Quote:
Originally Posted by Alan Walker PE
This is my fourth year in FRC as a mentor and my first post to Chief Delphi. My team started using bike chains last year. Why shouldn't we be using master links?
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The most recent thread to cover this ground is
Chain vs Belts?
The bottom line on master links is that they are the weak point in a chain. Even when they are mechanically as strong, they are a bit wider or thicker, and are more likely to get struck or snagged on other items. Shock forces seem to occasionally disassemble them.
In lieu of master links, we now use a tool which can build the chain in a seamless loop.
For #25, the
Dark Soul Chain Tool is the only one I've found. I recommend getting some extra pins; one of our students broke the extractor pin while learning to use it (most likely improper alignment).
For #35, we use
this tool.
Similar tools are available for larger size chain, as well.
These tools can be used to assemble chain "in place" if the run is long enough and there is enough access space, or to assemble the loop on the bench (preferred when you can). The #35 tool shown includes a holder to help "in-place" assembly.
Note that the Dark Soul tool is sized for "regular duty" #25 chain. With a bit extra torque on removal of the first pin or two, you can expand it to work on "heavy duty" chain, but once you do, you will not be able to use it easily on regular duty again (it will be too easy to push pins completely clear of the far plate).
Edit: Responding to Cothron's comments below: There are teams which use #40 bicycle chain. (Example: 364, Team Fusion of Gulfport, MS). While #40 bicycle chain and plate sprockets are easier to source locally than #25 and #35 (at least here in Slidell), interfacing these sprockets to FRC wheels and gearbox shafts requires machining precision that is beyond many teams, and often not worth the extra time for those who do have the capabilities.
Edit2: Another thing we do early in the build, though usually week 2 or 3, is the "design presentation". In the early weeks, most of the build chains spend at least a few days waiting on parts to arrive. At the point when we think this is at a maximum, we stand down for an hour or more to recalibrate the team. As technical director, I prepare the top level brief describing key game rules, our game & design strategy, and our design,to the level it has been determined. For items still working with a couple of options, we brief everything still on the table. We encourage questions to be asked as they arise, rather than waiting for a "questions window", to reduce the chance that questions will be forgotten. While I organize, I get the sub-teams to present the briefs when they are comfortable doing so, and to answer all but the simplest questions. The main point is to bring the team's understanding of what we're doing together. To do this, they need good gouge*.
*Good gouge is a US Navy term for "information and/or advice straight from the real experts (that is, those with real world experience) which has not been 'normalized' into what leadership thinks it ought to be". In the interest of full disclosure, I was never IN the Navy, but have worked as a federal employee FOR the Navy for over 28 years. If an actual sailor wants to tweak or replace my definition of good gouge, please do so!