one for the engineers out there

[rhmbus]

size of tapping size drill for a m2.5 tap please
ta ray

[Roksoff]

size of tapping size drill for a m2.5 tap please
ta ray
if you take the pitch away from the tap size you'll get the drill size..
e.g. M10 X 1.5 pitch = 10 - 1.5 = 8.5 dia drill.
M2.5 has a pitch of 0.45 so 2.5- 0.45 = 2.05, seeing as you wont get a 2.05 mm drill its gonna be 2 mm dia drill.
The rule about diameter - pitch ONLY works for metric threads and no imperial.....:D...and good luck, 2.5 mm is pretty small, no broken taps I hope
scott

[thrunobulaxx]

You can buy the exact size needed but they cost a lot of dosh, when i did pucks i had to have a range of drills to suit different spindles (they vary) i ended up having to get 7.2 / 7.3 / 7.4 /7.5 and 7.6mm to suit all the spindles for a nice non wobbly fit.

A 2mm drill will be fine for a M2.5 tap (which is also more expensive the smaller you go) so as said take it easy it will be tight, use oil and depending on the metal only take 1/6ths of a turn (or less) cuts before backing up to chip the swarth off.
Are you making a head shell plate then Ray or modding a Denon ? :)

[Roksoff]

If it helps Ray, I can post you a 2mm drill....I sure the stores at work has 2 mil drills...pm me if you want
scott

[rhmbus]

thanks guys i may well be on the scrounge .
my old dad was a toolmaker[place down in Tottenham Hale Thru] and i have inherited all of his tools and gear and have not found the urge to sift thro it will let you know whats there in case theres any thing that may come in usefull with you guys
i am making a new arm tube for my Mission 774 and found plenty of 6BA/m2.5 taps in my toy box but no sodding drills ,6 in the evening ,come to a grinding halt f*&$%£" frustrating .Still given me the impetus to sort the old guys kit out ,something i have put of for months.
will be back in touch
thanks again ray.

[Roksoff]

OK Ray...take it easy...it must be hard...PM me when you're ready if you need drill.
scott