Add loader arm V2 and jigs, update arm and panel geometry

Introduces new loader_arm_v2 module and supporting parameters for L-shaped loader arms, replacing the previous arm implementation. Adds 3D printed jig models for bolt hole cutting and welding. Updates lifetrac_v25.scad and lifetrac_v25_params.scad to use new arm geometry, adjust bucket and cross beam logic, and refines side panel profile and cutout calculations to match the new loader arm design.

Author: dorkmo

LifeTrac-v25/mechanical_design/openscad/3d_printed_bolt_hole_cutting_jigs/angle_iron_drill_jig.scad

@@ -0,0 +1,17 @@
+include <../../lifetrac_v25_params.scad>
+
+module angle_iron_drill_jig() {
+    leg = ANGLE_2X2_1_4[0];
+    wall = JIG_WALL_THICKNESS;
+    length = 100;
+    
+    difference() {
+        cube([leg + wall, leg + wall, length]);
+        translate([wall, wall, -1]) cube([leg + 1, leg + 1, length + 2]);
+        
+        // Drill holes
+        translate([wall + leg/2, 0, length/2]) rotate([90,0,0]) cylinder(d=5, h=wall*3, center=true, $fn=16);
+        translate([0, wall + leg/2, length/2]) rotate([0,90,0]) cylinder(d=5, h=wall*3, center=true, $fn=16);
+    }
+}
+angle_iron_drill_jig();

LifeTrac-v25/mechanical_design/openscad/3d_printed_bolt_hole_cutting_jigs/tube_drill_jig.scad

@@ -0,0 +1,26 @@
+include <../../lifetrac_v25_params.scad>
+
+module tube_drill_jig() {
+    // Fits over 2x6 tube
+    tube_w = TUBE_2X6_1_4[0];
+    tube_h = TUBE_2X6_1_4[1];
+    wall = JIG_WALL_THICKNESS;
+    
+    bolt_spacing_x = 100;
+    bolt_spacing_y = 80;
+    
+    difference() {
+        // Outer shell
+        cube([tube_h + 2*wall, tube_w + 2*wall, 50], center=true);
+        
+        // Inner cutout for tube
+        cube([tube_h + JIG_CLEARANCE, tube_w + JIG_CLEARANCE, 50+2], center=true);
+        
+        // Drill holes
+        for (x = [-bolt_spacing_y/2, bolt_spacing_y/2]) // Note: x/y swapped relative to tube orientation in arm file
+        for (y = [-bolt_spacing_x/2, bolt_spacing_x/2]) // This depends on how jig is oriented
+            translate([x, 0, 0]) cylinder(d=5, h=tube_w + 2*wall + 2, center=true, $fn=16); // Pilot holes
+    }
+}
+
+tube_drill_jig();

LifeTrac-v25/mechanical_design/openscad/3d_printed_welding_jigs/pivot_welding_jig.scad

@@ -0,0 +1,25 @@
+include <../../lifetrac_v25_params.scad>
+
+module pivot_welding_jig() {
+    // Holds two plates apart at TUBE_2X6_1_4[0] (2 inches)
+    // Aligns DOM pipe
+    
+    gap = TUBE_2X6_1_4[0];
+    pipe_od = DOM_PIPE_OD;
+    
+    difference() {
+        // Main block
+        cube([100, gap, 100], center=true);
+        
+        // Cutout for DOM pipe
+        rotate([90, 0, 0]) cylinder(d=pipe_od + JIG_CLEARANCE, h=gap+2, center=true, $fn=64);
+        
+        // Cutouts to save material
+        cube([80, gap+2, 80], center=true);
+    }
+    
+    // Add alignment tabs for plates?
+    // ...
+}
+
+pivot_welding_jig();

LifeTrac-v25/mechanical_design/openscad/lifetrac_v25.scad

@@ -12,6 +12,7 @@ use <modules/structural_steel.scad>
 use <modules/fasteners.scad>
 use <modules/hydraulics.scad>
 use <modules/wheels.scad>
+use <modules/loader_arm_v2.scad>
 
