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Perfectly ground Twist Drills every time.

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Clive Hartland10/05/2014 09:30:42
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2604 forum posts
40 photos

What i have found is that the smaller dia. drills (3mm or so) do not get a good lip profille and therefore do not drill well. I can do better freehand! Larger drills come out fine and drill well.

Clive

Howard Lewis11/05/2014 21:39:21
3605 forum posts
2 photos

Hi All!

Have just come back to have another look at this thread on the Forum, so need to catch up.

Firstly, Apologies to Tony Jeffree. I relied on my memory, which at my age is very dangerous! Should have checked before impugning your reputation..

As you get older your faculties fail, but I can't remember which one goes first!

Neil,

Secondary clearance is ground first, at 25 or 30 degrees (Does not seem particularly to matter which, or maybe thats just because of the odd bits of steel that use) The primary clearance comes next at ten degrees .

If I am having a good day, the rear edge of this runs parallel to the cutting edge. Being slap happy, the drill cuts better than before sharpening, which the object of the exercise, and a nice parallel rear edge is probably more cosmetic than functional? Any comments / corrections?

Now, I'll go back and catch up on the more recent comments, and learn some more.

Howard.

John Stevenson11/05/2014 22:44:18
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Moderator
5068 forum posts
3 photos

3 degree 10 minutes.

Can anyone tell me the relationship of this required 10 minutes on the average rough as a badgers arse bench grinder.

Is it related to how long it takes to read and repy to a post ?

I have to set hobs over to the lead angle in degrees and minutes, the machine is fitted with a 12" degree scale with vernier and it's doable.

In this case we have a die cast jig with cast in index lines as fat as a sumo wrestlers jock strap and you need to work to 10 minutes.

Sorry time up. smile p

John Stevenson12/05/2014 09:57:49
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Moderator
5068 forum posts
3 photos

Graham,

With all due respect I also practice engineering correctly, I must be doing something right as I still run my own but admittedly small company.

As regards picking holes in this thread I was only pointing out if people could be bothered looking that there are easier way to do this, industry doesn't use these jigs and not all drills sold are cheap Indian crap.

As regards being a moderator I still have my own views, MTM doesn't sell drill grinding jigs so I'm not going against company policy and getting another identity so it doesn't have moderator at the side would be pointless as I would still use my name because I don't hide on any forums I'm on.

One point I do known and it was made again to me over the weekend at the Harrogate show from the people I met was two fold.

Many said that they don't post because they don't want to be seen as beginners, not a lot you can say to that only try to encourage them to do so.

Second point was the same people admitted they were put off by virtually all the show and tell posts being of really high standard work they they thought they would never be able to replicate and of contributors quoting tolerances unachievable with their skills.

I know this exists because at the first Ascot show they had Cherry Hills models on show on the second floor. We were stood on the ground floor at the side of the escalator. You would watch a group of guys laughing and talking going up, only to come down all subdued 1/2 hour later, some even saying , I might as well not bother.

It wasn't just the odd couple either as when I twigged on what was happening and pointed it out others on the same SMEE stand saw the same.

RRMBK12/05/2014 10:58:48
135 forum posts
18 photos

What a shame to see yet another interesting, knowledgeable helpful and well explained thread descending into poor diatribe.

Graham- thanks for the information and helpful comments and clear explanatory photographs. It has persuaded me to get my jig out and give it another try, with far greater success than I have ever achieved before. Can you please explain how you hold and set for length 3mm and smaller, particularly short length drills please. I struggle with the back end stop fouling in the vee of the front portion of the clamp casting. Also I tend to use short stub drills for most of my accurate drilling and these are a real problem with this jig. What is the smallest diameter you find practicable to sharpen please?

John - my engineering will always be, to use your words – “ badgers arse “ standard, - it doesn’t mean I don’t need and gratefully accept advice from other people whether their standard of finish is better or worse than mine. As for show and tell, recent posts on engine builds and the photographs on various profiles on this forum are an absolute gold mine of information to give me the confidence and show possible ways to approach a problem that I may not have come across before despite a lifetime of work in various categories of engineering.

