How to prep blank on bandsaw?

I used to have the same problem. Many people use cardboard disks as guides for cutting out blanks. The basic idea is to tack the cardboard to the outside of the log about where you want the center of the bowl to be. The trick is to cut close to the edge of the cardboard without cutting the cardboard itself.

I use a 3tpi 1/4 blade for cutting out many of my blanks

Using a piece of 1/2 inch plywood I created a jig that has a small nail through it. Part of the jig has a knotch to allow the nail closer to the blade.

First I determine my center point on the chunk of wood and drill a small shallow hole on the flat side of the half log deep enough to receive the nail so the chunk rests flat on the plywood. The blank must have a flat side.

Then I place the chunk onto the nail and slide the jig up to the blade.

Then I clamp the jig to the bandsaw table and finally turn on the bandsaw while holding onto the piece of wood and slowly rotate the chunk into the blade.

Note the chunk must rest flat > I keep seeing these fancy-schmancy bowl blanks on turning videos and

I see one key tip: 3 tpi. I'm not sure how many tpi are on my blade, but it's definitely 6 or greater. I'm going to try fewer teeth and see what happens.

The knotch in your plywood makes sense too. I only had the kerf of my blade. A knotch would definitely be safer.

When I first received my bandsaw I had a 1 1/2" blade on it, started cutting limbs to see what would happen, then I kinked my blade... I was not happy about that, but I did find a place locally that could weld in a section of blade to fix the problem. That made me feel better since the blade was new and could be repaired.

You are right about the need for a flat bottom. If anyone is going to try this you must have a flat bottom (the flat bottom is the face of the half log that sits on the saw table).

It looks like you have good success. I'll see what happens. Thanks!

w... wrote:

Hi John

Here are 2 links to websites, the first is from Darrell Feltmate, the second is one of my albums. Darrell's website is one you should have and take a look at many times for all kinds of answers, not just preparing bowl blanks.

Now you'll see that we do not use band saws, but chain saws, for unless you need a perfect circle to be able to turn a 10" blank on a 10" lathe, there is no good reason to go through all the trouble to try cutting a half log bowl blank on a band saw, because even if you have a perfect circle half log, you still have the up and down of the half log shape when turning the blank to shape. This is not to say I never use my band saw for cutting that half log , but it is really seldom that I do, and at those times I use a wedge from a log and keep it under my blank while sawing the circle, the blank is then with the flat side up and I have marked the circle on that flat side, it's the way I do it, not what I recommend others to do.

Have fun and take care Leo Van Der Loo

Leo,

Thanks for the information. Makes sense! I'm guessing that those fancy-schmancy blanks in the videos and and super-duper demos are actually finished on a lathe. The ones I see look too perfect (but said to be made on a bandsaw)...

But, for the Myth Buster living deep inside me, do you, or anyone else out there, think it's possible to create a near perfect round blank (create your own definition for that... :) on a bandsaw? If someone else can do it, I'd like to (just to say I did it).

When you're doing a "Jason vs. Tree" (loosely translated, that means firing up a chainsaw), to prep a blank, do you use a regular cross cut chain or one of those nifty ripping chains?

Virtually, John

l... wrote:

Hi John

John I prepare my blanks in my shop, and use a regular chain on my electric chain saw, I don't like the smell and smoke of my gas saw in my chop.

As for the "is it possible" yes, but why bother, I rather turn than wrestle with a blank on a band saw, and it will get perfectly round that way :-)).

Have fun and take care Leo Van Der Loo

No secrets, just good sense, or Duginskie's The Bandsaw Book.

The blade should be coarse, preferably with set in the teeth for wet wood, and wide enough to have some beam strength on its own without overtensioning. I generally use no smaller than 3/8, for support reasons. The guides should be close, and I much prefer the ceramics on the left, at least, where the pressure can wear away soft types. Rollers will work, but require attention to cleanliness.

I think all turners of green wood should own a scrub plane. Where the saw failed at flat, a bit of sweat will compensate. Alternatively, you may screw a plywood disk, suitably shimmed, to the blank to give footing.

