Thread: Bandsaw Tracking

I don't know if this is available in the USA but a book called "Band Saw Handbook" by Mark Duginske is an excellent guide to tuning and using a bandsaw.

Macca

Mark Duginske's s book is ISBN 0-8069-6398-0 Publisher Sterling Publishing Co New York. He also makes a good DVD Mastering your Bandsaw published by Taunton.

Barrel cuts are probably due to lack of tension and or an incorrect blade selection. You also need to ensure the guides and thrust bearings are set up properly. Then try slowing the feed.
If that does not work increase the tension. If that does not work get a wider blade with less tooth per inch. If that does not wotk or you do not know how to do these things buy the book. It is a very good reference anyway and worth having.

Pusser

Brad, how hot is the blade getting when you attempt to resaw?

It occurs to me that the saw might work fine for small pieces, but fail on large resaws because the blade is heating up too much and expanding, thereby reducing the tension...

If the blade is slipping on the wheels, that could also be causing heat.

The fix might be as simple as increasing the tension some, or perhaps a different blade with less teeth - slower cuts.

woodbe.

If your tension is OK, another reason can be blade tracking. If you are using a long fence, and the blade isn't cutting exactly along the fence, one of 2 things can happen. Either it will try and push the timber away from the fence, or pull it against the fence. In the latter case, with nowhere to go, blade will continue to try and pull away, and bow away from the fence.

Traditionally, the cure is to establish the "drift angle" and then "skew" the fence so that the natural cut of the blade is parallel.

I have also found, that with high blade tension, the position of the blade on the wheels has more influence. What I do is make a test cut with the blade fully tensioned. If the cut wander TOWARDS the fence, (ie to the left facing the saw), I adjust the tracking to move the blade position towards the BACK of the upper wheel. I find that I can quickly achieve a neutral cutting line.

regards

You may find this reference site useful ~ Bandsaws and Blades information sites

Thanks a lot guys for your responses. I think I have gotten a few ideas I didn't think of. I'll give them a try and see what we come up with.

Hi Brad,

I had the same problem as you, nothing I did would over come the issue. I took drastic measures and rebuilt my bandsaw, see the thread Bandsaw Refit in this forum. After I made the adjustments I can cut hardwood veneers 1.5mm thick and parallel to under 0.2mm. Work great.

Band saw Basics need apply here. Most make a mistake when replacing blades by not going back to basics. When you put on a blade the giudes and bearings need to be taken out of the picture. Back off the guides and thrust bearings (upper and lower) concentrate on the tracking of the blade, Play with the tension and the tracking till the blade rides the crest of the wheels. Then and only then will the blade cut true. Next bring into play the thrust bearings. Place the lower & uppe thrust bearing where they just clear the back of the blade (dollar bill thickness) Now bring in the guides, Place them bvehind the teeth so they do not wipe out the set. Remember to allow for the blade being pushed back against the thrust bearing. (often fellows forget to allow for this and the set is wiped oput on the first cut) Bothe the upper and L&R guides need be set paper thickness way from the blade. Remember the guides are not there to hold the blade in place, the tracking and tension does that, the guides are there to keep you from pushing the blade off track with the cut.

Blade must ride on the crest. Forward of the crest will make the blade cut left, Behind the crest will make the blade cut right. If you keep the blade on the crest the blade will follow a straight line and the fence will be an asset to your saw. Poor tracking will defeat the need for a fence. Whining and cursing will follow.

Some useful stuff here:

http://www.highlandwoodworking.com/i...on=Custom&ID=3

I re-read your post and you said, " About half way through the length of my cut, the blade will bow out and cause the piece to be shaped like a curve. It doesn't do it on the thin cuts, just cuts of about 4 inches in thickness or more." Consider all I previously said about tracking etc., then consider that you are keeping the blade inside 4" of wood for a considerable time and friction builds and heat transmits throughout the 4" as well as the length of the blade. the blade grows in length due to natural occurance when metal is heated. Now the blade is not as tight as before and allows some flex and if the tracking is not exact and a slight drift will grow. This may be causing the problem.

Solution, (?) Cool blocks or roller guides to help reduce friction on the machine end. Teflon spray lube for the blade, Short segmented cuts then back out and allow to cool, Increase the tension as the cut progresses. Larger blade with course teeth 2-3 tpi and wide set.

OR ~ You may be forcing the cut as the kerf is clogged with debris and causing a slight drift, then as you see the drift you ease off and the blade returns to normal. Perhaps you are force feeding such a large piece.

I know the Craftsman is maxed out with a 1/2" blade but there are some 5/8" blades with 2-3tpi and they will work, A larger blade will work wonders for resawing.

Hickory, it does not alter the fact that cheap bandsaws will wander all over the place on certain types of cuts, no matter how it is tracking. Take the case of my one, before I rebuilt it I could twist the whole top blade guide assembly nearly 10mm because it was made of rubbish aluminium extrusion and the pressed steel housing also flexed.

This was certainly causing the problem because now it is solid I can cut thin veneers 160mm deep and less than 2mm thick with ease.

Stubchain. As I said before, the tracking and tension keeps the blade running true. The guides keep you from pushing the blade from its destined course. If the guides as you discribe are not up to par then they will not keep you from pushing the blade off course. The key is to have the blade running true and the guides preventing deflexion. your cheap guides as you call them were not doing their part but the blade has to be going true for it to make a difference as poor tracking blades don't pay any attention to guides anyway.

Sure Crappy guides are no help but good guides are no healp if the blade is not tracking true.