Reader map
What this page proves
Beam bending and proof loading in a welded frame. Start here for the build, question, measurement, and closeout proof.
What we are making
A bench H-frame press built from 2x2x0.125 in tube, steel plates, a bottle jack, and a measured proof setup.
Question answered
Does the welded frame bend as predicted under proof load, and what service label is justified by the recorded load?
What will be measured
Proof load, mid-span deflection, squareness, weld condition, and rating label.
Proof that closes it
03_frame_drawing.pdf, 03_cut_list.csv, 03_hand_calculation.pdf, 03_weld_log.pdf, 03_squareness_photo.jpg, 03_proof_load_table.csv, 03_deflection_chart.png, and 03_rating_label_photo.jpg.
A bottle jack pushes inside a steel frame. The top beam bends a tiny amount. The calculation predicts that bend before welding, and the proof test checks whether the real frame behaves like the math.
Words you need
Project terms
| Term | Meaning on this page |
|---|---|
| Shop press | Frame and jack used to push parts. |
| Bottle jack | Hydraulic jack supplying force. |
| Working load | Load allowed by the label. |
| Proof load | Measured test load. |
| Beam bending | Small deflection of a loaded beam. |
| Stress | Internal force per area. |
| Deflection | Measured movement. |
| Safety factor | Yield strength divided by stress. |
| Yield strength | Stress where steel permanently deforms. |
| Weld | Fused steel joint. |
| Dial indicator | Gauge for small movement. |
Capstone framing
Objective, requirements, constraints
| Type | Specific requirement |
|---|---|
| Objective | Build and proof a small welded press. |
| R1 | Drawing before cutting. |
| R2 | Hand calc for stress and deflection. |
| R3 | Weld procedure documented. |
| R4 | Squareness within 1/16 in. |
| R5 | Proof-load deflection recorded. |
| R6 | Label matches highest passed proof. |
| Adult operation | Welding, grinding, proof loading. |
Section 01 · Concept
Function and rating basis
A shop press pushes tight-fitting metal parts together or apart — bearings onto shafts, pins out of holes. It gives steady force where a hammer gives shock. This build covers the whole job: design it, calculate it, weld it, then prove it with a measured load.
What it is
Jack and fabricated frame
The jack supplies the force; it comes off the shelf. Everything around it is fabricated: a square-tube steel frame with a 6 in opening, plus two 4×4 in press plates.
Work presses between the jack's saddle and the upper plate — bearings onto shafts, bushings into housings, pins in or out. Every piece in the load path is sized on paper before any steel is cut.
Actual principle used
Beam bending and proof loading in a welded frame
Beam stress, expected bend, and the safety factor are all calculated before fabrication. The load test then measures the real numbers against the predictions.
Bending
10.9 ksi at 2,000 lb
Deflection
0.0045 in predicted
FOS
4.2 at 2,000 lb · 2.1 at jack max
Proof
1,000 lb measured · 50% load
Section 04 · Sequence
Build sequence and gates
The order is: define, cut, calculate, weld, finish, prove. Every checkpoint ends with something you can show — a calculation sheet, a squareness check, a load record, a label, a drawing.
Operating rules
Safety rules
Eye protection stays on for every press cycle, because pressed parts store energy and can let go fast. The work sits centered. Force goes straight down the jack's axis. The frame stays bolted to the bench.
PPE
eye protection
Load axis
centered on the jack
Proof
1,000 lb measured, held
Rating
labeled on frame
Sequence
Build sequence
Define. Fix the pressing tasks, set the working load at 2,000 lb — half the jack's 4,000 lb capacity — and issue the dimensioned drawing (DRAW-1).
Cut. Saw the two 12 in crossmembers and two 14 in columns from 2×2×0.125 in tube, to the drawing.
Plate. Cut two 4×4 in press plates from 3/8 in stock and drill two 17/32 in retention-pin holes in the lower plate on a 3 in square pattern.
Calculate. Publish the load-path sheet: 10.9 ksi bending, FOS 4.2 at 2,000 lb and 2.1 at jack max, 0.0045 in predicted deflection, weld and column checks.
