Number of teeth bandsaw blade

[Brian Deakin]

My understanding is the ideal number of teeth for cutting blanks for woodturning is 3 tpi

A friend who is a woodturner insists that if you predominantly cut dry wood you need 6 tpi

Thoughts please

[Richard Casey]

Do you mean roughing out blanks from log sections or cutting blanks round ready for the lathe?
Rgds,
Richard.

[Brian Deakin]

I would be interested to know your thoughts on both scenarios

[David Walser]

Brian -- The ideal number of teeth per inch depends on a number of factors. Whether the wood is wet or dry is only one of them. You should also consider the thickness of the material being cut, the type of cut being made (ripping, crosscut, or curves), and whether this is a 'finish cut' or a 'roughing cut'.

Having said that, for many woodturners, I think 3 tpi is a good place to start. The advantage of a low tpi blade is the larger gullets between the teeth make it easier for the swarf to be cleared from the cut. This prevents heat buildup and allows the wood to be cut more efficiently. These are the same reasons a rip blade for a table saw has fewer teeth and larger gullets. If you're cutting thin material, these advantages don't apply. There won't be enough swarf to fill the large gullets. Instead, if the material is thin enough, there may not be at least one tooth in the cut at all times -- which can produce severe vibration as the blank lifts up as one tooth leaves the cut and is then slammed back down as the next tooth takes its bite. For woodturning operations, most cuts will be in materials that are at least thick enough that two or more teeth are engaged in the cut at all times. (When selecting a blade, the thickness of the material is my primary consideration. If the material is not thick enough to engage at least two teeth at all times, I'll change the blade to a higher tpi blade.)

Wet wood argues for a lower tpi blade. The swarf from wet wood tends to clump and may be stringy, which makes it harder for the blade to eject the swarf from the cut. Larger gullets, which means fewer teeth, make it easier to remove the swarf from the cut. However, this is just a general rule. Some resinous woods, even when bone dry, produce swarf that is difficult to eject from the cut. Such woods may benefit from lower tpi blades whether wet or dry.

A 3 tpi blade won't leave as good a surface as a higher tpi blade, but that's generally not a consideration when cutting woodturning blanks. (It is a consideration when ripping a blank into quarters for an inside-out turning, for example. So, bandsaw cut quality isn't always irrelevant to woodturners.)

HTH

[Curt Harms]

This is what Highland Woodworking sells for woodturners. Intended for green wood:

https://www.highlandwoodworking.com/...dsawblade.aspx

3/8" (about 10mm) X 3 Teeth/inch alternate set.

[John K Jordan]

I don’t understand the reasoning. I’ve cut thousands of turning blanks on the shop bandsaws from green log sections and dry, some as small as 1/2” square and many as thick as 12”, and from a wide variety of wood from very dense to soft basswood. For woodturning blanks I always use 1/2” x 3 tpi blades for both wet and dry wood. If I run out I’ll use a 4 tpi blade until I get more of the coarser pitch.

I think 6 tpi is fine for relatively thin wood, especially if you want a smoother cut. The smoothness of the cut doesn’t make much difference for woodturning blanks. When cutting very thin wood a blade with more teeth per inch works well. But with thick wood the smaller gullets can load up with sawdust and impede the cut. This can require slower cuts and cause other problems, such as bowing in a thick cut.

Another thing: I usually sharpen a blade several times before replacing it. On my saw that means sharpening 426 teeth which takes me about 20 minutes. A 6 tpi blade on my saw would have 852 teeth. I think I’d get tired of that before I finished.

You might ask
- what kind of blanks he cuts with the finer blade,
- the type of wood (species),
- the thickness.
I’d like to know his reasoning for why 6tpi is needed for dry wood.

I’ll try to look in some of my books later today and see what they advise.

JKJ

My understanding is the ideal number of teeth for cutting blanks for woodturning is 3 tpi
A friend who is a woodturner insists that if you predominantly cut dry wood you need 6 tpi
Thoughts please

[Richard Coers]

Tooth count is about clearing the sawdust from the kerf, along with feed speed. In dry wood, you can get by with more teeth if you slow down. The next variable is moisture. A warm bandsaw blade inside wet wood will cause the sawdust to bind in the gullet of the tooth. With more teeth and smaller gullets you get a warmer blade than big teeth and big gullets. You have to decide what works for you.

[Reed Gray]

I have always used 3 tpi by 1/2 inch blades for rounding out bowl blanks, and that was suggested to me by the local bandsaw blade making place, after they asked me what I was planning on cutting. With a 1/2 inch blade, it is fairly simple to cut out a 5 inch diameter bowl blank. I think I can go smaller, but don't remember. I do use the thicker blades as well. Thin blades just don't hold up to cutting bowl blanks. Carbide tipped blades are for cutting veneers, not bowl blanks. I prefer the bimetal blades from Lennox. The teeth are M42 high speed steel, and if you hit a nail, they don't break. They do dull a tiny bit, but the blade is not ruined. They also cut straighter than the other blades.

robo hippy

[Brian Deakin]

Thank you to everyone for your posts in particular John and David for detailed information provided All of the posts reinforced my understanding of the various parameters that need to be considered

I will ask my friend John's questions

- what kind of blanks he cuts with the finer blade,
- the type of wood (species),
- the thickness.
I’d like to know his reasoning for why 6tpi is needed for dry wood.

Other
The most detailed post I have seen on Sawmill creek is this post from 2018 provided by Van Huskey

https://sawmillcreek.org/showthread....bandsaw-blades!