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

If safety is a concern then change to a slow grinder with one of these WHEELS it eliminates the worry of grinding on the side of a normal grinding wheel

Derek Lane - Derek, I did look at those diamond wheels.

So far the Silicon Carbide wheel from ................................... has been performing fine.

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

However, I have the choice of either upgrading or reinforcing my existing wheel.

One way of doing that is to bond a plywood or aluminium disc to the opposite face of the grinding wheel with Epoxy Resin Adhesive.

That way the wheel is unlikely to suffer any sudden fracture.

I have also been improving my Ducking Skills so if that should happen the wheel should theoretically go over my head and miss me completely! 

R

Edited By Richard Kent 1 on 02/06/2022 11:48:13

Edited By JasonB on 05/06/2022 18:37:55

Hi Richard, I don't know how you can reinforce your grinding wheel by bonding anything to the opposite side of it when the flanges that grip the wheel with the blotters should be of equal diameter and have an equal bearing area.

Mounting the wheel

Regards Nick.

Nicholas Farr - Nicolas, this is where too much reading and knowledge can be dangerous

Bonding a reinforcing disc to one side of the wheel should not present any issues in theory.

I'll let you know the results if I take that option.

R

Too much reading and knowledge are never dangerous. It's getting stuff wrong in the workshop that causes real damage!

Dave

SillyOldDuffer - Dave, Don't take my flippant or sarcastic comments too seriously as they are not meant to insult.

On a more serious note. Reading and knowledge is great but must be kept in context and balanced with alternative views.

Example in this post: Grinding wheel manufactures advise against grinding on the side of a grinding wheel. So based on that information alone you would not do it.

However, the Picador jig instructions say that it can be done providing you take small cuts.

Each individual should do their own reading on a subject and I am not suggesting anyone else has to follow what I do.

What I would recommend is that if anyone is going to do any engineering which deviates from the norms (including grinding on the side of a grinding wheel) then ensure you mitigate any risk with appropriate PPE etc.

Regarding your quote: "Too much reading and knowledge are never dangerous. It's getting stuff wrong in the workshop that causes real damage!"

That was an implicit statement

My workshop techniques are fine thanks very much

I don't want anyone getting their knickers in a twist over a drill grinding jig

This is not engineering advice so do not follow what I do 

Edited By Richard Kent 1 on 02/06/2022 16:23:00

Perhaps you should do more reading and gain a bit of knowledge then. What is this "Theory" you are on about, all guidelines from manufacturers and training say to use equal flanges to give an equal clamping force, a wheel should be perfectly balanced for it's high r.p.m. or you are really asking for trouble. Bonding a piece of ply or alloy to one side is probably the worst bit of workshop practice I've heard.

Bezzer - "Bonding a piece of ply or alloy to one side is probably the worst bit of workshop practice I've heard"

Great I'll try it and let you know what happens

Could work perfectly well

This is NOT engineering advice so do not UNDER ANY CIRCUMSTANCES follow what I do

Edited By Richard Kent 1 on 02/06/2022 16:27:48

I can't make my mind up if you are a troll or actually that far up yourself. Either way it doesn't matter as as the ignore button is about to be pressed , joining a few others I suspect.

I very occasionally use the side of my grinding wheels although I can fully see why the practice is frowned upon on safety grounds. But irrespective of this, surely a practical problem with regular use of the side of a wheel is the difficulty of regular dressing to maintain shape and cutting efficiency. Setting up a jig to routinely use the side of the wheel will run into this difficulty. Isn't this the type of job that cup wheels were invented for? They're all side!

Clive Brown 1 - Hi Clive, I was just showing it was possible to do with a standard bench grinder by following the Picador instructions.

This is NOT engineering advice so do not UNDER ANY CIRCUMSTANCES follow what I do

I must say I've never really understood the advice to not use the side of an abrasive wheel. It seems contradictory when you see some of the very fragile looking cup & saucer wheels that are made and intended for this very purpose.

Martin.

Hi Richard, if you wish to ignore established safety advice, that's up to you, providing no one else is involved while you are doing it. I can only give advice on what I've been trained and used in industry all my working life and the abrasive wheel courses that I've been on.

Regards Nick.

Nicholas Farr - Nick, see my disclaimer below................

This is NOT engineering advice so do not UNDER ANY CIRCUMSTANCES follow what I do

Deleted:- replying to a post over a page ago!

Edited By Mark Rand on 02/06/2022 19:02:34

I suppose one should take into account how long ago those old Picador instructions were printed. Things have moved on a lot since then regarding health and safety, users should do too.

The reason it is suggested not to use the side is that after prolonged use the outer edge will become undercut and likely to break away due to the rotational forces, bonding anything onto the opposite side is unlikely to do anything to reduce these forces. The lack of any side enclosure to the wheel on the grinder shown will also increase the risk of injury should the wheel fail.

JasonB - Please see my disclaimer below...............

This is NOT engineering advice so do not UNDER ANY CIRCUMSTANCES follow what I do

Ignoring this warning could cause severe physical or psychological damage!

Edited By Richard Kent 1 on 02/06/2022 20:15:44

In reality there is little risk of an originally good wheel becoming dangerously undercut.

These devices need a flat or near flat grinding surface to function.

Any significant hollowing will destroy the sharpening geometry leading to loss of clearance angle at the outer edges so "sharpening" the drill will make little difference to its cutting prowess. The larger the drill the sooner the effect occurs. Long before the wheel becomes dangerous the "(obscenity delated) useless sharpener thing" will have been binned, pitched into orbit or relegated to the darkest, most spider infested, corner at the back of the cupboard.

A barely noticeable hollowing of the side of the flat wheel I originally had on my grinder was sufficient to prevent proper sharpening of larger drills. Careful examination under magnification proved that there was no clearance at the outer ends of the cutting edges. I'd guess something significantly under 1/16" hollow would be enough to destroy all confidence.

I fitted a 3/8" (ish) wide straight cup wheel and wide table perpendicular to the spindle, Hemingway Worden style., to my inexpensive Whitecolt grinder. Which made it far nicer to use for tool sharpening duties. The better visibility made it clear that the actual cutting circle travels sideways across the wheel as the Picador device swings. With 20/20 hindsight my cup wheel was barely wide enough to manage 1/2" drills. Had to do a bit of careful shuffling of pivot mount position to get it all working well.

I suspect the Picador vertical pivot, 5 to 5 edge position, style has a rather greater shift of the cutting point during the swing than the alternative angled pivot, vertical edge position, style. Making it considerably more sensitive to wheel hollowing. But the Picador grind geometry is much more reliable over a range of drill sizes.

Clive

I’ve got a belt grinder so I was thinking of trying this.

Our Lab workshop wheels are dressed to a taper on the side of the wheel for probably a couple of inches which not only addresses the issue of undercutting but generates a surface that runs true. The fact that the surface is slightly conical in form matter very little.

regards Martin