bandsaw problem

Thanks, I never thought about the orientation of the point of rotation. I can't picture what your jig looks like. Can you describe it more, or send me a picture?

Robert

I also use a Griz 14 inch (with riser block) to cut bowl blanks. I made a jig with a pin for the blank to rotate on and start by drilling a hole in the center of the block of wood. The trick is to have the point of rotation at the right place (front to back). If it is too far past the cutting edge it will push the blade away from the center, if too far toward the front of the saw it will pull the blade toward the center of the block. Or is it the other way around? Anyway, that is the key--that and a sharp blade. Incidentally I use a 3/8 3 tpi timberwolf blade for green wood.

Rob first off get the right kind of blade to saw GREEN wood, get a 3 or 4 TPI blade that has a extra wide set. That will cut your blank. You don't need any circle cutting setup, this is NOT cabinet making, and also the reason many use a chainsaw to cot blanks to a fairly round chunk. Also get the bark off the wood, that's where the sand, grit and gravel hides, blades do not take kindly to that stuff. Give it a try and come back if you have more questions, we'll try to help out.

Have fun and take care Leo Van Der Loo

Leo doesn't understand. A circle jig is an excellent way to ensure even feed and curve. It is NOT for circle making. Equally as important is to have a flat surface to reference to the table so the blank can't tilt and pinch. For that, you can use a scrub and Jack plane. Moreover, if you're dealing with timber thicker than the 6" capacity of your saw or refining the blank by tapering off the endgrain, you can use your jig with table tilt.

Quick search on circle cutting jig should turn you all you need. It's a place to mount the pin and a way to set its position relative to the front of the blade

Rob I am one of those who use a chain saw to "rough round" a blank for the lathe. It is easier and faster than a band saw for larger blanks and for me that is anything over eight inches. However, for rounding on the band saw try (1) use a 3/8" 3 tooth per inch blade and keep it sharp (2) have a flat for reference and to keep the blank from rolling (3) use a guide for a good cut. I cut a series of circles out of card board ranging from 4" to 15". See one used with the chain saw at

(4) on the band saw lay the flat from the chain saw cut down on the table and fasten the circle to the back of the blank with a couple of nails (5) slowly cut around the circle. The gullets on the blade need time to clear the wet shavings and dust from the cut. Let us know if you still have hassles. My 25 year old, 10" (yes 10" not 14") Rockwell still cuts 5 1/2" thick wet blanks without difficulty. I jsut find the $80.00 electric chainsaw more appropriate in the shop for such a cut as I like to heave wet 14" rounds of wood as little as possible. They were lighter 20 years ago :-)

I have a 12" tilt-head Craftsman bandsaw and cut circles accurately down to 4" in diameter. Two things are needed for me to do this. Other people have different ways, this one works for me.

First, a good blade. I use a 1/2" 3tpi blade. This is important because the blade cuts a kerf that is wide enough to make a clean cut in the wood without the blade binding.

My jig:

- remove the blade fro the bandsaw

- get a piece of 1/2" or so plywood that will sit on the table squarely. I cut mine so that it protrudes about 2" off the side of the table

- cut a wood runner that will sit in the miter gauge slot of your table, same width and height.

- lay a thread of glue on the runner and press the plywood down onto it. You want the plywood to adhere to the runner so that it can be slid accross the table.

- I drill 2 small holes in which I insert 2 finishing nails through the plywood and the runner. Be extra careful not to drill through the bandsaw table. These are just markers so anywhere will do.

- remove the now joined plywood/runner and drill a couple of holes into which you can insert some short wood screws to better hold the runner in place.

- put this sliding jig back onto the bandsaw table and verify that it slides nicely.

- cut, position and screw and glue a block to stop the jig from going past the front of the bandsaw table.

- remove the jig and put the blade back into the saw

- once all adjustments have been made and all safety steps followed, turn on the saw and slide the jig into the blade as far as the stop block will allow

- shut off the saw and remove the jig

- using a square, draw a line 90 degrees to the front blade cut out to your right to the edge of the jig

- along this line, mark off some points. I have mine every 1/2". These will be the pivot points. Remember that a pivot 1/2" fro the blade will yield a 1" circle when cut. I started mine off at the 2" mark because realistically, a 4" circle is as small as I can cut with a 1/2 blade and even that is tight.

