For the past several months I've been using the WM 747's. I've been happy with the results as far as speed and accuracy. But blade life seems low. To explain they are 1 1/4" x .055 x 195" 747's. These are the first .055 I've tried. Anything else has been .042" and good life, no cracking.. I'll get maybe 3-4 sharpenings with the 747's. After that major multiple gullet cracks show up. Never had this before. Belts are good, 24" wheels, 35 HP Kubota diesel. Only using in WP. They do seem to cut longer and maybe I'm running to long between sharpening. Using a Cooks sharpener. As noted by others they do loose tips quick on a nail strike.
So long story short I've ordered The turbo 7's in .055 x 1 1/2". Others here seem to prefer these. Also ordered the BMS 250 sharpener.
I've been debating the move to CBN for a long time.
Thoughts???
I just got my TK sharpener, and may still be on the learning curve, but pretty luke warm.
4-5 sharpenings on .055" is about right.
Edit: I meant to say 3-4 sharpenings was about right. A total of five times on the mill from new.
As with any blade, much depends upon how long you sawn between blade changes. Saw until they are not sharp. If you run them until they are dull, your blade life will be greatly reduced.
Yes, there is a difference. You take care of your blades and your blades will take care of you.
I have seen increased life switching from Double Hards to Silver Tip bands, the additional plus is they are cheaper.
I don't have much experience with wood blades, yet! But before I retired recently I spent 25 plus years doing r & r on both bandsaw and carbide tipped circular blades cutting some of the toughest metals made.
Carbide tipped (cbn) is the most expensive but if your after production, (2 to 3 times faster cutting) is the way to go. Highest cost but high reward, but also high risk when you hit that nail 😤
Next would be bimetal, carbon backing with high speed steel edge for cutting. Two blade manufacturers are now using powder high speed wire for the cutting edge. About half the cost of carbide but more forgiving.
How long are you running the blades?
I've read articles/guides indicating exactly what you're reporting. lower hook angle blades crack in the gullet after a number of sharpenings,
causes being: hook angle too low, run too long, sharpening down through the gullet, generating too much heat and taking the temper out of the gullet area.
D
I'm averaging around 4 sharpenings on turbo 7's , .055. Using cbn wheel.
Quote from: dgdrls on June 01, 2021, 08:46:00 PM
How long are you running the blades?
I've read articles/guides indicating exactly what you're reporting. lower hook angle blades crack in the gullet after a number of sharpenings,
causes being: hook angle too low, run too long, sharpening down through the gullet, generating too much heat and taking the temper out of the gullet area.
D
Working alone a band would run maybe 2 hrs; 5 to 6 medium size WP. Cutting mainly 1" x 10". I sticker and stack each board as I go. Blade engagement stays on on my mill unlike others. Now wondering if blade is running more than .055" likes even on 24" wheels. I do lite sharpening but the cam match to profile isn't perfect. This is partially why I'm switch to CBN.
Quote from: Southside on June 01, 2021, 08:01:01 PM
I have seen increased life switching from Double Hards to Silver Tip bands, the additional plus is they are cheaper.
I agree; But WM rep. felt I wouldn't get much life out of the silver tip. ( I realize others on here are prefering them) The other issue is wait times in Ontario. Stocked sizes about 2 weeks. Anything else about 2 months. They mainly stock 10 degree for the majority. I was going to go for .045" as a compromise in T7 but would take longer on order.
I've always used 1¼x158x.045 Wood-Mizer Double Hards.
On average I'll get 12-18 sharpenings, doing a light sharpen, and not necessarily getting the full gullet!
I'm very satisfied with these results, as are some locals that I sharpen for!
I always disengage the blade when gigging back to the front!
The engagement time of the blade also affects blade-life!
Quote from: Chuck White on June 02, 2021, 07:06:13 AM
I've always used 1¼x158x.045 Wood-Mizer Double Hards.
On average I'll get 12-18 sharpenings, doing a light sharpen, and not necessarily getting the full gullet!
I'm very satisfied with these results, as are some locals that I sharpen for!
