My first injection mold and the Rabit HY-4 injection molder

[mekanik]

If you can get an engraving bit with the 60 deg angle you should be able to do it.
If you go over to http://www.model-engineer.co.uk/ and look up "D" bits this will show you how to make one from silver steel, drill your hole go in with the "D" bit to the required depth then tickle the hole with the engraving bit.
Good Luck
Mike

[gavztheouch]

Thanks Mike,

Most center drills are 60 degree I think? Shame they have a that little drill point on the end (Maybe I could turn that down to continue the 60 degree shape?). Anyway I should be able to pickup a 60 chamfer or engraving tool.

So I think the plan would be.

1. Drill 1mm hole straight through. (Hopefully easy in alu?)
2. Use 60 degree tool to hog out material and form 60 shape.
3. Use a small 90 degree tool widen the 1mm hole entrance
4. Use 4mm rad ballnose to blend the 60 and 90 degree shapes by eye?

[mekanik]

Yes first op is drill the hole, you then want to remove the bulk of the material as you would probably break the engraving tool if you tried to open it out with that, also just checked the angles the 60 deg is refering to the larger opening that blends with the 45deg, the taper that opens out the hole has an included angle of 30 deg so you need an engraving tool that size, so remove the bulk machining the 45deg taper then go in with your 8mm dia ball nose cutter then just blend out with the 60 deg taper and tickle out the 30 deg taper with the engraving tool. FYI a "D" bit is just a form tool you basically turn the required profile with the drive dia slightly offset then machine away the profile leaving it flat topped to the centre line of the driving diameter, this gives the profile a "D" shape and a cutting clearance.
Regards
Mike
Reg

[gavztheouch]

the taper that opens out the hole has an included angle of 30 deg so you need an engraving tool that size,

I think the 30 degree taper is not part of the mold but instead part of the machine that injects the plastic. My thoughts are this is a heated tip and the plastic will flow around this?

[mekanik]

That makes it relatively easy to make then, carry on number one.
Mike