Circle saw bit question

[Sawyerfortyish]

Whats the differance between Bf pattern and BDF ? Will BDF bits fit a BF pattern saw? Is there a differance in shanks?

[sawmill_john]

If I remember correctly, the saw blades are made to accept B or F or D shanks the teeth are interchangable, I couldn't find my paper work on the differences, I'm sure some one will offer up the correct info with research to back it up!
john

[Ron Wenrich]

I don't think there is any difference.  I've never seen a D pattern saw, so maybe they dropped the letter.  Besides, all you can buy anymore is Simonds. 

[Sawyerfortyish]

I was at a mill that will be up for auction soon and there is about 6 or 7 boxes of bdf bits unopened on the shelf. If they fit my saw I might see what they bring.

[Ron Wenrich]

Just take one of your BF bits to see if it matches the BDF.  I bet it does.  But, you could say loudly how you don't think they match, then put your bit in your pocket and walk off.   :D

[Frickman]

A little primer about circular saw bits and shanks.

There really isn't such a thing as a bf pattern saw, or even bdf. BDF bits will fit B, D, or F pattern saws. The difference is in the shanks, and their gullet capacity. From smallest to largest if F, then B, then D. F is about the same size as a 2 1/2 pattern shank, B is about the same as a 3 pattern, and D about the same as a 4 1/2.

So what do all these letters and numbers mean?

Saws with a number designation, 2 1/2, 3, 3 1/2, and 4 1/2, have single circle sockets. The shank and bit fit within the same circle in the saw. Letter designated saws, B, D, and F, have double circle sockets. This is a much stronger system than the single circle, and spreads the load over a greater area. All the shanks for the different sizes are different, as are the bits for the numbered size saws. The letter sized saws, B, D, and F, all use the same bit however. That's where BDF comes from. It's kind of strange though, because if you went by size it would be FBD or DBF. Instead it's called BDF.

You use different size shank and bit combinations for different applications. The larger saws for larger logs tend to have larger shanks. This is insure that the gullet has enough capacity to hold all the sawdust until it clears the log. The smaller saws have smaller shanks because they do not need to have as much gullet capacity, and the smaller shank/bit combination allows more teeth to be located around the rim of the saw. A D pattern shank would take up too much room on a 48" saw, and a F or 2 1/2 pattern wouldn't have enough gullet capacity for a 60" saw. Most of the new saws I've seen are F or B pattern, But the other patterns are still available as far as I know.

I've used both number and letter pattern saws, and I prefer the lettern pattern saws in the hardwood timber I cut. I still have a very old 50" number 3 saw I llike to get out now and then though.

I hope this helps.

[Ron Wenrich]

My understanding of the letter/number system is that the lettered saws are for hardwoods and the numbers are for softwoods.

I went for the F pattern saw back to the B pattern saw many years ago.  I seem to be able to feed much better with the B than with the F.  Only 4 teeth difference the two.

[Sawyerfortyish]

Thanks Frickman I now know my saw is a B pattern and not BF. Since the bits are interchangable thats how they do it when they lable a box of bits. My edger and cornell slab saw all took the same bits as the head saw. I have an old 60" Disston blade that takes style 33 teeth. I see the differance in gullets you talk about. The 33 when seated the back of the cutter hits the tip of the gullet that the shank rides in wereas the B pattern the back of the cutter head and the bottom of the bit seat in there own gullet and the shank has a differant gullet to ride in.

[Frickman]

Ron W.,

I've also heard that the letters are for hardwoods and numbers for softwoods, I didn't mention it because I've never really confirmed it. I do know that the lettered saws, the way they are designed, have much stronger bits and shanks. They seem to work real well in dense hardwoods. My number 3 saw works well in the softer hardwoods, like poplar and soft maple, but I have to be careful in oak and hickory. Most of the hardwood mills in my area are running B pattern saws.

[Ron Wenrich]

I've always had this theory.  The question is why do guys always run B or F pattern saws?  Why are there more right handed mills than left handed mills, except for in Wisconsin?

Then I got to thinking.  Guys have always ordered just like so-and-so down the road.  B pattern saws got to be in groups.  Right handed mills got to be in groups.  It all got down to the guy taking the orders.   

There is no right or wrong way in teeth, saw pattern, or handed ness of mill.  It all is whatever works for you.   ;D

[Sawyerfortyish]

So the guys in Wisconsin run backwards  to the rest of us and there sawmill suplier is left handed :D. Boy the things you learn here amaze me sometimes

[Frickman]

Sometimes I kind of envy the narrow band saw guys, with the WoodMizers, Bakers, etc. They can keep a variety of different bands on hand, with different widths, hook angles, etc., and match the band to the job. Now I know you can't justify changing a band halfway through a log, as the book says a different band will work better on the now smaller cant. But you can lline up all your pine logs, and run a certain band. Take a few minutes to change to a different band and you're sawing oak. You guys can really tailor the saw to the job at hand.

With the big circle saws we're talking about it isn't always so easy. You try to find a happy medium in your equipment selection that will saw about anything you encounter. A headsaw takes more than a few minutes to change, and most smaller mills might only take them off when there is a problem. If you switch to a different diameter saw you have to move your saw guide and splitter too. And different diameter saws will have different rim speeds.

Ron's right about everyone in an area running what the guy down the road has. Alot of it is because in a given area, most everyone is cutting the same type or types of timber. You find what works and tell your buddies about it and they use it too. The salesmen figure out what works good and recommend it also. Many of the mill owners in my area are related or connected somehow, and we end up "handing down" equipment from higher production mills to smaller outfits.

As far as right versus left-handed mills, I run a right as do most guys in this area. Friends up the road have a left-handed mill they brought in from Michigan though. Growing up I always thought that a left-handed mill made more sense. I don't know why, because I'm right-handed. Once I started running one though  a right-handed mill just felt more natural.