Another interesting concept.
What i envisioned this morning with your tube within a tube was that on one end of the cylinder and the inner tube would have an approximately 1" long slot and a thru pin that contained it and limited its travel. that and like an engine valve spring on the end so the stroke was kept tight and wouldn't rattle.
Sorry no drawing concept here!
I may head down that road myself in a redo to get the large swivel ends of the cylinder away from the pivot point on the rod end now..
Is there a connection of RWS and your name may being AL?
I see a reference in a comic yesterday about Weird Al and his album by your name that I never heard of.
Bill
EDIT: No connection to Al that I know of….
"There are none so blind as those who will not see"
I was completely looking at this wrongly sir. It took me all of yesterday to understand that I was looking at the problem "180 degrees out of phase”….
I feel like a complete nincompoop….
When I saw your “Collers” solution,
in MY head, it appeared to be limiting the “retraction length”.
I was so focused on solving that problem, I was not even paying attention to the actual problem.
HOWEVER NOW, after many hours of banging my head against a wall, I see that those collers actaully limit the
extension to ~7 inchs, by taking up 1 inch of space.
So here is a short comedy for y’all.
All yesterday I was chasing a problem that did not exist. This is probably the reason I don’t post until I have finished a project….But now that “The cat is out of the bag” that I am not 100% perfect(

) lets move on…….
Oh I almost forgot…..a little Public Service Announcement.
For all y’all that have this little green shelving unit.
The maximum allowed amount of metal is "this much"

Now back to our regularly scheduled program.
So yesterday thought I needed to “plug” the other end.
so I turn a piece, threaded it, and (Luckily) I just tacked it into place.
And yes, to add insult to injury, ……"When it rains, it F’ing pours”…….I F’ing tacked it to the wrong end…...
So it took me a few minutes to "Un F— it” and get it on the correct end.
Now here is where I begin to understand that I am as “F’d up as a football bat"……..
No matter what I do, I can’t get the extension and retraction lengths to work out….No matter what combination I try, one length is always about an inch off???????
like this
I notice that my “wallered out hole” idea don’t mean “Jack Sh1t” ?????
I even went so far as to cut out a “nice test handle” on the CNC plasma machine…..
But NOPE!!!!!!! NO DICE!!!!!!!
I don’t recall why, or what happened, but it hit me like a “sack of hammers”….
I, quite literally said outloud, “ You F———g dumbass…….” as I realized what the problem really is/was.
I just need to make it so that the “EXTENSION” is 7 inchs, and to do this, all I need to do is make the one end “slide” about an inch, to account for the 8 inch stroke.
So Bill you “hit the nail, on the head”.
Bravo sir!!!!!

Bravo!!!!!!
Here it is at full retraction
and here she is at full extension
Note: the “homemade nut” I was going to weld in place, is now going to be a “sliding nut” inside the outer tube.
SO……..The plan for the day is to figure out a few things.
I need to address whether or not I need Bills “spring idea”?
(BTW a "valve spring” is an awesome idea that I might steal

)
OR
do I actually need it?
In my head, if I “cap the end", and have that nut just sliding inside the outer tube, it should lock up nicely at both extremes…..?????????
Have you thought about dirt in that area. Dirt, sliding fits, and slots like that usually don't end well. Maybe a bellows to keep critical areas clean and lubricated withoutattracting dirt. I use a simple collet block for holding rounds on a vice. My little R8 one was cheap and handy for smaller diameters as you already have the collets. the 6 sided block is great for making accurate hexes on a mill. Thanks for taking us along on your projects.
Yes sir, this has crossed my mind…..I was thinking/hoping that if I installed the whole assembly “up-side down” it would keep it clean…but now that you mention it, I am reconsidering my position…….
(BTW the reason I have it oriented this way is for pics, and so I don't have to constantly bend over to look at it when I manually extend and retract the arms)
Lastly, did/do you mean you use one of these to hold round pieces for milling?
