Product Selection

Bandsaw Selection

What is your sawing application?

What is your sawing requirement-pieces on the floor, or blade life? Do you cut one thing continuously or many over the life of the blade? Different operating conditions and different expectations help determine what type of blade and what TPI is selected.

What is your material?

The "toughness" of metal affects tool life. Material can look the same but vary greatly in machinability, with one being much harder to cut than another. Material hardness also affects cutting performance, with annealed metals cutting more easily than hardened metals.

What shape is the material?

Work piece shape can affect cutting performance-structural materials and small solids tend to be harder on a band saw blade. Work piece positioning on the saw is another variable-try to position the material so there is as little cross section dimensional variance as possible across the blade's path.

What is the material dimension?

Do you cut mostly one dimension or a wide variety of dimensions on a regular basis? Determine what your most common dimension is, then select the proper TPI for your band saw blade. Remember -"one blade fits all" is not always the case-sometimes it is optimal to use more than one blade to cut a wide range of materials.

What is the best blade to use?

Band quality varies widely depending upon the blade type-carbon, bi-metal, or carbide-tipped. They differ in their ability to resist the heat generated while cutting and in their ability to resist the "shock" of entering and exiting the cut (a prime consideration when cutting structurals, pipe and tubing). Generally carbon bands are good for maintenance shops, general purpose low volume cutting, or for cutting wood, plastics and other non-ferrous materials. Bi-metal blades are the "everyday workhorse", handling everything from simple metal cutting to production cutting of the super alloys. Carbide tipped blades excel cutting the super alloys and in applications where high production rates and/or good surface finish is a requirement.

What is the correct TPI?

Too few teeth in the cut may straddle the work and break teeth. Too many teeth can cause gullet overload and strip teeth. Aim for a minimum of 3 teeth and a maximum of 24 teeth in the work piece, with 6 to 12 teeth in the work piece optimum for most applications.

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Tooth Set Selection

Variable Pitch

This tooth form combines a positive rake for more aggressive cutting, with multiple tooth pitches repeated throughout the band. This reduces chatter and vibration, while increasing blade life. Teeth are set alternately left and right, with raker teeth interspersed at regular intervals. Well suited for cutting structurals, pipe, tubing, solids, and a wide variety of shaped and sizes.

Raker or Regular Tooth Set

This tooth style has a zero degree rake angle and a full, rounded gullet. The teeth are set left, right, raker (unset); the pattern repeating throughout the band. This is the most widely used style for straight cut-off and contour cutting of both ferrous and non-ferrous materials.

Wavy Tooth Set

This style combines a neutral rake tooth with groups of teeth set to the right and the left in a wave-like pattern. This reduces the strain on individual teeth, allowing it to cut a wide variety of shaped and thickness without changing blades

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Tooth Pitch Selection

What tooth pitch do we use?

One of the most confusing areas to understand in bandsawing is how to select the right tooth pitch for the job. It is also important to understand that it is not practical to change a bandsaw blade each time you cut a different size material.

These two basic conditions are often in conflict, so we want to select a tooth pitch for each machine that is the best one for the average material being cut at that machine.  This information will also make it easier when we have to cut material at a machine that falls beyond the recommended range for that tooth size.  After you review this material, you may feel that the tooth pitch you are buying for your machine is wrong.  If that happens, check with your Scarney Industries and see if this should be changed.

Examine blade pitch

   Blade pitch is defined as the number of teeth per inch.  The number of teeth that come in contact with the workpiece can affect both blade performance and durability.  Too few teeth in contact with the work can lead to early tooth strippage. On the other hand, too many teeth can greatly reduce cutting rates and ultimately make the material impossible to cut.  Lower cutting rates mean less penetration per tooth, causing more rubbing than cutting, which can result in substantial work hardening of the material. 

   A cons tant pitch blade (uniform distance from one tooth tip to the next tip) can increase harmonic vibrations.  Harmonic vibrations can lead to excessive noise, undesirable saw or saw blade vibrations, and, in severe cases, bad cuts. A variable pitch blade –teeth that vary in gullet depth, set angle, and pitch- can greatly reduce harmonic vibrations.  With varying tooth spacing, sawing rhythms are interrupted, chip evacuation is improved, and less noise and a better overall cut.

