Measuring the Top Bar & Chains

I’m looking for suggestions & comments on the proper way to measure the top bar and chains so it can be documented in a wiki. I’m interested in this manual measurement since these are parameters that are entered into the Maslow Settings (Distance between motors) and Advanced Settings (Chain Length). Please forgive me, and let me know, if this has been captured somewhere. I know this sounds a bit trivial; please bear with me :slight_smile:

Top Bar Measurement
I think this is relatively straightforward, however we want to make sure the tape measure is not sagging. Just a little bit of sag makes a relatively big difference in the actual measurement. To reduce sag, like others have done, I duct taped the tape measure to the top bar every couple of feet, making sure it is straight along the top bar.

The dimension we want to measure is the center to center of each motor shaft. To make the measuring easier, I hooked the tape to the outside edge of the motor mount. Since we know the motor shaft center is 20 mm from the edge, subtract that from the total measurement.

Chain Measurement
I’m not so sure of the distance we want to measure here. Does it really matter to try to be so precise with the manual measurement since the maslow will measure the chain as part of the calibration process? I have a ~12’ top bar and was given a 25’ chain. I split the chain in half and have been entering 3810 mm for chain lengths. However, after measuring, it turns out my chain was a little longer than 25’ since my chains are measuring closer to 3828 mm for both. Does this difference matter to the calibration (entering 3810 vs 3828)?

I forgot to get a picture of the start of the tape measure but it is starting at the very tip of the link. I did the best I could to make the chain straight along the tape measure and used a pencil to pull and straighten the links, while holding one end with a weight, all the way down the length of the chain, then set the tape.


Thank you @WoodCutter4 for this neat contribution and pictures :slight_smile:
I agree with you the exact length of chains is not important as long as is long enough to avoid hiting the end during operation.

What is important about chain length is the resulting length beween 12O’clock position and the sled. And that needs calibration to reveal the specific and unique chain properties of the chains making each MaslowCNC.