I have been using different degree blades for different woods since I got my mill.
When I first starting milling 4 1/2 years ago, I used 10° for Pine and Poplar and 4° for harder woods.
For the last 3 months, I have used 4° for ALL WOODS......and done this purposely.
I can saw a lot more BF with a 4° sawing woods I used to use a 10° or 7°.
On all woods I use the 4° on, whether softwood or hardwood, the finish is smooth and the blade will saw more BF......BEFORE......it starts showing signs of getting dull.
Using a 4°, I actually can saw a little faster.
So my question......Why should a sawyer NOT use anything but a 4° on all logs he saws?
I'm convinced, a 4° blade is THE ONLY blade a band mill should use. If you could spend some time at my mill, I could prove what I am saying.
Just a little something that works for me. :)
I run 9* on softwood and 4* on harwood. I have to slow down with the 4*, seem to eat a lot more horsepower. I only had 25hp. I have now upgraded to a Super mill with the 42hp Kubota so may not have that problem. I was comtemplating going to 1 1/2" 7* with the Super and phase out my 1 1/4"'s. Will be watching this thread for insight on which is best.
Steve
I run a 29hp and I know HP has a lot to do with it.
The 4° does really well with my engine.
But I see no reason to have different blades when the 4° is the way to go for me.
I'm telling ya....a whole lot smoother lumber knotty or not. :)
I milled 755 bf of Cedar with 1......4° blade vs. 2... 10 degree blades and finished faster than if I had used a 10°. I use a debarked also.
I use 10* and 7* on a desiel mill but my small mill loves the 4's
Also makes sense if you have a mixed run of logs. I know newer mills are faster but a blade change takes at least 5 min on my mill and then if I don't line it up right, start multiplying the time.
I have an LT15 with a 15HP Kohler and WoodMizer recommends 10 degree bands for this saw. I don't saw any softwoods other than the rare ERC. Mostly white oak, hickory, and hackberry. My mill does labor on the big hickory and white oaks (20" ers). Would I be better off with a different degree band?
A 4° will saw some of the prettiest Poplar you have ever seen. And I can MORE board footage pre blade with the 4 than I do the 10.
I switched to 7deg about 10years ago and love them have not tried 4deg yet. Used to have different bands for different wood but got tired of the hassel of keeping them separated, life is slot simpler with one degree band. I do keep .045 and .055 thicknesses certain jobs, but mostly .045. I generally keep 200 bands on hand so simple is good.
Quote from: Gasawyer on March 04, 2015, 10:23:41 PM
Used to have different bands for different wood but got tired of the hassel of keeping them separated, life is slot simpler with one degree band.
Thats my point. :) I really think the quality of the finish of lumber is better with the 4.
You're right. I used a 4° Kasco blade in frozen EWP today, and the finish was smooth as a baby's bottom. Plus it was much less wavy than the 10's and 8's I was using. I liked the sound the blade made, more higher pitched, circle saw sounding. Now all I have to do is get a protractor and make my sharpner so that it can grind at 4° and I am going to do some converting. Also was thinking I'd play around with 6°. What do you set 4° blades at? Same as any?
Quote from: 4x4American on March 04, 2015, 10:35:03 PM
What do you set 4° blades at? Same as any?
Woodmizer does all my blades in Newman, Georgia. I'm very pleased with their work. :).....and a fast turn around.
Ahh icic...so how long do you keep blades on for I've been having trouble breaking blades and someone told me to swap em every 90 minutes...I had been running them til they got dull. I just look at the tip of the tooth, like anything you can tell if it's sharp or not. Something sharp won't shine, no peened over edge, look for a black line. Also if they aren't cutting well.
Quote from: 4x4American on March 04, 2015, 10:58:39 PM
..I had been running them til they got dull.
Not good. When I first detect my 4° blade making a hump over at least 1 knot, I change. For the simple reasons, I don't want a wave of ANY kind in my lumber and if I change the blade right then, I will get more re- sharps out of it.
I see. So don't let the blade tell you when to change, let the cant tell you.