 // Import individual part files
 use <parts/side_panel.scad>
@@ -163,7 +164,7 @@ animation_phase = animation_time < 0.5 ? (animation_time * 2) : (2 - animation_t
 
 // Default arm position: lowered to ground (animation_phase=0)
 // ARM_GROUND_ANGLE is the angle below horizontal needed to reach ground
-ARM_LIFT_ANGLE = -ARM_GROUND_ANGLE + (animation_phase * (60 + ARM_GROUND_ANGLE)); // Animate from ground to raised and back
+ARM_LIFT_ANGLE = -ARM_GROUND_ANGLE + ARM_V2_OFFSET_ANGLE + (animation_phase * (60 + ARM_GROUND_ANGLE)); // Animate from ground to raised and back
 
 // Cross beam positions along arm length (from pivot)
 // First cross beam positioned for bucket cylinder attachment
@@ -175,8 +176,9 @@ CROSS_BEAM_SIZE = TUBE_2X2_1_4[0];    // 2"x2" tube size
 CROSS_BEAM_CLEARANCE = 15;             // Extra clearance around cross beam in cutout
 
 // Arm rotation range for cutout calculations
-ARM_MIN_ANGLE = -ARM_GROUND_ANGLE;     // Lowest position (at ground)
-ARM_MAX_ANGLE = 60;                     // Maximum raised position
+// ARM_MIN_ANGLE and ARM_MAX_ANGLE are defined in lifetrac_v25_params.scad
+// ARM_MIN_ANGLE = -ARM_GROUND_ANGLE;     // Lowest position (at ground)
+// ARM_MAX_ANGLE = 60;                     // Maximum raised position
 
 // =============================================================================
 // CROSS BEAM CUTOUT GEOMETRY FUNCTIONS
@@ -237,9 +239,9 @@ BUCKET_HEIGHT = 450;
 
 // Bucket tilt angle calculation:
 // When arm is at ARM_LIFT_ANGLE, bucket needs to counter-rotate to stay level
-// At ground position (ARM_LIFT_ANGLE = -ARM_GROUND_ANGLE), bucket tilts forward to lay flat
-// The bucket bottom is horizontal when bucket tilt = ARM_GROUND_ANGLE (compensates for arm angle)
-BUCKET_GROUND_TILT = ARM_GROUND_ANGLE;  // Tilt needed to make bottom flat when arm at ground
+// At ground position (ARM_LIFT_ANGLE = ARM_MIN_ANGLE), bucket tilts forward to lay flat
+// The bucket bottom is horizontal when bucket tilt = -ARM_MIN_ANGLE (compensates for arm angle)
+BUCKET_GROUND_TILT = -ARM_MIN_ANGLE;  // Tilt needed to make bottom flat when arm at ground
 BUCKET_MAX_CURL = 60;  // Maximum curl angle when fully raised
 
 // Bucket actuates with the arm using the same animation_phase for looping
@@ -1497,7 +1499,7 @@ module stiffener_side_panel_cutters(is_inner, is_left) {
     // Mid Plate Parameters
     mid_y = 800;
     mid_z_start = FRAME_Z_OFFSET + 100;
-    mid_z_end = FRAME_Z_OFFSET + 825 - 25.4;
+    mid_z_end = FRAME_Z_OFFSET + 350;
     mid_h = mid_z_end - mid_z_start;
     mid_angle_size = [50.8, 6.35];
     mid_leg = mid_angle_size[0];
@@ -1813,7 +1815,7 @@ module base_frame() {
 
     // Mid plate (at Y=800 to avoid cylinder bolts at 700)
     // Top height at Y=800 is approx 825mm above frame bottom
-    mid_stiffener_plate(800, FRAME_Z_OFFSET + 100, FRAME_Z_OFFSET + 825 - 25.4);
+    mid_stiffener_plate(800, FRAME_Z_OFFSET + 100, FRAME_Z_OFFSET + 350);
 }
 
 // =============================================================================
@@ -2045,84 +2047,37 @@ module wheel_assemblies() {
 // LOADER ARMS
 // =============================================================================
 
