Band saw throwing blades ?

stern

stern

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Have a typical HF type bandsaw (4 1/2") and been having a lot of problems today with it throwing the blade off the inside wheels. I have tried the "tilt" adjustment on the one wheel in all possible positions but makes no difference. Got to the point today I ti9ghtened the blade so much it snapped.
Any trick to these things ?
 
I do not own one of the small saws like you have, but my experience with larger saws taught me to have a lot of patience with these things, and that tilt adjustments have to be made in VERY small increments. Additionally, check to make sure that the wheels are not damaged in some way, and that the blade guides still line up with the wheels. There may have been a problem with that particular blade, too, so try a new blade first before changing any of your settings.

Chances are good that someone else here has had the same problem with a saw similar to yours and may be able to chime in with more advice that is specific to your saw.
 
Thanks for the advise. Will have to grab a new blade tomorrow and looks like it will be a day of "little tweaks" until I get it to stay :)
 
I have one of the HF saws, and I experienced a couple of thrown blades earlier on, but for some reason it is far less a problem now. I dunno - maybe it broke itself in, or maybe the metal particles inside the housing is hold the blade on better? :thinking: I did change over to some better grade blades, so that might have something to do with it. Hope you resolve the issues easily to yours!

On a side note - I use it a lot, and I am surprised at the decent squareness of cuts and speed of getting through large pieces it can obtain. All I've done so far to it is mount the lift handle solidly, and extend the locking handle (vice) out about 5" so I don't hit my hand when cranking it closed.
 
Yea, going to get a quality blade for this (at least a couple). I must say mine gets quite a workout, as it spent most of the day cutting a 7" block lol. Almost made it before the blade broke lol
 
i may be able to help...
a sawblade doesn't ride straight on bandsaw wheels, that is they are purposefully canted and slightly misaligned in order to cut straight. seems backwards but it's a very old ,proven principle.
as pressure is being applied to the blade when you are cutting, that thin lil' band is trying to go every which way but straight.
one wheel is slightly closer to the work than the other wheel.
i'm not familiar with the HF saws, but i work on industrial high speed meat/bone cutting bandsaws.
there are generally adjustments . make very small adjustments when adjusting until you get the feel of what the blade is doing. after you adjust a little (1/8 turn) lock it down and run it, repeat as necessary until it tracks correctly.
it also helps to do only one wheel at a time if both wheels are adjustable, that way you will know if you made it better or worse really quick.
sometimes debris/swarf between a blade and the wheel can cause a detrimental effect as well.

i hope the info helps, if you post a picture of the adjusters i may be able to be more helpful!
 
I had one of these disasters for three years, and had nothing but one problem after another. This last winter I just gave up, and bought a cold cut saw from Northern tool. It does every thing I need, costs less, and takes up less room. I think that a lot of the problem was in me expecting the saw to make heavy duty cuts that it probable wasn't intended to do. Not the first time I have been disappointed after going cheap on a purchase.
 
Hi... My little HF machine is probably the most used item in the shop and once you know the machine is setup, blades coming off is usually a sign of the blade going bad or operator error. Getting the right tension and downward pressure are where operator error comes into play. After enough use, the blade starts bending such that the diameter of the toothed side is greater than the diameter of the backside. Basically, if the circular blade were just sitting on a table, it starts getting cone shaped (hope that made sense). They're on borrowed time when that happens. I've also had brand new (and half decent quality) blades break in the 1st hour of use -obviously a bad weld. When the arm starts bouncing up & down, that's another sign it's going to go soon.

Generally speaking I get from one to two months (sometimes 3) out of a blade and the teeth are usually good but the metal gets distorted. I usually save them and silver solder the ones that were defective with bad welds. And always buy 5-6 at a time so you don't have to worry about it.

Been half tempted to get a blade welder and buy bulk rolls or just get bulk rolls and silver solder them. The 1st ones I soldered were tricky. You need to really degrease them then, annneal the joint, hit the joint with a wire wheel (be careful there) then solder it.

I just had about 15 cuts of 2 & 3" diameter 316 and 308 stainless and that was time consuming -almost 2 hours per cut. The machine doesn't mind one bit, the blades hate it. I really want to get that bigger HF unit but it's not in the cards right now.

Ray
 
I have not had my HF horizontal saw that long but I have been using band saws for a long time.

First step. Take a deep breath and relax. It will work properly if you give it a chance.

Back off all the blade guides. Theoretically, you don't even need them except that the horizontal saw has a twist in blade to point it the right direction.

Put the blade on the saw and get it just tight enough to stay on the wheels. Unplug the saw. Everything you need to do you can use hand power.

Turn the wheels by hand and see what the blade does. Turn it forwards and backwards. What you want to start with is it staying centered on the wheels. This is when you adjust the tilt of the wheel adjustment. Get it riding centered.

Next, you want to adjust it a hair more so it will move back to the rim when you turn the wheel a 2 or 3 times in either direction. It just needs a "tendency" to work its way to the retaining ridge. If it goes back on one turn, you have it tilted too much. It will rub too hard on the retaining ring and create too much friction.

Now do the guides. Start with the back ones. Move them forward to where they *just* touch the blade. You should be able to hold them with one finger while turning the wheel by hand. Then one at a time bring in each of the front side guide bearings until they do the same. Now you need to bring in the back bearings to tilt the blade to the right angle. Bring them in until the blade is in full contact with the front bearings. You should still be able to turn the blade and stop the bearings with your finger.

Next tension the blade a bit tighter. You don't have to really crank it. Just enough that when you set the saw down on a piece of stock, the blade doesn't deflect. Pluck the blade like a guitar string and see how it sounds. It should be a clear tone without buzzing.

The final thing to do is adjust the tension on the feed. It should be just enough that the saw doesn't bounce with the teeth come into contact with the stock. Too much force will just make it track badly and tend to break teeth. It will also twist the blade and make your cut convex.
 
Throwing blades is apparently a common problem with the HF saws. I strongly suggest you join the Yahoo 4x6 gfroup and go to the files section. There, find a pdf by John Pitkin entitled, "Blade Tracking and Adjustment for 4x6 Metal Cutting Bandsaws". This is the widely accepted tuning guide for these saws and is where I would start.

The causes for this problem are many, including:
  • Bad blades with poor welds or broken teeth.
  • Wheels out of alingment (they should be in the same plane)
  • Guide bearings maladjusted (thrust bearing may be pushing blade forward, side bearings pinching)
  • Inadequate tension on blade.
  • Blade not correctly positioned on the wheels (they should just clear the rear rim of the wheels.
  • Bad wheel bearings, upper wheel mounting block may be crooked.
  • Many more.
Best place to start is that Pitkin article, then go from there.
 
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