I have a brandy new 4° WM blade here in a box waiting for it's turn. (No pun intended)
Hello,
I get to run many models of WM mills with different hp and saw lots of different woods. I mostly run the 7/39 Turbo blade. .045 1 1/4" width. I do saw as fast as the blade and the engine will go. I do keep 4 degree blades with me if I get into a bind. I was sawing Ash today. With a 92 LT40HD Onan 24 hp and a new LT40HDG26 I had 7/39 on both mills and the lumber looked good. We have many customers who use this 7/39 blade.
Even though the 10 degree blade is the world wide most common blade sold by WM and I think the other band blade companies sell this profile as the universal cutting blade. I very very rarely ever use it.
The 7 /39 will give you wash board lumber if the feed rate is reduced.
Thanks
Marty
Good reply Marty. Running all those different mills.....you lucky dog, that would be fun.
I like to keep experimenting with just my mill to see what changes I can make to produce a better board at a faster rate.
Its just fun. :)
What's the difference between the turbo and the regular 7°, @MartyParsons (https://forestryforum.com/board/index.php?action=profile;u=1823)
I was thinking the same thing, that sounds like fun to be running all sorts of different mills in different woods.
Hello,
I even get to go out in the field when the call comes in " my mill will not cut" Last week on a LT70 the customer only had 30 to 40 lbs in the blade tension air bag. So that was an easy one.
The 7/ 39 degree or Turbo blade has a 39 degree back angle. The 7 degree blade has a 34 degree back angle. The 39 degree back angle gives the tooth a positive set tooth and it penetrates the wood at a different angle. It also makes a larger chip which carries out of the cut. If the feed rate is slower than the tooth wants to cut then you get the wash board lumber. I am not sure why anyone would want to saw slow. ;)
We work with many customers who are in production and are using the .055 7/39 1"1/4 blade on the LT70 and WM4000.
Depending on what wood I am sawing I even use the 7/39 on the LT15 with the 18 or 19 hp engine.
If the 4 degree works for you keep using it. If you get a chance to saw with a 7 /39 blade try it. Feed rate needs to be increased compared to the 4. Engine drive belt needs to be at the correct tension. The Turbo needs hp and it will slip the drive belt if you are not careful.
We could go on all evening.
Marty
The 4° is the best match for my 29hp.....I'm happy.
Thanks for explaining the 7/39. I learned something Marty. :)
Ive just started swapping to the 7 turbos bands .45 1 1/2..
Found them great on some of the hardwoods and stuff we saw here in nz, but generally forgiving on speed when u need to slow down.
Im running 40hp diesel by the way..
cheers
Justin
You don't have to talk me into 4° blades, my sharpener has been set at 4° for the last 10 years and yes they cut more lumber straighter but take a hair more power. I also think I get more sharpening's out of a 4° blade. Steve
Its my understanding that 10 degree came about with the first band mills that were hand feed, as it made them easier to push into the log. Like a lot of things on mills folks just do stuff by wrote in other words they always used 10's and don't want to change for fear of upsetting something. Personally I don't notice much difference, my bands are 10 when I get them and 6 after I sharpen them. Be aware if you use a drag sharpener like the older WM or cats claw that the left side of the grinding wheel will tend to wear and give you a degree or two less than its set at, for the most part a good thing. I very seldom dress the Cooks ceramic wheels and they last a long long time. The only true way to know your angles is with a machnests protractor, have a white background and have a slight gap from the tool to the front of the tooth. Its tough to tell one or two degrees but it doesn't make much difference. Frank C.
Poston, on ERC it easy to cut most of time, did you notice any differences? Oops sorry I just reread and see where you did find a difference on cedar.
I agree with Marty when it comes to speed. The 7-13° blades will cut faster, however... I have been exclusively custom sawing in north central Ohio and normally have at least three or more species in the pile which have been cut one day to five years ago. The 4° blade is not as fast as the others, but it will cut straight lumber no matter how hard or soft the wood is.
I too have gone to using the 4° band exclusively. I also have switched to the .055 exclusively.
I am moving to SW Missouri and will probably start cutting mostly oak. I might have to experiment with other bands again.
The reason there are different bands is because there are different sawyers and different woods. You have to find the one that works for you.