Weld. Tack all four joints square with the jack axis on the plate centers, measure diagonals and tap true, then final-weld in an alternating sequence — opposite joints, opposite sides — to balance shrinkage. Run 0.030 in ER70S-6 at 130–140 A and 18–19 V with C25 gas at 20 cfh for the 0.125 in wall.
Finish. Weld the upper plate centered under the top crossmember and the lower plate to the base as the jack seat (1/8 in fillets, opposite edges), install the retention pins, then degrease, prime, paint, and apply the working-load label. Bolt the base to the bench through two 3/8 in holes.
Prove. Stack the crane scale in the press axis, exercise the frame once to 1,000 lb, release, and zero the indicator. Reload to a 1,000 lb reading, hold two minutes, record load and deflection, and inspect the welds.
Acceptance gates — owner: Kohler
Acceptance gates
Risk, judging, and closeout
What can fail and how the result is judged
What could go wrong
| Risk | Control | Failure action |
|---|---|---|
| Weld defect | Log settings and inspect. | Repair before higher load. |
| Off-axis load | Center work and use plates. | Unload and reset. |
| Stored energy | Stand clear. | Abort if work shifts. |
| Jack slip | Flat centered seat. | Unload and correct. |
| Frame instability | Level base. | Stop if frame walks. |
| Bad proof setup | Verified scale and indicator. | Repeat with verified tools. |
How the result will be judged
| Check | A-level result | Not acceptable |
|---|---|---|
| Calculation | Stress, deflection, weld, column checks. | Only CAD image. |
| Proof ladder | 500, 1000, 1500, 2000 lb holds if supported. | Unmeasured jack pump. |
| Deflection | Measured curve vs hand calc. | No dial record. |
| Rating | Label matches proof. | 2,000 lb claim without hold. |
Data package
Exact closeout filenames
- 03_frame_drawing.pdf
- 03_cut_list.csv
- 03_hand_calculation.pdf
- 03_weld_log.pdf
- 03_squareness_photo.jpg
- 03_proof_load_table.csv
- 03_deflection_chart.png
- 03_rating_label_photo.jpg
Senior capstone readiness
Current status: build plan; prototype and proof data pending. A-level requires hand calc reconciled with FEA, weld inspection, proof ladder, and complete drawing/spec package.
Definition of done
- Tube spec is 2x2x0.125 in everywhere.
- Drawing and cut list precede cutting.
- Proof ladder and deflection chart are recorded.
- Rating label matches passed proof load.
Section 02 · Structure
Load path and beam sizing
Force runs a loop through the frame: from the jack's ram, up through the work, and back down the columns to the jack's base. Every piece and weld on that loop is specified here, and the math comes before the cutting.
Frame elevation and load path · live model
Frame elevation: 2×2×0.125 in tube H-frame. Columns butt vertically between the crossmembers — 14 in of daylight, 18 in overall, ≈8 in of clear beam span, so the calculation's 12 in span is conservative — and a jack no taller than 7 in collapsed leaves the 6 in throat shown. Dimensioned drawing is gate DRAW-1.
Pre-build predictions
Pre-build calculations
I = (2⁴ − 1.75⁴)/12 = 0.552 in⁴ ; S = 0.552 in³ (nominal sharp-corner section)
M = PL/4 = 2,000 × 12 / 4 = 6,000 lb·in → σ = M/S = 10.9 ksi
A500B yield 46 ksi → FOS = 46 / 10.9 = 4.2 at 2,000 lb (target ≥ 2.0)
Jack max 4,000 lb → σ = 21.7 ksi, FOS = 2.1 — above the 2.0 target
δ = PL³/48EI = 2,000 × 12³ / (48 × 29×10⁶ × 0.552) = 0.0045 in at 2,000 lb ; ≈ 0.0022 in at 1,000 lb proof
Welds: 1/8 in fillet all around each joint (≈8 in per joint) → τ = 2,000 / (0.707 × 0.125 × 8) ≈ 2.8 ksi vs 21 ksi allowable
Columns: 1,000 lb tension each → σ ≈ 1.1 ksi ; base crossmember mirrors the top-beam case
These numbers are published before fabrication, with the assumptions stated plainly. The load test in Section 04 then loads the frame to a measured 1,000 lb and reads the bend on a dial gauge.
