Perfectly ground Twist Drills every time.

I'll have you know I would never wear moleskin. I'm very fond of moles.

Neil

Moles - Bloody scourge those things are.

We used to catch them as kids and bury them alive.

Well at long last I am a fully authenticated Model Engineer . Moleskin trousers, hairy jumper, very deep pockets ( yorkshire man in Aberdeenshire) Drive a 2CV .

On the subject of van Royen ...

I was somewhat amused/bemused by this on "myhobbystore"

MichaelG.

Hi, MEW 176 & 177, Drill Sharpening Jig, by John Shepherd, well worth a read.

2nd attempt. 1st showsin 'My posts', but not in thread .

.

Lynne,

Your 1st is there, at the bottom of page 3

MichaelG.

MichaelG, myhobbystore have clearly run out of bits, so we'll have to wait until they are re-stocked!

(But how come we can still see this web site?)

John,

Nice

MichaelG.

Thanks for that. I was gong to ask what the other settings were used for. When I find mine I can just pin the wobbly joint permanently.

Hi Gray,

thanks for the additional photos and explanations, much apprerciated.

Thor

Graham,

I had a 'play' with my plasplugs multi grinder yesterday. The drill holder is clever but imperfectly realised, although it's simple design does make a decent job of holding the bit at the same height for each flute.

Drills are ground at the top of the wheel, and the grinding is more or less normal to the cutting edge.

The setting jig has a triangular steel 'ramp' that sets the bit protrusion. A moveable 'V' at right angles to this sets the drill orientation by a four-point contact. You can use this as a check for symetrical grinding.

Drills are presented to the wheel with the bit turned slightly to the right, which more or less puts the cutting edge along a radius near the top of the wheel. An invisible, but presumably off-centre, pivot creates the backed-off edge as you turn the holder.

The weaknesses of the design are two fold - the tiny 70W motor struggles to keep the grinding wheel going at speed under any sort of pressure - so it's best for worn, not damaged, cutters. Secondly the plastic construction and some spindle end play mean you need to develop a consistent 'touch'. regularly turning the drill 9rather than doing one side at a time helps. The Tip angle seems to be accurate.

I suspect it would be worth duplicating the jig in metal.

Does anyone know how the sharpeners that have a drum with various holes for the drills to be poked into work?

Finally, anyone seeking the digital article (or other digital content) on MHS will be delighted to know that the effect of a system reset that rendered all digital editions 'out of stock' has now been rectified.

Neil

Hi Gray,

My jig appears to grind more or less accurate at 59 degrees, using an engineers protractor on the drill tip, a few days ago.

Neil

About 6 degrees, as best as I can tell by sighting across, but only a short portion of the pin is visible .

I deleted a duplicate post - the system seems to be throwing a few today.

Neil

Good guess - it's 52 degrees, to the nearest degree.

As with the mini lathe racks, it seems superficial similarity of design doesn't mean identical detail!

Neil

There seems to be a lot of variation between different versions. I have just dug my 25 year old version out of the drawer and it has the post leaning towards the wheel by 6° and the V for the drill is at 55° to the vertical. So the drill angle will be 112°.

I wonder how much difference it makes having 112° instead of 119°. I suspect none. I will however stick to using my four facet jig.

Russell.

Gray,

It looks like you have succeeded in making a rather fine Silk Purse from the proverbial Sow's Ear.

MichaelG.

Hi Russell

The main difference appears to be the tedium and potential for error introduced by having to grind away a lot of extra metal to get the 'new' angle, especially where the new angle is less than 119 degrees and the extra comes off the heel of the drill point.

Neil

Just a query and a thought on this subject,if you use the face of the wheel does the lip of the drill have to be exactly on the center line of the wheel? I am trying to envisage the set up if it was lower or higher. Any thoughts on this.

Clive

One more for the list of angles:

pin angle: 10-11° (protractor)

square bar (=vee) to vertical: 61.3° (digital gauge)

That would result in the angle vee -> pin of around 50° if my arithmetic is correct.

Clive, on my 170 mm grinder the drill touches between 1 and 2 o'clock! It would need a substantial block below the grinder to get near the center line (or the jig had to be mounted lower than the grinder).

Regards, HansR.