band recommendation for cutting curves in 8" maple

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merrill77

Master Scrap Maker
Chris
A neighbor is building a table and needs to cut some legs in 8" soft maple. I told him my saw (16" Jet) has that capacity, but I don't think any of my bands are suitable for the job. Seems like anything more than a 3/8" band will make the tighter curves tough...and that lower curve may need a 1/4" band? My 3/8" band is 7 TPI...which seems way too high for cutting 8" thickness. I've done resawing and I've done curvy stuff...but have no experience doing curves in material anywhere near 8" thick.


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I don't think he has any experience on bandsaws...and *I* really don't want to butcher his piece (I pointed him to this site for help).

What would y'all recommend?
 

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Mike Davis

Mike
Corporate Member
For material that thick I would use a skip tooth band in the 2-3 tooth per inch range. The skip tooth design gives extra room to carry the sawdust away from the kerf. Should be able to get that in 3/8 inch width.
 

chris_goris

Chris
Senior User
A neighbor is building a table and needs to cut some legs in 8" soft maple. I told him my saw (16" Jet) has that capacity, but I don't think any of my bands are suitable for the job. Seems like anything more than a 3/8" band will make the tighter curves tough...and that lower curve may need a 1/4" band? My 3/8" band is 7 TPI...which seems way too high for cutting 8" thickness. I've done resawing and I've done curvy stuff...but have no experience doing curves in material anywhere near 8" thick.


attachment.php


I don't think he has any experience on bandsaws...and *I* really don't want to butcher his piece (I pointed him to this site for help).

What would y'all recommend?
Im not sure how anyone from here can recommend a blade size without any dimensions on this picture. Im assuming you have a 2D profile drawing?. At first glance, youre going to need some relief cuts as someone mentioned , but beyond that, since this is 4 sided , youre going to have tape the cutoffs back on similar to doing a cabriolet leg. To determine the blade size, I would draw the profile on some 4/4 stock and cut it since thickness is irrelevant for the finished piece unless of course you dont have enough power.
 

Mike Davis

Mike
Corporate Member
Im not sure how anyone from here can recommend a blade size without any dimensions on this picture. Im assuming you have a 2D profile drawing?. At first glance, youre going to need some relief cuts as someone mentioned , but beyond that, since this is 4 sided , youre going to have tape the cutoffs back on similar to doing a cabriolet leg. To determine the blade size, I would draw the profile on some 4/4 stock and cut it since thickness is irrelevant for the finished piece unless of course you dont have enough power.

The OP stated that the thickness of the legs are 8 inches, all else can be estimated from that dimension.
 

Roy G

Roy
Senior User
You could do the relief cuts, like Sam suggested, and then smooth out the curves on a spindle sander.

Roy G
 

ehpoole

Administrator
Ethan
For material that thick I would use a skip tooth band in the 2-3 tooth per inch range. The skip tooth design gives extra room to carry the sawdust away from the kerf. Should be able to get that in 3/8 inch width.

Either a skip tooth or a deep hooked tooth pattern with deep gullets and 2 or 3 TPI will do well, though once the blade becomes sufficiently narrow the skip tooth will become the only practical option available for deep cuts.

Depending upon the characteristics of your selected wood, one may need to run with more tension than would ordinarily be run if using an especially narrow blade for the cuts to avoid barreling of the cut in an 8 inch deep block of wood, just don't overtension things to the point of breaking the blade though. For the bottom eliptical cove cut one could probably also use the tablesaw (look up cove moulding on the tablesaw). Remember that only tight internal (concave) curves require narrow blades and that external curves (convex) can be achieved though relief and interrupted cuts (essentially breaking it up into individual sections of each curve rather than trying to create the entire shape from start to finish using the same blade for all cuts) should one run into issues with barreling.
 

merrill77

Master Scrap Maker
Chris
Thanks for the advice! I knew I had heard of something along these lines, but "Skip tooth" had completely eluded my recall. I've found a 4TPI skip tooth in 3/8" for my saw (123").

How do y'all check for good blade tension manually? The tension gauge on my saw always seemed questionable...and then the needle on the gauge got bent, rendering it completely worthless. I've generally just plucked the blade and listened for any flapping sounds (too loose).

TIA!
 

Wyatt Co.

New User
Bill
Blade tension... Whoo boy. Now there's a discussion that has 17 different suggestions from only 8 people.

Me personally, if it's a low or general tension blade, I tap, literally "tap" the side of the blade (with the guides backed off or removed) and I'm looking for an 1/8" deflection. It's a practice and "feel" type thing.

Regardless of what anyone tells you. There is no absolute in tensioning a blade. Do's and don'ts yes. But an absolute method doesn't exist. Not in my unworthy opinion anyway.
 

junquecol

Bruce
Senior User
I would forget the relief cuts, as cut offs will have to be taped back on to support the leg while third and fourth cuts are made. The cut pattern will be drawn on all four sides. First and second cuts can be made while it's flat on the table, then tape back together and make third, and fourth cut.
 

ehpoole

Administrator
Ethan
I would forget the relief cuts, as cut offs will have to be taped back on to support the leg while third and fourth cuts are made. The cut pattern will be drawn on all four sides. First and second cuts can be made while it's flat on the table, then tape back together and make third, and fourth cut.