-module single_arm(side) {
-    mirror_x = (side == "left") ? -1 : 1;
-    arm_x = mirror_x * ARM_SPACING/2;
-    tube_size = ARM_TUBE_SIZE[0];
-    
-    color("Orange")
-    translate([arm_x, 0, 0])
-    {
-        // Main arm beam - extends from Y=0 (pivot) to Y=ARM_LENGTH (bucket end)
-        // Using a hollow square tube created directly with difference()
-        translate([0, ARM_LENGTH/2, 0])
-        difference() {
-            cube([tube_size, ARM_LENGTH, tube_size], center=true);
-            cube([tube_size - 2*ARM_TUBE_SIZE[1], ARM_LENGTH + 2, tube_size - 2*ARM_TUBE_SIZE[1]], center=true);
-        }
-        
-        // Pivot reinforcement - TYPE B: Two CNC plasma cut rings from 3/4" plate
-        // Welded to each side of arm tube at pivot point
-        translate([0, 0, 0])
-        rotate([0, 90, 0]) {
-            // Inner ring
-            translate([0, 0, -tube_size/2 + PLATE_3_4_INCH/2])
-            pivot_ring_large(tube_size + 30, PIVOT_PIN_DIA + 2);
-            // Outer ring
-            translate([0, 0, tube_size/2 - PLATE_3_4_INCH/2])
-            pivot_ring_large(tube_size + 30, PIVOT_PIN_DIA + 2);
-        }
-        
-        // Lift cylinder attachment - TYPE A: U-Channel from 3"x3" tube with pin
-        translate([0, LIFT_CYL_ARM_OFFSET, -tube_size/2 - TUBE_3X3_1_4[0]/2])
-        rotate([0, 0, 0])
-        u_channel_lug_with_pin(TUBE_3X3_1_4, 80, BOLT_DIA_1 + 2);
-        
-        // Note: Bucket cylinder brackets are now on the cross beam, not individual arms
-    }
-}
 
-module arm_cross_beams() {
-    tube_size = ARM_TUBE_SIZE[0];
-    cross_tube_size = TUBE_2X2_1_4[0];
-    wall_thickness = TUBE_2X2_1_4[1];
-    beam_length = ARM_SPACING + tube_size;  // Span full width including arm tubes
-    
-    // First cross beam - at bucket cylinder attachment position
-    color("Orange")
-    translate([0, CROSS_BEAM_1_POS, 0])
-    {
-        // Cross beam tube
-        difference() {
-            cube([beam_length, cross_tube_size, cross_tube_size], center=true);
-            cube([beam_length + 2, cross_tube_size - 2*wall_thickness, cross_tube_size - 2*wall_thickness], center=true);
-        }
-        
-        // Bucket cylinder mounting brackets - TYPE A: U-Channel from 3"x3" tube with pins
-        for (side = [-1, 1]) {
-            translate([side * BUCKET_CYL_X_SPACING, 0, cross_tube_size/2 + TUBE_3X3_1_4[0]/2])
-            u_channel_lug_with_pin(TUBE_3X3_1_4, 80, BOLT_DIA_3_4 + 2);
-        }
-    }
-    
-    // Second cross beam - near bucket (centered on X=0)
-    color("Orange")
-    translate([0, CROSS_BEAM_2_POS, 0])
-    difference() {
-        cube([beam_length, cross_tube_size, cross_tube_size], center=true);
-        cube([beam_length + 2, cross_tube_size - 2*wall_thickness, cross_tube_size - 2*wall_thickness], center=true);
-    }
-}
 
