Gallery, Projects and General > How do I??
snapped centre drill
ieezitin:
This is a great subject for people who are new to machining.
Sparky.... your a 100% correct about the tip on a center drill, I unintentionally made that statement to mean its a spotting drill in itself I see where it could be miss leading, I meant it to be the drill for the lead of a center drill.
I also use stub machine drills. I have a complete set number through fractional and letters, I only use them on critical work as i find them better than a spotting drill...... but over the years its just a habit for me to bore holes i really care about for accuracy, with the aid of a QCTP and always having a boring bar from 3/16 to 5/8 ready on center height i take that time to bore it.... drilling holes accurately to correct diameter is not easy and most new people think drills do the job and they do not.
If its that critical ill drill thread and use a button then bore.
Anthony.
Jonny:
Valid point Anthony I do exactly the same bore to size via 5 different tool choices.
I don't even centre drill, just plough straight in even for semi critical jobs you will see drill deflect so know its a no no and try other means! Mill I ultra rarely use centre or spotting drills, straight in with desired drill never ever a problem unless on a taper.
Gone off the subject rather than answer OP's requests.
How to get a busted centre drill out of a hole.
tomfilery:
Guys,
Rather than using Alum to dissolve the drill, use citric acid. Most of us in the steam engine world have a ready supply of citric acid for pickling components after silver soldering.
Just leave the component in overnight and by the morning you will find the centre dill has rusted badly and you'll probably be able to poke around and get it out. If not, leave it longer and eventually the drill will disintigrate.
Regards Tom
awemawson:
Tom,
That greatly surprises me, as I am a regular and avid user of Citric Acid for removing rust, and I've never had steel dissolve in it even when left for a long time :scratch:
It is excellent though at removing rust :med:
kayzed1:
***** just had notice my 3phase kit will be here 10th to 12th in the am...so that will be the weekend job****
Well, the kit did not arrive as stated in the sales bumf, so i have sent a message to the seller via ebay....but no
reply from them yesterday or today :hammer: i should have gone to collect it as i am only an hour away. :doh:
Lyn.
PS: thanks for the citric info, i will try and find some to test.
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