I always disengage the blade when gigging back to the front!
The engagement time of the blade also affects blade-life!
Thanks and I agree. I felt the .045 would be a good choice also but for availability here. Also I think now your also right about blade engagement time. My mill is wired remote accept for manual lever to idler at engine. I generally stay at the front. This method seemed to work well with the .042 band.
Thanks all for help and comments, especially southside. Greatly appreciated. Gonna try the silvertips.
On my Baker I've discovered that anything more than 2 hours of rotating time on the mill will result in gullet cracks. Usually I'm pulling them off while they are still sharp in order to minimize losses due to breaking.
Blade life depends on so many things, dirty bark, lubricant, the degree of set (less or more heat), blade tension. I own a TK sharper and I run a 40 degree on the front and back of the tooth. There is a set nylon block from TK that works but a little more inward degree keeps that gullet clean and moves the wood faster out of the channel.
Generally go through 3-4 pines before a blade will go on the sharpener.
I don't get good life out of .055" blades, 3-4 sharpenings and they go boom! I personally don't buy the "grind the micro-crack out of the gullet" theory, to stop the failures. I think they are only going to make it around the wheels so many times before metal fatigue gets them. Usually bands are hard to break by hand, to get them in smaller chunks to dispose of. When the .055 (and .050) break, the whole blade is fatigued to the point where I can fold them and they easily break at the fold. The metal is ready to just crumble.
I'll second the Silvertips. They cut just as well as the Doublehards with better flex life, they're cheaper, and you can also get them from secondary blade sellers if WM is backed up.
I have switched completely to Silver Tips over Double Hards. Lower price, much better flex life, cut just as long or longer. Win/win/win
I use .055 x 1.5" on an LT70
Quote from: YellowHammer on June 03, 2021, 12:13:00 PM
I have switched completely to Silver Tips over Double Hards. Lower price, much better flex life, cut just as long or longer. Win/win/win
I use .055 x 1.5" on an LT70
As I type that's the one I'm trying to get here in Ontario. Getting a price by southside suggestion.
I run Cook's Super Sharp 8* .055x1 1/2 blades and have found that if I just hit tips on front and back instead of following entire profile I can get 3 or 4 sharpenings. If I follow the entire profile and just barely clean up the gullet most blades will crack in the gullets and break during the next use. This is not a scientific study but has happened often enough to convince me to sharpen the bare minimum to get longer blade life. Y'all taikng about these silver tips has me thinking about trying them if Cook's can supply a cam for my Cat's Claw.
I remember in one of Cook's tech sharpening tip articles the brother that writes them was saying he thinks a lot of gullet cracks come from too heavy of a grind in the gullet getting the metal hot enough that it air hardens, makes sense to me.
I'm "assuming" similar to what happens when you're at the grinder to long with a chainsaw chain.
I tended to run my blades too long in the beginning. I ran my blades until they created a problem. About 1/4 of my lumber had sawing quality issues like waves on the face or edge, ridges from teeth being out of set, and "snipe" at the beginning of a cut.
When I started sharpening my own, I started changing blades more often. Blade life and board feet per blade over the blade's life have gone up. Fewer blades break early in their life, I can cut consistently faster, the mill runs better and the lumber is better. Sharpening is faster and doesn't wear the CBN wheel as fast. More frequent blade changes also helps eliminate the production of embarrassing lumber.
I had to convince myself that blades are like paper towels, they will only last so long and they are cheap enough to change as necessary. Blades are like oil filters, running one too long just creates problems so I change them often. The expense of changing a blade that's still cutting ok is more than made up in quality of the lumber and customer satisfaction (repeat customers and referrals).
It's the blade and the individual teeth where the the action is, all the rest of the sawmill apparatus is there to put the blade in the log at sufficient speed and with sufficient support to cut true. A dull blade defeats all that other apparatus and makes "designer firewood" (a commonly used Forum term that I borrowed from somewhere).
There's a point at which a blade is still sharp and not yet dull, that's the point at which to change it. Learning that point makes for better sawing.