I just swopped my Timberking 1600 over to 1&1/2" blades. I threw a big pine on the mill this morning to try out my new blades and roller guides. It cut great on the 1st log, but on the second log I got a huge dive, about an inch and a half. I cut 5/8" boards out of the 1st log, so I made lots of cuts, the blade being brand new and sharp is probably the only reason I got good cuts on the 1st log. I checked all my guides and made sure everything was level and square after I got that big dive. Eveyrthing was still where it needed to be. Then I pushed the blade down and it was really easy to shove it down from the roller guides, that's when it hit me that these bigger blades where going to need more pressure on them to get them to the correct tension than the 1&1/4" blades did. I cranked down on the tensioner, bottoming out the spring, which wasn't but a couple turns more than where the mark was for the smaller blades. I finished cutting that log and cut up another one with out any problems. My question is how do you guys get your blade tension right when you change blades? I am thinking that to much tension is not good for the bearings in the drive wheels. Is the only way to get it dialed in correctly to buy a band blade tensionmeter? The one on cooks site is $240! I'd hate to spend all that money for something I only use once.
Easy to push down from the roller guides? Do you have at least 1/4" down pressure. Is the blade level with the bunks before adding down pressure?. If the movable guide is like the TK 2000 do you have a plastic shim between the u shaped piece and the frame to keep the guide arm from lifting when extended. Steve
You can clamp on a 6" dial caliper to get your reading...
yes I have 1/4" down pressure, the blade is level to the bunks, and there is no shim on the slider arm (I don't think the 1600 has that), but its not moving. The blade was just easy to push down from the roller guides because there wasn't enough tension on it. The tension is different from the 1&1/4" & 1& 1/2" blades, I just need to get the tensioner dialed in.
So you open the caliber up a couple inches, clamp the arms down to the blade and take a reading, then tension it?
I'd be checking the down pressure again, granted a 1 1/2 blade need more tension but even tensioned up to where the 1 1/4 blade was the blade should not be easy to push down from the guide rollers. On the TK 2000 the movable guide arm wasn't sturdy enough and need a plastic shim above it to keep the arm level when extended. Also the blade has to be level with the deck before adding down pressure ,if not you will end up with more down pressure on one side or the other to keep it level with the deck . You shouldn't have had any problems cutting straight with a 1/1/4 band if everything was adjusted right. Also what brand of blades are you running, I tried one brand and sent them back as there was no way to cut straight with them. Steve
Yes, the blade was level before. and the down pressure hasn't changed. When I say easy I don't mean that a paper clip could push it down, its just easier than it should have been.
https://www.youtube.com/watch?v=XLkdVTCGyvs
I saw a few videos on youtube of them doing it with a caliper. Ill give it a try tomorrow and see what I come up with. Thanks for the tip
If it were me,, I would call TK, but in the meanwhile I would also check the blade lube, (heat) it can and will cause so many issues,,bigger means more, as in tension, so if the mill was designed for a 1-1/4" band, then you may be at the max? You may be able to cheat it,, with a spacer or the like,, a call to techs would be my move.
The blade I staying cool, no issue there. And calling TK is out of the question. I know it's the blade tension. That was easy enough to figure out. I just wanted to know if anyone knew of a way to get it right without the $240 tensionmeter.
I checked my mill this morning with the blade tensioned normal, yellow spring at 1 7/8" it takes quite a bit of pressure to push the blade off the roller guides. Steve
If you have the blade at tensioner at full adjustment and the blade is still loose, could the blade be 1/2 or an an inch longer? Have you tried another blade? (I know that's the standard question to ask, but...) I recently received some blades for my vertical bandsaw that I couldn't tension well, then compared and found out they were an inch too long. So there is not enough travel on my vertical bandsaw to tension a 133.5" blade on a 132.5" 'saw'. Can't image the same thing isn't true for the bandmills (though the length discrepancy may need to be larger)
Here is a cheap, safe and accurate way to check the tension in band saw blade and the background. I have learned the tension for blades can be 7-8% of the force when it breaks. As the steel in the blades body is similar to each other will such tension prolongs the blade about 1/1000 of the length you are checking. That means a narrow thin blade needs less force to be stretched. A wider and thicker blade needs a lot more force from the saw tension system. Some band saws are to weak and can't resist the force a wider blade needs without to be deformed.
Open the doors so you can see a long free part of the blade, the longer the better. The upper part of the blade can be the best part for this check.
Clamp two flat rods/iron to the blade, one clamp close to the left wheel and one clamp close to the right wheel. Leave an open distance between the rods ends about 10 – 20 mm. Measure the distance between the clamps. (Say it can be 1000 mm)
Take a caliper and measure the distance between the inner ends of the rods.
Now, start to crank up the tension. Take measurements until the distance between the inner ends is increased with 1 mm.
This is the same method as described with just the caliper but you will have a lot better accuracy this way.
Most of the expensive blade tension meters works this way and has a green sector for recommended tension.
I was not sure what color spring TK uses, so the reason for the call,, each spring applies (x) amount of pressure for a given distance of compression. Not knowing the allowable load allowed on your mills bearings, or anything else for that matter concerning your specific mill my comments are and have no valid point. It really sounds like you have a learning curve to take care of, and more than this know the limits of the mill you have,, even 6" band, high production mills have limits,, dives occur more times than not from to much feed, and or dull blades, and poor alignment. It sounds like according to Steve, Ladylake, a seasoned TK mill owner, would be the one to ask, if the engineers cant help.
All is well now. I used the caliper method and got the tension to 18,500 psi. No more dives.
Hopefully you don't have that yellow spring bottomed out to get that tension, no way I'd run my mill like that as it would be too hard on the bearings and blade. Steve
sounds like you slowed down a bit,, glad to hear,
It isn't bottomed out.
I'm still cutting at pretty much the same speed, I just go by the sound of the motor with my speed, which differs from log to log depending on knots and such. I am defiantly enjoying these 1&1/2" blades. I cut some 1x8's and 1x10's at the same time out of a cant today and it cut great all the way down. Ended up with a stack of (20) 1x10's and (20) 1x8's on the mill by the time I made the last pass thru.
Colt,
I have the tension guage. I'll bring it by when i come over. You can give it a shot and you dont have to buy it.
Doc
(https://forestryforum.com/gallery/albums/userpics/22511/DSCF0386.JPG?easyrotate_cache=1396654059)
Tight is good. ;)
Colt, the low tech way is just increase the tension until it cuts well. Bands will last a lot longer if their not over tensioned. What some call the flutter test. Put a goodly amount of tension on the band and cut. Keep releasing tension until the band flutters and doesn't cut well, then increase tension until it cuts well. Find a way to mark, measure that point. I don't have the foggiest how much tension I have on my bands but they last and cut well. Frank C.
Quote from: Peter Drouin on October 16, 2017, 07:47:49 PM
(https://forestryforum.com/gallery/albums/userpics/22511/DSCF0386.JPG?easyrotate_cache=1396654059)
Tight is good. ;)
Maybe cuts good but is hard on everything. Steve
Yea defiantly don't want to much pressure.
I'm just not scared. And it is a super. :D :D ;D