Is it the BS or the operator?

[Alex Berkovsky]

I was attempting to make a bridle joint using a bandsaw as described by David Marks on DIY web site (http://www.diynetwork.com/diy/ww_tables/article/0,2049,DIY_14446_2275128,00.html). As you can see, the cut did not come out straight; it looks as though it starts curved and then straightens out a bit. Is it something with my <cough>HF bandsaw</cough> or am I doing something wrong? I am using a new Suffolk Machinery 1/4" blade.
If the cut wasn't 3 1/2" deep, I would use a tenoning jig to make the cut on a TS, but the blade doesn't raise to that height.
Being a knucklehead that I am, instead of practicing on a scrap piece, I ruined one leg... live and learn the hard way :(

http://a6.cpimg.com/image/04/E7/56662276-c66d-018F0200-.jpg

[Mike Cutler]

Alex. I would do a few things differently.

Switch to a 1/2", 3-4 tpi blade, and increase the tension.

Start marking the cut lines on the wood. This lets you know immediately that the cut is off track

The 1/4" blade will do what you need it to do, but I think it would be faster and easier with a 1/2" blade. By the way, how many TPI are there on the 1/4' blade you are using.
Essentially you are doing a ripping cut, and the blade wants to wander along the grain. This is caused by the edge of the teeth biting into the wood, and leading into the cut.
You may need to center your blade a little better also, and increase tension. Try to ensure that the teeth are attacking the wood at the same angle on both side of the kerf.
If you want to use a fence to register all of the cuts to, make sure that the fence is angled to accomodate the drift, if present, or just freehand the cut along the marked line(s).
Keep your upper guides as close to the surface of the wood as possible, and still allow you to see where the cut is being made.

A few suggestions. I'm sure you will get some other good ideas too.

[Alex Berkovsky]

Switch to a 1/2", 3-4 tpi blade, and increase the tension. I hope the stock spring can produce the amount of tension required.

The 1/4" blade will do what you need it to do, but I think it would be faster and easier with a 1/2" blade. By the way, how many TPI are there on the 1/4' blade you are using. I was using 1/4" 6 TPI skip tooth blade. I do have a 1/2" 3 TPI blade.

If you want to use a fence to register all of the cuts to, make sure that the fence is angled to accomodate the driftI am not sure how to align for drift so I may have to freehand it this time.

Keep your upper guides as close to the surface of the wood as possible, and still allow you to see where the cut is being made.I couldn't lower the guides enough since the fence was bumping into the left guide for this cut.

I just swapped to a 1/2" blade and made a test cut - the cut came out straight this time. I woder if I can fix the leg that I messed up with a piece of veneer and glue it behind the apron where it's not visible.

[Vaughn McMillan]

Alex, there's a description partway down in this thread of how I set the fence for drift:

http://www.sawmillcreek.org/showthread.php?t=32413

I'm sure there are other ways, and likely better ways, but this method works for me.

On your last point (about the fence getting in the way of the guides), you can use a piece of scrap wood (like a piece of the leg that got messed up, about as long as your fence) laying flat next to the fence. The scrap then becomes a "low fence", parallel with the real fence.

HTH -

- Vaughn

[Alex Berkovsky]

Vaughn,
Thanks for the link and a tip about the fence. Here's a picture of the messed up leg. Can someone offer an idea on how to fix it. Should I make the left cut of the bridle joint wider to the left and the shim it?

http://a0.cpimg.com/image/C8/82/56667080-73f3-01420200-.jpg

[Richard Wolf]

Alex, I think I would cut a thin slice of cherry and glue it into the mistake. Once dry, it can be sanded and you may have to recut your joint.

Richard

[Mike Cutler]

Alex.

I'm not familiar with the HF line of bandsaws. Which model do you have?

I have a Jet 14" bandsaw, and the stock spring would generate about 10K of force. It wasn't adeqaute for resawing, but it was good for flatter stuff. The Itturra spring that I put on increased the tension to about 13,500 lbs force.

Aligning for drift is "typically" a component of successful resawing with smaller bandsaws.. I do it by taking a piece of hardwood, like maple or Jatoba, or even oak about 6" thick and three feet long. I mark a line along the edge, and freehand the material through the blade. You will quickly see that the material has to be held at an angle to the blade to keep it cutting along the line. With one hand I will hold the material in place, and with the other I will turn the machine off.
Without disturbing the piece of material that I am holding in place on the table. I draw a pencil line along the edge that is on the table, leaving a pencil line on the table. This should be very close to the correct "drift angle". Align your fence to this angle, and then give it a try. Move the angle of the fence away from the error, ie if the blade still wants to cut in towards the fence. The angle needs to be increased.

I should have thought about the fence interferring with the guides. Sorry :o
I have a "block of MDF, 4 inches wide. I just position it next to the fence. You just have to remember to compensate for the space it takes up.

I would fix that "test piece" just as Richard said. It will be easy to hide since it will be long grain running along long grain.

[Alex Berkovsky]

I'm not familiar with the HF line of bandsaws. Which model do you have?Mike,
I have this bandsaw (http://www.harborfreight.com/cpi/photos/32200-32299/32208.gif). I as green a woodworker as the color of the BS, but from what I heard, the spring on it needs to be replaced. I will order the Itturra spring very soon as I heard nothing but good things about it. As I said above, the 1/2" blade worked out great.

[Charlie Plesums]

The wider blades work better for straight cuts, the narrow blades for curves. Wider blades require more tension.

Since you are apparently using Timberwolf blades, which require less tension than many, and since the 1/2 inch blade worked well, your tension spring is apparently ok for now.

I had an almost new Timberwolf 1/4 inch blade, and hit something in the wood, and it totally ruined the blade... from that instant it would not cut a straight line, no matter what I tried. Could something have happened to your 1/4 inch blade?