Quote from: MartyParsons on March 04, 2015, 11:35:08 PM
Depending on what wood I am sawing I even use the 7/39 on the LT15 with the 18 or 19 hp engine.
Marty
Hi @MartyParsons (https://forestryforum.com/board/index.php?action=profile;u=1823) Could you elaborate on the types of wood you would use this blade with the lt15?
Hello,
Yes the 18 hp or now 19 hp is just enough hp to run the 7/39. If you would get into wide cuts like over 10 " you will find with the 7/39 on low hp mills is that you can not overcome the sawdust build up on the lumber or in the cut. The lumber will have fine sawdust it will look like pancake flour on the board. This creates heat in the blade and wash board will occur. You need to have enough feed rate so you are not double cutting all the sawdust. If you can not increase the feed rate because the engine is stalling or changing rpm then you need to run the 9 or 4 degree. So if you are full of energy and like to push the mill to the limit then try the 7/39.
So what woods would work well with the LT15 and the 7/39. Last week we were in Ridgway sawing frozen EWP. Here they wanted all live edge and some logs had a 1/2 of ice on them. Well just about all woods in the N East.
I would suggest you get a couple and try them. Sorry I can not be more specific but there are so many variables in wood, moisture, density, width etc.
I guess I am reserved every time we have a new customer with low hp LT15 or even a 25 hp. If they want to keep the feed rate low, then my best guess for what blade would work would be the 9 degree 29 degree back angle or 9/29. This blade has a low tooth and works will with low hp mills and slower cutting speeds.
Hope this helps.
Marty
These are some of the things I review during our owners day. We get everyone around the mill and saw. We take a few cuts together with different blade angles and review the results. Last year we had Osage Orange and Hickory. We did some tests on cutting speed using the 4 degree and the 7/39 and the 9 degree. We do a test with and without blade lube and a few other things . I try to see what everyone is interested in and what is the average mill model the attendees have. We try to have everything ready so we dont take up to much time. This usually takes about 1 hour to get some discussion going.
I do get some wavy cuts and make some heat in the blade so everyone learns what is to fast and what is to slow. So when they have a problem they may have an idea what may have caused it and what needs to be done to resolve it.
Got to go.
Marty
Marty- You are a wealth of information. Thanks for taking the time to share your knowledge.
Quote from: POSTONLT40HD on March 04, 2015, 09:35:26 PM...If you could spend some time at my mill, I could prove what I am saying...
David- I'm pretty sure this is just another scheme to get free help at your mill. ;D
You caught that too eh?
Quote from: Ga Mtn Man on March 05, 2015, 09:50:48 AM
Quote from: POSTONLT40HD on March 04, 2015, 09:35:26 PM...If you could spend some time at my mill, I could prove what I am saying...
David- I'm pretty sure this is just another scheme to get free help at your mill. ;D
:D :D :D.........and I'm pretty sure this is why you haven't been back. :D :D :D
Does anyone know how the 4* bands work on an lt35 with 25hp? Better than a 10*?
Downsouth I've got a 35 with a 25 the 4* work great with this mill on all but clear pine which it works well in I can make better time using 10*'s when sawing pine but if it's knotty stick with the 4*
Thanks, I don't know that it is worth the switch then. I saw a lot of pine.
It's worth a shot. WM and Kasco sent me free samples of their 4° blade. I have tried both and really like them. I am going to order some.
Funny Poston brought this up, and I never gave it much thought, but it is making a little sense, I have a pretty rinky dink sharpener set up, but one that works for me quite well. Well after many bands going through it with the setting on 7° or so I thought, I decided to do a little tweaking on the angle, The lines which indicate the angle are off, I have been grinding to 5° for a spell now, and working good. So really it boils down in my mind to use whatever works, some good input on this thread, thanks to all, it can only lead to further improvements for all.
Once I find a machinists protractor I am going to see what I can do with my cat claw sharpner.
Many times we do things because that is the way we started, they work well and we spend our time on other areas.
We have used different angles and thicknesses over time, but settled on 10 degrees because it has worked well on our scragg, resaw and LT30E25.
