Constucting a Cone

[B. Jacobs]

Can someone tell me the best way to construct a cone. I have a chamfer called out the reguires a 45degX.03 dimension. I have made two circle out of it. I am going into the construct mode and try to construct the cone.
I am not having any luck. The part is a cylinder with this cone on the inside.
Any thoughts about what to do?

Thanks

3.5MR2

[Paul Sarrach]

six surface points, but is that in metric? There are chamfer gages that work great for that.

[craiger_ny]

That's an aweful small cone. I'd worry about accuracy.

six surface points, but is that in metric? There are chamfer gages that work great for that.

If you try this then make sure you vector properly on the surface hits

Craig

[Devaney]

Can someone tell me the best way to construct a cone. I have a chamfer called out the reguires a 45degX.03 dimension. I have made two circle out of it. I am going into the construct mode and try to construct the cone.
I am not having any luck. The part is a cylinder with this cone on the inside.
Any thoughts about what to do?

Thanks

3.5MR2

Bill, I'm working with a huge csk right now and have had limited success with the auto cone. I can get it to work but I don't feel real comfortable with the results and are having them verified. I'm not sure if you'll ever get reliable results out of a 45°X.03".

[Andrew Gardner]

If you can, try to create three lines (at centerline) in the correct work plane. Then create points at the intersections. Dimension the 3D line angle, and the point distance. I have done this a few times with a little success.

[TRD_racing]

I have a chamfer called out the reguires a 45degX.03 dimension.

B. Jacobs,
I have done this a few times. I take points as close as you want (.001") up one side. Just take a vector or surface point on a nominal vector 1,0,0. Use pattern / paste w/ pattern to get the rest of the points. Basically you are making a profile. Then we put it into a cad package (solidwork). It is easier to work w/ in a cad package, more options. The cad can tell you your angle and size of the chamfer. Then you can do this very easy at 90 or 180° from the 1st profile. Hope this helps

[Paul Sarrach]

Also, if you are going to check that with the CMM, use the Surface points, but take a point just outside on the top surface and use that as a "rmeas" point. at least you should hit where you want to, if the feature was cut correctly

[dwade]

I've not had to do this in PC-DMIS yet but did it all the time at my last job using GeoMeasure. Either use 3 lines as suggested by Andrew or plane the surface then 2 lines and construct intersect. Make sure you take at least 3 or 4 hits and the chamfer surface, 2 or 3 hits on the ID,edge and make sure your IJK values are set to measure perp to the angled chamfer surface.

[56flh]

I may be doing this wrong, but to measure the D3 diameter of an SAE port and the angle of the chamfer below that diameter I've done the following:

Level to the surface at the top of the port.

Take 9 hits varying the location of the hits within the cone (example: 15 degree angle of an 1 1/16 port) to create the cone.

Create a circle where the cone intersects the plane to get the D3 dimension.

A chamfer gage cannot be used for this measurement as there is a radius at the point where the 15 degree angle meets the surface plane.

[george frick]

another option is to use dental impression material and check it on an optical comparator. we do this all the time with ms ports.

[B. Jacobs]

Sorry for not stating in the first post but the chamfer is inside a cylinder. The cylinder changes size iside and the chamfer is where the two sizes meet. I have used lead as a mold of the part. The only thing is we have to do 100% of all dim on the print and there are 80 pieces they are makeing.
This bites.

[cmmguy]

Had the exact same feature(problem).

Even if you can measure the chamfer as a cone, you will never get the dimensions that you are looking for. The cone will never be perfectly on axis with the other diameters and you will never get the intersections to work

This is what I ended up doing...... Its not perfect but works.
Measured the first bore, set zero on it.
Switched to a "side view" plane.
Measured the first bore with a line along the bottom of the bore.
Measured the chamfer with a line.
Measured the second with a line.

All lines were on center and along the axis.

Intersected each line to the next.

Evaluate the angle of the chamfer line to the bore axis for the chamfer angle.
Evaluate the distance between the two intersection points for the depth.

[JIM HARRIS]

I use the auto cone for chamf. all the time.Iam programing a job now that has a number of 45 x .020 chamf. and it works just fine.I have checked chamf. with molds and the cmm and them are pretty close.You might have to mess around with your settings a little but it works just fine.

[JamesMannes]

I would 2nd that opinion.

[cmmguy]

How would you intersect the cylinder of the bore with the cone to get the depth?? I agree that it would give you the angle but that is only half the answer.