 module loader_arms() {
     if (show_loader_arms) {
         translate([0, ARM_PIVOT_Y, ARM_PIVOT_Z])
-        rotate([ARM_LIFT_ANGLE, 0, 0])
-        translate([0, 0, 0])  // Local arm coordinate system
+        rotate([is_undef(ARM_LIFT_ANGLE) ? 0 : ARM_LIFT_ANGLE, 0, 0])
         {
-            single_arm("left");
-            single_arm("right");
-            arm_cross_beams();
+            // Left Arm
+            translate([-ARM_SPACING/2, 0, 0]) 
+                rotate([0, 0, 90])
+                translate([0, -TUBE_2X6_1_4[0]/2, -TUBE_2X6_1_4[1]/2])
+                loader_arm_v2(angle=0, side="left");
+            
+            // Right Arm
+            translate([ARM_SPACING/2, 0, 0]) 
+                rotate([0, 0, 90])
+                translate([0, -TUBE_2X6_1_4[0]/2, -TUBE_2X6_1_4[1]/2])
+                loader_arm_v2(angle=0, side="right");
+            
+            // Cross Beam
+            // Connects the elbow assemblies at the new mounting hole position
+            // Hole is at main_tube_len - 50 from pivot
+            // Z height is 0 relative to arm pivot (center of tube)
+            // Y position is ARM_PIVOT_Y + (ARM_MAIN_LEN - 50)
+            // But we are inside the rotated arm group, so we use local coordinates
+            // The arms are at +/- ARM_SPACING/2
+            // The cross beam spans between them
+            
+            translate([0, ARM_MAIN_LEN - 50, 0]) 
+                rotate([0, 90, 0])
+                cube([50.8, 152.4, ARM_SPACING], center=true); // 2x6 tube
         }
     }
 }
@@ -2249,8 +2204,8 @@ module bucket() {
 module bucket_attachment() {
     if (show_bucket) {
         translate([0, ARM_PIVOT_Y, ARM_PIVOT_Z])
-        rotate([ARM_LIFT_ANGLE, 0, 0])
-        translate([0, ARM_LENGTH, 0])
+        rotate([is_undef(ARM_LIFT_ANGLE) ? 0 : ARM_LIFT_ANGLE, 0, 0])
+        translate([0, ARM_TIP_X, ARM_TIP_Z])
         {
             // Pivot pin connecting arms to bucket
             // This is at the arm tip, aligned with arm centerline
@@ -2275,7 +2230,7 @@ module bucket_attachment() {
             // So we offset the bucket up so that point aligns with the arm tip (Z=0 here)
             // Additional offset to keep bucket bottom above ground
             rotate([BUCKET_TILT_ANGLE, 0, 0])
-            translate([0, 0, BOBCAT_QA_HEIGHT])  // Shift bucket up fully so bottom clears ground
+            translate([0, 100, BUCKET_HEIGHT - 100])  // Shift bucket up (less 100mm) to reach ground from raised pivot
             bucket();
         }
     }

LifeTrac-v25/mechanical_design/openscad/lifetrac_v25_params.scad

@@ -69,7 +69,7 @@ WHEEL_X_OFFSET = TRACK_WIDTH/2 + SANDWICH_SPACING/2 + PANEL_THICKNESS + WHEEL_WI
 
 // Design constraints
 BUCKET_GROUND_CLEARANCE = 0;      // Bucket bottom at ground level when lowered
-BUCKET_FRONT_CLEARANCE = 100;     // 100mm (~4") clearance between bucket back and front of machine
+BUCKET_FRONT_CLEARANCE = 0;       // Reduced from 100 to 0 to match shorter arms
 
 // Arm pivot point (at top rear of side panels - tall end)
 ARM_PIVOT_Y = 200;  // Near rear of machine, between sandwich plates  
@@ -84,9 +84,61 @@ ARM_GROUND_ANGLE = asin(ARM_PIVOT_Z / ARM_LENGTH);  // Angle below horizontal (d
 ARM_TUBE_SIZE = TUBE_3X3_1_4;         // 3"x3" arm tubing
 ARM_SPACING = TRACK_WIDTH;            // Distance between arm centerlines
 