- with the jig off the saw, drill out the pivot points. I drilled mine out 3/16" so I can use a 3/16" aluminium shelf pin.

- the jig is done

To use, I take my log and mark on the flatest side where I want my centre to be. I drill a small 1/4" deep hole with a 3/16" bit and insert the shelf pin in the hole. Pull out the jig a bit. Flip the log over and insert the pin in one of the holes. Start the bandsaw and slowly slide the jig forward, cutting into the wood, until the jig will go no further because of the stop piece at the front. Gently rotate the log until you have cut out a circle.

Wet wood sometimes will curve back on itself as you are cutting and this will cause the kerf to close and sometimes bind the blade. One way around that is to take a small scrap and wedge it into the kerf to keep it from closing further.

As I wrote this, I made a jpeg drawing with the instructions. I'm sending this directly to your email address. If you have any questions, just ask. If you don't receive the drawing, send me an email directly from your computer and I'll attach it to the reply.

Mike

I understand your problem to be blade flexing. It is not clear whether this just happens when you try to cut blanks or all the time.

I had the same problem with a new bandsaw, it would not even cut in a straight line whilst using the fence. If I used it to follow a straight pencil line freehand (not using the fence) I could do it but I noticed that the wood was apparently being fed to the blade at a slight angle.

I had bought a spare blade with the saw but from a different manufacturer so I changed the blade. Problem solved.

I managed to get the problem back when I tried to cut a screw. The blade just managed to catch the screw with one side of the blade and blunted the teeth that were set to the left.

If you try to cut with a blade like this it will flex. The problem, as I see it, is that the blade cuts better on one side than the other. When you have a decent thickness of wood the guides at top and bottom hold the blade straight but in the middle the blade tries to cut a circle and flexes.

This may not be anything to do with your problem but I would try cutting a flat sheet to see whether you have a straight feed.

Good luck.

BillR

When I used to chainsaw all my blanks, I would run into binding problems. It wasn't a blade tension problem, it was the bottom of the blank not being flat. The blank would tip when cutting (due to the downward pressure of the cutting action, similar to what can happen if you try to cross cut a round piece on the bandsaw), and this would bind and even break the blade. With your blade tension all the way up, if you push on the blade with your finger (with the saw off of course) there should be as much as 1/4 inch of deflection, with firm pressure. If there is more deflection than this, then there is a tensioning problem. You may be able to solve that by getting a slightly shorter blade, or you may have to harrass Grizzly about it.

I do keep a small sharp hand axe handy to touch up some blanks before putting on the bandsaw.

I don't use templates of a circle cutting jig. I use a compass to scribe a circle and keep your blades sharp.

Most blade tension guides are way off.

robo hippy

You probably already tried this but you didn't say how much cutting you have done with your blade. If the blade isn't sharp you will have to push and the blade will flex. You can really tell the difference when you switch to a new blade. Depending on your blade, whether or not you removed the bark and the type of wood your blade may get dull quicker than you think. I used my small Delta benchtop to cut bowl blanks and it worked okay as long as I had sharp blades.

If you have tried tightening the adjustments, the next most likely culpret could be the blade. Bandsaw blades do stretch over time and if your blade has been in use for a while that could be the problem and a simple blade replacement should be the solution. Properly tightened you shouldn't be having the problem you describe, unless of course you also have worn out bearings or other wear problems that emerge with a heavily used machine.

Thanks to everyone for helping. I ordered a Timber olf 3tpi blade and am going to try that when I get it and try some more suggestions I received.

I love woodturning and am not about to give it up, so I'll keep trying until I get it right or keep using my chainsaw to round the blanks. Robert

Robert - if you still encounter this problem with a new blade, I would check where the blade is running on the tire - if not centered it can pull to one side while cutting, causing this kind of problem - - at least that has been the case on my Jet.