LowRider v4 CNC tilt table

Construction sequence

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1. 010/5

   Build the temporary CNC deck

   Commission the LR4 and machine later project parts before committing to the permanent table.

   Prerequisite

   Count the LSL, plywood, MDF, ties, fasteners, and both CNC shipments.

   

   • Set four BORA Workhorse XT sawhorses on a level floor.
   • Build the provisional 62 × 112 in. LSL frame with supported sheet seams.
   • Install the plywood deck and replaceable 1/4 in. MDF wear layer.
   • Map every screw, restraint, hold-down, rail fixing, and metal keep-out.
   • Commission the LR4, verify square and reach, and prove test cuts.

   Hold point

   Do not cut final gantry tubes or fix rail and belt mounts until oversized-sheet travel is verified.

   Acceptance

   The machine makes proven test cuts and can produce jigs and permanent-table components.

2. 020/5

   Dry-fit the torsion box

   Build a light, stiff plywood box from interlocking ribs, reinforced splices, rims, and continuous skins.

   Plan size

   62 × 112 in. (provisional structural top)

   Structural thickness

   4.25 in. — two 3/4 in. plywood skins over the rib grid

   Rib grid

   Redesigned to suit identical modules: 13 longitudinal ribs (under all six long tracks, down each lane center, plus two edge rims) and 17 cross ribs (under the three transverse tracks, one between each hole column, plus two end rims); ribs interlock half-depth

   Dog-hole grid rule

   Every module has the identical 14-hole pattern (two rows at 2.5 and 7.5 in. across, seven columns at 3.0625 + 7k in. along); ribs are placed around that pattern so no hole ever lands on a rib

   Above the box

   The 3/4 in. MDF modules of Stage 03 add on top of the upper skin

   Prerequisite

   The temporary CNC is commissioned and actual plywood thickness is recorded.

   

   • Cut 13 longitudinal ribs (spliced and reinforced where over 8 ft) and 17 cross ribs on the module-matched layout.
   • Fit half-depth slots to measured material with tested clearance.
   • Reinforce the Y = 56 splice and all skin seams.
   • Dry-fit on a verified flat platform and compare diagonals.
   • Photograph backing, clearances, and service access before closing the box.

   Hold point

   Do not bond skins until inserts, dog holes, track lines, pivots, locks, and backing locations are coordinated.

   Acceptance

   The grid seats fully without twist, all seams are supported, and the reference plane remains flat.

3. 030/6

   Fit the modular work surface

   Ten equal-width removable MDF modules create a deck larger than the required CNC work field, divided by five internal T-track lines, surrounded by perimeter T-track, and registered to a square front-left X0/Y0 reference rail.

   MDF module field

   53 × 97 in., including four 3/4 in. longitudinal T-track seams and one 3/4 in. transverse seam

   Track-framed deck

   54.5 × 98.5 in., including a continuous 3/4 in. T-track perimeter on all four sides

   Required work field

   49 × 97 in. minimum, contained within the larger modular deck

   Module size

   Each module is 10 × 48.125 in.; two identical modules per lane and five equal-width lanes

   Module thickness

   3/4 in. MDF, bearing on the box's continuous upper skin

   Dog-hole grid

   Identical pattern in all ten modules: 20 mm holes, two rows 2.5 and 7.5 in. from the module edge, seven columns 7 in. apart starting 3.0625 in. from the module end; modules are fully interchangeable; deck centered on the box; positions on hold until machine-envelope testing

   Surface build-up

   4.25 in. box + 3/4 in. module ≈ 5 in. total working height over the rib core

   Prerequisite

   Actual track, cross junctions, ledges, MDF thickness, and reinforced insert coupons are approved.

   

   • Fit two identical 10 × 48.125 in. modules in each of five equal-width lanes.
   • Test underside rabbets so every module bears on the continuous plywood skin.
   • Install four longitudinal tracks, the transverse midpoint track, and a continuous 3/4 in. T-track perimeter around all four sides of the MDF field.
   • Fit a removable hard-maple L-rail immediately outside the perimeter track: 49 × 1-1/2 × 3/4 in. along the front for Y0 and 97 × 1-1/2 × 3/4 in. along the left for X0. Half-lap the corner 1-1/2 × 1-1/2 in. and 3/8 in. deep in each rail.
   • Add only reviewed 20 mm dog holes that follow the identical per-module pattern (rows 2.5 / 7.5 in., columns 3.0625 + 7k in.) and clear structure and metal.
   • Match the retention pattern on ten spare modules after the installed set is proven.

   Hold point

   The 53 × 97 in. module field, 54.5 × 98.5 in. track-framed deck, 49 × 97 in. minimum work field, hard-maple rail blanks, and the identical per-module dog-hole pattern are specified; final proud height, offsets, mounting holes, module running clearance, covers, actual dog-hole coordinates, and insert schedule remain unreleased until the machine envelope is tested.

   Acceptance

   Modules sit flat and remove cleanly, track access remains clear, and the front-left rail is straight, square, repeatable, and outside every cutter, gantry, clamp, and module keep-out.