If the shape is designed appropriately there need not necessarily be any need for taping back off-cuts to maintain stability when cutting the perpendicular faces. If the flare of the upper curve is kept equal in width, or even ever so slightly narrower, to the base then the entire shape should remain stable without the need for reattaching the off-cuts, in which case one may use whatever technique suits their needs at the time.

Another option would be to keep the bottom most section of the pedestal base (the portion with squared faces) wide enough to stabilize the shape, then trim it to final dimensions on the tablesaw after cutting to shape on the bandsaw. Done this way the waist of the S-curved upper could be made wider than the base without inhibiting stability without reattaching cutoffs.

Essentially the classic more than one way to get the job done, all equally valid, but perhaps it gives the OP some alternate possibilities as well that might simplify the scrollwork.
 

ehpoole

Administrator
Ethan
Thanks for the advice! I knew I had heard of something along these lines, but "Skip tooth" had completely eluded my recall. I've found a 4TPI skip tooth in 3/8" for my saw (123").

How do y'all check for good blade tension manually? The tension gauge on my saw always seemed questionable...and then the needle on the gauge got bent, rendering it completely worthless. I've generally just plucked the blade and listened for any flapping sounds (too loose).

TIA!

The tension guides in most bandsaws are highly dependent upon the actual length of your blades, and some manufacturers (such as Olsen) sell their blades oversized by up to an extra inch or more, which can really throw off the accuracy of the built in gauge.

The simple, but unsatisfying, answer to your question is that you will get a feel for blade tensioning with experience. Unfortunately, that is not entirely helpful when you are just starting out.

But in general, the greater the span between blade supports (your upper and lower guide bearings) and the thicker the cut the more tension you are likely to require, especially when using narrower and thinner blades stock, in order to prevent barrel cutting (where the center unsupported section of the cut tries to follow the wood grain and a curved, or barrel shaped, cross section results rather than the true vertical cut line you were expecting. The thicker and wider the band material (and these often go hand in hand with blade width, though not always) the less overtensioning you are likely to need to avoid barrel cuts because the wider and thicker blades are so much stiffer and resistant to deflection versus their narrower and thinner counterparts. That is why we often use our largest and thickest blade for thick resawing operations (where there are no curves to be concerned with).

A good starting point is to tension your blade to what you think may be adequate and pluck the backs side of the blade (the portion in the rear column) -- if the tone is muddy and not a pure tone it is definitely undertensioned. Once you have a clean and unmuddied (though often quite low pitch) tone you are at least in the right ballpark and you can adjust up from there based upon your depth of cut and blade width and thickness. Others prefer to judge by blade deflection, setting up the blade and guide bearings and then applying a modest amount of lateral force upon the blade to see how much it deflects, but, again, experience becomes your guide here as well.

Your best bet if you do not yet have that experience level is to save a scrap block of like wood of equal thickness and make some test cuts and curves in it after you have setup tensioning as your best guess suggests ought to work. Then use a straightedge at various points along your test cut and curves a to see if there was in barreling of the cut (convex or concave), if so then increase the tension again and make another test cut in the test block. On the other hand, if the test cut surfaces are true and flat in the cut plane then you likely have adequate tension and should be able to proceed with reasonable confidence and try the real thing.

Either way, you will get the hang of things in fairly short order and you will become much more confident in intuitively adjusting tension.

When you go to setup the guide bearings or blocks, when first learning fold a dollar bill in half, then fold that half in half again over the blade (two thicknesses of the bill, each side), then adjust the side guide bearings/blocks snug to the folded dollar bill (and remove the bill!). Adjust the rear guide bearings/blocks so that the blade is just missing making contact with the blade -- initially you can snug up to the dollar bill there as well. Then run your blade through a full revolution, or at least until the welded joint, and verify the weld joint does not bind with the guide bearings/blocks -- if it should bind then increase the gap between the side guide bearings (perhaps three bill thickness per per side for that blade or possibly smooth out the weld) until the weld clears cleanly with no binding at all. Of course, all of this should be done after you have the blade centered on your wheels and running true as there is no point in setting up the guide bearings until the blade is running stable and centered on your wheels. You will also want to first lower the upper blade guard to about a half-inch, or so, above the highest point of your workpiece before setting up the guide bearings as changing the guard height can affect the alignment of the guide bearings/blocks relative to the blade.

Good luc!. You will master tensioning and blade setup pretty quickly once you start using your bandsaw more, so just use some test cuts in the beginning to give you some initial confidence that things are setup correctly for your intended cuts without the excessive tensioning that can break a blade.
 
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