Gallery, Projects and General > How do I??

Drilling! - small holes on the mill and centre drills

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John Stevenson:
Sorry, I just make things........................

I did go to Oxford University, does that count ?
Didn't study anything, just delivered 28 tonnes of bricks.

John S

Dean W:
Aw Lew...  Lighten up just a bit, bud. 

But seriously, can you get me an autograph from 007?  It's not for me!
My Thirty-something daughter thinks he's great.

Rob.Wilson:

--- Quote from: craynerd on July 19, 2010, 06:51:00 AM ---Here comes one of  my dumb questions but I have to ask since I`ve learnt a lot from this thread. Rob - you sent a link for a 6mm spotting drill. Can I just clarify that you would have a set of these for each size hole? I`ve lost the plot a little as it seems that John is using them to cut the hole directly...say I wanted a 5mm hole and quite a depth, would I need a 5mm spotting drill to start the hole and then move onto my regular 5mm drill bit? Or say my hole was 5.5mm, would I use a 5mm spotting drill to "spot" the hole and then go in with my regular 5.5mm drill or whatever to finish it?   

I suppose I`m asking are these just used to spot the hole and I only need a couple of sizes or are you using them to drill through?

Chris

--- End quote ---

Hi Chris

Not a dumb question at all ,,,,,,,,,,,,, I only have a few sizes , about the same rang as a set of centre drills ,the example i posted was the first on  the Ebay search ,good price for a solid carbide drill , and as you said they are used for spotting for the drill , just the same as you would with a centre drill ,,, You can use them to drill all the way through the work as in the example  John S posted , when the hole to be drilled is not as deep as the flute length .

This is just an example ,,,,,,,, I need to drill the holes in the bolt pads on my engine casting  ,
10mm spot drill and large centre drill BSO3 i think

Centre drill in the chuck ,,,,,,,,,,it dose not reach the pad, chuck hits the casting

10mm spot drill ,, no problem ,as they are a bit longer ,,,,,,


Or you could spend more money and get long reach centre drills or just extend a standard one .
 

Regards Rob

raynerd:
Rob, nice one - makes sense, thanks for the info from you all. As Kwackers mentioned, I have inhereted many centre drills but as has been said, I have found the little stub break off and to be honest many are so old are worn they need binning. I think I`ll give spotting drills a go and order a few.

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