stragenmitsuko
Well-Known Member
- Joined
- Jan 19, 2016
- Messages
- 326
- Reaction score
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Here's something I think is worth sharing .
I needed to cross drill and tap 16mm hardened rods , wich will
eventually be the lineair rails for the router I'm building .
Only the outer skin , maybe 1mm is hardened , the core is reasonably soft .
These are not the chinese rails found on ebay , but german made by FAG , abt 20 years ago . They're HARD allright .
So I heard and read about using masonry drill bits to drill hard steel .
You can even drill out broken taps this way ???
Never really believed it , but I decided to give it a try as I had no off the shelve alternatives .
I must say , I'm speechless .
This actually works , and it works very good .
I was able to drill 2.5mm trough the hard skin , and then continue with a smaller regular tap size drill .
First thing I did was sharpen the drill bit like I would sharpen a "normal" drill bit for steel .
A diamond disk is needed . Mine is pretty coarse , but it's all I have .
The sharpened drill point looks a bit odd , as the spade blade isn't really shaped like a twist drill So my initial scepticism grew ....
Then some cutting oil , light feed and rpm of 350-ish .
Did a test on a piece of scrap from a previous project .
Cuts it like butter ,
So I set up everuthing in the mill , drilled 14 holes without any problem and the bit is still as sharp as it was .
Chips are blue-ish and very fine , almost like steel wool .
It makes a squeeking noise when drilling , and it stops making that noise once the hardened skin is cleared .
Pat
I needed to cross drill and tap 16mm hardened rods , wich will
eventually be the lineair rails for the router I'm building .
Only the outer skin , maybe 1mm is hardened , the core is reasonably soft .
These are not the chinese rails found on ebay , but german made by FAG , abt 20 years ago . They're HARD allright .
So I heard and read about using masonry drill bits to drill hard steel .
You can even drill out broken taps this way ???
Never really believed it , but I decided to give it a try as I had no off the shelve alternatives .
I must say , I'm speechless .
This actually works , and it works very good .
I was able to drill 2.5mm trough the hard skin , and then continue with a smaller regular tap size drill .
First thing I did was sharpen the drill bit like I would sharpen a "normal" drill bit for steel .
A diamond disk is needed . Mine is pretty coarse , but it's all I have .
The sharpened drill point looks a bit odd , as the spade blade isn't really shaped like a twist drill So my initial scepticism grew ....
Then some cutting oil , light feed and rpm of 350-ish .
Did a test on a piece of scrap from a previous project .
Cuts it like butter ,
So I set up everuthing in the mill , drilled 14 holes without any problem and the bit is still as sharp as it was .
Chips are blue-ish and very fine , almost like steel wool .
It makes a squeeking noise when drilling , and it stops making that noise once the hardened skin is cleared .
Pat