Band Saw Blade Length Calculator

Band Saw Blade Length Calculator for two- and three-wheel saws. Measure axle to axle with the upper wheel down and then up to see which stock blade lengths fit your tension travel.

Using the Band Saw Blade Length Calculator on Your Saw

The Band Saw Blade Length Calculator turns two axle-to-axle measurements into the blade loop your saw needs. It then checks which stock lengths fit inside the tension travel, so you can order a standard blade before paying for a custom weld.

It suits used saws with no manual, saws that just gained a riser block, and older machines whose nameplate is gone. It also covers benchtop three-wheel saws and saws with upper and lower wheels of different sizes.

Measuring Axle to Axle With the Wheel Down and Up

Take the blade off and turn the tension knob until the upper wheel stops at its lowest point. Measure from the center of the upper axle to the center of the lower axle. Then raise the wheel as far as it goes and measure again.

Enter both distances in Quick Setup with the wheel diameter, measured across the tire where the blade rides. If the old blade is still on and tensioned, pick One Distance, Blade On under Measuring Method and Riser. A three-wheel saw needs its three axle-to-axle spans instead.

The Loop Formula Blade Makers Print

A two-wheel blade wraps half of each wheel and covers the center distance twice. Olson Saw prints this as each wheel radius times pi, plus twice the center distance, in its band saw blade tips sheet. With equal wheels it reduces to one line.

$$L=\pi D+2C$$

Here L is the blade length, D is the wheel diameter and C is the axle-to-axle distance, all in inches. A common slip is putting the diameter into Olson's radius version, which adds a whole extra circumference, about 44 in on 14 in wheels.

When the upper and lower wheels differ, the calculator uses the exact tangent-line length rather than the averaged shortcut. The angle alpha comes from the radius difference divided by the center distance.

$$L=\pi (R_1+R_2)+2\alpha (R_1-R_2)+2C\cos \alpha$$

$$\alpha =\arcsin \left(\frac{R_1-R_2}{C}\right)$$

The exact length runs longer than the shortcut by roughly the diameter difference squared, divided by four times C. A 14 in wheel over a 12 in wheel at 24 in centers adds only 0.04 in. An 18 in wheel over a 12 in wheel adds about 3/8 in, which can change the stock size.

A three-wheel saw turns the blade through one full circle in total, whatever shape the triangle takes. So the loop is one wheel circumference plus the three straight spans, which is why Sawblade.com tells three-wheel owners to measure axle to axle all the way around.

$$L=S_1+S_2+S_3+\pi D$$

A riser block lengthens both straight runs, so a 6 in riser adds 12 in of blade. Enter a riser only when you measured before fitting it. Measurements taken with the riser installed already include it.

Wheels can run from 3 to 60 in and center distances up to 120 in. The center distance must exceed the average wheel diameter, or the wheels would overlap. The wheel-up reading must beat the wheel-down reading by no more than 12 in, and three-wheel spans must close into a real triangle.

Reading the Band Saw Blade Length Calculator's Fit Window

Highland Woodworking's bandsaw blade length guide explains the idea behind the first card. The wheel-down distance gives the shortest loop and the wheel-up distance gives the longest. A saw then takes blades from a little over the shortest to about 3/8 or 1/2 in under the longest.

The calculator sets that window at 1/4 in above the shortest loop and 1/2 in below the longest. The hero shows the loop at mid-travel, and the first card names the nearest stock length inside the window with its position as a share of the travel.

Highland's own riser-equipped Delta 14 in makes a good test. Its centers run from 30 in to 31-1/8 in on 14 in wheels, giving loops of 103.98 in and 106.23 in. The calculator returns a 104-1/4 to 105-3/4 in window and picks a 105 in blade at 45% of the travel, matching Highland's hand figures.

Between 25% and 75% of the travel counts as a comfortable fit. A blade low in the window is hard to slip on, and each re-weld shortens it further. A blade high in the window leaves little room for tension. When no stock size fits, the card switches to a custom weld at the computed length.

Some saws have far less room. Grizzly's G0555 spec sheet lists a blade length range of only 92-1/2 to 93-1/2 in. On a 1 in window, reading both wheel positions is the only way to know which end of that range your saw favors.

Blade Width, Teeth per Inch and Blade Speed

The other three cards use Olson's selection charts. Olson advises a blade as wide as the saw allows but narrow enough for the curve, so the second card returns the widest blade that can follow your tightest radius. At a 2 in radius that is 3/8 in, rated for 1-1/2 in.

