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Thread: Split point drill grinding
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7th May 2021, 01:54 PM #1
Split point drill grinding
What are your favoured methods to grind the tips of the grind split point twist drills ? I've seen where some use a dremel and a small wheel.
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7th May 2021, 03:44 PM #2Senior Member
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split point drill grinding
Hello Morrisman.
It is a lot easier to web thin the drill off hand. A good 6" bench grinder and an A80 wheel, dressed flat and a small radius is all you need. For split pointing it is better with a V jig to lay the drill in and pass under a tool and cutter wheel as accuracy is important.
We need a tool grinding forum.
Regards
BC
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7th May 2021, 04:53 PM #3
Hi Morrisman, Guys,
Built this drill grinder/sharpener ! There is a picture of mine right at the bottom of the page.
https://www.gadgetbuilder.com/DrillSharp.html#Facet4
I t works very well indeed ! I have only found one very small issue with sharpening a drill. Whilst you will get an almost perfect four facet point, when you come to use a drill that has a bend in it the hole is always oversize. It is not a fault of the grinder but you often cannot see the slight bend in a drill without clocking it !Best Regards:
Baron J.
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8th May 2021, 11:46 AM #4Senior Member
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drill web thinning
SAM_0759.jpgSAM_0760.jpgSAM_0761.jpg
Hello again. The first pics show my approach to the wheel. Moving the shank of the drill left or right changes the rake angle, or flute angle of the drill. You only need to take off 1-2mm. If you grind the whole edge out to the diameter to 0 deg the drill is Dubbed for brass and perspex. Rotating the drill a few degrees anti clockwise takes most of the edge away from the wheel and you only modify the drill near the web. Bring the drill edge up to the wheel and push the drill tip inwards till the drill is thinned at the web. Rotate and do the other side. The last pic shows a thinned web. All common drills 4mm and over in size come with wide web design. Take a few drills and practise, you will pick it up fast.
Regards
BC
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8th May 2021, 12:46 PM #5
Thanks
Hi BC
Yes, that web thinning you described and pictured is what I do as a normal part of the sharpening process.
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12th May 2021, 10:44 AM #6Senior Member
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splitting drill points
SAM_0770.jpgSAM_0771.jpgSAM_0772.jpg
Hi Morrisman and all in general.
I have shown these before but missread the request on this post.
The first pic shows point splitting a 1/2" drill. With a bit of fiddling you can get the drill point to pass under the wheel and there is no need for travel stops. I have left off the indexing arm for clarity. The Clarkson table cross feed and wheel height adjustment makes for an accurate job.
The last 2 pics have a shop made attachment that will split points on drills up to 2 1/2" after which I run out of room under the wheel. With the sub plate on the table my work envelope is more than doubled. By rotating the big drill against the brass button the lip can be positioned where you want, then the stop brought up behind the shank to secure it. This set up gives good control when dubbing drills for brass or other point work for difficult to drill work. If you don't have a T & C grinder make up an angle iron slide running inside angle iron.
Sorry to take so long I have had to work for a few days.
BC
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16th May 2021, 02:47 PM #7
more
Have a few hours to spare ?
http://unsworks.unsw.edu.au/fapi/dat...CE02?view=true
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17th May 2021, 03:21 PM #8Senior Member
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- Brisbane
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Split point drill grinding
SAM_0773.jpgHello Morrisman.
I'm more familiar with practical application texts. The Yanks are open with tech info and prices are OK too.
Regards
BC
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23rd May 2021, 06:19 PM #9Novice
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- May 2021
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- Surrey
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- 14
Mystery part
Thanks for posting the first picture. When I acquired my Simonnet DZ450 lathe, it came with all sots of goodies, one item I had no idea as to function. After all this time it’s the drill holder from a Clarkson tool grinder. I now need to see what I’m missing to create a functional tool grinder.
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23rd May 2021, 07:05 PM #10Most Valued Member
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- Oct 2010
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- melbourne, laverton
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- 1,910
Is there a movie?
UOTE=morrisman;1984565]Have a few hours to s
p
are ?
http://unsworks.unsw.edu.au/fapi/dat...CE02?view=true[/QUOTE]
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23rd May 2021, 10:04 PM #11
more
This is a good article I think
http://neme-s.org/2005%20May%20Meeting/drills.pdf
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