Wednesday, December 31, 2014

ShapeOko 2 Build: Part 1

I've been watching the ShapeOko2 from Inventables for the last year. I've been interested in DIY CNC for the last several years, but the time wasn't right to jump in. When their kit went on sale for "small business Saturday" I decided the time to order the kit had arrived. I decided to spring for "the works" kit which includes the Quiet Cut spindle and a bunch of other upgrades.

The kit was very complete, down to including all the tools you'd need for mechanical assembly, and well packed. The basic instructions on their website were also very good. However, I was a bit underwhelmed with the documentation included for the extras in "the works" kit. The inventables website did have a page: ShapeOko 2 "The Works" kit instructions- not really instructions, but has at least a few more details.

So far, I have the mechanical assembly complete, and have started to wire up the system. The first challenge was to attach the drag chains / cable chains included in the expanded kit. Mounting brackets were not included. The Shapeoko2 wiki did reference these 3D printable drag chain mounts, they look nice but they don't fit the drag chains included in the shapeoko2 "the works" kit. I ended up designing a set of brackets (files posted here on thingiverse) since I couldn't find any ones on Thingiverse that seemed to do what I'd like.

A few of the brackets I designed, ready for trial mounting. (these were old versions, I ended up not using them)

X-axis carriage with drag chain mount. Wires not yet routed through chain

Outboard X-axis drag chain mount installed, again wires not yet routed through chain

It's getting closer to running....

As soon as I have the steppers all wired I'll start in on the Quiet Cut spindle. There are a few different sets of installation instructions- I have yet to choose one to follow:

Quiet Cut Spindle installation instructions:

Quiet Cut Spindle w/TinyG electronics instructions:

Tuesday, December 2, 2014

45Nrth Vanhelga tubeless setup with Marge Lites

It was time for some new, more aggressive tires for the fatbike. The Husker Du's I have are great on dirt and hard pack snow, but in looser conditions they really struggle. I'm planning on putting them back on next spring. 

45Nrth has a new tubeless ready tire called the Vanhelga that has been getting great reviews- I decided to give it a try. It seems to be the widest, most aggressive tire I can fit in my old school 170mm 9:zero:7. New snowbike tires are not for the faint of heart-  they certainly lighten the wallet. I've never paid this much per tire for even car tires!

Apply for a loan before you bring these to the counter
I decided to go with the more expensive 120TPI version- even with the additional cost, it's probably the cheapest way to knock some serious weight off of a fatbike.

As soon as I got home I tossed the tires on the scale:

120TPI 45Nrth Vanhelga: 1279g & 1298g each

Amazing that this aggressive of a tire is as light as it is.

Motorcross or Snowbike Tire?

"old" tires: 45Nrth Husker Du, 60TPI
As I took parts off the bike in preparation for changing out the tires (and attempting a tubeless conversion) I put everything on the gram scale.

Old Front Wheel setup: 3380g (all up inc. tire, tube, etc)

Bare Front Wheel: 1345g

  • MargeLite rim
  • 907 135mm hub
  • 160mm rotor
  • spokes, etc

Surly rimstrip: 60g
Bontrager 26x2.50-2.80 Tube: 280g

45Nrth Husker Du, 60TPI: 1650g

I'm going to attempt a tubeless conversion, but not the full "ghetto" tubeless conversion with split inner tubes, sill foam, etc. I'm going to first just try a solid rim tape setup and go from there.

Supplies, ready to go


  • 3M 8898 Tape, 72mm width
  • Reflective Tape, cut down to ~43mm width
  • Stan's valve stems
  • Stan's sealant
  • Tires

1) remove tire, tube & rimstrip
2) true wheel
3) clean rim with rubbing alcohol
4) Cut down reflective tape & wrap around rim, securing at one end with small piece of tape, then stick to itself
5) apply 3M 8898, try to keep centered
6) carefully stick tape down to bead seat area of rim

Tire & rim strip removed, rim cleaned, truing it up. 
Starting to wrap inner layer of reflective tape- sticky side "out", reflective side in (to show through rim cut-outs)
Full wrap of reflective tape
Getting the 72mm wide 3M 8898 wrapped down tightly was tough- it's nice and tight over bead seat area but not in the center.

1384g after reflective rim strip & 72mm 3M 8898

That's one beefy tread pattern
It looked good and I had high hopes for an easy tubeless setup, but no luck. I couldn't get the bead to seat even using the tie down strap method, with valve core removed and an air compressor. I tried putting a tube in, seating the beads, popping one bead, removing the tube, and trying again- but no luck. There is just too much room between the tire bead and the center of the rim. I think it'd work fine using the sill foam tape trick, but that'll be for another day.

So, I gave up tubeless for now- re-installed tube. Even with a tube there was substantial weight savings from the new tire:
2920g Front wheel, new rim strips, tube & new tire = 460g savings from the front wheel alone

I repeated the process with the rear tire, minus the tubeless attempt.

Old Rear Tire on wheel: 3920g (all up, tire, tube, etc)

Bare rear wheel: 1897g (no rimstrip)

  • MargeLite
  • 907 170mm hub
  • 160mm rotor
  • Cassette w/ 42T Giant Cog
  • spokes, etc
Bare rear wheel with 72mm 3M 8898 & reflective tape: 1962g
rear wheel with Vanhelga, Tube: 3470g = 450g savings

So, just changing out tires and rim strips to the new 120TPI Vanhelga's yields 910g weight savings, just a hair over 2 pounds. Pretty amazing, especially considering the new tires are both wider and have much, much more aggressive tread patterns.

Still plenty of chain clearance with a 1x10 setup. A 2x10 might be pretty tight. 

A short ride around a frozen lake with 2-4" of snow shows the new tires function much better in loose snow- they tracked and gripped with authority. I'm hoping to ride some snow-covered singletrack this weekend!

I'm also going to search through Menard's and try to find some self adhesive foam tape for the tubeless conversion.