The Correct Way To Sharpen Drill Bits Using A Picador Drill Sharpening Jig With Custom Base

For anyone interested in setting up a Picador drill sharpening jig correctly.......................

Ensure you set the drill bit with the cutting edges at the 5-to-5 position which will in turn ensure that the chisel edge is ground to approximately 45 degrees to the cutting edge.

I found setting the jig to the 59 degree position which achieved a total 118 degrees point angle gave very good results.

If you are really lost with the terminology see the photos below which includes a diagram.


See photos below.................................

Edited By Richard Kent 1 on 31/05/2022 23:46:09

Edited By Richard Kent 1 on 31/05/2022 23:47:07

And Ps: I was taught "Never grind on the side of a grinding wheel" Where did that go out of the window ??

.

It is covered surprisingly well by the CAUTION on the box

MichaelG.

Edited By Michael Gilligan on 01/06/2022 06:46:16

Language is used in a context. The truth of a statement has to be assessed within the context in which it is made.

If we want to modify what you have been taught, we could say 'never FREEHAND grind on the side of a grinding wheel'.

There is a huge difference between you pressing a rusty bit of iron into the side of a wheel and the delicate, controlled movement and depth of cut the jig produces. One is freehand grinding where the advice is good and correct. The other is tool/cutter grinding where it has less validity.

If I mention cup and saucer wheels, can we have a discussion of what constitutes the side or face of these?

Dear All,

This thread has motivated me to re-commission my Picador drill grinding jig. I will make a similar base.

What a shame that it has been produced with such cheap and coarse screw threads.

John

My understanding for this, is that it's difficult to dress the side of the wheel.

David

@Michael Gilligan - Mike you are right. Normally you don't use the side of the wheel to grind but Picador advise you do it with caution.

Note, I am using a 20mm thick wheel for this reason. I also recommend you consider reinforcing the wheel on its opposite face with a metal or plywood disc.

R

Edited By Richard Kent 1 on 01/06/2022 09:15:25

John ATTLEE - John, I have uploaded a photo of the base for you which I used to mount the grinder and Picador jig.....

Note the additional plywood base to raise the level of the grinder so that the drill tip is approximately at the grinding wheel centreline......

Edited By Richard Kent 1 on 01/06/2022 09:14:51

Edited By Richard Kent 1 on 01/06/2022 09:19:30

I think the do not grind on the side of the wheel is a general piece of advice to cover the activities of complete idiots. To list exceptions will become a subjective list that an idiot will be unable to interpret sensibly. Tool rests often do not extend to the side and a light touch grind and a heavy grind are very different, wear on the side will eventually be an issue as will dressing. A diamond dresser is very different from a Huntingdon type starwheel dresser. I think the picador type tool is aimed at occasional use and is not a heavy duty tool. A cup wheel is designed for side grinding but they are for precision tool grinding rather than fetteling castings. These are my opinions and I am not at all qualified to advise on grinding operations but as an occasional side wheel user I have not had any problems but I have never needed to dress the side of the wheel either. If I used the side enough to need to dress it then I think I would consider using a grinder designed for this rather than an off hand workshop grinder.

Mike

Mike Poole - Mike I wanted to reassure you that if you use a 20mm wheel then you can grind on the side of the wheel with caution and taking small cuts as recommended in the Picador instructions. Perhaps reinforce the opposite side of the wheel with a metal or plywood disc as I suggested above.

When grinding like this wear full safety goggles and stand to the side of the grinder to mitigate risks further.

R

Edited By Richard Kent 1 on 01/06/2022 09:19:09

Edited By Richard Kent 1 on 01/06/2022 09:23:41

This has been aired several times over the years, and opinions differ. The Harold 'Hall Tool & cutter sharpening' book shows this method in a large colour picture on the cover, which may give a false impression of correctness for beginners if they don't read the full text inside.

To be honest, I find these jigs just a bit of a pain sometimes - the are OK for larger drills say 8 - 10mm + but give variable results under those sizes. OK it might be me - I'll admit it - but I have persevered with those on and off over a number of years with mixed results.

In the past i have knocked up special bases to permit the correct height setting when using the front edge of the grinding wheel, a sliding base to give a threaded micrometer-like feed to the jig (that was from an Internet idea) but nothing seemed wholly successful. It always seems to end up an issue cutting the second edge - they still seem to come out slightly uneven.

All the best, Mike

Removing and replacing the drill after setting the point projection before grinding the first edge gave me more consistent results.

Presumably the actual position taken up by the drill point when adjusting the projection can be slightly different from that resulting from simply putting the drill into a preset jig. Most likely due to the difference between sliding against the little rotation setting gauge on the end as you set projection and simply placing against it when merely inserting the drill. Any such effects mean the point grind will differ between the two edges.

Using identical insertion technique on both edges avoids this, very inconsistent, effect.

I also made a U section guide mount for my base. Needed to make it higher to reach the right part of my grinder so it seemed sensible to make sure it always stayed perpendicular to the wheel when setting the base. Plans to add a screw adjuster to reliably set the position and add the requisite tiny cuts between swings never reached fruition.

I did try making a tighter, more controlled swing pivot than the simple, rather flexible, plate across the cast Vee in the base. Which significantly dis-improved performance! On reflection many years later after getting my Clarkson attachment I reckon the flexible plate acts as a crude spring limiting the force on the drill point when grinding. The Clarkson has a proper spring for this. Presumably too solid a mount gives too much force on the wheel and poorly controlled grinding.

