Subject: Commission request - 3D print of PzIII Kommandantenkuppel (1/35 scale) ## CALIBRATION BASE (critical): - Wheel diameter (reference anchor): 14.75 mm → Scale 1/35.254 - Cupola exterior diameter (reference): 22.44 mm - Conversion factor: 0.02837 (derived from 22.44 ÷ 791 units) ## PERISCOPE MECHANISM NOTES (critical): - Periscope shields open at IRREGULAR angles (not uniform across all six segments) - When partially open/resting: “drooping eyelid” posture (slight downward angle) - When closed: upper section nests INSIDE lower section, held vertically and locked (NO drooping) - Opening motion: LOWER shield moves OUTWARD + DOWNWARD (compound pivot), not just downward - Model asymmetry into the opening angles — real-world examples show non-uniform positioning Operating Mechanism Description System Overview: Five periscopes arranged in the commander’s cupola Each operated by a horizontal bar lever positioned beneath each periscope Bar moves vertically (up/down) as angular lever Position Behavior: | Position | Bar Location | Movement Direction | |----------|--------------|---------------------| | Closed | Lower position, closer to wall | Bar descends toward wall | | Open | Higher position, farther from wall | Bar rises away from wall | Critical Geometric Constraint: The drop angle remains constant in both positions. The periscope shield maintains consistent orientation throughout the travel range—only linear position changes.
CUPOLA TOP VIEW MEASUREMENTS — RAW VALUES (Screen Calipers) | View | Raw Units | Converted to 1/35 | Description | |------|-----------|-------------------|-------------| | View 1 (Main Body) | 873 | 24.77 mm | Main body diameter | | View 2 (Outer Ring) | 767 | 21.76 mm | Outer ring diameter | | View 3 (Intermediate Body) | 719 | 20.40 mm | Intermediate body diameter | | View 4 (Central Opening) | 611 | 17.33 mm | Central opening diameter | | View 5 (Maximum Overall Diameter) | 791 | 22.44 mm | MAXIMUM overall diameter (REFERENCE) | | View 6 (Rectangular Component - Long) | 205 | 5.82 mm | Rectangular component (long dimension) | | View 7 (Rectangular Component - Wide) | 130 | 3.69 mm | Rectangular component (wide dimension) | | View 8 (Main Armour Thickness) | 33 | 0.94 mm | Main armour thickness | | View 9 (Height/Depth 1) | 209 | 5.93 mm | Height/depth measurement 1 | | View 10 (Height/Depth 2) | 174 | 4.94 mm | Height/depth measurement 2 | CUPOLA TOP VIEW — ADDITIONAL MEASUREMENTS (RAW VALUES) | Detail | Raw Units | Converted to 1/35 | Description | |--------|-----------|-------------------|-------------| | Detail 1 | 19 | 0.54 mm | Thin internal thickness / secondary element | | Detail 2 | 202 | 5.73 mm | Rectangular component (long dimension) | | Detail 3 | 28 | 0.79 mm | Wall thickness (narrow section) | | Detail 4 | 41 | 1.16 mm | Wall thickness (wide section) | CUPOLA ANGLES — VERIFIED FROM JENTZ DRAWINGS | Photo | Angle | Description | |-------|-------|-------------| | Photo 1 (Angle 1) | 220.91° | Hexagonal face-to-face diagonal — Relationship between opposing hexagonal segments | | Photo 2 (Angle 2) | 255° | Upper edge / diagonal line — Upper edge measurement of segment interface | | Photo 3 (Angle 3) | 289.96° | Main axis / full body diagonal — Complete diagonal across cupola structure | | Photo 4 (Angle 4) | 168.45° | Periscope shield drop angle — ~11.55° from flat (inclined surface) | | Photo 5 (Angle 5) | 270° | Orthogonal junction — Perfect 90° corner (interior equivalent) | | Photo 6 (Angle 6) | 176.11° | Cupola segment panel — Nearly vertical panel (~3.89° from vertical) | | Photo 7 (Angle 7) | 155.26° | Internal periscope angle — Internal structural angle near periscope mount | PERISCOPE DIMENSIONS | Parameter | Real Value (mm) | 1/35 (mm) | Notes | |-----------|-----------------|-----------|-------| | Height (closed) | 197 | 5.63 | Jentz