Y-Axis Limit Switch Not Hitting

It seems that the Y-Axis limit switch isn't being tripped by the Mendel90 on my build. If I manually push the bed into it, it does trip, but it takes a tiny bit of pressure. I'm just doing calibration and pressed Y Home for the first time - the switch didn't get pushed and the bed pushed up against the end of the rails for a few seconds.

I'm guessing the angle I put the screws into the limit switch was a bit off, so it is sat too far back by a tiny bit. To the eye it actually looks ok, but I guess it must be a bit out.

Am I ok to just shim the button? I could stick a tiny bit of plastic either to the button or the bearing that has to hit it and I suspect it will be fine. Perhaps this is a really obvious question, but I'm not 100% sure about the purpose of the limit switches. I guess the firmware "knows" how long the rods are, so once each axis has been homed, it know how far it is safe to use the motors. Presumably as long as there is 1mm tolerance built in to this, a 1mm shim on the switch will be fine?

Thanks

Did you check to make sure the tab on the bearing mounts is facing the correct way? (page 30 item #2) I would guess this is the problem. If it is facing the correct way you could try to unscrew and rescrew the switch in correctly. You should also make sure the switch is oreintated correctly. (Page 38 Picture & #3)

The limit switch needs to be hit in order to home the axis. As long as the bed can hit the switch you should be fine, being a couple mm off center of the bed won't make much difference unless you use the entire print bed for a print which is rare.

Thanks

I rescrewed the switch (had overlooked how easy to was to access actually) - seems to work better now but will keep a close eye on it. It was orientated correctly and the tabon the bearing was correct too.

Perhaps post a picture. The axis should be able to move 1mm past the switch so I can't imagine how it doesn't work.

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[www.hydraraptor.blogspot.com]

Notwithstanding my enthusiasm, I am never surprised when I manage to mess-up the un-mess-upable!

I've attached a pic showing the orientation of the switch and the tabbed bearing holder.

I've also made a short video showing the homing of the axies:
[www.youtube.com]

Thanks!

It doesn't sound normal and it should take the same force as X.

Does the axis hit anything other than the switch?

When you press on the switch itself does it feel any different to X?

Is that rust on the Y bar?

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[www.hydraraptor.blogspot.com]

It seems like the right hand bearing mount touches the right hand rod clamp as the left hand bearing mount hits the switch. Thus a little extra pressure is needed to actually engage the switch.

Pressing the switch feels the same. No rust on the bars - that is grease from the linear bearings. The rods were well degreased with meths before construction.

Thanks for the help!

I assume you mean "It seems like the left hand bearing mount touches the left hand rod clamp as the right hand bearing mount hits the switch. " looking from the front?

Odd there should be 1mm clearance. You could try loosening the screws on the front bar clamps and sliding the left one as far forwards as it will go and the right one as far back as it will go before tightening. The screw holes will have about 0.25mm clearance so you can make 0.5mm difference that way.

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[www.hydraraptor.blogspot.com]

Thanks, I loosed the clamps as you suggested and now it works great

Your X-belt is wrongly installed on tensioner side - it should go through bottom hole over the tensioner to the top clamp.