When do you change blades?

[FactorySeconds]

Personally, I take a few queues from the cut to tell me when to change:

Wavy cut not caused by knots
The blade hops when coming out of the cut
Metal strike

I was curious what others do. A specific length of time maybe? I'm sawing 100% live edge through frozen logs in winter so I'm certain I'm not getting the same blade life as most but are there some 'secret' tells from the cut beyond what I'm looking for?

[fluidpowerpro]

I notice that it makes a different sound when cutting. It starts the be a higher pitch. As soon as I start to hear that I change the blade.

[bushhog920]

Wavy cut in a knot is the first sign the blade is getting dull. I have a sharpener I don't wait until I start cutting bad lumber. Every couple of logs while it's still cutting good I take a 10min break and touch it up on my cooks sharpener.

[Magicman]

Do not wait until you see indications that the blade is "getting dull".  A blade that is "not sharp" but still sawing straight is ready to be replaced.  Replace "not sharp" blades before they get "dull".

Generally, two hours of continuous sawing is enough to reduce the sharpness enough to justify replacement. 

[scsmith42]

Years ago when I enquired about this I was told that blades will start to crack in the gullets, and after around 2.5 - 3 hours of rotation time they cracks will be deep enough that they might not be removed by sharpening.  Then the cracks grow and the blade breaks.

This is where some mills that stop band rotation except when the blade is in the log have an advantage over a mill such as a Baker.  On my Baker, unless the mill is idling the band is always turning, and  hence wearing the band in form of gullet cracks.

Thus, if I limit rotation time to 2 hours or so I'll have much longer band longevity than if I push it longer.  Sharpness is not as much of an issue here as rotations.

[beenthere]

Also, review yellowhammer's video where he points out watching the sawdust stream exiting the cut.  

Watch the rooster tail coming from the cut.

Professional Sawmill Secret to Increase Your Sawmill Speed and Quality at Hobby hardwood - YouTube

[Chuck White]

Watch your sawdust, it can tell a story too.

[OlJarhead]

WM says 2hrs regardless of how many bf.

[fluidpowerpro]

YH, thats a great video. I learned a lot. I'm going to start watching the exiting sawdust more closely.

[YellowHammer]

Thanks!

[FactorySeconds]

Watch your sawdust, it can tell a story too.

care to elaborate?

[ladylake]

 I think I go by sound the most, or the 2 hour rule.  steve

[FactorySeconds]

Also, review yellowhammer's video where he points out watching the sawdust stream exiting the cut.  

Watch the rooster tail coming from the cut.

Professional Sawmill Secret to Increase Your Sawmill Speed and Quality at Hobby hardwood - YouTube

I've watched that video countless times at this point. It's great. The rooster tail really helped to dial in and understand the relationship between setup and milling.

[Resonator]

A good sharp blade will cut the wood fibers into tiny "chips", a dull blade will abrade the wood like a sander, and make a finer dust than a sharp blade.  If you saw the same type of wood regularly, you get a feel for what the sawdust should look like coming out of the shoot. Also from running a manual mill, I can feel the resistance pushing through each cut get harder as the blade dulls.

[WV Sawmiller]

   I walk beside my mill and can feel when it starts to strain even though it is still cutting good. Many times I have said "I'll change blades when I finish this cant then a couple boards later DING - a broken blade."

[Chuck White]

Watch your sawdust, it can tell a story too.

care to elaborate?

Simply put, the sawdust will get finer as the blade dulls!

[SawyerTed]

The sound of the blade and the sound of the engine lets me know when the blade begins to get "not sharp".  There's a tone to a sharp clean cutting blade and the tone changes the "less sharp" the blade gets.

The sound of the engine changes as well.  Along with the engine note, the feed dial has to be turned ever so slightly more to maintain feed rate.  

Before I started doing my own sharpening, I was guilty of pushing the blade to dull.  When I started sharpening my own blades, I tended to change "sooner than later."   Besides making blades easier to sharpen, production is better and blades last longer.  

[fluidpowerpro]

  I walk beside my mill and can feel when it starts to strain even though it is still cutting good. Many times I have said "I'll change blades when I finish this cant then a couple boards later DING - a broken blade."

I've done the exact same thing and then when it happens I kick myself because I knew it was coming. Now I swap blades as soon as I hear the pitch change.

[barbender]

I hate changing blades so I push them no matter what🤷‍♂️😊. 

[Old Greenhorn]

I hate changing blades so I push them no matter what🤷‍♂️😊.

FINALLY! Somebody who has the courage to say out loud what I am always thinking. Just a couple more boards yet. :D ;D

[Southside]

Your sawdust should look like grits, not flour.   :D

[barbender]

If it's sawing straight, I don't care😁

I run 1.5" bands, .045" up to .055" thick. I think when my mill was built 1.5"x.045" was the "heavy" blade the crazy guys ran, and 1.25"x.042" was the standard production blade. Well, add in a debarker in the way, and changing blades on my mill is a chore and I avoid it until I have to. Besides that, it seems like every time I pull a blade early, thinking I'm doing the right thing, I install a new one and turn around and saw right into a backstop or something🤦‍♂️🤦‍♂️

[WV Sawmiller]

   It must be a lot easier to change blades on mine then. With the hinged covers its a minute or so to replace them then back to sawing.

[kelLOGg]

Your sawdust should look like grits, not flour.   :D

If I'm running a 4° band (as I always do now) the sawdust always looks like flour. I go by the "hop" to determine when the band needs replacing.

[Patrick NC]

I'm also guilty of sawing with a dull blade as long as it cut straight. Especially since I switched to 1.5" blades. They cut straight much longer than 1.25. Now that I have a sharpener I plan to kick that habit.