Finally I strongly believe the work of the likes of Cherry Hill, Gerald Wingrove et al serve far more as an encouragement and motivation than any negative aspect. Whilst we may not be able to achieve their standards , it does show us it is achievable and so maybe we should just give that last part we made another go and see if we can get it a bit better next time. Which of us who visited Harrogate could fail to be impressed and spurred on by many of the fantastic models, especially the beautiful Patriot on show. I spent a long time leafing through the accompanying booklet in sheer amazement at the workmanship.

I fear that remarks like yours will stem the free flow of such information and further discourage others from sharing it. Particularly so when this is seen to come from the recognised formal position of moderator.

NJH12/05/2014 11:04:47
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2314 forum posts
139 photos

John

You say:-

" ..................... at the first Ascot show they had Cherry Hills models on show on the second floor. We were stood on the ground floor at the side of the escalator. You would watch a group of guys laughing and talking going up, only to come down all subdued 1/2 hour later, some even saying , I might as well not bother. "

I was one of those who did just that. However the conclusion that you draw is, in my case, quite incorrect. Cherry Hills work is quite stunning and demonstrates to me just what is achievable. The "half hour" I spent looking at it is still memorable - equivalent to looking at the work of one of the great masters in an art gallery. Just as I will never become a great ( or even a poor!) artist I will never achieve anything approaching Cherry's standard. That doesn't prevent me from enjoying the hobby and working to a standard that I find acceptable. I see Cherry's work as representing the acme of model making and, realistically, I'm never going to achieve anything near that standard. That doesn't stop me trying to improve however and the only person I need to satisfy is myself. Whilst I think I may well have said " I might as well not bother" as I came down those stairs that would only be a lighthearted ( and realistic !) acceptance of my own limitations.

As far as "beginners" go I've been a "model engineer" for over 40 years and I'm still a beginner - if I ever cease to have things to learn or things that interest me I will pack up and find another hobby.

Regards

Norman

Michael Gilligan12/05/2014 11:44:53
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16358 forum posts
712 photos

If Duplex chose to use a 10° angle, instead of Van Royen's theoretical 3°10' then it seems reasonable to assume that their is some flexibility in the design. ... What really matters is the symmetry of the two flanks, and this can be readily achieved with stops.

MichaelG.

.

For those interested in the the theory, there is very useful link on this page.

Tony Pratt 112/05/2014 12:24:25
1225 forum posts
5 photos

Hi Graham,

Please do not be put off by comments negative or otherwise, at least you have got the guts to post pictures of your work and methods on the web! I count myself as a person qualified and experienced enough to appreciate how fine your projects are, I also don’t think your offerings are too good for this site, there is always something to learn whether an old hand or a new boy.

Beginners in this game have got to remember that we were all that once and I can still remember the thrill of going to work and making ‘stuff’ from metal, it beats tapping a keyboard any day!

Tony

jason udall12/05/2014 12:41:04
2026 forum posts
41 photos

OK.

I for one am excellent at shortening drills.

Freehand= hopeless.

In the production (cnc) envionment I have met adequate drill shapeners on free hand.

I have found unused drill jigs on shelves..."too slow"..

these drill typically drilling 5mm x100mm..holes with.0,05 mm concentrity and runout.and +/- 0.075 mm on dia

this with a 2 minute cycle time in en16t iq...

now if a drill is less than optimally ground it will wander and/or drill big [even seen small...? how i don't know]

so if hole not right then grind it again..

As I say drill jigs unused...

Can I freehand sharpen drills? ....not a chance... with a good jig..less than great..

So i read this thread with intrest...I might learn something

Btw in the above job...sharpen interval...300 parts...because thats a shift, tests show 450-600 before failure..[drill break]

RRMBK12/05/2014 13:00:25
135 forum posts
18 photos

Graham. If you intend to close this post, would it be possible to PM me with a response re holding short & small drills please?

Many thanks

Brian K.

_Paul_12/05/2014 13:53:44
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543 forum posts
31 photos
Posted by Graham Meek on 12/05/2014 12:21:09:

Generally

I have asked for this thread to be locked in light of what has been said.

Gray,

Gray, it will be a decided shame to close this quite stimulating thread, please do reconsider.

Regards

Paul

Gray12/05/2014 13:55:23
1038 forum posts
13 photos

Gray,

May I echo Tonys' comments. I have nothing but admiration for your work.