Load path and welds
Load path
Force runs one loop: ram, work, upper plate, top beam, columns, base member, jack base. Both cross members carry the same load, so one calculation covers both.
Members
2×2×0.125 in A500 tube
Welds
1/8 in ER70S-6 fillet
Throat
6 in
Alignment
jack axis to plate centers
Zoo / SolidWorks — build this model
Frame model and simulation check
Model the frame as a weldment built from square-tube profiles, plus the two press plates. SolidWorks Simulation then loads that model with 2,000 lb and reports stress and bend. The hand calculation on this page says 10.9 ksi of stress and 0.0045 in of bend. If the simulation lands far from those numbers, one of the two is wrong — find out which before cutting steel.
From the weldment, produce a cut list and one dimensioned frame drawing: every tube length and every hole location, readable at the saw. The export macro saves the drawing as this page's PNG. A working model of this build is embedded just below, and its STL download opens in SolidWorks, Onshape, or FreeCAD.
Runs in: Zoo (free — its Zookeeper agent builds from this prompt, edits by conversation, and answers design questions) · SolidWorks LEO · or by hand from the list above.
The Zoo file goes into the zoo-design-studio-projects folder shown at the top of Zoo’s Projects screen; the build then appears in the Projects list, dimensioned from this sheet. Paste the macro into SolidWorks (Tools → Macro → New) to export every drawing as a web image.
Model
weldment
Check
static FEA
Drawing
cut list + frame
Works on
student / Makers
Which license runs the simulation
Section 03 · Parts
Parts and cost
The steel is ordinary stock: about 6 ft of square tube and one square foot of 3/8 in plate. Only one mechanism gets bought — the jack itself.
Bill of materials
Parts and materials
| Item | Qty |
|---|---|
| 2-ton bottle jack — collapsed height ≤ 7 in, stroke ≥ 3.5 in (fits the 6 in throat) | 1 |
| Top crossmember — 2×2×0.125 in tube, 12 in | 1 |
| Side columns — 2×2×0.125 in tube, 14 in | 2 |
| Base crossmember — 2×2×0.125 in tube, 12 in | 1 |
| Press plates — 3/8 in steel plate, 4×4 in | 2 |
| Retention pins — 1/2 in bolt, locate the jack base | 2 |
| ER70S-6 MIG wire, 0.030 in | spool |
| Shielding gas — 75/25 Ar/CO₂ (cylinder owned with the welder; exchange fill $60–80) | fill |
| Crane scale — 1-ton (2,000 lb) digital, reads the proof load | 1 |
| Magnetic indicator base | 1 |
| Drill bits (17/32 in) and cutoff/flap discs | set |
| Degreaser, primer, red paint, and working-load label | set |
| Parts total | $130–240 |
The total assumes the welding-gas cylinder comes with the welder. A gas refill adds $60–80, which puts the range at $190–320.
Tools
Fabrication and measurement tools
A MIG welder joins the frame. A chop saw or bandsaw cuts the tube square. Clamps and a machinist square keep the fit-up true. Helmet, gloves, and jacket cover the arc work. A dial gauge reads the bend during the load test.
Time
20–30 h
Cost
$130–240 $190–320 with gas fill
Welder
MIG ER70S-6
Indicator
0.0005 in resolution
Section 05 · Scope
Scope and service limits
The press is tested at a measured 50% of its rating, then labeled. It only carries what the calculation allows. Full 2,000 lb use comes later, after higher test loads are run and recorded.
Service rating path
Service-load policy
Use starts at the proven level: a measured 1,000 lb held for two minutes, with the bend recorded against the prediction. Each higher recorded hold raises the permitted load. The label states the current limit.