Bandsaw blade terminology: terms, other names and abbreviations
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Full article
DIY bandsaw mill: how to build one and which blade to choose
You can build a bandsaw mill yourself. What matters most is the wheel diameter, the blade speed and tension, and good wheel covers. Drawing on our customers' experience, we show what a homemade sawmill is made of, what sizes to choose and which bandsaw blade to fit.
Diagram of a DIY bandsaw mill: 1 drive wheel, 2 tensioning wheel, 3 bandsaw blade, 4 guides, 5 motor with belt, 6 head lift with crank, 7 water tank, 8 carriage on rails, 9 log supports, 10 wheel covers
Overview
What a DIY bandsaw mill needs
If you only saw timber a few days a year, you don't need to buy a machine costing thousands or even tens of thousands of euros. Many of our customers have built their own bandsaw mill. From their experience and what we know about bandsaw blades, we have put together what to keep in mind when building one. You will find photos of their mills below.
min. 450 mm
wheel diameter for a 0.9 mm blade, at least 610 mm for 1.1 mm
20–35 m/s
blade speed on a bandsaw mill
200 N/mm²
roughly the tension a sawmill blade needs
1.1 TPI
tooth pitch of a sawmill blade (a tooth roughly every 23 mm)
What the mill is made of
1Drive wheel with pulley
2Tensioning wheel with springs
3Bandsaw blade, the lower run cuts the log
4Blade guides
5Motor and belt
6Head lift with crank and scale
7Water tank for cooling the blade
8Carriage running on rails
9Log supports and clamps
10Wheel covers
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total photos:
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total photos:
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Construction
Bandsaw mill wheels
On every revolution the blade bends twice over the wheels and straightens out twice. In an hour of work that adds up to tens of thousands of bends. The smaller the wheels, the more sharply the blade bends and the sooner it cracks.
The wheel diameter should be at least 500 times the blade thickness. That is the lower limit: for a 0.9 mm blade, wheels of at least 450 mm, and our customers have had good results with 550 mm. For wheels smaller than 610 mm, blade manufacturers recommend 0.9 mm at most, so 1.1 and 1.3 mm blades belong on larger wheels.
| Blade thickness | Minimum wheel diameter |
|---|---|
| 0.9 mm | 450 mm |
| 1.1 mm | 610 mm |
| 1.3 mm | 650 mm |
✓Steel or cast-iron wheels are rigid, and the blade is easy to set up on them.
✓Car wheels with tyres are also used by our customers. The tyre has some give and can better take up the blade's expansion as it heats up: a blade 15 °C warmer is about 1 mm longer over a length of 5 m.
✓Where to get wheels: flat pulleys or wheels from old farm machinery will also do. Check a used wheel for cracks and have it balanced: a 550 mm wheel turns at around 1,000 revolutions per minute.
✓The tensioning wheel needs springs or disc springs that hold the tension even when the blade stretches.
✓The teeth must overhang the front edge of the wheel; they must not sit on the wheel.
Drive and blade speed
Bandsaw mills cut at 20–35 m/s. Soft wood can take a higher speed, hard wood a lower one. The motor must be powerful enough that the blade does not slow down noticeably in the cut. Our customers fit their DIY mills with a motor of around 5 kW.
| Wood | m/s | m/min |
|---|---|---|
| Soft (spruce, pine, poplar) | 25–35 | 1,500–2,100 |
| Hard (oak, beech, black locust) | 20–30 | 1,200–1,800 |
| All-round setting | 25–30 | 1,500–1,800 |
How to size the pulleys
Blade speed depends on the wheel diameter and the wheel rpm: wheel revolutions per minute = blade speed (m/s) × 60 ÷ (3.14 × wheel diameter in metres). The ratio of the pulley diameters is then motor rpm ÷ wheel rpm.
More on cutting speed in the article Bandsaw setup for wood.
Setup
Blade tension
A sawmill blade is tensioned to a stress of roughly 200 N/mm², and RipperS blades to 170–210 N/mm². The cross-section is calculated from the blade width without the tooth height.
Under-tensioned blade
!wanders and the cut is wavy
!does not cut straight
!can come off the wheel
Over-tensioned blade
!cracks at the weld and elsewhere
!slows the wheels down
!strains the frame, the wheels and the bearings
Without a gauge (rough guide): with the machine switched off, the blade should deflect no more than 3 mm sideways under finger pressure, and it must not wander in the cut. If a blade cracks, lay it on a flat floor with its outer face down: if the ends lift by more than 10 mm, it was over-tensioned. A tension gauge gives the most accurate reading.
We describe how to judge and measure the tension in the article How to tension a bandsaw blade for wood.
Guides
The guides keep the blade flat close to the cut. What mainly keeps the blade from running off the wheels is the correct wheel tilt and tension; the guides are a safeguard. On DIY mills they are usually flanged rollers or side rollers with a thrust bearing at the back.
✓Set the side rollers as close to the blade as possible, but without sideways pressure. They must not touch the teeth.
✓The blade should not touch the rear thrust bearing when running idle. Otherwise the back edge gets peened and the blade cracks.