Many years ago I asked a person that had worked for George C Brown Co., (They made cedar paneling in NC for decades.) , why they made it the way they did. Was there a good reason to make it 1/4" to 5/16" and 3 1/2" wide and 1,2,3and 4'long He said no, it is just the way it had always been done. So I decided to make it 9/16" because we had an awful lot of jacket boards that were good one side. We have sold a rather large amount over the last 15 years.
Another reason to ask yourself, why do we do it this way.
This blade discussion should make everyone think about why they do the things they do the way they do them. Not just blades.
Good point.
The only bands I have ever used are 10s. So I can't compare the others but I feel they work good, and I'm going to buy a cbn sharpener and would like to only buy one wheel. All the bands I have are 10s so I'll just stick with them for now.
Quote from: Cedarman on March 06, 2015, 10:36:49 AM
This blade discussion should make everyone think about why they do the things they do the way they do them. Not just blades.
Good point Cedarman. Everything I've talked about works for me and the 29 HP engine I run.
I've done a lot of experimenting while sawing different jobs.
I encourage others not to get stuck in a groove but to experiment also. Your HP, speed, blade degree and what you are sawing will be different from others.
Its a lot of fun learning what best suits your needs. :)
No one has commented on my query as to whether my 15HP LDH15 would benefit from 4 degree blades sawing big hardwood. Any experience here?
Quote from: gfadvm on March 06, 2015, 09:01:25 PM
No one has commented on my query as to whether my 15HP LDH15 would benefit from 4 degree blades sawing big hardwood. Any experience here?
I am just guessing and again....this is just a guess....but I would think with a 15 HP engine and a 4° blade, you may get good results sawing Oak up to about a 10 inch width.
The mill may struggle a little on wider widths.
Maybe Marty will add something or correct me. :)
Quote from: MartyParsons on March 04, 2015, 11:35:08 PM
Hello,
I even get to go out in the field when the call comes in " my mill will not cut" Last week on a LT70 the customer only had 30 to 40 lbs in the blade tension air bag. So that was an easy one.
The 7/ 39 degree or Turbo blade has a 39 degree back angle. The 7 degree blade has a 34 degree back angle. The 39 degree back angle gives the tooth a positive set tooth and it penetrates the wood at a different angle. It also makes a larger chip which carries out of the cut. If the feed rate is slower than the tooth wants to cut then you get the wash board lumber. I am not sure why anyone would want to saw slow. ;)
We work with many customers who are in production and are using the .055 7/39 1"1/4 blade on the LT70 and WM4000.
Depending on what wood I am sawing I even use the 7/39 on the LT15 with the 18 or 19 hp engine.
If the 4 degree works for you keep using it. If you get a chance to saw with a 7 /39 blade try it. Feed rate needs to be increased compared to the 4. Engine drive belt needs to be at the correct tension. The Turbo needs hp and it will slip the drive belt if you are not careful.
We could go on all evening.
Marty
Well I was thinking of getting rid of my 1 1/4" bands and going to 1 1/2" since I have 42HP now. How do you folks running 1 1/2" bands feel? Is it worth the difference? I was under the impression that you could push a 1 ½ band faster as long as you had the hp to drive it. ???
I don't see much difference using 1 1/2" over 1 1/4" bands. I think you gain more going to a thicker band than going wider.
Quote from: POSTONLT40HD on March 06, 2015, 10:03:51 PM
Quote from: gfadvm on March 06, 2015, 09:01:25 PM
No one has commented on my query as to whether my 15HP LDH15 would benefit from 4 degree blades sawing big hardwood. Any experience here?
I am just guessing and again....this is just a guess....but I would think with a 15 HP engine and a 4° blade, you may get good results sawing Oak up to about a 10 inch width.
The mill may struggle a little on wider widths.
Thanks for the reply. My mill doesn't struggle with the 10-12" hardwoods at all. It's the 20+ inchers that it needs help with. Sounds like the 4 degree wouldn't help :(
Hey there's only one way to find out. You can buy a single blade from WM you don't have to buy a whole box.
There is a few of us that are taking a 7/39 turbo blades and sharpening them to 4/39 profile.
I never woulda thunk that the angle of the back of the tooth would play such a big role in the way it cuts.
