Bandsawing a Radius in Massive Beams
Here's a long discussion of equipment choices and methods for sawing a curve into giant timbers. July 26, 2010
Question
I need to cut 8 large oak beams. They are 14" x 11" x 60". I need to cut a very large radius through the 11" thickness. It must be very accurate. I will be finishing like furniture.
I've seen pictures of the portable band saws. But just for 8 beams, I can't justify it. Could this be accomplished on a large band saw with some kind of bearings on table system?
Forum Responses
(WOODnetWORK)
From contributor O:
Where are you located?
From contributor K:
I did this on a pergola I built of white oak. My timbers were 3" x 16" x 12'. No reason it won't work for you. Just be sure you use a coarse 3/8" or 1/2" blade. Make a male and female template out of plywood with a trammel on a router. One piece will be the pattern, and the other will be the guide surface. Cut a notch about 1/16" to 1/8" deep into the edge of the guide piece at its center of length. This notch will be where the blade travels through without cutting the pattern. Clamp the guide to the saw table with the notch at the blade. Set up a work piece on the pattern and make a way to fix the two together. I would just drive small finish nails or screws through to create resistance from slipping by pricking into the work piece 1/8". Set it up on the saw and keep the pattern riding against the guide piece and you're done!
From the original questioner:
I'm in Northwest Alabama. Thanks for the good info.
I'm thinking about diving in and purchasing one of the portable beam saws. I'm looking at Falberg and Mafell. Falberg can handle the largest timbers. Do any of you have experience with these?
From contributor K:
Yes, I rented one a few years ago. I think it was the Protool sbp285 or like it. I used it to do the scroll cuts on the purlins and beams for the pergola I referenced. I cut up to 8 x 8's with it with no problem in white oak. Any of these saws will work well for you, but have you priced them yet? Very pricey for a one time need, then to sit on the shelf. Which Falberg are you looking at, the Titan or Elf? They look heavy!
From contributor R:
Look around. Can you rent the portable bandsaw as opposed to buying it? I don't know how far you are from the Nashville, TN area, but we have a big Grizzly industrial bandsaw that we bought just for doing a big beam job. It can handle the cut and I'm sure we could work out a jig to track it.
From the original questioner:
Looking at the Titan for the size. I think it's 60 pounds. Talked to a guy yesterday that has used it for 3 years and really likes it. Got calls in for a few more references. It's expensive for a band saw. But sure seams like a better solution that trying to lug around massive timbers through accurate cuts.
From contributor K:
If accuracy is your goal, a stationary bandsaw, and pushing a timber the size you stated, is your best route. I have used both methods and it is truly a simple and very accurate process to saw this way. Remember, you are using a precise template to guide the cut, so every piece will be a perfect match to the last one. A 14 x 11 x 60" timber is not easy to lift, so you would need help getting it set on the saw. Infeed and outfeed supports will be necessary. You will need a helper no matter which method you choose. My choice for what you're doing would be the stationary machine. I've done both. All this said, sounds to me like you just want to buy a cool new toy... I have wanted one for a couple years now!
From the original questioner:
Toys are great. I love toys. Whether I decide on an oversized band saw or a portable Falberg or something, it will be a toy to me. But I really do want to find the right tool for the job. The more I think about it, the more unusual oversized timber projects I'm coming up with.
So, now let's talk about larger pieces. Let's say the same dimensions but longer. Instead of 60" long, let's say 120". Is the big band saw still the right tool? What about 14" x 18" x 120"? At what point is the portable band saw the appropriate product? Or are all these large timber sizes more accurate and efficient on the large band saw with appropriate tables, patterns, etc.?
There's one other problem I'm wondering about. We don't have 3 phase power here. Is it practical to use a big 3 phase bandsaw through a converter?
From contributor D:
Well, there is a company that is usually at IWF in Atlanta - Italian, I think - that makes a band saw that is on articulated support arms. The whole saw floats about, at a vertical, horizontal or angled cut. The demos are great (better than Ginzu knife), with one guy one-handing the saw through an intricate cut on the end of an 8x12.
From contributor R:
Since you asked the question about accurate curves in larger beams, I've been racking my brain trying to remember something I saw at IWF. It is a portable bandsaw mounted on a free swinging arm. Keeps the saw square and true while you guide it through the cut. Took me a while to find it - it's the Dario XV3 MAXI.
From the original questioner:
Yep. I was amazed by that saw at IWF. For 18,000 I can hire an army to lug around the beam or the saw, though. Everyday I am leaning a different direction. Tonight I'm thinking I should find a used 42" band saw and some lift tables with roller bearing setup. You guys have any favorite brands in the big band saws?
From contributor R:
I saw a video some time back where a contractor mounted his 14" bandsaw on wheels. He mounted the beams on stands at the proper height, then rolled the bandsaw around to make the cuts. He was building a pergola or some such, as I recall. As long as the floor was reasonably flat, it seems like a workable solution.
