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Very timely post. My limit switch came unglued Saturday and I ruined 2 switches trying to glue them back on.
The glue ran down and glued the little swicthie thingie. I didnāt learn on the first one and did it twice. Not to mention I almost glued my fingers together. Finally got one on but it doesnāt feel very secure. Gotta get some more switches.
I agree with you about the screws and tapping those tiny holes may prove difficult; though this was what I was contemplating. Will keep an eye on this thread and also see if I can come up with something (although as you can tell from my troubles with gluing, I may not be too bright)
I racked my brain trying to figure out this same thing.
I think the issue with it on the side is that your spindle mount has to be wide enough to trigger it or you have to add something for a trigger.
The linear Z that we both have has an inset on the front so it makes it difficult to mount there and be semi-compatible with other Z axis.
Iād be worried with a clamp that it would come loose during carving or that the switch would slide out. Maybe if you add a 2mm ādowelā to the clamp so that it fits into the switch mounting hole to better secure the switch. Those switches are small and Iād be worried you couldnāt get enough clamping force to keep it secure.
I ended up drilling and tapping 2 M3 holes on the front inset and screwing in the switch. The switches from Amazon allow for a 3mm hole to be drilled in them and not affect the switch operation. On the front, if the spindle mount didnāt go up enough, I was going to drill and tap a hole for a threaded rod/bolt to go in and give the necessary vertical adjustment.
I quickly came up with this. (Crude drawing and not to scale) The 2 hole side would go on the back of the back plate where I already have the support you (Phil) came up with screwed on. The switch would go where you have it in your design being held by a screw. Probably another pc. of aluminum or sheet metal between the screw and switch. also might have to bend the piece that triggers the switch some so it triggers before z runs out of travel.
I would think you want the switch in a shallow pocket. So it stays straight. maybe a small roll pins too to lock it this way you donāt need to pinch it so hard.
Straight isnāt a major concern. Stability is more of a concern. These switches arenāt about absolute accuracy (you donāt need it). They are all about being in the same place every time. This system needs good relative accuracy but not absolute accuracy considering the reference point is adjustable.
The purpose of home switches is to have a reliable and repeatable known location, wherever that may be. Even the X and Y are set based on a ballpark position and not an absolute.
then how about a solution that uses post that the switch inserts onto and a catch that snaps it into place. you know it would not take much force to stabilize the switch and it would be easy to replace.
Not good with 3D design but I believe that someone that is could make the design easy enough.
Under normal circumstances, this is true. Unless you use G92, your Z should be persistent.
I can think of a few exceptions:
bit shifted inside collet (collet nut not tight)
router shifted inside mount (mount not tight)
workpiece shifted up (possible with side clamping e.g. cam style)
X axis tilted up about the side plates (possible in a Z crash)
.5" is hard to imagine though. It would make me suspicious of lost steps.
EDIT:
Which reminded me of this.
This was a very weird situation. I once experimented with 2:1 gearing and 1:1 ustepping on the Z (as opposed to 1:1 gearing and 1:2 ustepping) and experienced consistently lost steps that were consistently affected based on acceleration and junction deviation values.
Thatās the problem. G92 is not persistent, when you hit the abort button itās gone. You could modify your macro to use G10 and that would be persistent across an abort or soft reset or power cycle.
Embed a neodinium magnet in the z axis , then make a bracket that hold the switch with another magnet that way if there is a crash it will just knock it off ā¦
Finally got one on but it doesnāt feel very secure. Gotta get some more switches.
