[devils4ever]

Okay,

I'm having trouble with my bandsaw cutting my logs into bowl blanks. The logs are split and 8" - 10" thick. When I try to cut the logs into circles, the blade pulls to the right and starts to bind. The bottom of the blade gets twisted more than the top. I even built a circle cutting jig, but it make no difference. I still get deflection and binding.

My bandsaw is the Delta 14" and it is tweaked for proper blade alignment. It has new thrust bearings and co-planar wheels.

I just bought a new 1/2" blade to see if this helps.

Anyone have any other ideas why this is happening?

 

[Dave Paine]

Is the flat side facing down or up?

 

[knika]

I believe that you need to adjust the tension and adjust the tracking on the tire. Most springs on a band saw tensioner lose tension over time and the indicater for the blade size is not true. Adjust the tracking of the blade on the wheel so that the blade runs straight. Also bevel the backside of the blade opposite the teeth. Use a wood block with 320 grit sand paper.

This should help a lot.

Jack

 

[john lucas]

Blade tension and feed rate are the two biggest factors. A 1/2" 3 TPI blade will help also but I've rounded out some pretty big blanks with my 1/4" 6TPI blade when I was too lazy to change blades. Oh forgot to mention, dull blades will do that also. I use a Delta 14" with riser blocks. I will occasionally get the bow type cut but it's usually me forcing the cut because I have a dull blade.
To check for blade tension what I do is loosen the blade and then adjust it so it doesn't wobble or vibrate when looking at the slot on the left side of the saw. The part that comes with the riser is open and you can see the blade. When I get the tension right it runs smooth and straight with no vibration.

 

[robert421960]

i have the delta 14" too and have the same problems
but i have figured out my problems
the bottom is cut with a chainsaw and it is not quite flat so when cutting it twists the blade
i bet you are having the same problem

 

[devils4ever]

Dave, flat side down.

knika, I think my bandsaw is correctly tension, but I'll check again. I do run with the wheels coplanar.

john, I've tried both a new 1/4" blade and a older 1/2". I have a new 1/2" I might try to see if it makes a difference.

robert421960, you may be right. I used a log splitter on the logs. The bottoms aren't flat. I do have a jointer, but I think the logs are too wide to use it. What do you do? Do you have any suggestions?

 

[HomeBody]

An electric hand planer would probably do it nicely. Gary

 

[devils4ever]

An electric hand planer would probably do it nicely. Gary

I do have one of those, but the wood's green. I guess I'll get a shower!

 

[robert421960]

i have learned that if i do have a really bad spot i can take a chisel and get it somewhat flatter

 

[Bonanza35]

I'm no bandsaw expert but when mine starts trying to cut in a curve or bogging down a lot the problem has always been solved with a fresh blade. These work well on my 14" jet. Not the cheapest but they do the job for me. http://www.highlandwoodworking.com/woodturners-bandsaw-blades.aspx

 

[firehawkmph]

Devil,
I have a 14" jet with and extension and use a timberwolf 1/2", 3tpi blade. I cut some pretty sizable logs into blanks and don't have too much trouble doing it. I take a hand plane and flatten the bottoms if they are a bit rough from the chainsaw. I have cardboard circles in various sizes and just tack one to the top of the log and follow it with the blade. Here's some walnut blanks that ended up around 10" x 8" tall.
Mike Hawkins

 

[john lucas]

Use wedges and a sacrificial board on the bottom to make it run flat and true. You can just hot glue the wedges in or sometimes simply screw the blank to the wood.
I bought 2 timber wolf blades. I ruined them in short order. They kink too easily if you get a catch in the wood. That's where the wedges come in, they prevent the wood from rocking which causes the catches. I now use cheap $6 blades my local saw sharpening guy makes up for me. They are 1/2" X 3TPI work great. Since they are so cheap when they get dull I just toss them. I used to sharpen the Timberwolf because they were expensive.

 

[Bonanza35]

Use wedges and a sacrificial board on the bottom to make it run flat and true. You can just hot glue the wedges in or sometimes simply screw the blank to the wood.
I bought 2 timber wolf blades. I ruined them in short order. They kink too easily if you get a catch in the wood. That's where the wedges come in, they prevent the wood from rocking which causes the catches. I now use cheap $6 blades my local saw sharpening guy makes up for me. They are 1/2" X 3TPI work great. Since they are so cheap when they get dull I just toss them. I used to sharpen the Timberwolf because they were expensive.

How did you sharpen them? I've tried using a round file with little success.

 

[john lucas]

I used a Dremel with a rounded stone in it similar to the chainsaw sharpening. You can do a quick get my by in a hurry job by running the blade backwards by hand and holding a diamond burr against the blade. This works if the saw is not very dull. I sharpens the outer tip.
To sharpen the gullet I use the chiansaw sharpeners in my dremel. I just try to duplicate the angle of the tooth and take a light cut. I put a mark on the blade so I know where I started. Usually on tooth above the weld is easy to see. I sharpen all the teeth going one angle and then switch my angle and sharpen all the other ones. it takes about 15 minutes.
I only do that in an emergency when I can't get a new blade quickly. I think if you did it very much it would be easy to make the blade wander, kind of like getting the teeth of a chainsaw off.

 

[devils4ever]

I tried using my electric plane on the bottom of the log and that helped a little. But, I put in a new blade and that helped a lot more. I still had some issues, but I think my base of my circle cutting jib isn't flat either. The plywood base is a little warped. In any case, thanks for all the help from everyone.

 

[kwoodhands]

I tried using my electric plane on the bottom of the log and that helped a little. But, I put in a new blade and that helped a lot more. I still had some issues, but I think my base of my circle cutting jib isn't flat either. The plywood base is a little warped. In any case, thanks for all the help from everyone.

You could make a sled for a router to flatten the bottom. Another way is to screw a piece of MDF or plywood to the bottom with a wedge here and there to level it by eye. Now you have a flat bottom and the blade will not twist.
I have used the latter several times to cut bowl blanks. I did this for other people as I rarely turn bowls, mostly spindle turning. Make sure the screws are not on the perimeter where the hole would show. Don't ask me why I give this advice.
mike

 

[_Ogre]

devil hasn't logged on in 8 years
hopefully he figured it out