New Plasma Build

Bob, one of the other things I did after using it was to add an adjustment screw on the opposite side to the proximity sensor.



This let me adjust the mechanism so there was minimal movement on the slide before the float switch sensor tripped.

And my home made magnetic torch breakaway. MK II as the first idea failed.
Rounded dowels were machined using a ball turner on my manual lathe. Proximity sensor used as a sensor.


I think if I did it again, I'd be lazy and buy one of these snapncut.com/

That looks good!

Sorry guys I'm a bit late to the party. My floating head has about .25" of mechanical travel. The micro switch isn't adjustable leaving me with .09" of offset.

Rod

Nice looking magnetic break away. Mine is modeled after seanp's on Plasmaspiders design and works very well, I have posted photos showing it on other topics. I have a mechanical switch and it is very sensitive, a PITA sometimes but it really does save the bacon when hitting a tip up. When the switch finally dies I will replace it with a small prox switch like the HT one uses.

Just a quick refresher I used three about 12mm ball bearings for the locating features ( the old three points define a plane and on an equal lateral triangle so the sesitivity is the same from all directions) and the magnet is out of a hard drive to hold the parts together. The only points of contact are the three locating bearings ( glued to one side of the assembly).

John

Floating Z axis for plasma head.

Catching up...

An option for a floating Z might be leaf-spring suspension. A pair of leaves top and bottom should hold a torch in place repeatedly. No wear parts and nothing to get fouled by grit.
For extra fun you can strain-gauge the flexures as the sensing element.
This isn't entirely my idea, it's based on the Z-height adjusters of a set of machines I used to work on, used to set strikers sub-micron distances above chip wafers to mechanically test bonds .

I wonder if magnetic handbag clasps could be used for a break-away system? I bought some for a project and they do give the impression that they "want" to be used for this sort of task, if mounted in triples.

islander261 wrote: Sorry guys I'm a bit late to the party. My floating head has about .25" of mechanical travel. The micro switch isn't adjustable leaving me with .09" of offset.

Rod

Nice looking magnetic break away. Mine is modeled after seanp's on Plasmaspiders design and works very well, I have posted photos showing it on other topics. I have a mechanical switch and it is very sensitive, a PITA sometimes but it really does save the bacon when hitting a tip up. When the switch finally dies I will replace it with a small prox switch like the HT one uses.

Just a quick refresher I used three about 12mm ball bearings for the locating features ( the old three points define a plane and on an equal lateral triangle so the sesitivity is the same from all directions) and the magnet is out of a hard drive to hold the parts together. The only points of contact are the three locating bearings ( glued to one side of the assembly).

John

John . I have just come across this do you have a link to the photo's of it. How are the ball bearings mounted?

Thanks

The bearing balls are glued in with JB Weld on my version of this which is closer to Sean's Mk1 design.

www.plasmaspider.com/viewtopic.php?f=103...499&p=152510#p152510

www.plasmaspider.com/viewtopic.php?f=103...279&p=117983#p117983

John

I had to find a reason to use the ball turner I made so I machined the end of a dowel (which is glued in cos, I got the tolerances wrong for a press fit....

rodw wrote: I had to find a reason to use the ball turner I made so I machined the end of a dowel (which is glued in cos, I got the tolerances wrong for a press fit....

I have a small lathe Myford S7 this is the creature that got me in to linuxcnc so I should be able to make the dowel ends. If I can work out the code.