Can you add limit switches to a one finite.
I believe other have but not sure why you would. The ones that have I believe are using a different Controller but I know the Controller can support it as well.
Just recently there was a thread where someone was hooking up limit switches to the OEM controller. Haven’t yet seen the pics he said he would post. I run an aftermarket controller and don’t use them. I personally like the very clean & simple wiring afforded by not having them. Homing is a bit more involved than just hitting the home sequence button, but it’s not bad.
The problem with limit switches, or at least the smile reed style switches is sawdust and wood chips don’t play nice with them. If I was going to do it I would use a magnetic switch. I think the idea behind stall homing is that just less parts to go wrong.
I just don’t like the stall homing. Isn’t a bit hard on the motors
Not really. During homing, the motors are cut off when they reach a certain current spike from stalling. Nothing that the stepper motor isn’t designed to easily handle without damage.
I deal with steppers and servos at work. They all use home flags vs the stall homing. It’s a little rare but the home sensor does fail. When it does the driver just keeps driving the motor (which can’t turn) making a horrible noise. Because the tools don’t monitor the current they have a time delay of about 30 seconds before the driver shuts off. I can’t remember changing out a bad servo motor in the last 20+ years.
The only real issue is that stall homing isn’t as accurate. But that’s not an issue since the zero is what counts and it’s not tied to the home, but to the where the work piece is located.
The only thing I’ve seen regarding stall homing that I don’t care for is that the homing takes place when the linear bearings meets the support blocks. The probability is high that swarf & buildup on the rails becomes part of the dimensional stack-up (and probably not identical on both sides) when homing. Additionally, the linear bearings are mounted in a thru hole and not into a shouldered hole, meaning they can potentially loosen up & lose their original location after being bumped home so many times. Either way, swarf or loose bearing, you’re forcing the machine to home in a non-square orientation. This is why I strongly advocate for installing hard stops for homing. Once installed, these spacers touch the X & Y bearing blocks and not the bearing, and allow for about a millimeter of swarf being pushed by the linear bearings without affecting homing accuracy or repeatability.
I know I’ve seen a post about adding these spacers, but can’t seem to find it. Can you point me to it?
Thanks for easing my concerns I will be placing my order soon. Now to figure out which machine Woodworker or Journeymen?
I couldn’t find the post I made here on it (not certain I actually did), but here’s a link to the Facebook group post:
Thanks Bill! This looks like the picture I remembered so it may have been on Facebook instead of the forum. I thought I had saved the link but couldn’t find it.
Hey Mr. Blades could you show me how this works? Do you lose 1" of machine travel when using these?
No sir, since the bearing sticks out .750 and these are .787 (20mm) long, you only lose .037" (about 1mm) travel. The machine bumps these for home instead of the bearing. Unfortunately this pic is all I’ve got at the moment… my machine is disassembled & packed for the move to AZ.
@Techrise, I should clarify that the hard stops hit the bearing housing block, not the bearing.
Found the Facebook thread! One question, did you add these to both the y and x axis? What about z?
Carroll, added them to both X and Y. Z didn’t lend itself to using these. And X, like Z, both utilize single point homing so there’s nothing to get out of square when these 2 axis home. Y is the critical usage point. And honestly, the only reason I put one on X is because there’s 5 in a pack.
How much does that improve accuracy vs limit switches?
So you take off a nut from the bolt and then install this coupler in its place?
How many did you put on? 1 on the homing end of X and each Y, or more?
Correct, 1 on X and 2 on Y