Tapping Aluminium extrusion

[Web Goblin]

Jonathon,
thought about that one last night but I would need to get it accurate. Flat bar bent to a right angle with a 12mm tapped hole, then G-clamp the long bit to the side of the extrusion. I have already machined the linear bearing guide blocks which will be bolted to these sections.
Ive had a look on the suppliers website and they say they have self threading core screws but dont give any lengths on them and they are still on holiday. Also they would need to be cap screws. I think a spiral flute tap would be easier once I get one.
I just hate having to wait on things.

Ian

[Jonathan]

Also they would need to be cap screws. I think a spiral flute tap would be easier once I get one.
I just hate having to wait on things.

Can you get one with a left hand thread so the chips fall down through the extrusion? Might be too expensive.

Edit: I meant left hand spiral...

[Wobblybootie]

KJN and Hepco do a series of self tapping 'core screws' for their extrusions. http://www.aluminium-profile.co.uk/a...ore_Screw.html For the 45 X 45 I used, the central 'hole' is 10mm but it is not a 'plain hole' ... more like a star washer. I used 12mm dia and about 30mm long with a size 50 Torx head. They are designed to join profiles together at 90 deg. To build a T, you would drill a 10-11 mm hole through the centre of the cross piece, the screw is slid along the lower slot of the cross piece until the head is visible through the drilled hole, bring up the vertical extrusion and the screw is screwed into the central hole. The Torx bit being inserted through the drilled hole. A very secure fixing but if the end of the extrusion is not absolutely square then the 'joint' will not be.