Resawing on a bandsaw

[Scott Brandstetter]

I have a Jet 14 inch with 6 inch riser block, 1 1/2 HP. Looking to upgrade but had someone tell me that going to a large HP machine isn't going to make any real difference in speeds when resawing. This does not make sense to me. I was looking to go to a 2HP , maybe a 3HP but now I'm not sure of anything.

[David Nelson1]

I cant answer the HP question other than to say more is better. I have a Jet 14 DXpro which has a 1.25 hp motor. I was having trouble resawing African Mahagony 10 - 11 inchs till I switched back to 3/4 3 tooth alternating blade after that all was fine.

I was using a 1/2 in wide band prior to that because most folks thought I wouldn't be able to properly tension the 3/4 blade. This blade (1/2) must have been been dull on one side or something else wrong because it was cutting i/2 moons about 6 inch into the cut and then getting stuck. I wont go into how much cussing and down time that was, I even went way past what was indicated on the saw for tension and past the old school deflection test for tension and it still cut 1/2 moons.

After I switched it out, I tensioned it according to the direction on the back of the Timber Wolf packing. I let it run for a few mins. made a few shallow cuts in scrap wood. I re-tensioned the blade and made a test cut in the piece I just ruined from the other end. Went thru it like butter.

I will say that the saw was maxed out tension wise and I might be able to relax the tension a bit just don't know yet. With your riser block I'm not certain how that will relate to how well you can tighten the band. I was close to pulling the trigger on a much larger saw and still will later next year, I'm just glad I did make another effort.

[Art Mann]

What the person told you has some validity. Here is why. When you are resawing, the cut makes a lot of sawdust. The faster you go the more it makes. After a while, the gulletts fill before the individual teeth make it all he way through the material and block the blade from cutting any more aggressively. At that point more horsepower won't help much. If you want to cut faster, you also have to use a more aggressive blade with bigger gullets and fewer teeth. That is where the increased horsepower comes in. Small motors can't furnish enough power to drive the big blade through the wood at maximum speed.

Mt conclusion is that more power is better but you also need a more aggressive resaw blade.

[M Toupin]

While power is a factor in the ability of a given BS to resaw, it's only part of the equation. More important it the blade design, TPI, sharpness and blade speed surface feet per minute. SFPM is dependent on wheel diameter, larger wheels can be run faster than smaller wheels. A 14" BS generally runs in the 3,300 sfpm while a 20" generally run in the 4,000 sfpm range and some of the larger 30-36": saws in the 5,000 sfpm range. Everything being equal, a higher sfpm will cut faster as more teeth are passing the material in a given time. That's assuming you have the optimal blade and enough power that you're not bogging down the saw which reduces the sfpm and from there it's a down hill slide to slower and slower cutting.

So it would seem that the simple fix is to increase the sfpm but if you exceed the range for your wheel size all sorts of bad things happen when physics take over. BTDT. A had a 14" that I rebuilt and replaced the old pulleys. It wouldn't track and kept throwing blades ever time it was started. Vicious machine! It even tried to rip my face off when it threw a blade miserable thing! After much cussing and investigation I discovered I made a serious math error when I figured the pulley diameters and inadvertently had the blade running at about 5,000sfpm. Backing the speed down to 3,300sfpm solved everything. The moral is don't exceed the design speed and recommended sfpm ranges for you're wheel diameter.

In short, he proper blade will cure a multitude of perceived problems.Make sure you have the proper blade for the task first before you explore a new motor.

Mike

Edit - Art types faster than me but he's spot on!

[Prashun Patel]

The problem with some 14" saws with riser blocks is that you cannot adequately tension the thicker, stiffer blades.

I agree that the first factor is a low tpi blade, and proper feed rate. But all things equal, my 19" 2hp saw cuts way more consistently than my 14" with riser did.

There are stories of guys who can resaw with a 14" saw and a 1/4" blade. Can be done, just requires touch.

When you have a big honking saw, you just don't have to worry as much about it.

[Jim Becker]

The larger saw primarily benefits from a more stable sawing environment for the "thick" cuts that resawing brings as well as the stiffness that Prashun mentions. Yes, greater power does help keep things from bogging down, but resawing will never be a "fast" process for the reason that others have mentioned...material needs time to get cleared from the blade gullets. If you push though a cut too fast, that process becomes less efficient, resulting in greater heat from friction and more stress on the blade and blade support system.

That said, I'm glad I have the bigger saw for even "small" resawing cuts. Most of my work around that is in 3"-4" tall material and it's a pleasure not to have to force a cut. That makes for greater safety, too...if you're pushing and pulling, there's more opportunity for an accident to happen.

[Peter Quinn]

You can put a 10hp motor on the saw, it won't matter, the frame limits the blade you can tension, and that limits the cuts you can take. The 1 1/2hp motor will adequately push the largest blade that saw can take, if you want more speed, it's time for a bigger saw, not a bigger motor. As mentioned stick to a good resaw blade with 2-3 teeth max, 1/2" is about what I've found 14" cast iron delta clones are comfortable tensioning, that will maximize your saw, not much else matters.

[Peter Aeschliman]

Ditto on what Art said regarding sawdust in the gullets.

This video is an awesome illustration. Matthias Wandel is my nerd hero!

[David Ragan]

All this is true.

And, the spine of the machine must be able to handle the tension of the blade. There are different camps of how to measure tension, how high it really needs to be, and so forth.

The one thing that made the biggest improvement for me, after getting the MM16 and a RK blade, was accounting for drift with each new job/setup.

At the time, I was doing a lot of veneer work, and wanted the resulting surfaces to be as smooth as possible.

It's been said that such small details don't matter all that much in a substance that swells, warps, and moves over time. I guess that a lot of little things, taken together do make a difference.

[Jeff Ramsey]

What Matthias said in the video is precisely why I gave up resawing on my PM 14" with a 6" riser. I couldn't get enough beam strength with a wider blade and have enough force from the motor to cut effectively. I had so much force in a 3/4" 3TPI blade that the Carter quick release literally exploded, with a metal fatigue break.

[Rick Moyer]

Peter, I had seen that before but that is an outstanding tutorial on the effects of blade geometry, tension and saw HP. Thanks for sharing.

[Bill Adamsen]

Peter, thanks for sharing. I've enjoyed Matthias' tutorials on creating box joints, and even though I don't use his methods, have learned much from his tutorials.

[Scott Brandstetter]

All, thanks so much for the education. Peter, video was so enlightening. I have learned so much and now know what to look for if I decide to move up in a saw.