7.2 Types of Saws
Tim A. Bacon
Horizontal Saws
The saw that is parallel to the floor of the shop is called the horizontal bandsaw. It is capable of cutting large pieces of stock quickly and accurately. These saws are gravity fed using a hydraulic cylinder to control the rate of drop, or feed, of the blade. The horizontal saw has a pivoting vise integrated into the frame to facilitate holding the material when being cut. Most of these saws also have some type of fluid system that floods the cut area to control temperature and remove chips.
Because of the automatic nature of the blade feeding through the material, the horizontal bandsaw can be set up to cut large pieces of material while unattended. The material is supported by a stand or table that will allow the bars being cut to slide forward once the vise is released.
Horizontal band saws use a vise to hold parts that are typically very long. Bar stock comes in from the suppliers at around five feet in length or more. The material is cut to a size that matches more closely to the finish dimensions of the part being made.
Vertical Saws
The vertical saw is very similar to the horizontal saw, and as the name implies, it stands upright. It shares several common characteristics with the horizontal saw. Some of the differences are the lack of a vise to hold the parts and coolant to reduce temperature. The benefit of a vertical saw is that the machinist can control the cut path by using their hands when they are at a safe distance from the blade. Using a push stick will help keep fingers away from the blade when the parts are small.
The most challenging parts to cut on these saws are small parts and round parts. Smaller parts are often clamped down to a sacrificial plate or nested between other material when they are being cut. Using a push stick can aid in cutting small parts and keep the heat away from fingers. For round parts, a square or “C” channel piece of material can be clamped to the part to keep it from rotating while being cut. The parts will become hot; DO NOT wear gloves. A glove can get caught in the blade and pull the hand and fingers into the blade.
Abrasive Saws
The abrasive saw is also referred to as a cutoff, or chop saw. These saws are a good choice in a production environment where accuracy is less of an issue. The material being cut should be in an annealed or non-hardened state and in the family of carbon steels. Hardened materials can be cut but will require a special blade and a coolant source.
- A shower of sparks will be created when using a chop saw. This is a fire hazard. Know where the sparks are going and have a fire extinguisher at hand. For a more in-depth discussion of safety, please refer to the earlier chapter on machine shop safety.
When using the chop saw, maintain awareness of the heat-affected zone. This is the area on either side of the blade where the cut is being made. It will get hot and can change the structure of the material, making it harder to cut later on. In simple terms, the abrasive disc is rubbing on the material and creating heat. The abrasive nature of the disc will wear away the material. The disc is similar to a grinding wheel. It is made of bonded abrasive particles. Each of the particles acts as a small cutting edge and can produce a cut. With the high rotational speed of the blade, these saws are relatively quick at cutting material. The tradeoff is that they create a great deal of dust and sparks, which can be harmful to the equipment or personnel if proper personal protective equipment (PPE) is not used. Safety glasses, and ear protection are always required.
Attributions
- Figure 7.7: Horizontal bandsaw by T. Bacon, courtesy of Bates Technical College, for WA Open ProfTech, © SBCTC, CC BY 4.0
- Figure 7.8: Metal cutting bandsaw (01) by S.J. de Waard is released under CC BY 2.5 Generic
- Figure 7.9: Vertical bandsaw by T. Bacon, courtesy of Bates Technical College, for WA Open ProfTech, © SBCTC, CC BY 4.0
- Figure 7.10: Vertical bandsaw workholding by T. Bacon, courtesy of Bates Technical College, for WA Open ProfTech, © SBCTC, CC BY 4.0
- Figure 7.11: Makita cut-off saw by Bill Bradley is released under CC BY-SA 3.0
- Figure 7.12: US Navy 070713-N-9760Z-023 Cpl. Jeffery Kline, assigned to the Red Devils of Marine Fighter Attack Squadron (VMFA) 232, cuts doorframes with a friction blade aboard nuclear-powered aircraft carrier USS Nimitz (CVN 68) by U.S. Navy/Mass Communication Specialist 3rd Class Eduardo Zaragoza in the Public Domain; This file is a work of a sailor or employee of the U.S. Navy, taken or made as part of that person’s official duties. As a work of the U.S. federal government, it is in the public domain in the United States.
a machine that uses a thin metal strip moving in a loop with cutting teeth on the edge, oriented parallel to the floor using gravity to cut material.
any object that can be used to push parts through the saw instead of fingers.