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Smoking bandsaw

R

Raif Harik

Joined
Jan 14, 2020
Messages
279
Likes
100
Location
Austin, TX
Hi, I have an old Rockwell bandsaw that I just upgraded the motor on to a baldor 1.5hp. Which was fun :). But before the upgrade and now still, when I cut pieces of logs, it just smokes and smokes. I have a new blade on there, 3/8in 6tpi. The piece I was cutting yesterday was pecan about 5 or 6 in thick, a long the grain. It started smoking at about 2 in in.
Before the motor upgrade I was cross cutting a branch of something maybe pecan that was like 4in and it was like a barbeque too.
Any thoughts would be appreciated,
Thanks
R
 
Raif Harik said:
I have a new blade on there, 3/8in 6tpi. The piece I was cutting yesterday was pecan about 5 or 6 in thick, a long the grain. It started smoking at about 2 in in.

Thanks
R
Click to expand...

Tim Hunter said:
6tpi is too fine for that sort of work.

Tim
Click to expand...

Agreed. You should be in the 3tpi range. If the tooth count is too high, the blade can't clear the cuttings from the gullets and loads up, severely diminishing the cutting abilities, then friction is all you got going on. Depending on how green the wood is, you may want to investigate an alternating set blade that cuts a wider kerf. Water in the wood will turn to steam and close the kerf if the blade has too fine of a set.
 
Raif Harik said:
Any thoughts would be appreciated,
Click to expand...

A sharp blade 6 tpi should cut without smoking. A 3 Tpi blade is much better.
Try a new blade preferably 3 Tpi.
Slowing the feed rate can let the sawdust feed out better.
Check the guides for alignment - poorly set guides can put a slight twist in the blade causing it to rub on the kerf sides.
Do check that the teeth are pointing down. Like @Leo Van Der Loo , I have seen this.
Sometimes cutting very thin wood there are cleaner cuts with an upside down blade.
Also some pieces will close on the kerf from tension in the wood - I use a wedge to keep the kerf open
Cutting too tight a curve for the blade will twist it causing it to rub on the kerf sides.

I found the Bandsaw handbook by duginski a great reference.
 
Last edited:
Wow, interesting stuff.
I'm unclear how it would be possible to put a blade on backwards.
I think a 3tpi blade will help and in the meantime I should slow my role.
Thanks for the help
R
 
Raif, it is very possible that the blade unrolled opposite from what is “normal”. Always check that the teeth are pointed the correct way before installing.
 
My first thought is dull blade. Second thought is too fine teeth, and/or not enough set to the teeth. I like the Lennox bimetal Diemaster blades. They cut long and last a long time, and can be resharpened a couple of times. I was watching a portable bandsaw video the other day, and that guy used a specialty blade from Woodmizer. It was carbide toothed, and the teeth could be sharpened a number of times. He had tried the bimetal blades and thought the carbide tipped one worked much better, and longer. I may have to try one for my big bandsaw. I had not heard of them before. No clue as to the price, but I will check with my local bandsaw blade maker first. The Lennox carbide blade they had, had very tiny teeth that could not be resharpened. When I first asked about those blades, they told me that carbide was for cutting veneers.

robo hippy
 
I agree 6tpi should not smoke though not optimal for cutting that thickness of wood, especially if green. Backwards would do it, or a really crappy blade. I purchased a Grizzly G0636X, which is not a cheap bandsaw, and the blade it came with could not cut butter.
I recommend getting Lenox blades, I purchase from BandSawBladesDirect but others sell Lenox too. For the price perfomance they are great. I have purchased Timberwolf blades and they are good but don't stay sharp as long as the Lenox blades.
 
I use the Lennox carbide blades to rip my thin stock for segments. I was told they can be sharpened; that information was incorrect for the three I got done. I was offered and did receive a refund for the wasted sharpening. 1/2” blade cost me about $128 which is up about $20 since inflation. They cut like butter when new; Bloodwood and Purpleheart kill the sharpness so I rip those woods last. They greatly outlast standard tooth blades; they continue to cut okay when dulled; everything visits the Drumsander for uniform sizing once cut so feed rate is quick and fast. I recommend these blades; they are worth the extra $$.
 
Russ Braun said:
I use the Lennox carbide blades
Click to expand...
I heard the carbide blades are great, especially for resawing. Are you using the Lenox Tri-master? That is the blade I heard most use for resawing dry hardwood. For my saw that blade is $320.

Most of my use is green wood so I use a Lenox 1 1/4" 1.3 TPI bi-metal for slabbing logs or resaw to planks. I also use the Lenox 1/2" 3 TPI flex-back carbon blades for cutting blanks round. They last a long time with green wood.
 
