You won't find one at Bunnings "where lowest pries are just the beginning ,,,,, of your problems " but you you will find them at most good machine supply shops like Hare & Forbes for instance .
I get most of my odd size stuff from L & P Toolmakers in Victoria
They also sell on Evilpay
Virtually no tapping drill will be found in a set of Jobbing Drills that you buy from a hardwear store or auto store .
However 11.5 mm is a standard size in a metric drill set and unless you are using very expensive drills very few will drill a hole accurate to 0.4 mm ≠ 0.015" at that size and a good High speed steel taper tap will sort that 0.015" out ( first cut to USA readers )
Under sized holes are not a problem if you cut the thread slowly and use good thread cutting lube
Over sized holes are
FWIW
29/64" is 11.51mm ( so a pooftenth bigger than 11.5 mm drill
15/32" is 11.91mm so a poofteenth bigger than the nominal correct size of 11.9 mm
Both of the above are std inclusions in a 1/16" to 1/2" set of jobber drills.
Tapping drills are also offered in sets of exactly the right size and are made to a much higher tollerance ( thus expense ) and in particular sharpened much more precisely
Accurate holes are drilled then honed or bored Or drilled, bored then honed if you want them really accurate and of course have to be done with a lathe or mill
You won't find one at Bunnings "where lowest pries are just the beginning ,,,,, of your problems " but you you will find them at most good machine supply shops like Hare & Forbes for instance .
I get most of my odd size stuff from L & P Toolmakers in Victoria
They also sell on Evilpay
Virtually no tapping drill will be found in a set of Jobbing Drills that you buy from a hardwear store or auto store .
However 11.5 mm is a standard size in a metric drill set and unless you are using very expensive drills very few will drill a hole accurate to 0.4 mm ≠ 0.015" at that size and a good High speed steel taper tap will sort that 0.015" out ( first cut to USA readers )
Under sized holes are not a problem if you cut the thread slowly and use good thread cutting lube
Over sized holes are
FWIW
29/64" is 11.51mm ( so a pooftenth bigger than 11.5 mm drill
15/32" is 11.91mm so a poofteenth bigger than the nominal correct size of 11.9 mm
Both of the above are std inclusions in a 1/16" to 1/2" set of jobber drills.
Tapping drills are also offered in sets of exactly the right size and are made to a much higher tollerance ( thus expense ) and in particular sharpened much more precisely
Accurate holes are drilled then honed or bored Or drilled, bored then honed if you want them really accurate and of course have to be done with a lathe or mill
I got a tapping drill on eBay and my friend will, after doing some machining on the part, drill the hole and tap it for me on his lathe.