✓Set the guides about 3 mm lower than the point where the blade leaves the wheels, so that they push it down slightly and keep it flat.
✓Set the position of the blade on the wheels by tilting the tensioning wheel, so that the blade does not creep forwards or backwards.
✓Make at least one guide adjustable so that you can slide it up to the log. The shorter the free length of blade, the straighter it cuts.
You will find a detailed procedure for setting the wheels and guides in the article Bandsaw setup for wood.
Head lift and carriage
Cable lift
✓easier to make
✓wind the cables evenly onto the drum
✓check that the saw stays level
Threaded rod lift
✓two rods linked by a chain
✓the chain makes sure the saw rises evenly on both sides
Add a toothed wheel to the crank to give a fixed step, for example 1 tooth = 1 mm up or down. A measuring scale shows the height. Add the blade kerf to the board thickness, about 2–3 mm with RipperS. A pawl holds the saw at the set height; vibration must not let it creep down by itself. Before you do anything under the saw, prop it up – do not rely on the pawl and the cables alone.
●For the track, our customers have had the best results with angle iron and grooved wheels: they are simple and cheap.
●Anchor the rails on sleepers or set them in concrete. A solid base keeps the track level.
●Both rails must be straight, parallel and at the same height, and the blade must be the same height above the log bed along the whole track. Otherwise the board will vary in thickness.
●Fit solid end stops at both ends of the track so that the saw cannot run off the rails.
●Design the log bunks, angle stops and log clamps so that the logs are easy to handle and easy to clamp alongside the track.
Cooling and cleaning the blade
✓A jerrycan with a tap and a thin hose above the saw is all you need. The water should run onto the blade before it enters the wood.
✓Water with washing-up liquid or baking soda helps with resin build-up.
✓Keep brushes and scrapers clean. Good sawdust extraction reduces friction and heat build-up in the blade.
Bandsaw blade
Which blade for a homemade sawmill
Blade thickness is determined by the wheels: for wheels of around 550 mm, choose a 0.9 mm blade, and a 1.1 mm blade only for wheels of 610 mm and above (table in the Wheels section). In the article Sawmill blades: how to choose the width, thickness and tooth type, we describe how to choose the width and tooth to suit the wood, what kerf the blade makes and which blades can be resharpened.
What blade length to order
You can work out the approximate blade length from the saw's dimensions: length = 2 × wheel centre distance + 3.14 × wheel diameter (both wheels the same size). Measure the diameter where the blade sits on the wheel; on a wheel with a tyre, measure over the tyre. The centre distance changes as you tension the blade, so calculate with the tensioning wheel in the middle of its travel. Finally, check the length on the finished saw.
Safety
Wheel covers and safe working
The blade can come off the wheel, or crack and fly out. That is why you should cover the wheels:
✓Bend the cover downwards so that it catches a broken blade.
✓The cover should extend forwards beyond the wheels, below the level of the upper run of the blade. If the blade comes off, it stays inside the cover.
✓Keep the gap between the wheel and the cover as small as possible, and make sure the cover is firmly secured while the saw is running. Best of all is a hinged cover with a limit switch that prevents the saw from starting when the cover is open.
✓The safest option is to cover both wheels, the non-cutting part of the blade and the belt with its pulleys. Only the section of blade that does the cutting is left exposed.
✓No one should stand next to the saw while it is cutting. Take boards off only once the blade has stopped. Before adjusting, cleaning or changing the blade, pull the plug out of the socket and wait for the wheels to stop. Only then turn a wheel by hand.
✓Connect the motor through a switch with an emergency stop button and a no-volt release, which stops the motor from restarting by itself after a power cut. Protect the electrics from water and sawdust, and have an electrician do the wiring.
✓Handle the blade and logs wearing cut-resistant gloves. Never reach towards the running wheels, belt or blade with gloves on or in loose clothing. Wear safety glasses and ear defenders when sawing.
In practice
Frequently asked questions
?What wheel diameter should I choose?
For a 0.9 mm blade, wheels of at least 450 mm, ideally 550 mm. A 1.1 mm blade needs wheels of at least 610 mm, a 1.3 mm blade at least 650 mm. On small wheels the blade bends more sharply and cracks.
?How fast should the blade run?
Bandsaw mills cut at 20–35 m/s, most often 25–30 m/s. Soft wood can take more, hard wood less. We show how to work out the speed in the section Drive and blade speed.
?Will a weaker motor do if I change the gearing?
Gearing does not increase the motor's power, it only changes the speed and the torque. The blade has to run at 20–35 m/s even in the cut. With a weak motor it slows down or stops in a hard or wide log. That is why our customers fit motors of around 5 kW.
?How do I tension the blade without a gauge?
With the machine switched off, the blade should deflect no more than 3 mm sideways under finger pressure, and it must not wander in the cut. If a cracked blade lifts its ends by more than 10 mm on a flat floor, it was over-tensioned. More in the article How to tension a bandsaw blade for wood.
?What blade length should I order?
