Curve5ax has the lead/lag you want. The fillet CL would be the toolpath of the ball center. But CURVE5AX needs a surface to reference for the initial surface normals, to which it adds the lead/lag. Since the fillet surface is the same distance from the CL, you can't use that. Make a ruled surface between the rails of the fillet surface, and use that as your reference surface for CURVE5AX.

To avoid a rotation shift with axis substitution, the parameters must be CW, -90.

Machinery's Handbook spells it out very well. Otherwise, make a gear with the same pitch, and use the number for circular pitch that GEAR.DLL gives you. This is the linear pitch along the pitch line. You can also use the tooth height and depth from the gear. The walls will be the pressure angle.

Whoops. The new variable's name is nt. It will be output with the letter N.

fmt N 1 nt # Make a new variable N ######^ Ref. a 1 0 fs (probably not fs 1) nt = t

If nothing else works, and you really have to force it, you can define your cam curve as a spline, then break into many pieces. In the straight sections, that will be an overkill maybe, but you can eliminate the facets. If your groove is a cam, the best fit for the follower will be by using the groove CENTERLINE as the drive contour, and use the ROLLDIE c-hook and use the slot option. This is the best way to get the opposite sides of the groove parallel.

Well, you seem to know that the buffer count starts at 1. Zero is reserved to find the size of buffers that already have data. WBUF and RBUF are the write and read function names, not the write count and read count. Change WBUF:1 to WC1:1, and RBUF:1 to RC1:1. The read line should be workofs$ = rbuf(1, rc1). Be aware that RC1 is incremented automatically on each read. So is WC1. The 10 in FBUF probably should be 1 [wide]. Send me the post if you still have trouble. You may not need to make a separate subroutine of PREADBUF and PWRITEBUF, but that depends on the structure of the rest of the post.

Sometimes unrolled geometry comes out one revolution from where you want it. It is 'legal' to translate any unrolled geometry one OR MORE circumferences (pi*rotary diameter). Then you have to recognize that the repeated geometry is the SAME geometry that you translated, not new geometry.

After looking at the part, scaling the helix does make sense. The helix axis is on Z, so scaling it in X,Y but not Z would give the right kind of offset. So would 'offset contour'.

I'm not sure I understand your part thoroughly. Maybe you could send me a part file. I don't think you want to scale a helix. The curve I was talking about would result from unrolling a straight line entry/exit line.

This looks like a roll/unroll problem that hasn't really been addressed. Let's assume that you're geometry is unrolled (a straight line). Roll it up, and add straight entry and exit lines. Then unroll it. Now the entry/exit lines are curved in the unrolled domain. Or you could just add the lines to the already flat helix to keep from breaking it up.

Thrash, That drill flute section is unique. Unless I'm really mixed up, it appears that you can cut half the flute from one side (with the cutting edge 'up'), then cut the other half with the non-cutting edge 'up'. It looks like a job for ROLLDIE. The geometry is on centerline, and the distance from side wall to centerline is expressed as XY stock thickness. For all depth cuts, the helical cut would be the same -- in other words, each start position would be a point in the main, followed by a helical cut sub. I need a little help myself, and I'll send you a file when I get this organized.

Or you can update the prv.. with !xabs,!yabs,!zabs, OR prv_xabs = vequ(xabs) (upates all 3).

XABS... is already formatted. Copy the vector XABS,YABS,ZABS to another vector (3d point) which is formatted with no letter prefix.

If you unrolled the helix and used axis substitution, you could just translate the helix 10 degrees. You need to be able to convert the 10 degrees into a Y dimension. Y/(pi*dia) = A/360 sets up the basic proportions. Then Y=A*pi*dia/360 The inverse of this, A=Y*360/(pi*dia) is also useful. If the rolled helix is in the right place, it should land in the right place if you use CW,-90 for unrolling parameters. I'd send you a drawing, but I don't know the part diameter. The advantage of working in the flat is that you can break the helix line into just a few pieces. If the mill is set up for 'short way', each segment must be less than 180 deg. THRASH, I think I could help you if I had a sketch with all the dimensions. I'd also like to know what cutter you would be using.

Sorry, Heavy, I should have metioned that if you change the control def, you would have to change the machine setting, which is apparently 'short way'. Just break the line into 6 pieces or so, and everything should be OK.

Yes. But you only need 2 points. You could change the end point by hand. I guess you're going to skip the 45 deg. option. It's really a form of lead/lag machining. The chip making process is much better.

When you're using roll/unroll, always set the parameters to CW,-90 to get the geometry match you're looking for. If you looked at the cylinder in the side view, wrapping CW, when flattened, would go in the +Y direction, and the side view zero degrees (+Y direction), would end up on the origin, so you need the -90 to get the top point on the cylinder to the origin.

Mic6, if you send me an email, I'll send you a picture, well, a part file.

Generally, you use the diameter of the cylinder. If there is some depth to the part, I like to use the minor depth. Then the arcs will show the max. cutter you can use. If you still have trouble, email me your part.

If you know the circular space width, you can find the circular tooth width. tooth = pitch - space. The point here is that the space must be greater or equal to half the pitch. If you don't enter the tooth width, it will be. Anything less for the tooth width will be clearance (bigger space). Let GEAR.DLL figure out the dimension between pins. You have to enter YOUR pin diameter, which might be slightly different from 'the book'.

So Sorry. I was right the first time. I'm fighting some serious med's. Really. When you establish a helix in the flat, the basic rectangle is X=pitch, Y=circumference. The helix is the diagonal. Now the X travel is 1.5555 * pitch. The helix angle doesn't change. Just extend it to the total X travel.

Whoops. Y should simply be the circumference, pi*dia. I hate to cut with the end of the ball. For this kind of cut, I much prefer to cut, say, 45 degrees from vertical. You can, of course, jimmy up a post, or you can post to BALL CENTER (not to tip), and rotate the two points in the side view.

A layout in the flat is a nice check to make sure you have the right numbers. 560 deg. / 360 deg. = 1.5555 turns. 1.5555 * .1033 = .1654 total X travel. In the flat, lay out a rectangle X=.1654, Y=1.5555 * pi * diameter. The helix is a diagonal line corner to corner (you didn't say right or left hand). Use the same diameter for axis substitution. You only need 2 points, the first and last.

Try the old method. Stick an indicator in the spindle of a Bridgeport and tram the boss.