Quill stem bolt hard case.

curzons246

Über Member
Location
derbyshire
I'm trying to drill the hex head off a quill stem bolt. It is deeply recessed in the stem. It resisted the every day drills I've got so I invested in a De Walt extreme industrial cobolt pilot point drill. I've filled the recess with oil, drilled at a slow speed and kept it very cool. No progress at all, what am I up against?
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
Bloody hard steel. I'd use small drill bits, and progressively go bigger.
 
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curzons246

curzons246

Über Member
Location
derbyshire
I often drill into stainless, and if you go too gently, ie let the drill rub rather than make progress, the material work hardens, and is near impossible to drill after that. This may be what's happened in your case?
Ok, I'll give it an aggresive go but I might have already done the damage with my everyday drills. Failing that it will have to be caustic soda which I'd hope to avoid but there you go.
 
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curzons246

curzons246

Über Member
Location
derbyshire
Forget Caustic soda - it will eat into the aluminium of the stem and leave the steel bolt untouched.


You don't need to drill away the whole shaft of the bolt ? Just remove the head?
That's all I'm trying to do.
 

midlife

Guru
Have you any big torx keys you can smack in? If you don't want the stem I'd think about hacksawing the top of and hitting the bolt you can see to release the expander :smile:
 

silva

Senior Member
Location
Belgium
I once used the next size up allen key, grinded off the faces of the hexagon to just be able to hammer it in. Then max torque as Venod said, also the good quality allen key.
 
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curzons246

curzons246

Über Member
Location
derbyshire
Is the steel black?
If so, it might be grade 12.9, hard and brittle.
There are dry diamond drills, for ex to mount on an angle grinder, available in different diameters.
https://www.carat-tools.com/en/product/35?f[0]=field_usage:79
It's a cilinder, covered with diamonds, filled with a cooling substance.
Diameter about the bolt thread section, the hexagon provides a centering.
Bolt is silver, those drills look great but not long enough I'm afraid.
 
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