Perfectly ground Twist Drills every time.

Gray,

You do have me hooked, I must try and find the thing now.

My replacement base will probably be around 3" x 2" x 1-1/2" and in steel so the mag table on my aged Norton T & C grinder has something to grab onto.

Paul

Hi , MEW 176 &177, drill sharpening jig, by John Shepherd; well worth a read.

Lynne.

To bring this thread back to on-topic:

Graham, would it be possible for you to produce and present a drawing of that new part on the foot of the jig (visible in pictures 2 and 4 on the first page)?

Although I have no problems with the wedge, I'm completely lost with this. Obviously I'm the only one - but that's no big news for me.

I think it would be easier than waiting for the day when something shows up in MEW (Or the other one, unmentionable here...?)

Greetings, HansR.

No Graham, you have got fixated because I mentioned CNC.

Try doing a search for patents on the 1950's pre CNC [ if I dare mention that ] They are the virtual same machine as regards the mechanics of the grinding process.

I must admit that I didn't have any joy only finding the later patents hence the mention of [ no we wont mention that again ]

I have one of these grinding jigs, and gave up using it, because it was so imprecise.

I am unhappy with locating the drill flute against a stop, as any axial movement changes the angular position.

(Which is why I am not happy with the Hemingway Mk2 drill grinding accessory. Sorry Mr Jeffree, otherwise your design is excellent)

Instead, I now four facet grind using an ER20 collet holder mounted on the Hemingway 31 degree base for the Worden Cutter Grinder, setting the drill edge vertical. Four facet grinding is good, but I find it slow to set up.

The Worden has a tapped hole in the base ready to take this "Picador" type attachment, and I think that Tony Jeffree did design a base which allows precise advance of the device.

So PLEASE Graham, do publish the drawings for your improvement. I am sure that your version improves the gadget to the point, where mounted on a base with graduated advance, it can sharpen drills accurately and consistently.

Howard

Howard -

Not guilty I'm afraid - I have built a Worden from the Hemmingway kit, and I did buy their drill grinding kit at the same time (and have failed as yet to build it), but I had nothing to do with its design, or the adaptation for the Picador device, for that matter.

Of course, if I had, it would work flawlessly

Regards,

Tony

I'm so sorry Graham, it seems I could not express clearly what I meant. I said I have no problems with the wedge - meaning I understand its purpose.

What I really don't understand is the other part, which looks like a very substantial bearing for the small vertical stem of the jig. Maybe, instead of a drawing, you could try to tell in a few words how to make it? (length, thickness, the purpose of the tangential clamp(?) screw - which part is still movable when this really iy a clamp?). In the description you wrote something about 'dialling in the eccentricity...) Is there a scale somewhere?

Oh, how difficult to express ones thoughts when one has nothing than a photo...

Greetings, HansR.

Hi Howard,

What angle do you use for the cutting and secondary clearance when you grind 4-facet drills?

Sir J.That video is worth a thousand words!

Neil

Edited By Neil Wyatt on 05/05/2014 20:32:40

For those with a penchant for Patents, this one from 1949 is definitely worth a look.

... Those with no interest, please just ignore it and accept my apologies for the intrusion.

MichaelG.

.

Showed a profit for once then, - it was only 900 frames long............

Many thanks Graham, now all is clear!

Well, maybe not - could it be that different species of these jigs exist? As I have other (better) means for drill grinding up to 13 mm, I don't use it often. Also the positioning lip was ground away long time ago, so setting up is more or less a matter of luck.

However, I tried it again today with a 15 mm drill. Without a wedge under the foot, and with the jig on the 59 deg. mark, I measured a tip angle of 120 deg, +/- 2 deg maybe. Due to the eyeball setup the drill cut about 0.2 mm oversize (directly into Alu and steel, without using a center drill...)

It seems what I really need is Mr. Hall's 180 deg. switchover gadget. Also a longer guide rod and something which prevents the different nuts from moving due to the vibrations.

Now I think I have stressed your patience enough,

Greetings, HansR.

Nice one Micheal.

Looks to be the original of the Picador version with vertical pivot post and 5 to 5 drill lip alignment.

Clive

I have a similar model jig made in the US by General Tools. It must be forty years old and still in the wrapper. I was told years ago by various metalworkers that they were an abomination to use, so I never did unpack it. Now I will definitely give it a go with Graham's mod. Mod! That word of brings back memories .... of paisley shirts, mini skirts and Meccano erections.

If you look back far enough there were a load in 1908 and 1903 all based on the swing post method of operation.

Like many thing mechanical, nothing is new. it's only materials and electronics that are enhancing some of the old Victorian designs.

There is a thread going at the moment on the Eureka relieving tool. The basis of that was an advert from a magazine also from the 1900 era that Prof Chaddock and Ivan Law tried, and succeeded to reverse engineer from the sketch.

.

Neil and/or John,

Am I right in thinking that this comment belongs in the Eureka thread ?

... I searched here last night, but couldn't find any video posted by John.

MichaelG.

I thing Neil was trying to save electrons by replying to two posts in the same reply.

Typical model engineer, tight arsed, moleskin trousers with deep pockets and drives a Reliant

Cheers, John

MichaelG.

.

... forgot to mention; mine was a Scimitar Coupé with a nice "blueprinted" V6 and decent wheels & tyres.

MichaelG.

Michael

Well I don't think a Scimitar  is too useful a vehicle for everyday use. On the other hand I suppose it might be useful to subdue JS comments! ( sorry John )

Norman

Edited By NJH on 06/05/2014 12:48:24