Grub screw hole size for threading!

[Enoch]

If you are going past Bracknell in the near future bring em along and I can drill em and tap em for you.
Dave.

[gingea1pom]

Enoch,

What are you up to on Thursday; I have a free day, if it’s not too much bother.

Cheers Ginge

[spud69]

Hi Ginge,

Build is looking good on your build thread.

They look like course threads on the grub screws, Depth of thread = 0.866 of the Pitch of the thread so 8-(0.866x1.25)=7.02mm so a 7mm drill would be fine for the M8 thread. Plus the cast of the upright taps easy.

Keep it up....AndyH

[mark]

You can get a cheap tap and die set that goes from m4 to m12 for about £25 it will even have the wrenches in

No good for everyday use but fine for the odd bit whilst building your car

[alga]

Spud, it's not that simple. Both ends of the triangular profile are beveled, and the nominal diameter of the thread is not measured at the tips of the triangles (Dmaj+H/8), but the actual height of the external thread (Dmaj), so the math is a bit more complex. The drill diameter is Dmin here.



More info on wikipedia, as always: http://en.wikipedia.org/wiki/ISO_metric_screw_thread

[gingea1pom]

OH MY GOD

That diagram / drawing is awesome if not a little mind bending.

6.8mm then!!

[davidimurray]

Get your self a copy of the 'Zeus' book. A brilliant pocket book full of all sorts of useful engineering info. Your overalls shouldn't be without a copy!

[Enoch]

Ginge, I have an MOT first thing in the morning, I need to spend a few hours in the office and expect to be home at about 3pm. I will PM you my phone number so you can call and see if I am free before coming over.
Dave.

[gingea1pom]

sounds perfect to me