Clean Room Build

I did a clean room build of the eShapeOko (using the spindle mounts from my ShapeOko, because ours haven’t arrived yet). The bad news is that I found several problems. The good news is that I got a working machine in the end, and it’s very nice. All problems are fixable, and they won’t delay the kits more than a few days. Here’s a list. The asterisks mark what we will do for the kits already ordered:

  • BOM error: a belt tensioner (ES-LBT) is missing from the dual-Y upgrade BOM.  Fix*: add a belt tensioner.
  • Model error leading to assembly problem: the screws for the X motor are too long. Temporary fix: added some washers.  Permanent fix*: supply M3 x 6 mm screws instead of 8 mm.
  • Model error leading to assembly problem: the spacers for the Y motors are too short.  Longer spacers allow motors with shafts shorter than 20 mm to work on Y, and make the assembly easier.  Temporary fix: added three 1.58 mm (1/16″) nylon washers on each screw.  Permanent fix*: replace 19.05 mm (3/4″) nylon spacers with 23.81 mm (15/16″) spacers.
  • Model error leading to assembly problem: the screws for the Z motor are too long.  The next shortest screw available is too short.  Fix*: two 1.58 mm (1/16″) nylon washers on each screw.  This was a problem with my ShapeOko kit too, but it’s more pronounced with the eShapeOko because our Z motor mount is slightly thinner.
  • Laser cutting error: the central hole in the Z motor mount plate is ever so slightly too small — should have been 22.00 mm minimum, it is actually 21.96 mm.  The bearings are 21.98 mm diameter, so they don’t fit.  Temporary fix*: enlarged the hole slightly.  Permanent fix: change the drawings to call for a larger hole, because the tolerances specified were ignored by the fabricator.
  • Laser cutting error: some of the 7.14 mm holes for the eccentric spacers are slightly oval, measuring about 7.14 x 7.11 mm.  The diameter of the eccentric spacers varies a little too: some fit (barely), some don’t.  Temporary fix*: reamed all eccentric spacer holes to the proper diameter (9/32″).  Permanent fix: change the drawings to call for a slightly larger hole.
  • Part design and quality problem: the belt clamps aren’t very good.  They are soft, hard to tighten well, and unless tightened very well, they slip.  Zip ties work better and are easier to fit.  Fix*: use zip ties instead of belt clamps.  A toothed belt clip would be ideal, but they are very expensive off the shelf.  We’re looking for a way to make a cheap one.
  • Assembly difficulty: the Z leadscrew wobbles if the locking washer is used.  Fix*: discard the locking washer; tighten the nuts directly against the inner ring of the Z bearing.  No wobble!

As you can see, there’s some reaming and minor Dremeling to do, and new screws and spacers (and zip ties) to order.  It’s very likely that everything will be here this week, so that we can pack the kits over the weekend and ship them out on Monday.

The good things: except for the missing belt tensioner, the BOM was otherwise accurate; every single washer found its place, and nothing was missing. The machine looks good, works well and seems sturdy.  It’s not terribly difficult to assemble and adjust.  The belt tensioners are sweet.  Everyone ordered the dual Y drive; the next largest source of unwanted movement is the X V-wheels, where the dual X rail will help (I have yet to do a clean room build for the dual X option).  The Z axis is very solid, and the good quality allthread helps a lot.

Complete tool list:

  • 4 mm Allen key (for the M5 screws)
  • 2.5 mm Allen key (for the M3 screws)
  • 2 mm Allen key (for the flexible coupler grub screws)
  • 1.5 mm Allen key (for the MXL pulley grub screws)
  • 8 mm spanner (for the M5 nuts and the eccentric spacers); an adjustable wrench can be used, but it needs to be narrow enough to fit on the eccentric spacers.  An open-ended and ring “combination spanner”, like this one, is best
  • two 13 mm spanners (for the M8 nuts); adjustable wrenches will do, or a vice and one spanner/wrench (there are only two M8 nuts to tigthen, but they need to be tight)
  • M5 tap and tap handle (for the MakerSlide and belt tensioners — both are aluminium)
  • tapping fluid (or almost any kind of oil, including WD40 and mineral oil from the pharmacy. Boots Baby Sensitive Oil is better than WD40 and doesn’t smell)
  • small open container (e.g. a ramekin) for the tapping oil (if needed)
  • plastic brush to clean the tap (old toothbrush or nail brush)
  • sandpaper for metal (200 to 400 grit), a piece the size of a business card (to deburr the MakerSlide ends)
  • permanent marker (to mark the eccentric spacers)
  • set square (to align the X rail)
  • adhesive aluminium foil (a tiny amount is needed to help center the Z leadscrew in the coupler) — will be included in the kit
  • scissors (for the belt and aluminium foil)
  • small diagonal cutters (for the zip ties)

One thought on “Clean Room Build

  1. This sounds not to bad, all minor problems which should not be a big problem for anybody with some experience and tools, screws, spacers lying arround ;_)
    Do you have some pics of the build – can’t wait to held my kit in hands!

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