I don't think it plays into it at all. When you go from 34 degrees on the regular 7 to 39 degrees on the Turbo the tooth gets taller and that is what makes the difference. While they do cut faster that taller tooth takes material from the body of the band. I can't sharpen as much before it wants to wave.
The standard 7 works best for me. Lot to tooth geometry and I keep learning.
Thanks for sharing.
4° blade cut through this frozen spruce like it was tulip poplar.
(https://forestryforum.com/gallery/albums/userpics/34510/photo_1_281129.JPG)
Hello,
Not sure what a 15 hp LDH is.
I think if it is not a orange mill I have no room to comment. I have lots of sawing time on the orange mills but not sure what the other guys (company's) are doing with band speed, guides, tension and the list goes on. We always try to talk about why one WM mill cuts a little better than the other. We are learning just like everyone. We are always looking to make the orange mills cut better, faster and more efficient. We have been out giving advice to other mills not WM on blade choice. When we do this we check band tension, blade speed SFM, guides, blade tilt, belt tension and the list goes on. Some times we even change the guides to the WM style. There is no use changing the blade hook angle, thickness, width ect. unless the mill is set up correctly.
I always say picking out a blade for someone is like getting a pair of shoes with no information other than a name. These will fit! My advice is to check you mill, alignment, ask questions on the FF and see what works for owners with the same mill, and live in the same area cutting like wood. For us in the North East we can come pretty close to helping pick out the correct blade because we work with many WM owners with the same hp, mill etc.
I have gave my 2 cents. Sorry about rambling on.
If you were in my area with a 15 hp LT15 and were sawing normal wood in the North East region, I would say use the 9/29 blade. Not saying the 4 degree would not work, most LT15's G15 left the shop with the 9/29 blade and they seem to be working.
Marty
Quote from: MartyParsons on March 07, 2015, 04:53:25 PM
I always say picking out a blade for someone is like getting a pair of shoes with no information other than a name. These will fit!
Marty
Old saying. ;D
I agree Marty, but I love keeping mental records of how my mill is sawing, with what blade degree vs. what species I'm sawing and the time I'm gaining etc.
But I will add this that I failed to mention......I ALWAYS keep my blade tension at 2800-3000 psi. Whether this comes into play, I do not know....but it seems to work better on my mill. :)
After around 4 times of putting on a brand new 10° blade that cut wavy on the first cut and then sharpening that same blade at 4° and cutting perfectly straight 1/4" below the crappy 10° cut my sharpener stays at 4°. Proof enough for me. This is in wide white oak. Steve
:D :D :D :D :D
Marty, My brain saw LT15 but my fingers typed something else! Sorry about the confusion and I appreciate the replies. Sounds like I'd best stick with the 10 degrees and save up for more HP to cut big hardwoods.
Quote from: gfadvm on March 07, 2015, 08:49:05 PM
Marty, My brain saw LT15 but my fingers typed something else! Sorry about the confusion and I appreciate the replies. Sounds like I'd best stick with the 10 degrees and save up for more HP to cut big hardwoods.
That's funny, I thought you were talking about an lt 15 the whole time too, I didn't even catch it til he brought it up! Funny how brains work..
There are some of us guys on this forum that make our entire living with our mills and we tend to swap info a bit over the phone and in PM's. It is always interesting that we have to remember that even though we are all cutting similar species that the wood is different since it comes from different parts of the country. When someone is giving advice don't forget to look at their profile and see where they are cutting at.
With my mill, woodland, I been using 10 degree blades, I'm cutting red oak. After about maybe 200 bf, I find that the mill has to fight thru a cut. I'm cutting fresh fell logs. Heck, water pours out the ends. I tried using no lube to a lot or even cutting it on and off thru a cut. The logs avg size are about 20".
So, what I'm seeing is that I need more HP to used a 7 or 4 degree blade?
Quote from: fishfighter on March 08, 2015, 06:31:53 AM
With my mill, woodland, I been using 10 degree blades, I'm cutting red oak. After about maybe 200 bf, I find that the mill has to fight thru a cut. I'm cutting fresh fell logs. Heck, water pours out the ends. I tried using no lube to a lot or even cutting it on and off thru a cut. The logs avg size are about 20".