Some terms and abbreviations have been used.  They are as follows:

TPI = Teeth per inch

3 Tooth Rule = Recommended minimum number of teeth in contact with the workpiece at any given time to help share the load and prevent stripping.

24 Tooth Rule = Recommended maximum number of teeth in contact with the workpiece at any given time to eliminate gullet loading.  Gullet loading causes a variety of cutting problems including crooked cuts, stripped teeth and bandsaw blade breakage.

Always strive for a minimum of 3 teeth and a maximum of 24 teeth in the cut
(6 to 12 teeth in the cut at any time is the optimum)
Soft materials (example: carbon)..........3- 6 teeth in the cut average
Hard materials (example: die steels)..........18-24 teeth in the cut average
Tough materials (example: Inconel)..........12-18 teeth in the cut average

Average Variable Pitch Teeth

Example:

4" bar stock-using a 3-4 TPI blade
Avg. TPI = 3 + 4 ÷ 2 = 3.5
(Bar stock size, multiplied by the average TPI = no. of teeth in the cut)
(4 X 3.5 = 14)
3-4 pitch would give us 14 teeth in the cut
4-6 pitch would give us 20 teeth in the cut
5-8 pitch would give us 26 teeth in the cut
6-10 pitch would give us 32 teeth in the cut

Items that influence tooth pitch selection

Material Shape

• Complex shapes can easily strip teeth. It is best to use a blade with less face rake angle when cutting structurals and other complex shapes.

Chip Formation

• Hard material require a small, strong tooth shape.
• Soft materials make large chips that fill up a gullet quickly. Select a large gulleted blade.

Chip Length

• The longer the tooth is in a cut, the more chip that will be generated, and the more gullet area that will be needed to hold the chip.
• Cutting stops when gullets are full

WHAT TOOTH PITCH DO WE USE?

Tooth pitch	Cross Section
24 tpi	up to 1/4"
18 tpi	up to 1/2"
14 tpi	up to 3/4"
10 tpi	3/4" - 1-1/4"
8 tpi	1" - 2"
6 tpi	2" - 3"
4 tpi	3" - 5"
3 tpi	5" - 8"
2 tpi	8" -16"
1.25 tpi	12" - 32"
0.75 tpi	28" - 100"

Tooth pitch	Cross Section
10-14 tpi	up to 1-1/4"
8-12 tpi	3/4-2"
6-10 tpi	1'- 2-1/2"
5-8 tpi	1-1/2" - 3"
4-6 tpi	2" - 4"
4-5 tpi	2" - 5"
3-4 tpi	3" - 6"
2-3 tpi	5" - 14"
1.4-2 tpi	10" -24"
0.75-1.25 tpi	20"-48"
0.55-0.75 tpi	40'-120"

Cutting Tubes and Profiles

Teeth per inch (TPI)

outside diameter wall thickness inches	3/4"	1-1/2"	2-3/8"	3-1/8"	4"	5"	6"	8"	12"	20"
1/8"	14	10/14	10/14	8/12	8/12	8/12	8/12	6/10	6/10	5/8
5/32"	10/14	10/14	8/12	8/12	8/12	6/10	6/10	5/8	5/8	4/6
3/16"	10/14	10/14	8/12	8/12	6/10	6/10	5/8	4/6	4/6	4/6
1/4"	10/14	8/12	8/12	6/10	6/10	5/8	5/8	4/6	4/6	4/6
5/16"	10/14	8/12	8/12	6/10	5/8	5/8	4/6	4/6	4/6	4/6
3/8"		8/12	6/10	5/8	4/6	4/6	4/6	4/6	4/6	4/5
1/2"		8/12	6/10	4/6	4/6	4/6	4/6	4/6	4/6	4/5
5/8"		8/12	6/10	4/6	4/6	4/6	4/6	4/5	4/5	4/5
3/4"			4/6	4/6	4/6	4/6	4/6	4/5	4/5	3/4
1-1/4"				4/6	4/6	4/5	4/5	4/5	4/5	2/3
2"							4/5	3/4	2/3	2/3
3-1/8"								3/4	2/3	2/3
4"									2/3	1.5/2

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