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From time to time I will blog things that I think you will find useful. If you would like to see something here, then let me know and I will try to blog it .

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How do I fit my TCT blade?

Posted on December 17, 2012 at 6:10 AM

Most of you know how to do this, but sometimes I do get asked. I have even been called out to a customer who compained his sharpened blade was burning wood - he had fitted it the wrong way round ! He had never done it before and never will again, but now I never assume you know how to do this.

Be sure your machine is maintained in perfect condition and free from bearing play. The saw blade must run true on the mandrel and be in perfect line with the fence or saw guide. Make sure that clamping flanges are clean and flat and the blade is clamped securely on the arbor. Even a small piece of dirt on a clamping flange can cause the outside cutting edge to run out of true enough to cause problems.

Keep the blade clean and free of resin. This will prevent overheating or burning of the blade body and ensure longer blade life and freer cutting.

Carbide tips are extremely hard and are also very brittle and should not be subjected to sharp blows from other hard objects. Always exercise care when handling your blade.

Do I need a positive or negative rake angle?

Posted on December 17, 2012 at 5:55 AM

The rake or hook angle is the angle of lean on the front of the tooth. You can check it by placing a straight edge between opposite teeth and going through the centre of the blade. The steeper the hook angle the more aggressive the cut - i.e. it bites into the material more.

Woodcutting on portable and table saws typically requires a positive hook.

Negative hook gives resistance to feed so will not climb into the cut, this avoids 'grabbing'. Ideal for cutting using chopsaws and radial arm machines for crosscutting.

There are exceptions to these general rules so refer to your machine's reference guide unless replacing blades like for like or if you are cutting new or unusual materials - aluminium and plastics can be a problem

How long does my band need to be?

Posted on December 17, 2012 at 5:40 AM

I am amazed at how many customers do not know how long their band needs to be! Write it down somewhere please!!!

You can calculate the length of band needed with some simple measurements and maths. First adjust the wheels so they are close to the middle of their adjustment range. Measure the radius of the first wheel and multiply by 3.1416. Measure the radius of the second wheel and multiply by 3.1416. Measure the distance between wheel centres and multiply by 2.  Now add up the three numbers and that should be the length of band needed.

(radius 1 x 3.1416) + (radius 2 x 3.1416) + (centre to centre x 2) = band length

 

Should I use a cutting fluid?

Posted on December 17, 2012 at 5:40 AM

The simple answer is yes if you are cutting metals. Use a good quality cutting fluid with an extreme pressure additive and it will prolong the life of your band. There are very few metals which do not require a cutting fluid and it has to be used with virtually all steel or steel alloy materials. It is generally cheaper to use water soluble fluids when cutting low carbon, low alloy or general materials. You will get improved results with neat cutting oil when cutting high carbon, high alloy or stainless steel materials.

Coolant should flow fast enough to ensure the work is kept cool and to flush swarf from the area otherwise the work piece will heat up and allow swarf to adhere to the blade causing choking and teeth to strip.

Usually it is better to dry cut cast iron. Aluminium is better cut using paraffin as a coolent in general.

Do not mix different coolants in the same machine.

 

How do I recoil a band for storage?

Posted on December 17, 2012 at 5:35 AM

Ask me to show you next time I visit – it’s quite simple when you know


How do I know if I am using the correct feed rate?

Posted on December 17, 2012 at 5:30 AM

Whilst this is important for all types of material being cut, I will focus on metals because they seem to cause the most problems.

Chips are the pieces of material that have been cut away and can be the best clue to incorrect feed rates. If they are powdery, then increase the feed rate. If they have a blue colour (burnt) then decrease the feed rate. If they are free-curling and not discoloured, then the feed rate is right.

Increasing the feed rate will produce bigger chips. Increasing the band speed will make more teeth pass through the cut per minute ensuring a smoother cut.

If you are cutting wood and it is burning - reduce the feed rate, use a courser tooth or give me the blade for sharpening - or all three

Does my new band really have to be 'run in'?

Posted on December 17, 2012 at 5:30 AM

Yes it does ! Most bands are accurately heat treated and have an extremely sharp cutting edge and if you want to keep it that way for the longest time possible then it needs running in. To do this reduce the feed pressure by about one third of normal for the first 500square cm of cutting. While doing this it is important not to reduce the band’s surface speed and to avoid vibration, shock or mechanical abuse. In otherwords, slow and steady when feeding work in

How do I set up the guides on my verticle machine?

Posted on December 17, 2012 at 5:25 AM

First thing to do before you try to set up your guides is to get the band tension set properly. Then it is simple – just move the back and side guides so they just touch the band without deflecting it from the path it wants to follow naturally.

Why do my bands crack?

Posted on December 17, 2012 at 5:15 AM

This is often due to incorrect tension of the band. Correct tension is vital if you want to get the best life from a band. I cannot stress this enough. Generally speaking, the band should be tensioned so it does not slip while it is working. Your manufacture’s manual will give you detailed information about this.

From time to time, it may be necessary to make adjustments for band stretch. And something that most people do not do is to take off the tension when the machine is not being used – at least do this overnightand at weekends please.


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