So, what I'm seeing is that I need more HP to used a 7 or 4 degree blade?
Sounds like a dull blade after 200' . A sharp blade should go through a log with ease. :)
200' and dull? That fast?
Quote from: fishfighter on March 08, 2015, 08:12:05 AM
200' and dull? That fast?
You can dull a blade in one pass. :)
^he's right I've tried it before!
I have a question, do I have worry about disturbing the set when handling the blades? I like to keep my blades uncoiled at home cause then I know I can't disturb the set. Another thing is when I install a fresh blade, sometimes the teeth will get caught up on the metal going in. I always try to be as gentle as I can but sometimes, it happens.
When I put a blade on my mill, you'd think I was roping a calf in the rodeo. :D
Do you charge admission, or just make your money off of concessions?
I am using the 10* blade and generally have been happy BUT i ve not tried others. Been think may be trying a 7*
I am sawing frozen white spruce right now an i am getting a 12 inch long 3/16ths ish bump in the first 18 inches of the cut on about a 1/3 of the opening cuts. it trims off just fine but it is annoying to say the least.
Any ideas on solving that one?
Also do i need a different grinding wheel for my CBN grinder to sharpen the 7/39 bands?
Quote from: Dave Shepard on March 08, 2015, 10:02:38 AM
Do you charge admission, or just make your money off of concessions?
I think there's more than me that would pay to watch him. :D :D :D
Quote from: fishfighter on March 08, 2015, 06:31:53 AMI'm cutting fresh fell logs.
Quote from: fishfighter on March 08, 2015, 08:12:05 AM
200' and dull? That fast?
What kind/brand of blade are you using? Are you sawing dirty logs?
I have heard of Goat Ropings but I have never seen one.
Question for Marty.. I notice in one of your posts you mentioned a 9/29 blade. Is this a new way of describing characteristics of blades ? I assume the 9 designates a 9 degree hook angle. Does the 29 descibe the back angle and if so, from the horizontal or vertical ? It's been my experience that the back angle on a tooth can have just as much influence on performance as the hook angle. Case in point. I do a little sharpening for some local norwood sawyers. They tend to buy blades from whomever has the best price at the moment. One of them brought me some blades that had what appeared to about a 10 deg hook angle. The back angle was rather severe, resulting in a tall skinny tooth with a sharp point. After sharpening, those things cut like gangbusters, the downside was I could only get less than 100 bd ft before they dulled a bunch. Also, they needed re-setting more often than I like..Like most everything else on a sawmill, it's a compromise, you can cut fast or cut longer, but not both..
Piney
I think your right, Cooks supersharp that has those high back angle teeth which cut fine but can't take a nail hit and dull easy. I think WM 7° turbo blades are headed in that direction but not as bad. Steve
One pass on clean logs to dull a blade? Come on, really.
Quote from: fishfighter on March 08, 2015, 08:11:42 PM
One pass on clean logs to dull a blade? Come on, really.
I guess if it has a nail in it. :)
It only takes one embedded stone to kill a band.
QuoteQuoteIt only takes one embedded stone to kill a band.
or silica infested bark.
The teeth like to cut wood, they don't like to cut anything else
Quote from: 4x4American on March 08, 2015, 10:56:54 PM
The teeth like to cut wood, they don't like to cut anything else
Oh, I don't know.
I'd bet they saw through flesh and bone without much complaint. :o
Poston is right on the money in regards to the 4 deg blade profile. The 4 deg blade would be my blade of choice if I were operating a mill with under 25 HP. That is based on the variety of hardwood species that are native to our region. I have been using 4 deg blades now for over 3 months. The only blade profile that is able to productively saw frozen hardwoods. I use 4 deg blades on frozen, extremely dense, or dry hardwoods. The 7/39 Turbo profile blade is used as the blade of choice for all other general sawing needs. Within a 30 mile radius of me, there are 10 full time bandmills in operation. We all are using the same 2 blade profiles. Not a one of us would even think of using a 10 deg blade. Even if it was given to use for free.
I feel that the WM description of their 10 deg blade as a general purpose blade is way outdated. For those of you that are in doubt. Try cutting W Oak, or better yet, hickory accurately and productively with a 10 deg blade.
