How To: Manually Reset Chains, the Easy Way

[madgrizzle]

Every now and then you may find that you need to readjust the chains back to a known position. This could occur if you power/connection issue and the controller lost it’s position, had a chain skip, took apart something for some reason, etc… Fortunately, there’s a way to reset the chains without a lot of work.

During calibration, after you set the sprockets vertical, you extend the chains out to reconnect to the sled. If your “Extend Chain Distance” is a multiple of a full revolution of the sprocket (i.e., 63.5 mm for a stock sprocket), both sprockets should end up with the same tooth back at vertical. Note: see @dlang’s comment below. Take a permanent marker and mark on the link that is sitting on top of the vertical tooth of each sprocket. I’ve heard some people have used nail polish, but so far a permanent marker has remained permanent enough for me.

If Using Ground Control

When you find yourself in a situation where you have to reset your chains, set both sprockets vertical using "Actions->Set Chain Lengths - Automatic" but **DO NOT** press "Set Zero" .. instead press "Quit". You'll get a message about quitting calibration early and then be brought back to the Actions menu. Now, re-place the marked links of each chain back to the top teeth of the sprockets. If all is well, the sled will be in the same position as it was had you actually gone through the adjust chain process. Lastly, press "Actions->Advanced->Set Chain Lengths - Manual". This will send a code to the controller to tell it that the chains have been extended. Voila.. chains reset.. the easy way.

If Using WebControl

Set both sprockets vertical using "Actions->Set Sprockets Vertical" (It's in the Calibration/Setup group). Once both sprockets are set vertical, re-place the marked links of each chain back on the top teeth of the sprockets. If all is well, the sled will be in the same position as it was had you actually gone through the adjust chain process. Press "Manually Set Chains At XXXX mm" (XXXX will be whatever Extend Chain Distance is in your settings). Voila, chains reset.. the easy way.

[dlang]

it doesn’t matter which tooth is at 12 o’clock, so you don’t need to mark the
sprocket, just make one of them straight up and put the marked link of the chain
on the tooth and set the distances.

David Lang

[WoodCutter4]

@dlang

it doesn’t matter which tooth is at 12 o’clock

As long as you press “set zero”, right? If you use a different tooth and you don’t zero it, doesn’t the software think it’s in a different position?

[madgrizzle]

No, you don’t need to press “Set Zero” in either case. Without getting into too much technical details, pressing “Set Zero” sends a command to the controller to set its position based upon the chain lengths being 0 mm. When you press “Set Chain Lengths - Manual” button, it sends a command to tell the controller to set the position based upon the chain lengths being equal to the “Extend Chain Distance” (e.g., 1651mm, 2032mm, etc). Basically, there’s no need to tell the controller that the chain lengths are zero and then immediately tell the controller they are something else… if you follow.

[Metalmaslow]

This seems very easy. So easy that it should be part or the kit to begin with. Chains marked exactly where they need to be and a unistrut or similar top beam shipped with the kit with pre drilled motor brackets. That way the motor spacing is exactly the same on every kit. In theory calibration could be skipped. People would just put the marked chains on the 12 o clock sprockets enter in the details and be ready to cut.

[dlang]

where you would want to mark the chains depends on your machine size. you then
have to worry about starting from the right end of the chain.

The motor spacing depends on the length of the top beam, and where the mount is
mounted on the beam.

you would have to ship the top beam, which would be very expensive.

David Lang

[Metalmaslow]

It would only cost about $15 to ship a top beam if broken into 2 or 3 part in the USA. Some people spend hrs calibrating the machine and would gladly pay that for the convenience IMHO.
putting a zip tie on the “start” of the chain would be easy to mark correct end. Nail polish could be used to mark the chain length. Maybe it’s not practical, but I think the idea has potential. I hate to see people struggle with the setup, it can be very frustrating.

[dlang]

I would be very interested in how you can ship a top beam for only $15

and how would you make a top beam that breaks down that reassembles with sub-mm
accuracy in it’s length and no flex

If this can be done, it would raise the cost of the kit, but make it much easier
to get started.

David Lang

[Metalmaslow]

Many metal suppliers have CNC saws that will cut bulk orders exactly the same. A tube inside of a tube connection (telescoping) is generally very Stiff
1.5” square steel tube perhaps
And getting cheap shipping prices is just a matter of volume the more you ship the bigger discount you achieve

[Metalmaslow]

I put some request for quotes out for laser tube cutting. Only got one quote back and it was $8 to cut a tube 6’ long with 4 holes in the end plus metal cost and shipping cost. . Not sure of repeat ability. Hoping for 10 thousandths or less.

[WoodCutter4]

That video was very satisfying to watch. Beautiful controls! Amazing!

[Jatt]

Would someone with the standard chains that have marked their chains be so kind as to count how many links from the end that is attached to the sled to the marked chain? This way people should be able to always get the correct number of links to do if their marks wear off without having to go through calibration again.

[madgrizzle]

It depends on a number of factors, but if you are using standard chains and the ‘Extend Chain Length’ in settings is the default 1651 mm, then simply divide the chain pitch (6.35 mm per link) into that distance to get the number of links… 1651 mm / 6.35 mm per link = 260 links. Someone with a bigger top beam, like a 12-foot beam, would need a bigger ‘Extend Chain Length’ and therefore have a different number of links.

[emilecantin]

I’ve tried to explain it before but nobody understood, so I went ahead and did it:

1. I centered my Maslow
2. Then I marked a random link and where it sits on the sprocket, like so:
   
   

If I need to remove or re-set the chains for some reason, I can just:

1. Center my Maslow
2. Put the painted link onto the painted tooth, so it matches the above picture

Much simpler than everything else that’s discussed here, so I must be missing something. What wouldn’t work with such an approach?

[madgrizzle]

If you lose connection/power the Arduino controller won’t know the position of the chains and after a reset of chains, you have to tell the controller how much chain has been extended. There’s a built in function to do that for 0 mm and the extend chain length… but not an arbitrary value… though I think you can send a gcode to do it.