I for one am not afraid to post pictures of my badgers arse engineering, it works for me and work to the standard you and some others produce just encourages me to go out and try again - only harder.

I don't see the display your work as any kind of ego trip. Your analysis of a problem and the subsequent description and worked examples of the solution are commendable. Please do not stop this excellent work.

its about time that people on here stopped posting useless diatribe and kept their opinions to themselves unless they have something helpful and constructive to say!!

This is not the only thread where this has happened.

Kind regards

Graeme

Neil Wyatt12/05/2014 14:04:18
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Moderator
18232 forum posts
714 photos
77 articles

I'm, not locking this thread. There is no dispute that the off-the shelf drill grinding jigs leave much to be desired, and any modification that makes them work better and easier to operate is worthwhile.

The issue of where the line is between inspiring and discouraging beginners (and even the more experienced but less able, like me) is a real one. I have seen photographs of tools made by 'Duplex' that have their non-functional surfaces scraped. I also saw a few very functional tools at Harrogate none of which had been given such treatment - I was very disappointed not to see many more.

But this is a separate discussion and if people want to explore it, please start another thread.

Neil

P.S. Badgers caused me enough issues in my previous job, without them dogging my steps here...

Thor12/05/2014 14:47:48
1275 forum posts
39 photos

Hi Gray,

As Paul say, I hope you reconsider and let the thread continue. I'm just an amateur in this game and I have learned a lot from your posts as well as others.

Thor

John Alexander Stewart12/05/2014 15:16:44
776 forum posts
52 photos

Gray - Thumbs up from me on your work.

I find that there's nothing wrong with trying to improve and get better through life; whether dealing with others, or trying to build things "better" in my workshop.

Gosh, if we did not strive to improve, why even bother?

Another JohnS

John Shepherd12/05/2014 15:28:20
216 forum posts
7 photos

Graham

Another vote of thanks and encouragement from me.

I have been following the thread with interest and it has made me think of adding an offset adjustment to my own jig (MEW 176). Although I find it works well enough, I think the extra refinement will be worthwhile.

Regards

John Shepherd

Phil P12/05/2014 17:14:55
656 forum posts
166 photos

Gray

I have no intention of modifying or using one of these sharpening jigs, I sharpen my drills using the four facet method on my tool and cutter grinder, or just use the old fashioned hand and eye method if I am in a hurry.

Despite that I have really enjoyed reading this thread and have learned quite a lot from it, so keep up the good work and dont be put off posting some more interesting articles.

Phil

Falco13/05/2014 00:19:31
65 forum posts
7 photos

We are lucky to have Neil as an enlightened Moderator on the forum.

I am delighted Graham Meek’s thread is not going to be locked. It really is too bad that someone who has gone to the trouble to research a well -known problem and tried to offer a solution to fellow model engineers would feel his efforts so slighted as to want to withdraw his work. And why? All because he works to a high standard! I would have thought that working to a high standard was the very essence of model engineering.

As a beginner I avidly study projects like Graham’s. Some of them are indeed beyond my skill level at the minute but that only spurs me on. I can try some bits of projects and as a result can do a lot more today than I could this time last year. There are skills like gear-cutting that I may never get to but in the projects that I can attempt, I would rather aim at the levels that Graham Meek exhibits in his work than settle for mediocrity. I suspect that I am not alone in this.

Graham, I have followed this thread with great interest because I have tried to improve a similar sharpening jig myself with fair success. The offset mechanism you suggested was new to me. One question if I may? The offset you give would depend on the measurements of the eccentric adjuster. You did not add the measurements of this piece to the drawing you posted. Any chance that you could give them?

Thanks for a most interesting post

John

Edited By Falco on 13/05/2014 00:20:20

Chris Trice13/05/2014 00:52:18
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1362 forum posts
9 photos

As with all forms of modelling, the end product only has to suit the standards of the builder. No one is a superb engineer from the word go. We learn by doing so people should do and get better as they go.

Chris Trice13/05/2014 00:55:58
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1362 forum posts
9 photos

And while I often marvel at the good quality of much of the work (which personally I consider a benchmark to strive for), I also get much from simply seeing people's solution to any number of problems regardless of how well the metal has been fettled. Ultimately, any standards set have to be no better than good enough to suit the intended purpose.

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