I strongly recommend a circle cutting jig. People who don't turn over the bed can plan on first-time everytime rotation, but it can be frustrating for over-the-bed turners to find and eliminate high spots or sacrifice diameter with chainsaw roughing. Not particularly good for the bar and chain to cut unsupported on one side or at an angle either. Circle jig is in the book, features that centering pin, a miter gage bar, and a stop so that the blade teeth are tangent and blade perpendicular to the radius for efficient cutting.

Best preparation can involve one, two if the saw is underpowered or three runs if the blank is over thick. For saws which can't saw tapered blanks in one run, make the first for circular, second, with table tilted, to whittle and balance the piece a bit by removing the thick endgrain. Makes things easier on the lathe bearings and stand, too. If you have a small capacity saw, you may have to run a tilt on each side then run the middle to gain best advantage of the saw's capabilities.

John, I understand that you are talking about making blanks perfectly round with a bandsaw like we see on videos and that you particularly want to do it because 'it's there'. Probably not the only thing you see on videos that differs a little from real life.

However if you are trying to get rid of the "whack-whacking", how you rough to round _on a lathe_ becomes important. I won't expound and burden your thread except to remind you to rough at an angle neither truly axially nor radially. Someone else can explain or deny.

I suspect most of us and that includes videomakers, make blanks _reasonably_ round with hatchet, chainsaw or band saw then use a lathe for making them _perfectly_ round. It's a fine machine for doing so, even better than a bandsaw. :)

Turn to Safety, Arch Fortiter

You didn't say what diameter your bowl blanks were. The diameter determines the blade width. You can find charts for what the minimum radius is for a given blade width. Use the widest blade you can up to 1/2"

Whenever possible, I use my 1/2", 4tpi, skip-tooth, hook-tooth blade. Every other tooth has been removed, so it ends up 1/2" between blades. If you can't get a skip-tooth, then get a 2tpi blade. The hook-tooth shape makes for easier cleaning of the gullet, faster cuts, and less force applied on the stock to make thick cuts.

I rigged a circle cutter attachment on my small bandsaw to get perfect circles. I don't use it for blanks, but a person could. I doubt if it is worthwhile for turning. Instead, just use a big roughing gouge with long handle.

Dan

The key is that with thick material use fewer teeth per inch.

I buy several of the blades a year from Timberwolf and I'm about to replace my current blade after cutting out a bunch of purple heart and pink ivory blanks. The blade was already old and getting dull when I started.

I still managed to use the blade to secti> I see one key tip: 3 tpi. I'm not sure how many tpi are on my blade,

John... just to add to what others will say.. tpi shouldn't be a problem on your saw, you have lots of power, just slow the cut a bit..

As to the 1/4" blade, that would scare me on my 14" saw, much less a 16"... I prefer a 3/8" 3 or 4 tpi blade on mine.. maybe 5/8 or 3/4 would be better on a

16", dunno..

After trying beam compasses, etc., I made a bunch of disks out of hardboard in about 1" diameter steps from 5" to 12"... sort of a pain to store but they work well when you need them.. I make the center hole just large enough to fit a pencil or crayon and make sure to mark center at the time that I draw the circle..

I've tried a few nail type jigs but just cutting along a line free hand works for me... Chainsaw (or use your 16 incher) the log half again to remove a section of bark and give yourself a flat surface parallel to the cut down the pith to give yourself a surface to lay the blank on the BS table..

I got started with Darrell Feltmate's page on the subject:

Mac

John.. speaking of videos, if you haven't seen Bill Grumbine's DVD yet, I'd strongly recommend it:

I only wish that I'd watched it years ago, before I picked up so many bad habits.. *g*

Mac

I think nearly everything that can be said has been covered in the large number of posts to your question. However, I don't think anyone mentioned that the beautifully round blanks that you see being put on lathes on the videos are made from sawn boards; i.e., they are flat on both sides and of equal thickness. For those, you simply draw a circle on the blank and then with the bandsaw freehand you saw on the line. The blank will then be virtually round and the center point for drawing the circle can be either a point for drilling a hole for a screw chuck or a point for the tailcenter to hold the blank centered against the face of the chuck jaws for roughing out the outside and foot of the bowl. Most of us don't have that option because we work with log halves. However, people like Richard Raffan purchase their stock from a mill and have flat pieces to start making their bowls.

