MC doesn't have a specific thread cycle for the big threads, but there is a simple method to create a suitable toolpath. If rick (rdshear) sends me the data I asked for, maybe we can post the solution.

I think there's an easy solution in MC. Does your lathe threading cycle do the runout? If you send me a normal threading cycle (the long cycle), I think we can put something together.

FlattenSurf.dll MAP.DLL will map more accurately. If you don't like those results, send me what you did, and we'll figure out what you need. There are a lot of ways to map to a sphere, some better than others. See if you can figure out how to make your flat space match your sphere space. You may have to make a new sphereical surface -- for instance, a band around the middle. Just use a part of a semicircle instead of the whole thing.

To other helpers. The 'specs' are what R&C doesn't know. You need roller diameter and pitch. R&C knows OD and root diameter (but only approximately). I don't trust the dimension for root radius, because it doesn't match what he would need for pitch. He needs to find out the chain dimensions.

With standard chain, a 1.75 pitch has a 1 in. roller, and a 2 in. pitch has a 1.125 roller. If you use the 2 in. pitch, the root diameter is 18 inches. The 1.75 pitch would give you a 15.734 root diameter. See if you can verify the chain pitch and roller diameter. It is very unlikely to be non-standard.

I don't think the c-hook is for V9. SPROCKET.ZIP is in Text_&_post_files_&_misc on the FTP site. All you need to know is the pitch, no. of teeth, and the roller diameter. When you run the 'post', you get prompted for these 3 parameters. Read in the SPROCKET.DOC file into MC with FILE-CONVERT-ASCII... Input the file twice, once as lines, once as points. You have to make 3 arcs (Circ pt+edge), and trim them to make half of a tooth. Email me if you have trouble. If you read the 'post', you see how complicated it is to extract a sprocket from 'the book'. The c-hook is for X.

I have put a file PARABOLA ARCS.MCX in FTP site MCX_FILES. The arcs are tangent to each other. I can make a file for your parabola if you want to test it out, or you can run the algorithm yourself.

I think I can help. Can you send me the parabola formula? I'm not sure it will make much difference, but we can try. It depends on the control. How many places can it read?

I have had great success milling bending dies with a flat end mill or face mill (depends on size), and about 45 degrees lead/lag. Large ball mills are very expensive, and don't cut as well as flat mills or face mills. Email me if you need more help.

Hardmill, see UNBEND.MCX in the FTP X4 directory. I rotated each tab about their fillet axis, then translated parallel to the fillet axis by the fillet length at .47 stock thickness. The fillet radius is almost 3 times the stock thickness, so the neutral radius is almost .5 times stock thickness. I'll send you all the numbers if you're interested. This kind of bend is not the kind that FLATTENSURF is designed for. FYI everybody -- the 't' fraction of stock thickness for bend allowance is on the wrong side of the stock in WICKIPEDIA.

Just a reminder to all that FlattenSurf does not factor in any 'draw' (stretch) involved in bending a surface. The constant-parameter lines end up in their true length. Usually, it makes more sense to flatten a surface in one direction rather than the other. Hardmill, I'd be glad to look at your part.

One way to get curves that lie on the surface is with a flowline toolpath. In 3 axis, use the smallest cutter the system will accept. In 5-axis, any cutter, TIP, control comp. OFF.

Somewhere, a long time ago, I saw an article on microdrilling, where the microdrill had a pulley mounted to the shank, and was spun in a v-block, which eliminated runout.

I don't think CURVE5AX ramps, but it's a good idea. I think you're going to make successive depth cuts.

I don't know what you mean by "helix the curve". Helix in the ramp, or does the helix help define the curve?

A blank line (LF) will separate strings.

I may be able to help. Send me the data file.

When you're roughing a shaft, don't forget the lead/lag option. Even 1/2 degree moves the cutter contact from the center to the edge of the cutter.

That's good. It's right on the money. Rotate the whole part 90 degrees in the right view, and make a new toolpath, or rotate the toolpath you have. The toolpath is a 5-axis type toolpath (limited to 4 axis). I think your contour was a 3-axis toolpath. Big difference. Do you think you can make the part now? Make the helix surface long enough for runout off the part. Send me your part file if you need more help.

I'll send you a sample part. See how that posts.

The match between TOP view and RIGHT view is awful. In the TOP view, zero is on the X axis. In RIGHT view, zero is in the right view X,Y system, so it's on the X axis in that view, which is the Y axis in TOP, making it 90 degrees from the TOP view. For a quick fix. rotate your data 90 degrees, and see how it goes.

MIG, the helix is not conical. Try this: Create a surface at ball center. I'm guessing that a curve thru the ball centers is an arc, but it could be a spline (not an arc). Make a surface of revolution with this curve. Make a helix at a diameter larger than the part, and another at a diameter smaller than the smallest radius of the groove. Make a surface with these two helixes. I will call this a radial helix surface. The intersection of these two surfaces is the ball center toolpath curve. Cut it with CURVE5AX, in 4 axis mode. If the groove is shallow enough, you can add lead/lag (always lead) without gouging the side. If you need more help, send me the part file.

Running a postprocessor is probably the easiest way of finding A and B angles. Drill a fake hole in each plane, and make a 5-axis drill toolpath. If you need more help, send me a part. We can work something out. Think of this kind of postprocessor as a cheap c-hook. Moreover, it's easier to collect the input data as a toolpath. You can do all the planes at once.

I don't know if you can work it out, but I prefer to use 4-axis lead/lag with a bullnose with inserts. The tip radius is small, but the workpiece sees a large radius.

How about a fixture with a pin parallel to the trunnion axis? It should tram the same at A=90 as it does at A=0.