How do you calculate cutterhead fabrication cost?

Multiply welded cutter housings by the per-housing fabrication rate by first-pass weld yield, then add the hub and bearing-plate setup. For 48 housings at $3,200, 85% yield and $95,000 setup, the total is $225,560.

What is the per-housing cost in the example?

$4,699.17 per housing — the $225,560 total divided across 48 housings, well above the $3,200 base rate because the large fixed hub setup is spread across a small housing count.

Why weight fabrication cost by first-pass weld yield?

An 85% first-pass yield means 15% of housings need weld rework before passing NDT. Folding yield into the estimate keeps the number honest for a heavy, code-governed weldment.

What is a good first-pass weld yield for TBM cutter housings?

For thick-section, radiographically inspected structural welds, 85-95% first-pass is realistic; below 85% points to procedure, fit-up or welder-qualification issues worth addressing before the run.

Why is the hub setup such a large share of the total?

At $95,000 the hub and bearing-plate machining setup is 42% of the $225,560 total. Cutterhead hubs are large, precision-machined single pieces, so their fixed setup dominates low-volume builds.

Does this cover the full cutterhead cost?

No. It covers housing fabrication and hub setup. Cutters, cutter mounts, wear plates, final assembly, NDT and paint are separate line items in a complete cutterhead estimate.

Tunnel Boring & Heavy Civil Equipment calculator

Cutterhead Fabrication Cost Calculator

Cutterhead Fabrication Cost estimates what it takes to fabricate the welded cutter housings and machined hub of a tunnel boring machine cutterhead, weighted by first-pass weld yield. Estimators and fabrication managers on heavy-civil and TBM programs use it because a cutterhead is a low-volume, high-consequence weldment where a single failed radiographic weld can blow a schedule. Unlike a flat labor estimate, it folds weld yield into the number so the cost reflects the reality that not every seam passes NDT first time. On a project where TBM downtime runs into six figures a day, that fabrication estimate needs to be honest before the steel is cut.

What this calculator does

Estimates the shop cost to fabricate a TBM cutterhead from disc-cutter housing count, per-pocket build rate, weld yield, and one-time hub tooling.
Use it when bidding a custom cutterhead build to size weld-shop labor and steel exposure against the hub and bearing setup that is fixed regardless of cutter count.
It multiplies welded cutter housings by the per-housing fabrication rate and first-pass weld yield, then adds the fixed hub and bearing-plate setup.

Formula used

Total = housings x fabrication rate x (first-pass yield ÷ 100) + hub setup
Per housing = total cost ÷ number of welded cutter housings

Inputs explained

Welded cutter housings in the build:
Fabrication cost per welded housing:
First-pass weld yield:
Hub and bearing-plate machining setup:

How to use the result

Use it when estimating a cutterhead fabrication package or comparing an in-house weld shop against an outsourced fabricator.
It models yield-adjusted fabrication and fixed hub setup, but not weld repair labor, NDT cost, or the fit-up and assembly of the completed cutterhead.

Current U.S. benchmarks

Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate cutterhead fabrication cost? Multiply welded cutter housings by the per-housing fabrication rate by first-pass weld yield, then add the hub and bearing-plate setup. For 48 housings at $3,200, 85% yield and $95,000 setup, the total is $225,560.
What is the per-housing cost in the example? $4,699.17 per housing — the $225,560 total divided across 48 housings, well above the $3,200 base rate because the large fixed hub setup is spread across a small housing count.
Why weight fabrication cost by first-pass weld yield? An 85% first-pass yield means 15% of housings need weld rework before passing NDT. Folding yield into the estimate keeps the number honest for a heavy, code-governed weldment.
What is a good first-pass weld yield for TBM cutter housings? For thick-section, radiographically inspected structural welds, 85-95% first-pass is realistic; below 85% points to procedure, fit-up or welder-qualification issues worth addressing before the run.
Why is the hub setup such a large share of the total? At $95,000 the hub and bearing-plate machining setup is 42% of the $225,560 total. Cutterhead hubs are large, precision-machined single pieces, so their fixed setup dominates low-volume builds.

Last reviewed 2026-05-12.