Treat that chart as a starting point. On LumberJocks, one woodworker notes that tooth set matters as much as width, and reports that Olson's 1/4 in blades would not turn the charted 5/8 in radius.

The third card follows Olson's rule of at least three teeth in the work. It picks the coarsest pitch that keeps three teeth in your stock. For 3/4 in boards that is 4 TPI, which Olson calls a fast cut, while 14 TPI cuts slower and leaves a smoother face.

Olson pairs each pitch with the thinnest stock it can cut while keeping three teeth engaged. The third card reads from this chart, which the tool itself does not display.

Olson recommends 2 to 3 TPI for resawing stock up to 8 in, so the card turns amber above that. For resawing, the Rough to Finished Lumber Calculator shows what each slice leaves after the kerf, and the Workshop Layout Calculator checks infeed and outfeed room.

The fourth card finds blade speed from the motor nameplate RPM and the two pulley diameters. Wheel speed is the motor RPM times the motor pulley divided by the wheel pulley.

$$N_w=N_m\times \frac{d_m}{d_w}$$

Olson then converts wheel RPM to surface feet per minute with a 0.262 factor, which is pi divided by 12. With mixed wheel sizes, the calculator treats the lower wheel as the drive wheel.

$$SFPM=N_w\times D\times 0.262$$

The default 1,725 RPM motor with a 2-1/2 in pulley on a 5 in wheel pulley gives 863 wheel RPM. On 13-3/4 in wheels that is about 3,105 SFPM, just over the 3,000 SFM ceiling Olson sets for spring-steel wood blades. Olson rates its carbon flex-back blades to 8,000 SFM, and the card turns red past that.

Real safe speed also depends on the blade maker, blade condition and belt slip, so check the rating printed on the blade before running near either limit. Turners rounding bowl blanks on the band saw can take the blank diameter to the Lathe Speed Calculator next.

Measuring Slips That Order the Wrong Blade

Taking one reading with the tension cranked all the way up is the most common trap. That length fits only at the very top of the travel, and forum advice on TractorByNet warns against measuring at full tension for that reason.

Adding 12 in to an assumed 93-1/2 in base is another. In a Router Forums thread about a Grizzly riser kit, replies ranged from 105 in to 110 in because posters started from different base lengths.

The last is counting the riser twice. Center distances measured with the riser installed already include it, so entering the riser height again adds another 12 in.

Straight Answers on Band Saw Blade Sizes

What size blade does a 14-inch band saw take?

Most cast-iron 14 in saws on the old Delta pattern take 93-1/2 in, and Olson's saw list gives that for Delta 14 in, Jet JWBS-14 and Powermatic PWBS-14CS models. The Olson blade finder matches lengths by saw model.

Other 14 in saws vary widely. Olson lists 111 in for the Rikon 10-325 and 104-1/2 in for the Laguna LT14, and Laguna's 14|12 takes 115 in. A Woodworking Talk member adds that many newer Taiwanese-made 14 in saws take 92-1/2 in.

How much blade does a 6-inch riser block add?

In theory it adds 12 in, which puts a 93-1/2 in saw at 105-1/2 in. Yet the standard riser size is 105 in, as Olson lists for Delta 14 in saws, and members in a Sawmill Creek thread run 105 in blades on Delta and Jet risers.

Both lengths usually fit because both fall inside the tension window. Highland's riser-equipped Delta takes 104-1/4 to 105-3/4 in, and a 105-1/2 in blade would sit at about two-thirds of its travel.

Will a blade 1/2 in longer or shorter than the listed size fit?

It often will, though not on every saw. Highland notes that most saws accept lengths across a range up to 2 in wide, and that a measured 114-5/8 in blade can usually be replaced by a 114 in or 115 in one.

The Woodworking Talk thread above shows the other side, with a 93-1/2 in blade too long to tension on a Ridgid 14 in. Entering both wheel positions settles this before you order.

How do I measure the length of an old blade?

Mark the blade, stand it on the floor at the start of a tape measure and roll it until the mark comes around again. Highland treats that reading as a target, and a blade that has been re-welded after a break will read short.

Can I measure the loop with a string?

A string works if it cannot stretch. Woodworkers on NC Woodworker and TractorByNet describe wrapping mason's line around the wheels along the blade path with the upper wheel near mid-travel. It gives one length at one wheel position, so treat it as a cross-check on the calculated loop.