How do you sharpen a 1/8 or 3/16 bandsaw blade?

[Derek Cohen]

To repeat: leave the gullets alone! The round diamond burrs will change the cutting angle, and this will destroy the blade. Only file/grind the back of the tooth with a flat disk.

Regards from Perth

Derek

[Alan S]

Many sharpen successfully as Derek suggests with a flat on the back of each tooth.  His work amply demonstrates its effectiveness.  But the round burrs can work too.  If the size of the burr is well matched to the gullet, it can help to limit the metal you remove.  I have had good results that way.  It may be that repeated and/or careless sharpening may lead more rapidly to uneven teeth using this approach, and that might be what Derek warns of.  Consistency is important.

But the way I prefer is taken from one of Lousi Sauzedde's "Tips from a shipwright" videos, as shown here.  He sharpens large bandsaw blades while on the saw using a flat file guided by the bandsaw table.  A wooden guide between the file and table holds the file at a constant rake angle, allowing each tooth's face to be filed in turn.  Using this approach it is quite easy to consistently remove the same amount from each tooth.  Power is not needed.

On 3 TPI bimetal blades a diamond card sharpener used flat to the table converts a hook tooth to a skip tooth while you're at it, making an Olson MVP cut better than new.  Louis's more complex sharpening geometry seems overkill for these smaller blades, and I've never tried sharpening the many teeth suggested by the OP.

[mike4244]

To repeat: leave the gullets alone! The round diamond burrs will change the cutting angle, and this will destroy the blade. Only file/grind the back of the tooth with a flat disk.

Regards from Perth

Derek

Derek, I respectfully disagree with you. I do not try to sharpen 1/8" or 3/16"  blades , not worth the trouble for me.  I have sharpened re-saw blades from 1-1/2TPI / 3TPI many times. I was taught when I was 15 years old using round chain saw files. Not sure when Dremel tools came out but I started in 1959. I can't imagine how many blades of various lengths and TPI I have sharpened over the years.
You cannot change the cutting angle if you sharpen properly. Band saw blades are filed straight across, no tilt laterally or up and down. 
The cylindrical stones for chainsaw sharpening are what I use. I file the gullets and the tooth points at the same time. Others that use this method have found that the blade is sharper than when purchased. Most band saw blades are punched ,but not ground at the factory.
I have sharpened some blades more than 5 times. Probably 10 times, never counted. I sharpen the same blade til it fails. 
By only sharpening the tip , I would think you may only get 2 grinds as you will not have enough tooth left for more grinds. The gullets being ground at the same time as the tip leaves you with a blade that can be sharpened as many times as needed.
mike

[Derek Cohen]

Mike, I remove a smidgeon each time ... really only the wear bevel. I have 3/8" and 1/2" bimetal blades which have been sharpened a half dozen time to date, and still going strong. I sharpened a carbide 1" Lenox Woodmaster CT at least 4 times, when the maker stated that it was good for a single resharpening.

Regards from Perth

Derek

[mike4244]

Mike, I remove a smidgeon each time ... really only the wear bevel. I have 3/8" and 1/2" bimetal blades which have been sharpened a half dozen time to date, and still going strong. I sharpened a carbide 1" Lenox Woodmaster CT at least 4 times, when the maker stated that it was good for a single resharpening.

Regards from Perth

Derek

Derek, I understand you now. I was trying to say that sharpening the gullet is the way I do it , and it works for me. I can see your way if the blade has more than 6  TPI. Takes me about 15 minutes to sharpen a 113- 1/2" blade with 3 TPI. My 16" saw will take 3/16" / 1" wide blades. Probably would take a 1/2 hour to sharpen a blade with say 10 TPI. 
Never sharpened a carbide tipped blade, do you use the same cut off wheel that you use on bi-metal? 
mike

[Derek Cohen]

Never sharpened a carbide tipped blade, do you use the same cut off wheel that you use on bi-metal?
mike

Mike, a diamond wheel will cut everything.

Regards from Perth

Derek

[Timberwolf]

Many sharpen successfully as Derek suggests with a flat on the back of each tooth.  His work amply demonstrates its effectiveness.  But the round burrs can work too.  If the size of the burr is well matched to the gullet, it can help to limit the metal you remove.  I have had good results that way.  It may be that repeated and/or careless sharpening may lead more rapidly to uneven teeth using this approach, and that might be what Derek warns of.  Consistency is important.

But the way I prefer is taken from one of Lousi Sauzedde's "Tips from a shipwright" videos, as shown here.  He sharpens large bandsaw blades while on the saw using a flat file guided by the bandsaw table.  A wooden guide between the file and table holds the file at a constant rake angle, allowing each tooth's face to be filed in turn.  Using this approach it is quite easy to consistently remove the same amount from each tooth.  Power is not needed.

On 3 TPI bimetal blades a diamond card sharpener used flat to the table converts a hook tooth to a skip tooth while you're at it, making an Olson MVP cut better than new.  Louis's more complex sharpening geometry seems overkill for these smaller blades, and I've never tried sharpening the many teeth suggested by the OP.

...................
But the round burrs can work too.

Definitely....I posted that method nearly 15yrs ago on this forum...But it also depends on the "shape" of the gullet as to which method I use...A rounded gullet dictates a rounded diamond burr...The point is NOT to enlarge the gullet but to maintain the shape of the "hook" the gullet forms on the teeth..Using a disc on the top of the teeth "can" change the cutting angle very easily, especially doing it freehand...Altho, when done correctly, either method can work..Some blades with many PPI will have gullets too small for a rounded burr or they may not have a rounded gullet at all...depending on what they are intended to cut..At any rate, a blade with "ground" teeth will outperform one that has "punched" teeth, IMO.

[Arlin Eastman]

To repeat: leave the gullets alone! The round diamond burrs will change the cutting angle, and this will destroy the blade. Only file/grind the back of the tooth with a flat disk.

Regards from Perth

Derek

Just remember Derek your way is not the only way.  I do not widen the gullet but the under side of the tip which does not shorten it nor change the angle.

[Timberwolf]

Just remember Derek your way is not the only way.  I do not widen the gullet but the under side of the tip which does not shorten it nor change the angle.

................
Here's pic of some different shaped gullets........The top row can easily be sharpened with cylindrical burrs..Others would be better sharpened with a thin disc.

[Derek Cohen]

Just remember Derek your way is not the only way.  I do not widen the gullet but the under side of the tip which does not shorten it nor change the angle.

Arlin, I would never claim to have the only way, or even the best way. There are indeed many ways. However, I have done this enough to recognise that some ways are better for those starting down this path. My intent here is to alert you to the dangers lurking around the corner. In the end, everyone must make their own decision.

Regards from Perth

Derek