user2538: So, the Blade Speed retiming tool in FCPX is half-awesome.
But once I have put a blade marker in I can't work out how to:

remove it (apart from immediate undo, i.e. later on)
move its position in relation to the src clip, i.e. I put the blade point in the wrong place, I want to move it without adjusting the retiming either side of the point
join adjacent retimed segments... related to above, if I put in a new blade point in the correct position I can't remove the wrong one (1) or see a way to join/merge the adjacent retiming segments 


user11417: For #3 of your question, I could find some relevant info at apple support page. 
To remove a through edit, do one of the following:

Select either or both sides of the through edit point, and choose Trim > Join Clips (or press Delete).
Select the clips on both sides of the through edit, and choose Trim > Join Clips.


user2538: Partial answer...
I still don't know how to remove a single blade speed point.  It is possible to remove all speed points for a clip by selecting the clip and choosing a new speed (eg Normal 100%) from the Retiming menu.
I still don't know how to join adjacent segments (kind of same thing as above).
Found out how to move the blade speed point relative to the clip itself without retiming:

double-click the blade speed centre handle and click the 'Edit' button



You get this icon you can drag in the timeline:


(classic bit of Apple "hidden UI" gotcha)
If you are zoomed in and you have a big speed differential either side of the centre point then it may not be at all obvious that you really are moving the src frame (fooled me before) because the preview changes are complex. But with Normal speed both sides it is clear this does what I wanted.

2538: <p>So, the Blade Speed retiming tool in FCPX is half-awesome.</p>

<p>But once I have put a blade marker in I can't work out how to:</p>

<ol>
<li>remove it (apart from immediate undo, i.e. later on)</li>
<li>move its position in relation to the src clip, i.e. I put the blade point in the wrong place, I want to move it without adjusting the retiming either side of the point</li>
<li>join adjacent retimed segments... related to above, if I put in a new blade point in the correct position I can't remove the wrong one (1) or see a way to join/merge the adjacent retiming segments </li>
</ol>
 11417: <p>For #3 of your question, I could find some relevant info at <a href="https://support.apple.com/kb/PH12549?locale=en_US&amp;viewlocale=en_US" rel="nofollow">apple support page</a>. </p>

<p>To remove a through edit, do one of the following:</p>

<ul>
<li><p>Select either or both sides of the through edit point, and choose <em>Trim > Join Clips</em> (or press Delete).</p></li>
<li><p>Select the clips on both sides of the through edit, and choose <em>Trim > Join Clips</em>.</p></li>
</ul>
 2538: <p>Partial answer...</p>

<p>I still don't know how to remove a single blade speed point.  It is possible to remove <em>all</em> speed points for a clip by selecting the clip and choosing a new speed (eg Normal 100%) from the Retiming menu.</p>

<p>I still don't know how to join adjacent segments (kind of same thing as above).</p>

<p>Found out how to move the blade speed point relative to the clip itself without retiming:</p>

<ol>
<li>double-click the blade speed centre handle and click the 'Edit' button</li>
</ol>

<p><img src="https://i.stack.imgur.com/elXZK.png" alt="enter image description here"></p>

<ol start="2">
<li>You get this icon you can drag in the timeline:</li>
</ol>

<p><img src="https://i.stack.imgur.com/q89Tb.png" alt="enter image description here"></p>

<p>(classic bit of Apple "hidden UI" gotcha)</p>

<p>If you are zoomed in and you have a big speed differential either side of the centre point then it may not be at all obvious that you really are moving the src frame (fooled me before) because the preview changes are complex. But with Normal speed both sides it is clear this does what I wanted.</p>