4. 040/8

   Build the mobile cradle

   A freestanding plywood base carries the pivots while keeping the center open for the full rotation sweep. Each end frame is a fluid rounded-triangle form: rounded triangular plywood layers milled on the temporary CNC table, then laminated together into a deep sculptural end frame. Pivot axis sits 34–36 in. above the floor; the base footprint approaches the 62 in. top width so the assembly is stable with the top vertical.

   Prerequisite

   The temporary table can machine cradle members; caster height, plate patterns, table mass, center of gravity, and pivot reactions are measured.

   

   • Mill the rounded triangular plywood layers for both end frames on the temporary CNC table — the CNC-cut curves give the fluid, sculpted shape no straight-saw layout can match.
   • Laminate the rounded triangular layers into each end frame with full glue coverage and clamping; stack enough layers for the required depth and pivot bearing support.
   • Cut the single central spine from a 2 × 6 LSL — factory-laminated, so no glue-up; mill its ends square and to length on the temporary CNC table.
   • Glue-and-fasten the bearing pads, caster pads, and lock backing as full lamination schedules.
   • Through-bolt six matching 6 × 2 in. polyurethane casters to solid laminated pads.
   • Fit four stabilizers and four working legs for repeatable support.
   • Set the pivot axis 34–36 in. above the floor (31.1 in. absolute minimum for the 62 in. top's corner swing).
   • Leave the cradle center open and measure every hardware protrusion.

   Hold point

   Do not release base dimensions until the entire moving envelope and garage travel route are checked.

   Acceptance

   The unloaded base rolls without racking and rests solidly on supports with caster loads relieved.

5. 050/5

   Prototype pivots and locks

   Separate hardware carries rotation, controls movement, and positively locks both end positions.

   Prerequisite

   Completed moving mass, center of gravity, worst-case leverage, and bearing reactions are known.

   

   • Align bearing and shaft assemblies at both short ends.
   • Transfer reactions through steel plates and through-bolted plywood backing.
   • Provide axial shaft retention independent of the drive.
   • Fit visible steel-to-steel lock pins at horizontal and vertical positions.
   • Select a rated controlled drive only after measured-load calculations.

   Hold point

   The nominal 1 in. shaft is only a space allowance; no bearing, shaft, actuator, winch, or lock is released.

   Acceptance

   A reviewed prototype proves alignment, full pin engagement, retention, and a continuous structural load path.

6. 060/6

   Install and verify the LR4

   Set the LowRider v4 around the real work envelope rather than assuming the support field equals cutter travel.

   Prerequisite

   The table is locked horizontal, supported on working legs, level, and the surface system is proven.

   

   • Install the LR4 round guide rail and opposite flat wheel runway to measured geometry.
   • Indicate the front-left reference rail square to machine travel, record its X0/Y0 offsets, and verify repeatability after removal and reinstallation.
   • Verify travel with a 48.5 × 96.5 in. stock record at full size.
   • Check cutter sweep, dust shoe, clamps, lead-ins, hard stops, belts, and carriage clearance separately.
   • Surface only to the measured safe depth above metal and required rabbet lips.
   • Prove CAM output and the Jackpot controller workflow with the MacBook.

   Hold point

   Do not mark oversized stock machine-ready until actual outside-profile travel and fixture clearance pass.

   Acceptance

   Stock footprint, support, tool-center travel, fixture keep-outs, and the calibrated front-left X0/Y0 datum are documented as separate envelopes.

7. 070/5

   Commission the controlled tilt

   Exercise the full sweep only with the machine and every loose item removed from the moving top.

   Prerequisite

   Pivot, drive, locks, supports, clearances, mass, and center of gravity have passed review.

   

   • Remove gantry, router, stock, hoses, covers, jigs, clamps, and loose fittings.
   • Deploy stabilizers and verify the cradle is level and immobile.
   • Release supports and locks only in the reviewed order.
   • Rotate under positive control while observing both ends and the floor sweep.
   • Engage both storage locks and verify visible full pin engagement.

   Hold point

   Never rely on a drive or gas spring as a structural lock, and never stand inside the sweep.

   Acceptance

   The top travels without collision, uncontrolled acceleration, binding, racking, or partial lock engagement.

8. 080/5

   Verify storage and changeover

   Store the top near vertical to reclaim floor space while the removed gantry lives in its own compact cabinet.

   Prerequisite

   Both vertical locks are engaged and retained; all loose equipment is accounted for.

   

   • Measure the real stored height, footprint, hardware projection, and garage clearances.
   • Confirm the 112 in. length stays horizontal and the 62 in. width clears vertically.
   • Store the removed gantry safely in the separate front-access cabinet.
   • Check the seated MacBook position from the 23 in. stool.
   • Record the complete reverse sequence for returning to CNC mode.

   Hold point

   About 66 in. stored height is an allowance, not a guaranteed clearance.

   Acceptance

   The table fits the garage and travel route without wall or ceiling attachment and changes modes repeatably.