# Is it, or isn't it? What is it. Is it a drill bit sharpening



## garywayne (17 Dec 2006)

I went car-booting this morning and saw what I think is a drill bit sharpening jig. It is an "Eclipse 39". I googled it and couldn't find anything.

Is it a drill bit sharpening jig? If it is does anyone know how to use it. If so could you please explain it to me. I for the life of me can't figure it out.


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## Roger (17 Dec 2006)

Does it look like this?
Eclipse


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## bugbear (18 Dec 2006)

garywayne":3d4s47v2 said:


> I went car-booting this morning and saw what I think is a drill bit sharpening jig. It is an "Eclipse 39". I googled it and couldn't find anything.
> 
> Is it a drill bit sharpening jig? If it is does anyone know how to use it. If so could you please explain it to me. I for the life of me can't figure it out.



http://groups.google.com/group/rec.craf ... urce&hl=en

BugBear (with a long memory)


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## garywayne (18 Dec 2006)

Roger. Yes, that's the one. I intended to post some pictures today, but alas bugbear beat me to it with the apropriat instructions.

Thanks bugbear.


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## bugbear (18 Dec 2006)

IIRC Rob Lee speaks quite highly of it, having sharpened many drills in the early days of Lee Valley, when he was drilling cast iron BBQ's prior to assembly.

BugBear


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## David C (19 Dec 2006)

From memory, it works well for larger drill bits, and not for small.

David C


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## garywayne (19 Dec 2006)

I gave it a quick go yesterday with a 6mm (1/4") bit. I was quite surprised actually. Not bad at all. It is definitely better than doing it freehand.

Thank you all for your help and comments. :ho2


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## woodbloke (19 Dec 2006)

Gary - if you have a small grinder, its quite easy (tho' it is an aquired 'knack') to grind HSS drills freehand, does get a little tricky 4mm and smaller - Rob


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## garywayne (19 Dec 2006)

Thanks Rob.

I used to have to grind my own when I worked as a precision engineer. 

Have a good one.:ho2


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## bugbear (19 Dec 2006)

garywayne":2qdtehnc said:


> Thanks Rob.
> 
> I used to have to grind my own when I worked as a precision engineer.
> 
> Have a good one.:ho2



Interesting; one of the things I've read in engineering books is that sharpening a drill so it cuts nicely is quite easy.

Sharpening it symmetrically (both flutes) enough so it cuts accurately to size, however, was deemed impossible without equipment so sophisticated "jig" seems an inadequate word.

BugBear


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## garywayne (19 Dec 2006)

Sorry bugbear, what's your point :?:


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## bugbear (19 Dec 2006)

garywayne":3avvf7so said:


> Sorry bugbear, what's your point :?:



Only that there are various degrees of perfection in drill sharpening, and that some of them require fancy equipment to achieve. (and some of them may not be needed in some instance, of course)

(this information from references - the only way I've ever sharpened a drill is using an Eclipse #39!)

BugBear


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## David C (19 Dec 2006)

Old time toolmakers did a lot of freehand drill grinding.

Colen Clenton told me he could do extremely accurate work, and I believe him.

I was recently advised that if you want a slightly oversized hole, clearance or sliding fit say, grind one edge deliberately longer than the other....................!!!

David C


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## woodbloke (19 Dec 2006)

I was shown how to sharpen freehand HSS drills by an old time served mechanical engineer many years ago and so now do all my own drill grinding. Also would agree that there are degrees of accuracy in grinding them but for my purposes in the 'shop at home the accuracy I can achieve is more than adequate - Rob


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## garywayne (20 Dec 2006)

I am not very good at anything, so I try to do everything that I do do as well as I can. When I was engineering I was not very good at sharpening drill bits. This jig has made things so much easier.
The phrase, "That will do" doesn't exist in my vocabulary. But when I have done the best that I can then "That will have to do " comes in, but the next time I will still try and do better.

David.
What you where told about over sized holes is correct.

Have a good one everybody. :ho2


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## philip marcou (25 Dec 2006)

I was recently advised that if you want a slightly oversized hole, clearance or sliding fit say, grind one edge deliberately longer than the other....................!!!

That is quite correct- I have suffered this phenomenon on occasion, having thought I had "just quickly touched up this drill". These days I am very careful about drill bit sharpening, preferring to sharpen little and often freehand, no longer using the bench grinder unless a major recovery is required. I "polish" by use of a disc to which 400 grit silicn carbide is glued.
More than one Old Timer has told me that twist drills can be made to drill slightly smaller than the ir nominal diameter, by radiusing the shoulders- I have not confirmed it


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## Losos (26 Dec 2006)

I always sharpen by hand. This is because the only jig I ever tried (It was a cheapo) made me so mad I eventually threw it at the barn door :lol: 

And yes, it did eventualy dawn on me that if the two flutes weren't equal I got slightly larger holes, and even oblong shaped holes  

As mentioned above, a quick touch up on a fine grit on absolutely flat surface does seem to work well. is quick, and generally keeps the flutes pretty even. (I count the number of strokes on each side)

I wouldn't class my mechanical work as 'precision engineering' but it seems to be OK for what I do.


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