bandsaw drift – function of wood??
Greetings
Novice advice. I fijnished setting up my new garage-sale bandsaw with new blade, etc, and tested it out on some 3/4″ MDF scraps, and pine 2X4s. I couldn’t detect any measurable (within my limited ability) drift angle. My first project with it is to resaw some 8/4 curly maple. Is it unreasonable to expect no-drift using “real” hardwood? Does the drift angle change with what you are cutting, or is it only a function of balde age? The maple is too pretty on which to experiment.
Thanks
stan
Replies
Stan,
I'm not sure there's a definite answer to your question, as resawing is one of those areas where a lot of different things come into play - feed rate, blade quality and imperfections, blade tension, etc. In my limited experience, the wood also comes into play, so when I resaw I use a scrap of the same species to test for lead. If you are unwilling to cut a thin piece off your curly maple to check lead (and I don't blame you), use a piece of scrap maple, since that's about the closest you'll come to it. I don't know how wide your stock is, but make sure your fence supports it at or close to its full height. If necessary, build an auxiliary fence out of mdf or whatever to attach to the existing fence, and use a featherboard to keep the stock against it if you're not comfortable with your technique. And don't rush the cut. You can't go too slow, but if you go too fast, you can bow even a properly tensioned blade, and the gullets can only hold so much.
Hope this helps.
Froed
Is it unreasonable to expect no-drift using "real" hardwood?
YES -- considering the current state of the "art" of most bandsaw blades! There is likely considerable variation in tooth side clearance. Tooth bite is almost certain to produce a chip that will not be retained in the gullet thus leading to spillage.
Does the drift angle change with what you are cutting?
YES -- a function of grain angle, density variation plus the variables of tool set up.
or is it only a function of blade age?
YES -- though blade age is less important than tooth sharpness (generally the two are correlated).
Thanks for the input. I cut the maple with a close eye to drift and managed to do OK. It wasn't that much wood. but I did detect enough drift not to ignore. I did use a taller fence than I ahd planned.
Get Duginske's book on bandsaws.
While material has some affect, drift has a lot to do with tooth set, sharpness, chip clearance in relation to tooth pitch and gullet size. Each blade will have it's own characteristics of drift so the fence must be set to each blade so it makes sense to use a single point fence to allow for drift, especially with blades 1" and under on a regular bandsaw. Resaws use very wide blades.
The man that is Stan,
These other posts are right. Go slow on the cut, but do make sure that you have an after-market, sharper than average bandsaw blade, not the ho-hum variety that either came with the saw or is sold by the saw manufacturer. Sharp band-saw blades will really rock your bandsaw world, and open some doors for you. I have always run my tension a little high also, sometimes I pay for it with a sudden "snap", but usually I get pretty decent cut. A break now and then is worth a no-drift cut and that wonderful sense of satisfaction.
Chow,
Joe
"Hide not your talents, they were for use made. What's a sun-dial in the shade?"
- Benjamin Franklin
every bandsaw has it's own drift signature, and every blade has it's own personality. I believe the wood you are working with has a lot to do with it as well, but that distills down to technique before equipment.
If I am about to resaw, I will setup my saw using a piece of scrap from the stack I'm about to work with. I do have a homemade fence, that I prefer over the stock Jet fence, however neither offer adjustment for drift so I will use freehand cut the scrap to establish how much drift I'm getting, and then shim my homemade fence to accomodate.
ditto on the comment about sharp blades, they do make a dramatic difference, especially with very hard woods like birch.
Someday I hope to have enough developed skill to resaw better than I do today, it just take time and experience... and a lot of tinkering.
I would be curious to hear from anyone using the Carter guides on this subject.
Just went through this exercise while tuning up my BS. I mostly use three blades, 3/16-10, 1/4-6 and 3/4-3, so had to check each one. IMO, checking blade drift on 3/4 anything is of limited use. Drift due to blade bias will be proportional to cut thickness, so I tested each blade on 6" hardwood rip, with no guide blocks. Found a 1/4 drifting, labeled it as rough junk and switched to a new blade. These are all Suffolk blades, and being run at "low tension" as they suggest. In general, however, give yourself some room to experiment. Don't take anybodies suggestion as any more than a starting point, and see what happens when you change it. In general, you always want to run any blade at the lowest tension that gives you acceptable results with that combination of blade, saw and wood.
Along that note, I also tested each blade for crowning in 6" hardwood rip. The 3/16 showed considerable crowning, measured with a straight edge and feeler. Slowing the feed rate by 3-4 times didn't change anything. Changing the tension from the 1/8 setting up to past 1/4 gave only a very small improvement. Yes, this will vary with the wood type, thickness and direction of cut, but this gave me a baseline, and showed the dependencies on feed rate and tension for this blade. For this type of cut, I'll probably move to a 3/16-6 in order to get the radius I need for some projects.
At the end, as an example of what can be obtained, I used the 3/4 to resaw a thin veneer, 6-inches wide, and got 0.024 +/- .004. If that blade had any appreciable drift angle, I would have had to adjust it for both the width and the wood, which would have been rather difficult.
Gerry
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