"From Ballroom Competition Figures Marcus Hilton."
Serendipidy's description matches that in Geoffrey Hearn's book 'A Technique of Advanced Standard Ballroom Figures' which I would expect as he produced the Marcus Hilton video.

Guy Howard's book has a different version where most of the turn is made at the beginning, and therefore needs a slight difference in rise. Some may refer to this figure as a hairpin.

1: LF fwd facing LOD, HT, rise e/o 1, turn up to 1/2 L
2: RF fwd, small step, R side leading, towards alignment of 3, T, Up
3: LF fwd in CBMP, facing DC ALOD or ALOD, TH, lower e/o 3 (heel does not lower until next step is taken).

He also notes that following a reverse or slip pivot, step 1 will be taken in CBMP.

Social Dancer. Unless somebody has changed the name a Hairpin is a Hairpin Feather. It usually follows a Curving Three Step followed by a Chasse, a Pivot, and a Change of Direction. This brings up a timing thing.
If the whole group started with a Feather Step, a Reverse Turn into the Curving Three Step and so on. At the end of the Change of Direction with the LF passing should be on beats 3 4. The whole group having taken eight bars of music. If it comes out on bar seven you will be out of phrase with the music unless you did a Contre Check or something else that fits that group.
But if you started on the wrong beat at the beginning of of the Feather, which should be RF forward on 1 2 and not 3 4. Let us not forget that an introduction is not a step. If you do an introductory step, which can only be done once, it should not be on beats 1 2. This throws the whole group out of rythm and out of phrase.

"Anonymous. If we are starting on the LF for the Curving Three Step the footwork is
" LF. forward facing LOD. H T. Turning 1/8 to the left RF forward facing DC. with Left Sway, Toe."

Yes, the second step is toe. The person who raised the possibility of doing otherwise was yourself, serendipity, when you commented on using the same footwork as in the ordinary three step - in which that step on the right foot is of course HT.

If there's a correction to be made based on the information you quoted above, it's to your post, not to mine. Or perhaps you'd simply like to clarify that you were warning against trying to use the same footwork - at any rate, the only person who even raised the possibility of a heel there was yourself.

"I know the first two steps are straight with most of the body turn on the third,"

Who told you that?
That sounds more like the description of a change of direction.

My mistake,thanks All.

I took the trouble to hunt for the video where Marcus Hilton does a Curving Three Step.
Cdroge. wins the argument. There are two straight steps by the man taking the floor boards as a guide. What can be deceiving is the turn of the body to the left. But the second step goes straight ahead in fact it looks like a step to the side. but is straight ahead taking the first step as a marker. Does that make sense.

I don't see how the first two steps can be straight. How would you lead the lady into the curved 3-step. You would have strong CBM, but there is a need to 'cut the lady off' so she realises it's a curved 3-step. If all the turn is made on the last step, it would be more like a 'dog-legged' 3-step!!
I think a description from Geoffrey Hearn's book had 1/8 of turn on second step. That sounds about correct.
Remember also the figure can curve to the right. Been dancing curved 3-steps (to the right) for years. Not perfectly of course, but getting better

"There are two straight steps by the man taking the floor boards as a guide"

But what was the direction of the preceding step 3???

To have two straight steps would imply that the footprints of three steps (3, 1, 2) can be connected by a straight line. If that isn't the case, then you haven't taken two straight steps.

Anonymous. He is facing straight down the Lod parallel with the floor boards. This how I can tell which direction he is stepping by taking the floor boards as a guide.

"Anonymous. He is facing straight down the Lod parallel with the floor boards."

You've answered the wrong question.

I didn't ask the alignment, I asked the direction of the previous step.

You must then further consider the position (location) of the step. Can three successive footprints be connected by a single straight line? Or do they make two line segments with an angle between them.