Sawing
Sawing separates stock with a toothed blade — band, circular or cold saw — and is the default first operation on bar, tube and plate.
- Part
- Cutting
- Revised
- 2026-08-11
At a glance
- Family
- Mechanical
- Typical tolerances
- Band saw ±0.030 in (±0.75 mm) typical, ±0.010 in (±0.25 mm) with careful setup; cold saw ±0.005–0.010 in (±0.13–0.25 mm); abrasive saw ±0.020 in (±0.5 mm) or looser
- Surface finish
- Roughly 125–500 µin Ra (3.2–12.5 µm) as-sawn, with cold saw cuts at the fine end and abrasive cuts at the coarse end
- Typical volumes
- 1 to unlimited; bundle cutting makes high volumes efficient
- Lead time
- Minutes per cut; same-day service at any metal supplier or fabrication shop
- Materials
- Metal, Wood, Plastic, Composite
What it is
Sawing separates stock with a toothed blade and is almost always the first operation performed on bar, tube, plate and structural section. Three machine types cover the field: the horizontal band saw, the general-purpose workhorse for metal; the cold saw, a slow-turning circular blade under flood coolant that gives the squarest and cleanest cut; and the abrasive chop saw, which is fast, crude and hot.
Blade selection follows one rule above all others: keep at least 3 teeth engaged in the cut at all times and no more than about 24. Too few and the teeth strip out; too many and the chips cannot clear the gullets.
Expect ±0.030 in (±0.75 mm) from a production band saw and ±0.005–0.010 in (±0.13–0.25 mm) from a cold saw, and leave 0.030–0.125 in (0.8–3 mm) of facing stock per end on anything that will be machined afterward.
How it works
- Tooth pitch selection. Pitch is chosen from the thickness of material the blade passes through, not from the overall size of the part — a 4 in tube with a 0.120 in wall needs a fine pitch, not a coarse one. Variable-pitch blades (4/6, 6/10, 10/14) are standard because the varying tooth spacing breaks up the harmonic that causes chatter.
- Blade speed. Bimetal bands run roughly 200–300 SFM (60–90 m/min) in mild steel and 100–150 SFM (30–45 m/min) in stainless; carbide-tipped blades in aluminum run an order of magnitude faster. Cold saws turn HSS blades at far lower surface speeds under flood coolant, which is where their finish and squareness come from.
- Break-in. A new blade is run at reduced feed for the first several cuts to hone a controlled radius onto each tooth tip. Skipping break-in strips teeth and is the most common cause of premature blade failure.
- Clamping. The vise must grip on both sides of the blade. Unsupported tube collapses, and unsupported bar rolls into the blade and strips teeth.
- The cut. Feed pressure is set so each tooth takes a real chip. Too light and the teeth rub and work-harden the material — particularly destructive in stainless.
- Blade drift. A dull, mis-tensioned or wrongly guided band wanders, producing an out-of-square cut and a barrel-shaped face. Squareness, not length, is usually the first thing to go wrong.
- Deburring. A saw cut leaves a burr at exit that has to be removed before the next operation.
Design guidelines
Leave facing stock
Specify cut length with enough extra material for a facing operation: 0.030–0.060 in (0.8–1.5 mm) per end for cold-saw cuts and 0.060–0.125 in (1.5–3 mm) per end for band-saw cuts. Asking a saw for a finished length in one operation is asking for a rework.
Match the machine to the squareness requirement
Band saws are fast and cheap but hold squareness loosely; cold saws are slower but produce a face square and clean enough to weld or machine directly; abrasive saws are the fastest and the least accurate, and they heat the cut end. Choose deliberately rather than defaulting.
Pick pitch from the thinnest section the blade crosses
| Section thickness at the cut | Typical variable pitch |
|---|---|
| Under 0.125 in (3 mm) — thin wall tube | 10/14 or 14/18 |
| 0.125–0.25 in (3–6 mm) | 8/12 or 10/14 |
| 0.25–1 in (6–25 mm) | 6/10 or 5/8 |
| 1–3 in (25–75 mm) solid | 4/6 or 3/4 |
| Over 3 in (75 mm) solid | 2/3 or 1.4/2.0 |
Budget the kerf
Band saw kerf runs 0.035–0.065 in (0.9–1.65 mm) depending on blade width, cold saw 0.060–0.125 in (1.5–3 mm), and abrasive wheels wider still. On short parts cut from bar, kerf plus facing stock can be a substantial share of the material.
