Interpreting taper standard

[moon161]

I'm modeling and making a drawing for a male leur lock fitting, taking a close look at things because the previous drafter got the taper off by a factor of 2. Hopefully the mold was made correctly, because the drawing also reference ANSI-HIMA MD70.1-1983 for the luer taper. ISO and ANSI specs for the luer are on my desk.

If you dimension a tapered end with a fillet do you dimension to the end of the fillet, or the vertex that the fillet removed? The ANSI and ISO for the taper are not so clear on this. The diameter spec for the end of the taper is given as 3.990-3.925 mm, max fillet radius 0.5mm. (.1545-.1571", .020" max rad).

On to modeling, is it correct to model the taper exactly, then add a cap to the end w/ the fillet which does not affect the end diameter of the taper? Or more correct to model the taper correctly, and then fillet the end (then inspection is looking for a missing vertex to measure, but they'll really just use a go/no go gage)?

Or really what's the best way to think it through for this time and the next?

Thanks,

 

[MechNorth]

Dimension to the intersection point, adding INT PT after the diameter dimension. For modelling, do the same, and then add a blend radius at the end. If you need more length of contact in the taper, increase the overall length before adding the rad.

As for inspection, as long as the blend at the end is tangent to the end surface, they can determine an intersection point if they need an actual number. The only way to properly control a conical taper is by means of a surface profile control; inspection isn't too difficult then, either, as it's either within the boundary, or not.

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com

 

[moon161]

Thanks Jim. Makes more sense now.

Andy