I really like the Trimaster carbide blades. One came on my used Mini-max saw, 1", 2 TPI, I think, the fellow said it was nearing the end of its life. I've since put about a mile of wood through it and still can start sanding at 150-180 grit. Made some 1 mm cherry veneer this morning and pretty much could have used it straight off the band saw. I usually prep green wood for turning only with a chain saw, but I slabbed part of a big holly log for lumber a couple months ago and it worked just fine. Cut as fast as I could push the wood through. I actually bought a replacement blade when I bought the saw, but it's still hanging on the wall.
 
Is the wood smoking all along during the cut or after you are several inches into the cut? Is the cut a long straight one or several tighter curves? Just like on a table saw some boards like ash will spring in or out during the cut depending on the grain. The wood can sometimes close up into the kerf thus pinching the blade causing the smoke. That's why a riving knife is used directly behind the saw blade to keep the wood from pinching the spinning blade. If pinching occurs on a bandsaw I sometimes put a tiny wedge in the kerf behind the blade to prevent the wood from pinching and burning.

On a bandsaw smoke can be caused in various ways:

Dull or abused teeth
Using wrong TPI for the wood type, depth and moisture content. There should be only 3-4 teeth in 1" depth of wood at any given time. Thinner boards (1/8" - 3/8") require more TPI maybe 6-10 TPI, but a wide 6" to 12" thick log or board is best cut with 2-3 TPI blade.
Cutting wet wood with the wrong blade or cutting too fast
Tooth set is worn away from cutting tight curves. Kerf is no longer wider than blade causing wood to pinch going through cut. Depends on wood speices.
Residue build up on the blade (ie: pitch, resin glue)
Upper and lower wheels out of alignment causing blade to wobble slightly or move slightly from back to front when running
Upper and lower blade guides not in alignment causing blade to fight itself to run true
 
Might be a dumb sounding question but since you just replaced the motor, did you confirm that it is spinning in the right direction? Nothing was crossed in the wiring to make it spin backwards causing it to have the blade moving up instead of down.
 
There's a neat trick you can do with a dull blade on your bandsaw. Mount the blade backwards, teeth pointing up. If you have speed adjustment set it to the highest speed.

Then you can saw thin steel by friction sawing. Enough heat is generated by friction to soften/melt the metal. I don't recall trying it on a 14" Delta type saw, not sure if the blade speed is high enough to be successful. Dedicated friction saws ran very fast. There're so many ways to cut sheet metal in production these days friction sawing is not something you hear much about any more.

It can also be done on a Skilsaw with the blade backwards. I had an employee
trimming too wide garage doors made of a thin corrugated steel. I gave him my Bosch jigsaw with a fine tooth blade to do the trimming. Instead he used his Skilsaw. It did the job nicely, way too noisy to want to do in a quiet residential neighborhood ever again.
 
Raif Harik said:
Wow, interesting stuff.
I'm unclear how it would be possible to put a blade on backwards.
I think a 3tpi blade will help and in the meantime I should slow my role.
Thanks for the help
Backwards -- teeth pointing toward the back of the saw -- is hard to miss but today I started to put one on upside down (teeth and gullet pointing up), which actually amounts to being inside-out.
Click to expand...
 
I just installed a TimberWolf bandsaw blade for green wood 3/8" 3tpi alternate set on my bandsaw. It cuts much better than the dry timber blades I've been using so far. The blade wide set clears the wood much better than on the other blades.
 
Raif Harik said:
Wow, interesting stuff.
I'm unclear how it would be possible to put a blade on backwards.
I think a 3tpi blade will help and in the meantime I should slow my role.
Thanks for the help
R
Click to expand...
If you turn the blade inside-out it can be put on with teeth pointing up. I learned this the hard way.
 
Hi, just checking back as I'm about to order new blade. Lots more great comments! Thanks!
Just for clarity,
the blade is on correctly
the motor is turning the correct direction
the wood is green-ish
the smoking starts pretty much with the cutting.
the cut is either very long curve or straight
the kerf is not closing on it.
motor is running a lot faster than previous but within acceptable params ( can't remember off top of my head but there are some neat calculators on line for it )
So, I won't be buying the Lenox blade as it's pretty expensive, and I'm already annoyed by the cutting height and will have to get a riser when I have forgotten about previous ptsd around customizing tools ( probably a week :) )
I"m going to go with the timber wolf 3/8 3AS, which is not that much cheaper than the lenox but I cant stand looking at blades anymore, so I'm just going to order :)
I'll report back.
 
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