To touch on a topic which Jake mentioned in a earlier post on changing the 7/39 Turbo profile being converted to a 4/39 profile. There are 5 mills, including mine, testing this converted profile this winter with nothing but positive results. The plan is to be able to use the penetration factor of the 7/39 Turbo in a less aggressive 4 deg hook angle. As an added benefit, we all can purchase one blade profile to cover all our sawing needs. The conversion is made by using a custom made CBN wheel. This is a custom profile only offered from this company. http://www.rixsaws.com/wpimages/wpb8f0d819_06.png If any one is interested in trying this conversion check into these wheels.
That link is not good. try this one. http://www.rixsaws.com/page4.html
gmmills-
What is the theory behind a less aggressive tooth angle giving better performance on a higher powered mill?
QuoteI've been having trouble breaking blades and someone told me to swap em every 90 minutes...I had been running them til they got dull.
Do we want to discuss this?
If you are having issues like this then ask these questions.
Where did the blade break? If it broke at the weld and it has never been sharpened then it is a good chance it is a bad weld. If it broke at the gullet then it is most likely a flex life issue. We recommend 500 to 800 bd/ft per sharpening. If you are running the blade longer that that then the stress cracks are forming and will not be removed during the sharpening process.
Who is sharpening you blade?I have heard it a few times. "You only need to sharpen the tooth". Well yes that is correct to make the band cut, but the cracks form in the gullet and they need to be removed. It they are not removed during the sharpening process then the blade will break at these stress cracks.
I would think every band saw owner needs to be aware of the flex life of the band. I very thin blade like .035 will flex for a long time and a very thick blade like the .055 will flex less. What do you give up with a thick blade? Flex life. What do you give up with a thin blade? Beam strength or resistance to dive during the cut. A thicker blade will also use more hp. If you have a 10 hp gas engine band saw and put a .055 blade on and cut then you would be wasting money on the blade because the increase performance would be wasted in loss of hp and flex life would be shorter. If you have a 35 hp or larger engine and you are sawing some lumber of more value and you have employees and every bd/ft must count then the thicker blade would have some value. Production and quality may be improved by using the stiffer blade.
There are a few other things that may make the blade fail or have a short run time. Tracking, ( pushing the blade back into the guide) Heat. Belted wheels. Sap under the band wheels causing the blade to bend or flex more often. Wheel alignment.
During training I always ask them to be Sherlock Homes when they have a blade failure. I have seen some throw blades in the scrap before trying to solve the issue. If you stop and look at the failure then recognize what caused it things will work much better in the future.
Hope this helps.
Marty
You asked a question about why I refereed the 9 degree frozen blade as a 9/29. I guess to clarify the hook angle and the back angle all has effect on the performance of the blade. If you take a 10 degree 30 degree back angle blade and just change the hook angle then it would not be the same.
Comment on changing the degree of the blade to another angle with the CBN wheel. You will wear the wheel a little sooner than sharpening the proper hook angle blade with the proper angled wheel.
Quote from: MartyParsons on March 09, 2015, 03:16:43 PM
Comment on changing the degree of the blade to another angle with the CBN wheel. You will wear the wheel a little sooner than sharpening the proper hook angle blade with the proper angled wheel.
Actually, this CBN wheel was specifically engineered and manufactured for this application. 2 light passes with sharpener is all it takes. The change in the profile could be measured in thousanths of an inch. Once the hook angle is established, subsequent sharpenings are no different than any other blade.
Thanks, Marty. The reason why I was breaking bands was because the back of the band was hitting the flange on the guide roller. I only had them set at 1/8" gap. I now set them to 1/4" and so far so good.
When pineywoods raised the question about the different angles I got confused... and found this picture. Hope this helps for the discussion.
(https://forestryforum.com/gallery/albums/userpics/31167/Tooth_profile.png)
Also the question from Ga Mnt Man came to my mind reading this tread, any answers from the specialists? :P
Quote from: Ga Mtn Man on March 09, 2015, 08:55:45 AM
gmmills-
What is the theory behind a less aggressive tooth angle giving better performance on a higher powered mill?