The grinding a hollow in the wheel objection is valid but probably moot given that this is a consumer grade product and that most won't get enough use to seriously consume the wheel. I put a cup wheel on my grinder. Not only a complete solution to any such worries but also letting me fit a large grinding rest perpendicular to the spindle. Simplified Hemingway Worden style. The Picador base lived underneath. Two studs and wing nuts held the table down so it could esily be removed for drill grinding.

John is a bit unfair in in his comments about cheap screw threads. Its fair to say that, as an unfortunate necessity to meet a price / performance ratio acceptable to its target market, the constructional and engineering standards of the Picador are lower than one would ideally like. As is the case with all such devices.

I got mine around 1972-74 on a special offer price, reduced from £7-50 to £5 as I recall things, when I was earning maybe £650 a year. In those days cheap crap wasn't cheap! You could buy a half decent 1/64" to 1/4" drill set for similar money.

Significantly better engineering would have been unaffordable.

If you were going to make a better device you'd use a different design.

feel its a great pity that an updated version of the concept using the ingenious flip over Vee drill carrier and drill point projection gauge used on the original PlasPlugs drill sharpening system has never been produced. This would effectively mechanically resolve pretty much all the set-up related issues.

I imagine that given the will a really nicely engineered set-up to use with your grinder could be made for less than the rather cheaply made "£40 (ish)" PlasPlugs grinder system knock offs with integral grinder from the usual suspects.

Clive

Edited By Clive Foster on 01/06/2022 09:39:29

Mike Hurley - Mike, I always blame my tools when I get things wrong

But seriously, these jigs work perfectly for even small drill bits if you ensure you set up the jig properly and you ensure the cutting edges are at the 5-to-5 position.

I have recently sharpened 3mm drill bits with no problem at all.

Clive Foster - Clive, if you set up the grinder and jig as shown you will get perfectly good drill bits. There is no need for any further modification.

The versions I had were Draper brand, and from what I remeber the instructions were limited and a bit confusing, the diagrams smudgy. Yours seems to be fairlly vague about how far the drill tip should project, as best as I can read it says 1/16th" or increased for 1/4" drills and larger. The ones I had always said to specifically project one half of the drills diameter, and there was nothing about this 5 to 5 positioning.

Perhaps I'll give mine another go with 'your' instructions!

regards Mike

Regarding where I purchased the Silicon Carbide grinding wheel

Speak to 

If anybody wishes to purchase from .................. they can use the discount code of ................. = 10% discount on all wheels

https://www...........................

I'm using the Pure Green Silicon Carbide 100 grit wheel in my photos but you might also want to try his White Aluminium Oxide or Blue Ceramic wheels.

Edited By Richard Kent 1 on 01/06/2022 10:14:38

Edited By Richard Kent 1 on 01/06/2022 10:15:06

Edited By JasonB on 05/06/2022 18:33:44

A couple more points

1. The seeded gel/ceramic wheels are really excellent for drill sharpening and HSS in general
2. Ideally, the drill would be addressed to the lower side of the right hand wheel or the upper side of the left hand wheel. This is so that the abrasive travels normal to the cutting edge, does not produce a burr and does not lead to a weakened edge, which parallel ginding does.
3. It can be well worth replacing the 3/8" square bar with one that is longer. This makes sharpening Morse taper drills possible.
4. The ultimate in the Picador type sharpeners is the one describes by Duplex in the 1951 ME artcicles.
5. That's more than a couple

Might I suggest a search of the forum as there have been a number of threads concerning this topic. In particular, try a search for "Spiralux" and also a search for "Graham Meek - Mods to (copies of ) Picador drill grinding jigs."

I own one of the Spiralux jigs which incorporates a slight angle on the spindle around which the actual jig rotates. My reading is that this "lean" is beneficial. Sorry, I can't tell you what the angle is, or which way, although I think it's toward the grinding wheel. Obviously mine works which means that I haven't paid any real attention to these threads.

I have found that for drills below 3.0mm, well, forget it! For drills between 3.0 & 4.0mm, it is possible but requires a lot of care. Drills between 4.0mm and, oh, dunno, 10mm say, the jig is satisfactory - as long as you can get the drill into the jig. The end result is that for drills below 4.0mm, I buy in packs of 5, others I sharpen.

Grinding on the side of the wheel. Well, enough has been said already. It is acceptable as long as the loads are kept light.

Cheers,

Peter G. Shaw

p.s Incidently, my biggest problem is that my grinder, bought some 30+ years ago, gets hot, very hot, sometimes too much to touch, if used continuously, hence I limit my grinding until the grinder becomes noticeably warm.

Great to see someone getting good results with a Picador drill grinding attachment. i acquired one many years ago and thought what a load of rubbish. Never the less I gave it a go and was surprised at just how good a job it did once I had sorted out the mounting of it on the grinder.

Two things I did with it, firstly I removed the drill clamping thing. Light finger pressure held the drill in place and made swapping the cutting edge over much easier, important as this needs to be done frequently to ensure perfectly mirrored edges.

Secondly, I made the end stop screw somewhat stiffer in operation, it had a tendency to move during use.

Not used the tool in a while now, I have a drill grinder that, if I'm honest, doesn't do a better job but is more versatile with regard to angles and point thinning.

John

Mark Rand - You raised some good points.

Lots of opportunity to refine and modify once someone has the basic setup.

The purpose of the post was to keep it simple initially so that the user can gain confidence and experience.

R