Roughly 2 × wheel centre distance + 3.14 × wheel diameter, with the tensioning wheel in the middle of its travel. Check the length on the saw – we weld the blade to the length you need. Calculating the length
?Why do blades crack on a homemade mill?
Most often because of small wheels, over-tensioning or a rear bearing that touches the blade even when running idle. You will find the causes, sorted by where the blade cracked, in the article Why do bandsaw blades for wood break.
Have you built a bandsaw mill of your own? Share your experience in the discussion below the article. We are also happy to answer your questions at info@dudrsaw.eu.
Your questions
Dear Mr. Prendin, thank you for your inquiry. If the flywheel width is indeed 140 mm and the diameter is 1300 mm, this is a large sawmill. For machines of this type, bandsaw blades with a width of about 160 mm and a thickness of 1.3 mm are typically used.
Unfortunately, we do not produce such wide blades. For this type of product, I recommend contacting our sister company Dudr Tools s.r.o., which specializes in this segment. You can find more information on their website: www.dudr.cz
Thank you for your understanding, and best regards.
Pavel Dudr
Hello, thank you for your question. The cross-sectional area of the saw blade will be slightly smaller, as the tooth height of approximately 5 mm needs to be subtracted from the width. For a home environment, we recommend tensioning the saw blade so that it does not float in the cut. And then, if you lay a torn blade on the floor and the ends of the saw blade lift up, it means it was tensioned too much.
Sincerely, Pavel Dudr
Good day, companies Řetězy Olomouc or TYMA offer something like this.
In general, as an alternative, I would look for either flat pulleys or wheels from old agricultural machinery.
Good day, I assume it is a saw for textiles with three wheels. If you can set the belt speed to about 900 meters per minute, then probably yes. Then it probably depends on the rigidity of the saw, after all, you need more rigidity for wood than for textiles, as well as e.g. the wear of some parts such as the support guides. Sawdust will probably remain in the machine if there is no extraction, so count on it. I also wonder if the wheels are classic aluminum with a rubber band, hopefully not e.g. plastic, so as not to damage them. Don't forget, if so, to choose a belt thickness of only 0.6 mm if the wheels are e.g. only 300 mm in diameter (belt thickness = wheel diameter / 500). If the band saw has 3 driven wheels, the saw blade bends and straightens on the wheels 3 times per cycle, and therefore a thicker blade may crack.
Good luck with your experiments ;-), regards Pavel Dudr
Good day, thank you for your inquiry. You will lose power through gearing, and you need a saw band speed of at least 15 m/s, and the saw band must not stop while cutting. However, it is true that perhaps the smallest log band saw Holzmann BBS350 has a 2.2 kW motor, it only has a speed of 14 m/s. However, this saw has a saw band size of only 19x0.9 mm, and with this width, you cannot achieve a larger tooth pitch than 2 teeth per inch, so you can only cut very small logs. I would recommend considering a saw band of at least 32x0.9 width, where the standard pitch for logs of 1.1 TPI (pitch approx. 22mm) is also available. And if you look on the internet, for example, with log band saws of the brand LUMAG, the power is selected from 4 to 7.5 kW.
I hope I have helped you a little, we are not involved in the production of machines... Thank you, good luck. Regards Pavel Dudr
Good day, we have an article about it https://www.dudrsaw.eu/technical-articles-and-advice/how-to-tension-a-band-saw-blade-for-metal
In general, however, the blade needs to be tensioned "firmly", but still be able to be moved slightly by 2-3 mm.
Good day, thank you for your correct remark. Regarding the covers, you are right, we forgot to mention it in the article (we will try to fix it).
I discussed the covers with the gentleman who made the green saw in the photo. He said that his cover is sufficient and suitable for him. Of course, he approaches the machine with respect, and no one else moves around the saw. He described his experience that a broken belt always flies in the same direction as the driven wheel. It is also important that the cover is bent downwards in the upper part near the drive wheel, so that the belt does not fly outwards, but downwards towards the ground. If I may say so, the saw blade gets stuck in the wood. And when the belt accidentally falls off the wheels (slips), it gets caught in the upper cover (precisely for this reason, the cover reaches low enough).
Besides, the gentleman has a rule that no one stands or walks next to the saw while it is cutting. If he is removing cut boards, he has the saw in front of him and removes the boards from behind. If he has an assistant, he cuts the wood in front of the saw, but only when the saw is sufficiently far back (as seen in the photos – his saw moves on "rails"). He also mentioned that the belt slipped off while he was adjusting it and broke while he was cutting. However, it has never happened to him that the belt broke or slipped off the wheels when the saw is stationary and running idle.
Some people have all the wheels and the belt covered, but this is not common. In any case, safety always comes first – one must approach such a machine with respect again and again...
Yes, we deliver saw blades custom-welded and sharpened for soft (SOFT) or hard (HARD) wood. Please order in advance – it takes longer because we sharpen and set the blades only after custom welding. Please send us a photo of your saw, how you have solved its construction and covering (email info@simonds.cz). We will be happy to publish the photos (for others too), so people have inspiration ;-).
Thank you, good luck.
Sincerely,
Pavel Dudr