If you have been using your cold saw blade well enough, you would know that, eventually, it would become blunt. It is, therefore, essential to be aware of the maintenance practices required to keep it in good shape. These practices center around the sharpening of the cold saw blades. You, therefore, need to understand the basics of cold saw blade sharpening– the pros and cons, etc. This article focuses on addressing all your concerns and worries as regards cold saw blade sharpening.
Set of a circular cold saw blade used for metal cutting
Table of Contents
- 1. What Factors Affect Sharpening?
- 2. When Do I Need To Sharpen?
- 3. How Often Do I Sharpen?
- 4. What Should I Pay Attention To When Sharpening?
- 5. Pricing And Costing?
- 6. Mode Of Sharpening?
- 7. What To Avoid When Sharpening?
Figure 1: Set of a circular cold saw blade used for metal cutting.
1. What Factors Affect Sharpening?
The act of sharpening your cold saw blade revolves around some factors. These factors help you determine how to sharpen your cold saw blade. Failure to consider these various factors can cause improper sharpening and job delay. It would translate to the poor performance of your cold-cut saw blade and loss of money and sometimes valuable customers. Below are the factors:
I. Cold saw blade tip:
For an excellent performance of cold saw blades when cutting different metals, they are typically manufactured and finished at the tip/teeth with either HSS (high-speed steel) or Carbide. Although Carbide tipped cold saw blades are powerful and tend to last long due to the hard nature of Carbide, this makes the sharpening somewhat tricky as well. Unlike the HSS-tipped cold saw blade, which is relatively easier to sharpen but has lesser cutting ability than carbide-tipped.
ii. Nature of metal:
Mild steel, Stainless steel, Aluminium, etc., are among the numerous metals a cold saw blade can easily cut. Cold saw blades would have varying performance due to the type of metal they cut- This implies that the blades’ teeth would get blunt quickly depending on how strong the metal it cuts is. Hollow or solid metal rods or bars also contribute to the wear of a blade, so does it contribute to the sharpening.
Close-up picture of Carbide tipped cold cut saw blade
Figure 2: Close-up picture of Carbide tipped cold cut saw blades
2. When Do I Need To Sharpen?
Usually, it is left to you to determine when to sharpen your blade(s) based on its performance. Remember that for every sharpening of the blade’s tooth, some portion of the blade gets ground off- This further affects all the critical angles of a typical blade, which alters the original dimensions of your blades.
The implication is that you should only sharpen your blade when the teeth become blunt and cannot cut anymore or take longer than usual. Hence, no rigid or specific date is attached to sharpening your cold saw blades. In essence, plan to sharpen your blade only when it can no longer cut your desired metals. The best you can do is to estimate the average period your blade last before getting blunt based on your usage. Finally, kindly note that whatever works for you might not work for others, so stick to your unique sharpening plan and schedule.
The performance of your cold saw blades can be measured using the following yardsticks:
Increment in tear-out and chipping during cutting
Higher resistance to cutting
Difficulty in following cut lines
Increase in the noise of electric/saw motor
Signs of wear and damage.
Inspection all teeth
Close-up picture of a blade undergoing sharpening
Figure 3: Close-up picture of a blade undergoing sharpening.
3. How Often Do I Sharpen?
Larger diameter cold saw blades can be re-sharpened and re-used up to about 15 to 20 times before discarding and replacing with a new one. Discard the small-diameter blade.
The carbide-tipped cold saw can be re-sharpened up to 4 or 5 times. Again, a rough estimation shows that freshly sharpened blades last between 15 to 20 cuts before it gets blunt still.
The type of metal to cut also contributes to how frequently you sharpen your blades. If you cut Aluminium more than steel, then your cold saw blade is likely to get blunt earlier than that.
Sharpening of blade ongoing
Figure 4: Sharpening of blade ongoing.
4. What Should I Pay Attention To When Sharpening?
When sharpening your blade, key factors to pay careful attention to are as follows:
i. Hook angle:
It is important not to tamper with the hook angle of the cold saw blades as this can negatively affect the blade’s balance when mounted for use and can even give an inferior cutting surface finish to the workpiece.
ii. Tooth thickness:
A common rule of thumb is that you never let your cold saw blades get blunter than 0.008′ (8/1,000 inches) edge radius. The maximum allowable bluntness is 0.004′, which is the same as the thickness of a piece of paper.
Showing tooth thickness and hook angle of a cold cut saw blade
Figure 5: Showing tooth thickness and hook angle of a cold cut saw blade
5. Pricing And Costing?
The cost of sharpening a typical cold saw blade is $10 to $20 for a 10 to 14-inch diameter cold saw blade. Prices vary with the diameter and number of teeth of the blade. In the cold saw blade sharpening business, the cost of sharpening an HSS-tipped cold saw blade is solely based on the blade diameter, while for a carbide-tipped blade, the price is dependent on the number of teeth. In simpler terms, a 20″ or 100″ carbide-tipped blade would cost the same to sharpen but differ if it is an HSS-tipped. As the number of blades you intend to sharpen increases, so does the discount on the price.
6. Mode Of Sharpening?
Over time, technological advancement has made sharpening blade an effortless job. Nowadays, you can purchase a personal sharpening machine, and with the manual, you can efficiently operate and do your sharpening yourself. Although there are two major ways to go about sharpening your blade, namely:
i.Manual/ Semi-Automated Filing:
This involves using a circular saw to sharpen the teeth of cold saw blades one after the other. In doing this, ensure you wear the appropriate safety gear to protect yourself from the hot chips. Firstly, you remove the cold saw blade from the table and mount that on the circular saw. Next, you use a jig to hold the cold-cut saw blade in place. Once you set up the arrangement, start the electric motor saw blade next to the cold saw blade across the tooth one after the other. Make sure to mark the point you started so you can stop at that point too.
On the other hand, a hand file can also do the job of sharpening. You can place the hand file at an angle of 20 degrees against the teeth and stroke 3 to 4 times across each tooth.
ii. Machine Filing:
Machines eliminate human intervention in sharpening. Machines are either four or six-axis servo-controlled -they grind the face, top, and every angle of the tooth just in one pass. This machine saves time and effort. This machine is fully automated with an LED screen to instruct the operator on what to do. The cutting angle, blade diameter, and blade thickness are the required input needed to start the sharpening.
CNC automatic sharpening of a circular cold-cut blade
Figure 6: CNC automatic sharpening of a circular cold cut blade.
7. What To Avoid When Sharpening?
If you have decided to carry out sharpening yourself, then you might need to take note of the following preventive measures to avoid injuries or accidents of any form:
1. Put off the electrical switch and socket when switching the cold saw blades for the diamond saw blade.
2. Use safety goggles to avoid fine chips from entering your eye.
3. Safety gloves and ear-muffs are also essential to prevent cuts to the hands and unbearable noise.
Operator wearing a glove and other protective wear as he cuts metal
Figure 7: Operator wearing a glove and other protective wear as he cuts metal.
In summary, having read through this article, you should be able to determine if you need to sharpen your cold saw blades and other related matters arising from sharpening. NCCuttingtools is known to be the number-one solution provider on saw blades and similar related services at the most competitive price you can find in the market. Do well to contact and partner with us on your next cutting tool project; we are sure you will not be disappointed.