+// =============================================================================
+// LOADER ARM V2 PARAMETERS (L-SHAPE)
+// =============================================================================
+
+TUBE_2X6_1_4 = [50.8, 152.4, 6.35]; // 2"x6" rectangular tubing
+ARM_ANGLE = 120; // Main arm angle in degrees
+ARM_PLATE_THICKNESS = PLATE_1_4_INCH;
+DOM_PIPE_OD = 50.8; // Approximate OD for pivot holder (2" DOM)
+DOM_PIPE_ID = 38.1; // ID matching 1.5" pivot pin
+JIG_WALL_THICKNESS = 4; // Standard wall thickness for 3D printed jigs
+JIG_CLEARANCE = 0.5; // Clearance for fit
+
+echo("DEBUG: Loading lifetrac_v25_params.scad - Version with Fixes");
+
+// Arm Dimensions for Calculation
+ARM_MAIN_LEN = 1100; // Reduced from 1200 to bring bucket closer
+ARM_DROP_LEN = 550; // Shortened from 600
+ARM_OVERLAP = 200;
+ARM_DROP_EXT = 80; // Extension for bucket clearance
+ARM_PIVOT_EXT = 40; // Pivot hole offset from end of drop
+
+// Calculate Effective Arm Length and Angle
+// Vector from Main Pivot to Bucket Pivot
+_bend_angle = 180 - ARM_ANGLE;
+_drop_vec_len = ARM_DROP_LEN + ARM_PIVOT_EXT;
+_tube_h = TUBE_2X6_1_4[1];
+
+_dx = _drop_vec_len * cos(_bend_angle) + (-_tube_h/2) * sin(_bend_angle);
+_dz = -_drop_vec_len * sin(_bend_angle) + (-_tube_h/2) * cos(_bend_angle);
+
+ARM_TIP_X = (ARM_MAIN_LEN + ARM_OVERLAP + 50) + _dx;
+ARM_TIP_Z = _tube_h + _dz;
+
+_x_rel = ARM_TIP_X;
+_z_rel = ARM_TIP_Z - _tube_h/2;
+
+_arm_eff_len = sqrt(pow(_x_rel, 2) + pow(_z_rel, 2));
+arm_alpha_calc = atan2(-_z_rel, _x_rel); // Angle below horizontal (positive value)
+
+// Target Angle Calculation
+_target_height = 100; // Raised to 100mm (approx 4") to keep arm tip off ground
+_theta_rad = asin((_target_height - ARM_PIVOT_Z) / _arm_eff_len);
+theta_deg_calc = _theta_rad; 
+
+echo("DEBUG: theta_deg_calc", theta_deg_calc);
+echo("DEBUG: arm_alpha_calc", arm_alpha_calc);
+
+ARM_MIN_ANGLE_COMPUTED = (is_undef(theta_deg_calc) || is_undef(arm_alpha_calc)) ? 0 : theta_deg_calc + arm_alpha_calc; 
+echo("DEBUG: ARM_MIN_ANGLE_COMPUTED", ARM_MIN_ANGLE_COMPUTED);
+
 // Arm angle limits
-ARM_MIN_ANGLE = -ARM_GROUND_ANGLE;     // Lowest position (at ground)
-ARM_MAX_ANGLE = 60;                     // Maximum raised position
+// Calculated to keep bucket pivot ~50mm above ground at lowest position
+ARM_V2_OFFSET_ANGLE = ARM_MIN_ANGLE_COMPUTED + ARM_GROUND_ANGLE; // Difference from straight arm
+ARM_MIN_ANGLE = ARM_MIN_ANGLE_COMPUTED;     // Lowest position (at ground)
+ARM_MAX_ANGLE = 60 + ARM_V2_OFFSET_ANGLE;                     // Maximum raised position
 
 // Cross beam configuration
 CROSS_BEAM_SIZE = TUBE_2X2_1_4[0];    // 2"x2" tube size
@@ -285,3 +337,12 @@ assert(PLATFORM_PIVOT_PIN_DIA > PLATFORM_LOCK_PIN_DIA,
 _crossmember_top_z = FRAME_Z_OFFSET + MACHINE_HEIGHT * 0.7;
 assert(PLATFORM_PIVOT_HEIGHT + PLATFORM_ARM_LENGTH < _crossmember_top_z, 
     "Stowed position lock hole must be within rear crossmember height");
+
+// =============================================================================
+// JIG PARAMETERS & NEW ARM PARAMETERS
+// =============================================================================
+
+
+
+
+