20 Dec Continuing Machine Modifications
The machine has been a bit more finicky than anticipated and we have had to integrate modifications in a “trial and error way” to eliminate the problems.
We are experiencing problems with “chain skip” and “roll under” and this has kept the machine down for an extended period of time.
This has been using a bottom chain feed setup.
It was after the machine initially appeared to be working ok that we then began to experience problems. We are guessing that something environmentally had changed that caused the problems (dust/dirt on the chain, the magnification of a slight chain misalignment, etc.).
Chain Skip
Chain Skip Example from Maslow forums
After looking online, it appeared that the lack of continuous tension might be the root cause of the problem. There didn’t seem to be enough tension on the tension side and the chain would (for lack of a better description) roll up and “over” the sprocket and this would allow the chain to skip one link. Thus, effectively taking the machine completely out of calibration. This was when the sprocket was feeding chain length to the sled side. Another problem that never manifested, but we thought was a possibility, was the chain coming off of the sprocket altogether (see below), so it was imperative to eliminate the chain problems completely.
Chain Roll Up
Chain wrap example from the Maslow forums
Then, when feeding chain to the tension side, the chain would catch on the sprocket and would begin rolling onto the sprocket…if left for too long, we are assuming that the chain would eventually fall away from the sprocket and destroy the chain and the sled/router (we are still in process of creating a safety harness for the sled and we will cover this in an upcoming post).
There are a lot of elegant fixes that we weren’t really able to affect, so came up with our own with the materials that were on-hand.
We utilized a system that we found online (modified slightly) to place continuous tension on the tension side of the chain. This involved removing the initial system that came with the Maslow and placing a rearranged middle bushing area and additional arms/pulleys strategically to run weights behind the work surface. We opted not to place the weights directly under the motors due to lateral deflection of the chain taking it out of the plane of the chain movement. The weights are 1 gallon milk jugs. The milk jugs are nice because water can be added/removed to achieve the optimal weight based on what is felt to be appropriate. The only bad thing is we now can’t store additional large sheets on the back of the frame…the milk jugs are in the way. Hooks have been placed on the top of the back side of the frame, for the milk jugs, to take tension off of the system when not in use.
The new center bushing placement was a bit worrisome when we were doing the modifications. The alignment of the rope from the chain to the weights (on both sides of the center bushings) was slightly out of alignment, so a “shoulder” was added on the chain side and a “top cover” was added. This was done to (hopefully) eliminate the possibility of the rope rolling off the bushings.
We did the chain feed modifications and performed a full re-calibration of the machine. The calibration appears to be pretty good, but we will continue to get this dialed in better as time goes on. Afterward, we did some testing for a “house number” placard project. The machine has been running good since the mods. We are still keeping a close eye on the machine after the modifications (and will continue to do so) just to make sure there aren’t any mishaps.
Below are some pics of the modifications currently in place: