06/2020 13:51:12|
|2817 forum posts|
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.
Edited By Clive Foster on 11/06/2020 13:51:53
Edited By Clive Foster on 11/06/2020 13:52:26
|144 forum posts|
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.
4689 forum posts
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
|525 forum posts|
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.
|John Baron||11/06/2020 16:55:25|
487 forum posts
I can recommend having a look at
Under drill grinders. I built the Four Facet drill grinder and can vouch for its ability to produce accurate repeatable sharp drills.
1193 forum posts
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.
|Brian H||11/06/2020 18:11:38|
2214 forum posts
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.
|Clive Foster||11/06/2020 18:20:38|
|2817 forum posts|
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.
1193 forum posts
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. 🤔.
|135 forum posts|
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
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