reference verified | | Height (open) | 246 | 7.03 | Vertical travel included | | Vertical travel | 49 | 1.40 | Movement range | | Depth (closed) | 61 | 1.74 | From wall | | Depth (open) | 69 | 1.97 | From wall | | Pad width | 109 | 3.11 | Filled leather pads | | Pad depth | 36 | 1.03 | Filled leather pads | | Glass-to-armour gap | 22 | 0.63 | Internal clearance | | Outer wall to inner pad center | 75 | 2.15 | Top view measurement | | Outer wall to periscope pad center | 74 | 2.11 | Top view measurement | | Offset difference | 0.29 | 0.08 | Negligible tolerance | PERISCOPE ARMOUR CROSS-SECTION MEASUREMENTS — RAW VALUES (Screen Calipers) | Photo | Raw Units | Converted to 1/35 | Description | |-------|-----------|-------------------|-------------| | Photo 1 | 104 | 5.63 mm | Periscope section height (vertical cross-section, closed) | | Photo 2 | 75 | 4.06 mm | Lower section height (lower cut) | | Photo 3 | 55 | 2.98 mm | Internal section height (mid-height cut) | | Photo 4 | 118 | 6.38 mm | Periscope component width (horizontal span) | | Photo 5 | 12 | 0.65 mm | Glass-to-armour gap (internal clearance) | PERISCOPE MECHANISM ANGLES — VERIFIED FROM ORIGINAL DRAWINGS | Photo | Angle | Description | |-------|-------|-------------| | Photo 1 (Periscope Angle 1) | 206.93° | Periscope mechanism lever arm — Initial/closed position of horizontal bar lever | | Photo 2 (Periscope Angle 2) | 221.91° | Periscope shield angle — Intermediate position during opening cycle | | Photo 3 (Periscope Angle 3) | 228.7° | Periscope housing angle — Full open position with max lever extension | | Photo 4 (Periscope Angle 4) | 225° | Vertical lever reference — Reference for vertical lever movement axis | Mechanism Summary: The horizontal bar lever moves vertically beneath each periscope. When closed, the bar descends toward the wall (lower position). When open, the bar rises away from the wall (higher position).
The drop angle of the shield remains CONSTANT in both positions. ## IMPORTANT DESIGN NOTES: - This is the LATER cupola type used on Ausf. J/L (Kommandantenkuppel mit 6 Sichtschlitzen) - Part number: 021 B 39032 (Daimler-Benz, factory spec sheet D 652/26, 1 November 1942) - Ausf. J with short-barrel 5 cm KwK 38 L/42 (gun remains inside hull silhouette) ## DESIGN REQUIREMENTS: 1. Periscope housings with correct angles and positions (non-uniform opening angles) 2. Internal detail including periscope mounts and hatch mechanism 3. Correct hatch profile (single-piece, not split) 4. Sliding cover plates for periscope slots 5. Rivet/bolt heads consistent with Krupp manufacturing style 6. All measurements must reference the calibration base above (wheel 14.75mm, cupola 22.44mm)
The two cupolas look very similar from a distance. I think it best to post your reference photo here (or, part of it).
One difference is in the upper profile edge…it’s exactly vertical in the earlier cupola, and slanted in the later one. But if there’s any doubt, an overall photo should be used.
David
Dear David,
Here is my reference photo. The upper profile edge shows a slant, not vertical — so this should be the later cupola version, not the Ausf.H which has a vertical edge.
Please confirm if this matches what you need.
Dioni
Thank you for all that data.
I’ve been busy with life, but I got back on this topic yesterday.
The cupola on Panzer “7” in your set of photos, is not the final version.
It’s the second-last version, and indeed, all of the other reference photos posted later, are the same type.
I found several excellent German diagrams of it, but there was slight distortion in them, so I had to wrestle with them to figure where and when they went wrong by one or two millimeters. I think that I solved that and obtained the true dimensions.
So, now I have a sense of how the whole project would go.
That’s the basic internal shell.
David