Fred Holder

John, Your saw came with a 1 1/2 inch blade? Does this mean that your bandsaw will cut 16 inches high? This changes a few things. A 1 1/2 inch blade is for resawing, not radius cutting. I have 2 bandsaws, one cuts 6 inches high, the other 16 inches. I use the big saw to make slabs for bowl blanks, and the other to cut the rounds (1/2 x 3 tpi).

To prepare the slab, first cut the log in half, along the pith. It helps to mark lines down the centers on both ends, and along the top. I prefer the chainsaw for this, and a sharp chain helps the cuts to go straighter. You want the face to be as flat as possible so that the blank doesn't wobble when cutting on the bandsaw, as this can make the blade bind and break. Next to the bandsaw. I will square up one end to the flat face (flat face on table, then cross cut). Then I stand the blank on end, and true the face. I will sometimes scribe a line to make the cut more accurate (you will be cutting parallel to the grain, which can make a lot of hair like shavings which can plug up the dust collector hose). I then take the trued face, and set it against the fence to true (parallel) the bottom of the blank. Next I scribe a circle with a compas, and then take it to the smaller bandsaw to cut the circle freehand. If the blank is higher than 6 inches, I cut the corners on the big saw. You need to leave enough of a flat surface on the bottom to support the work while cutting the circle. If there isn't enough flat, the blank can tip, and the blade binds and breaks. You can put the cardboard or other circle on the bottom and cut it from there also. Rounds do not cut well on bandsaws because they want to roll when the blade engages, which I think you have already learned. The job can all be done with a chainsaw, but as I use the bandsaw more and more I find that it is a much more efficient machine. It is more accurate, and you get a smoother blank which greatly reduces the roughing out part of turning the blank. No matter how careful you are when cutting the circle, you still have to mount the face plate, or as I do on smaller blanks, drill a hole with the forstner bit to expand a chuck into, for turning the bottom. No matter how careful you are, there will be some errors, and if the blank runs true, then it is luck. Talk to the guy who fixed your bandsaw blade about what you are doing, and see what he suggests for a blade. I use the Lennox bimetal blades. They last the longest and are best for this kind of work. I did splurge and get a carbide tipped blade, and it is wonderful, but like my guy says, it should be used for resawing, not bowl blanks and bark. robo hippy

As noted by others, you need the least TPI you can get. I messed that one up myself, as I had only used a bandsaw for metal prior to getting the one in my shop and thought that more teeth = better cut. But I discovered that more teeth = more burning (I'm now the less than proud owner of 3 specially ordered 24 TPI bandsaw blades that I'm sure will last forever, because they're useless in anything but steel)

The other part of it is that a 3/8" or even half inch blade should cut the radius on any turning blank of reasonable size. To be honest, I've never cut a turning blank on my bandsaw, but that I do when I cut curves for table legs is make several relief cuts (say 1/4" apart) through the waste area up to my mark (or just shy of it), and then make the final (bandsaw) cut. This does at least three things that I can see- first, it dramatically reduces the chance of wrecking the blade it the workpiece tips as there is only a sliver holding the waste wood on. Second, if something does go wrong with the cut for any reason, you don't have to try and back the blade out of the kerf. And Third, if the blade wanders over your line, it is much easier to correct, because you can start fresh on the next segment.

There may be other reasons use this method, but nothing I could claim for certain. It may also be unnecessary with your saw- I've just got a little 10" benchtop one that never sees anything rougher or thicker than an almost finished table leg needing a curve or taper. A big saw might make all the difference, though I still use this method when using them.

Of course after all that, I'd point out that I have a special tool used just for making round things... I even hear they devoted a newsgroup to it. :)

Seriously, a chainsaw works just fine for me, and if I miss an annoying high spot, I've got a good sharp 1.5" framing chisel that is the equal of any wood I've encountered.

A lot of outstanding information. Thanks to everyone for your input. I'm impressed with the intelligence, knowledge, and helpfulness here.

Leo, I like the link to the following two pictures you sent:

That sawbuck is the slickest thing I've seen in a while. It's so simple. That thing should help me out a lot!

Funny! I'm going to start searching for that newsgroup... I think it may help me out a lot. So, what is this tool that makes things round?... Where do I start? Hmmm... Wait, don't tell me, I like to think things like this out for myself...