Design Spec (Infrastructure-Grade)

This is not a “monolift.” This is a fixed, overbuilt rack-pull fortress that borrows monolift geometry (front-clear hooks) but removes the weak links (swing arms, bearings, hinge pins).

You’re building a static structure that can tolerate:

  • 1000 kg static load
  • shock load from set-downs
  • bar whip + side load
  • human error

Target safety: ≥ 2.0× on main structure. (If you can’t hit this, don’t build it.)

1) The concept

Make it a 

4-post, anchored frame

 with:

  • Fixed J-hooks (front clearance, no swing)
  • Redundant catches (straps or pins BELOW pull height)
  • Wide base outriggers to kill tipping
  • Gussets everywhere to kill racking (side-to-side sway)

Think: squat stand meets bridge truss.

2) Key dimensions (battle-tested proportions)

Overall footprint (recommended):

  • Width: 72 in (1830 mm) outside-to-outside uprights
  • Depth: 60 in (1525 mm) base depth (front-to-back)
  • Height: 96 in (2440 mm) (8 ft) so you have multiple pull heights + headroom

Upright spacing (inside clear):

  • Inside width: 50–52 in (1270–1320 mm) (fits wide-grip, straps, big bodies)
  • Inside depth: 36–40 in (915–1015 mm) (enough for bar path + belly brace + safety hardware)

Rack pull height adjust:

  • Hole spacing: 1 in (25 mm) Westside spacing through the pull zones (knee to mid-thigh), 2 in elsewhere.

3) Steel choice (don’t cheap out)

Uprights & primary frame

  • Option A (beast mode, common):
    6” x 6” x 1/4” (150 x 150 x 6.35 mm) square tube
  • Option B (nuclear):
    6” x 6” x 3/8” (150 x 150 x 9.5 mm) square tube

For 1000 kg + shock, Option A can work if gusseted + anchored + cross-braced. Option B is “sleep at night.”

Base rails / crossmembers

  • Minimum: 4” x 4” x 1/4” (100 x 100 x 6.35 mm) tube
  • Better: match uprights with 6x6x1/4 for uniform stiffness.

Plates / gussets

  • Gussets: 3/8” (10 mm) plate minimum
  • Hook plates & pin plates: 1/2”–3/4” (12–19 mm) plate

4) The hooks (the real secret)

You want fixed, front-clear hooks that don’t rely on a moving mechanism.

Hook architecture

  • Build hooks from laminated plate, not thin formed steel.
  • Hook body: (2) layers of 1/2” plate (or (1) 3/4” plate) per hook side, boxed if possible.
  • Add a backing plate that wraps the upright like a saddle to reduce point stress.

Hook interface

  • Hooks should mount via:
    • 1.25” (32 mm) solid pin minimum, OR
    • 2-pin system (one load pin + one anti-rotation pin)

Pins should be:

  • Alloy steel, high shear strength
  • Retained with heavy detent + secondary keeper (don’t trust one clip)

Hook liner

  • UHMW liner for bar protection, but the hook must still be 100% steel-strong without it.

5) Redundant safeties (non-negotiable)

You need two layers of “if something slips, nobody dies.”

Safety Layer A: Straps (best shock absorption)

  • Strap width: 4 in (100 mm)
  • Rating: at least 20,000 lb (9,000 kg) per pair, minimum
  • Mount: wrap over 1.5” (38 mm) solid pins or heavy strap brackets

Safety Layer B: Pins (hard stop)

  • Pin diameter: 1.25” (32 mm)
  • Use as a backup below strap level or as secondary.

Set safeties 1–2 inches below the pull height so the bar doesn’t free-fall.

6) Anti-rack bracing (what keeps it from “walking”)

A 1000 kg pull will try to twist your frame.

Must-have bracing

  • Rear X-brace using:
    • 2” x 2” x 1/4” tube, OR
    • 1/4” wall flat bar diagonals
  • Top crossmember front and back
  • Corner gussets at every upright-to-base joint (big triangles)

If you want maximum stiffness: add side triangles (upright → mid-base) like a crane boom.

7) Anchoring & base (where real safety lives)

If it’s not anchored, it’s not real.

Anchor spec (typical best practice)

  • Concrete slab: minimum 6” thick, 4000 psi
  • Anchors: 5/8” or 3/4” wedge anchors (or epoxy anchors), 4 per upright minimum
  • Add base plates under each upright:
    • Size: 12” x 12” x 1/2” plate minimum
    • Better: 14” x 14” x 3/4” if you can

Outriggers (anti-tip)

Add front and rear outriggers so the base depth becomes a “platform.”

  • Outrigger length: 10–16 in beyond uprights
  • Tie them with a front crossmember.

8) Build details (the stuff that prevents failure)

Welding

  • Use a competent structural welder.
  • Full penetration where possible on primary joints.
  • Add gussets so welds are not the only thing resisting rotation.

Hole drilling

  • Hole diameter for pins: match your pin system precisely.
  • Deburr everything. Chamfer edges to prevent stress risers.

Corrosion & finish

  • Powdercoat is fine, but don’t coat inside faces that need tight tolerance.
  • Paint inside of tubes or cap them to prevent rust from inside-out.

9) Load testing protocol (prove it before you pull)

You don’t “trust.” You validate.

  1. Static test at 125% of target (1250 kg equivalent) supported on hooks
  2. Set-down test from 1–2 inches (controlled drop) onto safeties
  3. Check:
    • any permanent deformation
    • hole ovalization
    • pin bending
    • weld hairlines
    • anchor movement

If anything moves permanently: reinforce, gusset, or upgrade steel.

10) Bill of Materials (clean shopping list)

Primary steel

  • 6x6x1/4 tube (uprights + base + top)
  • 4x4x1/4 or 6×6 crossmembers
  • 3/8” plate gussets (lots)
  • 1/2–3/4” plate for hooks + base plates

Hardware

  • 1.25” alloy pins + retainers
  • 4” heavy straps rated ≥20k lb (pair) + strap pins/brackets
  • 5/8”–3/4” anchors + washers + nuts (industrial)
  • UHMW liners + fasteners

11) “Monolift feel” upgrade (optional)

If you still want the monolift vibe without swing-arm risk:

  • Add front-clear hook geometry (hooks protrude forward and up)
  • Add a bar guide lip so it can’t roll forward off the hook
  • Add a secondary “keeper” tab that you manually flip after racking (simple, reliable)

No bearings. No swing. No hinges. Simple = unkillable.

If you tell me these 3 things, I’ll lock the exact final blueprint dimensions

  1. Your bar length (power bar? axle? specialty?)
  2. Your ideal pull height (below knee / knee / above knee / mid-thigh)
  3. Floor situation: concrete slab thickness and whether you can anchor

Then I’ll spec:

  • exact upright spacing
  • hook depth + angle
  • strap/pin placement
  • brace layout so it doesn’t rack even a millimeter under war-load.