Band Saw Blade Selection
We supply bandsaw blades for many standard sized machines and blades made up to order using blade stock made by L.S. Starrett in either Scotland or the USA. Blade widths and TPI (Teeth Per Inch) available are indicated below.
In choosing a blade you might consider the following.
- It is good practice to have at least three teeth in the cut at any one time (it follows that thinner stock needs a higher teeth count).
- It is a given that for all powered, toothed saw blades there is an optimum feed rate for efficient cutting and maximising the life of the teeth edge.
- At the micro level teeth get very hot - even in relatively benign materials such as wood - which reinforces the above point about optimum feed rates.
- It is also a given that too light a pressure and too slow a feed rate will tend to lessen the life of an edge - in other words a saw must be worked.
- Tooth gullet capacity (the gullet is the gap between the teeth which carries the shaving which, when full, slows feed rate), the power of your machine, blade speed and of course sharpness largely determine the possible feed rate - the speed work can be cut.
- A blade with a high tooth count cutting a large cross section of wood will tend to bog down because the relatively small capacity gullets are overloaded and the cutting efficiency of the blade drops off.
- Faster feed rates equals rougher cuts, slower feed rates equals a finer cut.
- It follows then that halving the feed rate more or less doubles the effective tooth count.
- For a given feed rate, more teeth per inch equals a finer but slower cut and fewer teeth equals faster but coarser cuts.
- Generally (but not always) work faces cut on the bandsaw are re-worked after the cut so instances where an off-saw cut is appropriate to an end use are the exception.
- If you accept this then trueness and speed of cut may ultimately be more important than smoothness.
- Greater blade width means less ability to take corners and narrower blades are good at cornering. See the radius table below.
- Wide blades rip more accurately and are better at straight cutting.
- Wider blades are essential for cutting veneers usually with a fence. This is probably the most demanding bandsaw operation and it requires a perfectly and equally set blade, the highest tension you are willing to risk and often a fence with a few degrees of tweak so that you can follow the blade’s tendency to cut very slightly askew.
- If you need a tweakable fence, try making a subfence attachable to the main fence with some angle adjustability.
- Higher blade tension and attention to blade guides reduce blade wandering.
- Higher blade tension is less likely to cause blade breakage in wider blades which have a wider and stronger weld.
- Pay close attention to blade guides with cheek guides adjusted to within a millimetre of the beginning of a tooth.
- Blades which predictably cut askew are likely to have unequal set. (Set: the degree of splay usually in adjacent teeth, ideally equal, and necessary to allow the blade to have the clearance to cut and not jamb).
- The blade has a native thickness and a blade with set creates a cut width called the kerf.)
- Blades which randomly cut askew are usually blunt or poorly guided or poorly tensioned or overfed or of low quality.
- Blades should probably best track on or just backwards of centre of the wheels.
- Blades which pull off the wheels when work is pulled out of a cut are usually tracking too close to the front of the wheels or are running under less than optimum tension. Have a small wedge to hand to press into the kerf which can close up after the cut and hinder withdrawal in stopped cuts.
- Using standard blade stock thickness on small diameter wheels can cause fatigue cracks in the blade and/or premature weld failure.
- Mass produced, pre-packaged blades and blades fitted to new machines are generally of poorer quality than the made-to-order blades we supply.
- Never run bandsaws with the wheel guards removed. When a blade breaks it is as startling as a gun shot at close range and remember the powered lower wheel keeps turning and can cause serious injury if the blade remains are not contained.
- I cannot extract any enthusiasm from my saw doctor supplier for tungsten carbide tipped (TCT) band saw blades. I suspect this is because of the unyielding and problematic nature of the weld between the TCT tips and the blade.
- We do offer bi-material high speed steel blades for many metal operations and some wood.
ORDERING
We need to know the length of blade you require. To ascertain this, wind down the top wheel about 2/3 rds of its travel - i.e not right to the bottom limit but close to it - and either stretch a tape measure or a length of twine around both wheels and measure the length. Hint: Note this measurement in felt tip pen inside the top wheel housing cover.
Then using the available blade widths and TPI’s in the table below select your blade and email us for a quote info@thewoodworks.com.au
Table 1 - Lists options for smaller diameter two or three wheel machines with wheels under 280mm which require thinner blade stock.
Table 2 - Lists options for all general purpose two wheel machines with wheels over about 280-300mm.
Table 3 - Lists bi-metal blades which are indicated for cutting metals or highly abrasive, gritty woods such as recycled railway sleepers. Bi-metal blades are indicated for some exotic tropical woods which have pores loaded with silica deposits - for practical purposes stone - which is drawn up while in solution into the tree while alive and which is murderously hard on cutting edges.
TABLE 1 TPI-->
| 2 | 3 | 4 | 6 | 8 |
10 |
14 | 18 | 24 |
32 |
||
| 6mm | 1/4″ | 6 |
10 |
14 | |||||||
| 10mm | 3/8″ | 3 |
4 |
6 |
8 |
10 |
14 | 18 |
|||
| 12mm | 1/2″ | 4 |
6 |
10 | 14 |
TABLE 2 TPI-->
| 2 | 3 | 4 | 6 | 8 |
10 |
14 | 18 | 24 |
32 |
||
| 3mm | 1/8″ | 18* | |||||||||
| 5mm | 3/16″ | ||||||||||
| 6mm | 1/4″ | 3 |
4 |
6 |
8 |
10 |
14 | 18 | 24 | ||
| 10mm | 3/8″ | 3 |
4 |
6 |
8 |
10 |
14 | 18 |
24 | 32 | |
| 12mm | 1/2″ | 3 |
4 |
6 |
8 |
10 | 14 | 18 |
24 | 32 | |
| 16mm | 5/8″ | 3 |
4 | 10 | 14 | ||||||
| 19mm | 3/4″ | 3 |
4 | 8 | 10 | 14 | |||||
| 25mm | 1″ | 2 |
* Sorry we cannot warrant this blade against breakage due to its small width.
TABLE 3 TPI-->
| 2 | 3 | 4 | 6 | 8 |
10 |
14 | 18 | 24 |
32 |
||
| 12mm | 1/2″ | 4 |
6 | 6~10^ | 10~14^ | 14 |
18 | ||||
| 19mm | 3/4″ | 4~6^ |
5~8^ | 8~12^ | 18 | ||||||
| 25mm | 1″ | 2~3^ | 3~4^ | 5~8^ |
6~10^ |
Note: ^ These are variable pitch blades with sequential groups of as specified teeth per inch. For example an 8-12 has approximately 1/2 an inch of 8 TPI followed by 1/2 an inch of 12 TPI. Variable pitch bi-metal blades are used principally on slower running, metal cutting bandsaws and excel at cutting tubing, universal beams and rolled hollow squares (RHS) steel sections and are of limited general interest to woodworkers who will typically use band saws running at higher blade speeds.
Taking Corners
A chart to indicate achievable cutting radii for a given blade width.
Use this as a guide - there are other variables such as the degree of set, thickness of stock and sharpness of the back corners of the blade which will influence the minimum radius which can be cut.
While this may seem a dangerous practise, although identical in risk to cutting wood on a band saw, it is possible the improve the turning ability of a blade by holding a diamond honing plate or block of wood with sandpaper wrapped around it and slightly rounding and smoothing the back arises of the blade while the machine is running. Needless to say take extra care doing this!
Constructive corrections and comments welcome.
Revised 30/05/20