From contributor U:
Ditto what contributor R says. Mount your bandsaw on 4 swivel wheels.
From the original questioner:
Thanks again for the good, thoughtful information. I really do like the idea of rolling the saw, but...
Today, I am leaning toward one of the larger bandsaws. Generally thinking about a 36 or more likely a 42 Tennewitz. There is a 36 Northfield with an asking price of $2000 (seems high?). And there are several Tennewitz 42 and 36's available. I would love to be able to handle the largest (diameter) timber possible.
Doesn't this leave me no option but to use the "roll the beam over small roller bearings" system? What brands of these large band saws do you like? What do you look for when buying older used large band saws like this? I don't have 3 phase power. Where should I purchase a converter? Requirements?
From contributor K:
You obviously need to be weighing what you are going to be using the bandsaw for and how much. Also, if you see this one job expanding into more of the same, then an investment right now in the right tool would be wise! If this is the only time you think you will do this, and you have a larger stationary machine, to me that's the way to go.
I did not use the portable bandsaw I rented for long and large radius cutting, so I don't know how it would work for that, but I can't imagine it would not be a good tool for it. Simply said, when applicable, the stationary machine will be more precise to work with and more easily repeatable for multiple cuts. My saw is a 5hp, 36" Tannewitz and is an outstanding machine for timber cutting like this. That said, It would take some heavy duty infeed and outfeed tables to push 14" x 11" x 20' oak timbers through it, but the machine can cut it with the correct blade.
I would not want too much weight only on the machine's table. I would look into the roller bearing concept for support and ease of guiding the work piece. They're a must for multi-directional control.
As for big saws, Tannewitz, Northfield, and old Olivers are great saws! Even Yates, if they were well maintained, are good machines. Look for a machine with modern bearings (not Babbit bearings). I like the direct drive 3ph. 5hp or larger. I don't know anything about phase converters, so can't help there. There isn't a lot that can be wrong with these machines, but look it over for abuse and how it was maintained. Check out the guides for bad wear - you may decide to replace them with new Carter guides. My machine has grease fittings on the motor; some maintenance like this doesn't necessarily mean a lesser machine. It gives you the control.
Good luck - timber frame work is a lot of fun, but different that cabinetmaking!
From the original questioner:
Just got off the phone with a 30 year woodworker that didn't think 5 hp was enough for cutting these massive 24" possibly green oak timbers. Also he suggested the type that's not direct drive. Thought these were much better for working on the motor or replacing the motor with a larger one if need be. Is a 3 horsepower enough for a 42 Tennewitz? Should I look for direct drive or the other? What else should I look for in this used giant? Any advantage of a 36 Tennewitz over a 42?
Looking like the 3 phase is not an issue any longer. So we can skip that subject.
From contributor K:
This is the first you have mentioned a 24" deep cut! Yeah, that will make a difference in horsepower needed. That is getting beyond my experience, but if I had to guess, you would need more. As for direct drive, yes, if you think you would need to add horsepower, replacing a motor is easier than rebuilding one and you can always sell the dropped off one.
Machine size may have an effect on throat height. Be sure to ask that dimension on the machine. My 36" has a max height of 20" and the table height off the floor is 41". A 42" machine will be around 47" off the floor if I'm doing the math right. That means you will be working with material pretty high off the floor. I have seen where a guy had a 42" machine and recessed it down into the floor 6" - 8" for a proper table height. But even more than that, the 42" machine was at least another 12" taller with the guide down than the same make 36" machine and he had to cut the ceiling out and raise it over the machine wide enough to get the machine in place. My machine is basically 101" tall and with the guide all the way up is 115" tall. So be sure you have clearance for whatever you buy.
From contributor W:
You mentioned cutting 24" deep. I built a custom saw to do just that [Falberg]. I know they're expensive. I can only make 24 saws a year to serve the 25 framers that really need a big portable band saw. China won't make you a cheap bandsaw when they're only going to sell 24 per year. Those 24, however, unanimously tell me that the saw paid for itself the first time they used it and they continue to profit whenever they drag it out. It's not for the average bandsawyer. It's a specialized industrial tool. It becomes a business of its own. And no, you can't wrangle big timbers through a puny little Tannewitz and get detailed cuts. Have you seen the size of some of those custom timbers?!
From contributor K:
I'm a timber framer in Northern AZ. I use bandsaws every day. Portable is the only way to go. Bring the saw to the work; it's a lot easier. The Falberg saws are the best on the market for the money by far! I also have an Oliver machine, portable 8", which is great for the small stuff. The Falberg Titan has all the balls you'll need to get through big timbers, up to 18". Seldom need bigger than that. And if you do, it would be more cost effective to hire a local mill to make the cuts than to buy a big honking 3 phase bandsaw and do all that setup.
