Putting on Bed/Carriage and Alisgnment

Hi, I'm building a Mendel90 from nophead's kid and have two issues I'd appreciate clarification on.

I'm on p39 of the current manual - Y Axis Assembly, specifically step 9 which says:

Quote
9. Slide the Y bars through the bar clamps and the carriage bearings. Tighten the clamps to grip the bars lightly but do not over-tighten them. Slide the carriage up and down to align the right hand bearing and bar clamps. Tighten the bearing first and then move it to each end and tighten the clamps.

So the current situation is that several bearings/clamps are screwed in loosely. Now the bed is mounted I need to tighten things. Trouble is, the allen key sockets to tighten the bearing are under the heat mat and can't be reached. At least not with any of the 3 allen keys of that size I have. I take it that it is the bearings on the underside of the carraige that are being referred to there?

Maybe I should unscrew the heat mat and tip it up (ribbon cable all clamped in now) and do the tightening.

Or have I confused myself?

The ribbon cable that attaches to the heat mat seems to be doing the correct snaking, but it is very close to the heat mat surface. I tried to make it a little further away, but if it goes from its solder point towards the centre of the mat (about 2cm), then loops back on itself; through the first clamp, immediatley through the second clamp then it seems had to give it much space.

When I had it all screwed up, I guess 0.5cm of the ribbon was touching. I've since pushed it away from the bed, bending the ribbon a little and its currenlty not touching. I'm wondering if there is a "best practice" photo anywhere. I can take a picture of mine perhaps too.

Thanks

If you don't have a short Allen key then yes you will need to take the bed off to tighten the right hand bearing. At this stage the left hand bearings should have already been tightened.

There is a picture of how the cable curls away from the bed here: [reprap.org]
It is easier to see on the Acrylic version of the machine.

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[www.hydraraptor.blogspot.com]

Thanks for that. I managed to find a low profile Allen key set for an entire £1 today, so i've managed to get in there.

My ribbon cable doesn't look too dissimilar that that picture linked - although it is a bit less symmetrical due to my poor soldering. I took a picture of mine:
[imgur.com]
[imgur.com]

I have another question if I may. It seems to me that my ribbon cable is too short (or my red plastic too long). The picture below has the red strip uncut - its about 300mm and needs to be 271mm. I think I'd need to take at least an extra 15mm off it to have it terminate at the clamp. Is there any harm in doing this?
[imgur.com]

Thanks

Clamp the ribbon cable and red strip down and then slide your bed all the way forward to ensure the ribbon cable and red strip are long enough. If they are you should be good to go. The thing you need to make sure of is that the ribbon clamp doesn't restrict the movement of the bed.

Clamp the ribbon as close to the end as you can and slide the strip as far as you can when the bed is in the mid position and then trim it to clear the connections.

The lengths aren't critical but it looks like you used a bit more for the connections at each end than I do.

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[www.hydraraptor.blogspot.com]

Thanks all done - motion looks good so far.