Bundle cutting is where the savings are
Multiple bars clamped and cut together divide machine time across every piece. It requires a machine and vise that can hold the bundle rigidly, and it trades some squareness for throughput.
| Material | Sawing notes |
|---|---|
| Mild and alloy steel | The reference case; bimetal band at 200–300 SFM (60–90 m/min) |
| Stainless steel | Work hardens if the feed is too light — maintain real chip load |
| Aluminum | Carbide-tipped blades, high speed, coarse pitch, chip clearance is everything |
| Titanium | Slow speeds, heavy coolant, sharp blades; heat is the enemy |
| Cast iron | Cuts dry readily; abrasive on blades |
| Plastics and acrylics | Melt and re-weld behind the blade; coarse pitch, high speed, no coolant |
| Wood and composites | Circular and band saws; carbide or diamond for abrasive laminates |
| Feature | Recommended | Limit | Why |
|---|---|---|---|
| Teeth engaged in cut | 6–12 | 3 minimum, ~24 maximum | Fewer strips teeth, more clogs gullets |
| Facing stock per end | 0.060 in (1.5 mm) | 0.030 in (0.8 mm) | Saw cuts are not finished faces |
| Length tolerance, band saw | ±0.030 in (±0.75 mm) | ±0.010 in (±0.25 mm) | Blade drift and clamping |
| Length tolerance, cold saw | ±0.010 in (±0.25 mm) | ±0.005 in (±0.13 mm) | Rigid circular blade, flood coolant |
| Kerf allowance, band saw | 0.050 in (1.3 mm) | 0.035–0.065 in (0.9–1.65 mm) | Blade width dependent |
| Minimum tube wall | 0.030 in (0.8 mm) | Thinner needs support | Wall collapses under vise pressure |
Cost drivers
Sawing is cheap per cut and expensive in aggregate, because almost every metal part starts with one and the material it consumes never comes back.
Cuts per bar. Kerf plus facing stock is lost on every piece. On a 2 in long part cut from bar, that loss can approach 10% of the material.
Machine choice. A cold saw costs more per cut than a band saw and can save a facing operation downstream. If the sawn face is a finished face, that trade usually pays.
Bundle capability. Cutting a bundle divides machine time across every piece in it and is the largest single lever on cost for volume work.
Blade life. Blades are consumables. Correct pitch, correct speed, proper break-in and adequate chip load extend life several times over; the same blade misapplied in stainless can fail in a shift.
Material. Stainless and titanium cut slowly and consume blades quickly; aluminum cuts fast with carbide.
Three ways to take cost out:
- Cut in bundles wherever the machine and the tolerance allow.
- Use a cold saw when the sawn face is a finished face, and a band saw when it is going to be machined anyway.
- Choose part lengths that divide cleanly into standard 12 or 20 ft (3.6 or 6 m) mill lengths so remnants are minimized.
Questions
6 questionsHow do I choose the right saw blade pitch?
Keep at least 3 teeth engaged in the cut at all times and no more than about 24, and select from the thickness of material the blade actually passes through rather than the overall part size. A 4 in tube with a 0.120 in wall needs a fine 10/14 pitch, not the coarse pitch its diameter would suggest. Variable-pitch blades are standard because the varying spacing suppresses chatter.
What tolerance can a saw cut hold?
A production band saw holds about ±0.030 in (±0.75 mm), tightening to ±0.010 in (±0.25 mm) with careful setup. A cold saw holds ±0.005–0.010 in (±0.13–0.25 mm) and produces a much squarer face. Abrasive chop saws are looser than either and heat the cut end. Squareness usually degrades before length does.
How much extra length should I leave for facing?
0.030–0.060 in (0.8–1.5 mm) per end after a cold saw and 0.060–0.125 in (1.5–3 mm) per end after a band saw. A saw cut is a stock-preparation operation, not a finishing one, and expecting a finished length straight off the saw is the most common cause of rework at the lathe.
Why do saw blades fail early?
Usually skipped break-in or insufficient chip load. A new blade should run at reduced feed for the first several cuts to hone a controlled radius onto each tooth tip. Feeding too lightly is equally damaging, especially in stainless, where rubbing rather than cutting work-hardens the surface ahead of the teeth.
What is the kerf of a band saw?
About 0.035–0.065 in (0.9–1.65 mm) depending on blade width, compared with 0.060–0.125 in (1.5–3 mm) for a cold saw and wider still for abrasive wheels. On short parts cut from bar, kerf plus facing stock can consume close to a tenth of the material, which is worth calculating before ordering stock.
Should I saw or laser cut tube?
Saw a plain length; laser cut anything with features. A saw cut is far cheaper per piece, but once the part needs holes, notches, a coped end or joint geometry, tube laser cutting produces all of it in one operation and eliminates the drilling, notching and fixturing that would otherwise follow the saw.