To make an effective cut and get the most efficiency from a hacksaw, the blade TPI (teeth per inch) needs to match the specified material thickness.
The following chart is a general guideline, based on Lenox hacksaw blades.
|Wood and Thick Metal Use||14||1/8″ – 1/2″|
|Heavy Metal Use||18||1/8″ – 1/2″|
|Medium Metal Use||24||3/32″ – 5/16″|
|Thin Metal Use||32||less than 1/8″|
|Glass, Ceramics, Marble, Fiberglass and Steel||Carbide Rod||–|
Blade TPI and nominal material thickness varies slightly between blade manufacturers. This information is printed on individual packaging and we suggest following manufacturers guidelines for best results.
We’ve made a few notes describing the possible variations from one blade manufacturer to the next.
Note 1: A Lenox 14-TPI blade has a minimum thickness rating of 1/8″, whereas a Morse 14-TPI blade has a minimum thickness rating of 3/16″. We tested both brands of blades to find the truth in these specifications.
- The Lenox 14-TPI blade effectively cuts 1/8″ thick material, as stated.
- The Morse 14-TPI blade struggled to cut below 3/16″ and is ineffective in cutting 1/8″ thick material.
Note 2: A DeWALT 18-TPI blade has a material thickness rating of 1/4″ – 1/2″. Most other 18-TPI blades have a minimal material thickness rating of 1/8″.
The DeWALT 18-TPI blade also effectively cuts a minimum of 1/8″ thick material. A very confusing discrepancy in DeWALT’s nominal material thickness.
Note 3: Material thickness (not diameter) relates to blade TPI. When cutting a tube – the wall thickness relates to the required blade TPI – and not the overall diameter.
Continue reading to find more in-depth TPI blade and material cutting information…
The lower the TPI…the larger the gap between teeth…and the longer the tooth. This allows more material removal and clean-out with each saw stroke, thus saving cutting time.
The higher the TPI…the smaller the gap between teeth…and the shorter the tooth. This allows the different blade TPI to cut a minimal material thickness without getting hung up in the material. Reference the image: Cutting with a 32-TPI blade.
Cutting with a 14-TPI hacksaw blade
|Square Bar||Round Bar||Plate / Sheet||Angle||Structural|
I am not sure why Lenox suggests using a 14-TPI blade for cutting wood. After several thick wood cutting tests (softwood and hardwood), I discovered a 14-TPI hacksaw blade is hopeless at cutting wood. The blade constantly gets hung up in the material. We also tried a Morse 14-TPI blade and it too suffered the same ineffectiveness to cut thick wood.
Considering a hand saw to cut wood has an even lower TPI blade, I’ll chalk this up to the more generic design of a a fine-tooth hacksaw blade and its struggle to cut wood with such a low tooth count.
If you want to cut wood with a hacksaw, a 18-24 TPI blade works effectively.
Cutting thick metal with a 14-TPI blade works well. Using a 14-TPI blade to cut thick metal (over 1/8″) will speed up the cutting process compared to a 18-TPI blade. Although, I question the need for a homeowner projects.
|1/8″ Steel U-Channel||27 sec.||30 sec.|
|1/2″ Rebar||24 sec.||26 sec.|
Note: Finding 14-TPI blades at local home improvement stores may not be possible, and many of the hacksaw blade brands don’t offer a 14-TPI model. Don’t worry, a 14-TPI blade isn’t needed for homeowner projects. However, a tradesman may want to experiment with a 14-TPI blade compared to using a 18-TPI blade if hand sawing heavy metal regularly.
Cutting with a 18-TPI hacksaw blade
|Square Bar||Round Bar||Plate / Sheet||Angle||PVC / Tubing|
A 18-TPI blade gives you many of the same cutting abilities as a 14-TPI blade, but with less effort and smoother cutting.
Cut a wide range of wood thicknesses. A hacksaw isn’t the ideal choice for cutting wood, but for random projects where precision cutting isn’t needed, a hacksaw will get the job done, e.g. cutting a tree limb, demoing a small wall or building structure.
A hacksaw is very effective for plumbing projects that use PVC. A 18-TPI blade cuts through PVC tubing, whether trying to cut and remove existing plumbing, or cutting new PVC to length for a plumbing project. E.g. replacing a garbage disposal, sump pump, or an outdoor drainage project. Use a utility knife to deburr the PVC after each cut.
Cutting with a 24-TPI hacksaw blade
|Square Bar||Round Bar / Wood Dowel||Plate / Sheet||Angle||PVC / Tubing|
A 24-TPI comes standard on hacksaws and from our tests offers the most range. The tooth count and size isn’t too small nor too large.
As an example: Lenox rates their 24-TPI blade to cut 3/32″ thru 5/16″ for hardened materials, but you have more cutting flexibility on other materials.
- Cutting PVC with a 24-TPI blade is just as effective as using a 18-TPI blade.
- Rough cut wood lumber and wood dowels from 1/16″ and thicker.
Because of the softer materials compared to hardened metals, material thickness isn’t as much a consideration.
Note: For precision cutting, a power or hand miter saw is recommended. I recommend the Nobex Champion 180 miter saw for many reasons, including: quick and precise cuts without the dust of an electric miter saw. Great for indoor projects. We’ll be doing a future review of the Nobex saw.
Cutting with a 32-TPI hacksaw blade
|Square Bar||Round Bar / Wood Dowel||Plate / Sheet||Angle||Tubing|
A 32-TPI blade is a must when cutting thin material, e.g. electrical conduit and copper pipe. The short and closely spaced teeth can cut the material – and not just hook into it (impeding the cutting).
Stay at the lower range of specified material thickness. A 32-TPI blade is rated to cut material up to 1/8″ material, but a 24-TPI blade cuts just as effectively and faster for materials above 3/32″ (roughly).
Cutting gutter downspouts. Once in a while a gutter downspout gets damaged and needs replacing. Unfortunately, a hacksaw (even with a 32-TPI blade) isn’t an economic solution to cut a new downspout to length. The ultra thin material causes the teeth to get hung up. For cutting gutter and downspout material use a circular saw with a metal cutting blade.
Combining a hacksaw with a basic miter box is an economical way to help make more precise cuts.
Read our replacing shower door seals article on how a hacksaw and miter box is a great solution for cutting new shower seals to length.