SDS MK4 swerve wheel tread jigs

Triple Helix designed and fabricated a set of drilling jigs to prepare replacement strips of treads for the Swerve Drive Specialties MK4 and MK4i swerve module. These jigs reproduce the hole spacing for black neoprene and blue nitrile tread material shared by SDS’s Patrick Woolfenden here; treads prepared using these tools install tightly on the nominal 4″ diameter x 1.5″ wide MK4 swerve wheel. Triple Helix used our 130W laser cutter to cut the components of the tread tools from 1/4″ Delrin sheet.

Onshape document

Assembly instructions:

  • Laser cut the top and bottom plates from 1/4″ sheet.
  • Laser cut the spacer plate(s) to match the thickness of the tread material.
  • Drill and tap the holes around the perimeter of the bottom plate to 8-32.
  • Drill the corresponding holes on the other 2 plates to provide clearance for an 8-32 fastener.
  • Install drill bushings (McMaster 96511A666) into the top plate such that they are flush with the lower surface.
  • Assemble the drill jig with SHCS 8-32 x 5/8″ LG fasteners.

Converting Festo’s flow rate spec to Cv

Festo gives the flow rate through their solenoid valves in terms of “standard nominal flow rate”. What does this mean? How does it compare with other valves on the market?

Here’s a spreadsheet that converts the specified flow rate (which is actually a mass flow rate even though it’s in units of volume/time) into a flow coefficient or Cv. This lets you directly compare the size of the valve to other vendors’ stuff.

Spreadsheet

Chief Delphi discussion

2363 builds a drivetrain

When we recruit new students, one of our favorite lines is, “Nobody who joins the team knows how to build a robot. We’ll teach you.” As an established team, we go to competitions and see younger teams, some of whom don’t have engineering mentors, struggling to learn lessons we have learned the hard way. We see our role in growing FRC as helping those struggling teams become better more quickly, so they remain inspired, and don’t fold.

Last fall our students came up with the idea of producing a series of instructional videos. These would teach our incoming rookies the skills they would need to be productive robot builders. We see this video series, and the ones which will follow, as a tool which can help educate inexperienced students on our own team as well as other teams across FRC.

Video series

Chief Delphi post

Making a Triple Helix style climbing rope

During the quarter-finals of our last competition, our Pilot looked out over the field and noted that 3 of the teams of the field were using our climbing ropes, one of which was on the opposing alliance. After seeing so many posts about ropes failing in competition, 2363 has decided to share our method for making ropes with the FRC community.

Instructional video

Chief Delphi post