I’ve been working on a pair of adjustable, demountable motor brackets. I’m about to mount them on the frame but, remember a thread on here a couple of weeks back that mentioned a new chain take-up arrangement running along the top bar of the new frame design. I’m keen, while at this stage, to incorporate this new innovation, but can’t fathom out how to do it effectively. Would it be possible for someone working on the new chain arrangement to give me a hint as to how to achieve it, or some of the preliminary ideas. I’ve so far only managed to think of an idea where the two slack chain ends are attached by spring or elastic horizontally along the top bar.
Any help most gratefully appreciated.
This?
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Thanks Tom, that’s kind of what I’d come up with but didn’t want to set it up without knowledge that the clever techies had worked their magic with GC to enable the ‘chain over cog’ as per this new arrangement.
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Think you just set a negative value in GC on the length between motors to invert them…
If you use a plastic channel to have the chain inside… like this one…
2 channels going over the length of the top bar(if needed)… hiding the chain and the stretchy string…
Using the nylon chain guide to guide the chain into the channel.or something like this…
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The latest version of GC and firmware include the abilityto run the chain the
other direction.
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It lookslikethings work reasonably well without any channel needed. I think we
should look at using eights to replace the stretchy string (the string is
providing the least amount of force when the most force is needed and the most
amount of force when the tension on the chain is the least and gear backlash
could come into play)
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Where is that setting? invert motors
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I’ve seen it talked about as chain above or below the sprocket, or chain to the
left/right of the sprocket. It was mentioned in this week’s update.
There’s some here:
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Okay, so I’m at the calibration stage with the new motor mounts.
I’m all up-to-date software wise.
How does one measure chains and machine size when selecting ‘BOTTOM’? Is it a question of some over-and-under action, or does one merely calibrate as before and swap around at the last minute?
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That’s what I did. Rather, since I had already been through the motor measurement and test cuts, I:
- changed to ‘Bottom’,
- did the obligatory quit/restart of GC to trigger the needed restart of the Arduino,
- re-rigged to the ‘Top’ layout and
- did the chain calibration.
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I’m working on re-writing the calibration process to allow for it, but until I get that done (hopefully in 1.07) we’re stuck doing what you guys just described.
On a side note I love how you mounted your brackets upside down. 
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That is a very good arrangement, both very solid and adjustable.
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I’m glad that you’ve not noticed the reversed expanding drywall anchor bolts I’ve used to hold the motors to the wood. It’s all I had at whatever it was past midnight! But, does the job just perfectly ;¬)
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