Types of Metal Saws

1. Types of Metal Saws Unit 35

2. Methods of Cutting Off Material • Five most common methods of cutting off material • Hacksawing • Bandsawing • Abrasive cutting • Cold sawing • Friction sawing

3. Power Hacksaw • Reciprocating type of saw • Frame and blade travel back and forth • Pressure applied automatically on forward stroke • Limited use in machine shop work • Usually permanently mounted to floor

4. Power Hacksaw

5. Power Hacksaw

6. Power Hacksaw

7. Horizontal Bandsaw • Flexible, belt like "endless", blade that cuts continuously in one direction • Thin, continuous blade travels over rims of two pulley wheels and passes through roller guide brackets • Support blade and keep it running true • Popular for high production and versatility

8. Horizontal Bandsaw

9. Abrasive Cutoff Saw • Cuts by means of thin, abrasive wheel revolving at high speed • Well suited for cutting most metals and materials such as glass and ceramics • Can cut to close tolerances • Can be performed under dry conditions • Use of cutting fluid keeps work and saw cooler and produces better surface finish

10. Abrasive Cutoff Saw

11. Cold Circular Cutoff Saw • Uses circular blade similar to one used on wood-cutting table saw • Generally made of chrome-vanadium steel • Carbide-tipped blades used for some applications • Suited for cutting aluminum, brass, copper, machine steel, and stainless steel

12. Cold Circular Cutoff Saw

13. Friction Sawing • Burning process by which saw band (with or without) saw teeth, is run at high speeds to burn or melt its way through metal • 10,000 to 25,000 sf/min • Cannot be used on solid metal • Amount of heat generated • Excellent for cutting structural and honeycombed parts of machine or stainless steel

14. Horizontal Bandsaw Parts • Frame - hinged at motor end with two pulley wheels over which continuous blade passes • Step Pulleys - Used to vary speed of blade • Roller guide brackets - Provide rigidity for section of blade • Blade tension handle - Used to adjust tension on saw blade • Vise - Mounted on table, adjusted to hold work

15. Saw Blades • Commonly made of high-speed tungsten and high-speed molybdenum steel • Hardened completely for power hacksaw • Flexible blades on bandsaws have teeth hardened • Manufactured in various degrees of coarseness, ranging from 4-14 pitch • 10-pitch blade used for general-purpose sawing • Always select saw blade as coarse as possible • Always have two teeth of blade in contact with work at all times

16. Installing a Blade • Make sure teeth are pointing in direction of saw travel or toward motor end of machine • Adjust blade tension to prevent blade from twisting or wandering during cut • Rotate work ½ turn in vise, if need to replace blade before cut finished • Prevent new blade from jamming

17. Sawing • Important that correct type and pitch of saw blade be selected and run at proper speed • Blades • Finer tooth when cutting thin cross sections and extra-hard materials • Coarser tooth used for thick cross sections and soft, stringy material • Speed • Should suit type and thickness of material • Too fast will dull saw teeth quickly

18. Sawing Hints • Never attempt to mount, measure, or remove work unless saw is stopped • Guard long material at both ends to prevent anyone from coming in contact with it • Use cutting fluid whenever possible to help prolong life of saw blade

19. When sawing thin pieces, hold material flat in vise to prevent saw teeth from stripping • Use caution when applying extra force to saw frame • Generally causes work to be cut out of square • Set stop gage when several pieces of same length are required • Place short piece of same thickness in opposite end of vise when holding short work