Metal cutting bandsaw-HELP!!!!!!!!!!!

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  #1  
Old 08-08-03, 08:16 AM
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jackmd
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Metal cutting bandsaw-HELP!!!!!!!!!!!

TO ANYONE WHO OWNS OR USES A METAL CUTTING BANDSAW! HELP!!!!
I own a Jet HVBS-463 metal cutting bandsaw, and I've been trying to change a blade and get it to run properly for about 5 days now.
I broke the original 3 year old blade, trying to cut 5"x 2"x 3/16" tubing. I realize that this is a large piece of material to cut for this type of saw, but the manual stated that it was within the size limit of the saw, so I tried.
I purchased a new 1/2"x 0.025"x 64-1/2" blade and read the entire manual from top to bottom to farmilarize myself with the procedure.
It took me a couple of hours just to get the blade to stay on the blade wheels while trying to run the saw.
I finally managed to get it to stay on, and tried to cut the tubing again. I was going very slow, with very little pressure, when the blade broke again, on the last wall of the tubing!
I requested the help from the tools forum on this site, and GregH responded. He told me this was large steel, and to go slow and use lubricant to cut .
With my next new blade, I began the mounting procdure again, reading over the entire manual again, trying to find anything that I might have misunderstood. The blade, once again, kept popping off the blade wheels, no matter how I adjusted the many bearings and blade guides. The manual states that the tracking should't need further adjusting, but it seemed that the blade kept tring to slip off the blade wheels. I adjusted the blade tracking in small amounts, and the blade seemed to move on to the wheels where it was to be, as stated in the manual. I tightened the tracking assembly,and then noticed that the blade had lost a lot of tension. I then started the whole procedure again trying to keep the tension on the blade.
The manual states that the tension should be approx. .004" with finger pressure on the blade.
Every time I get it that tight, (AND WOW IS THAT TIGHT!) the blade keeps working it's way off the bade wheels!
At this point, I can't even get the blade to stay mounted on the wheels, with the saw running.

Is there anybody that knows the basic setup of a metal cutting bandsaw?
Am I perhaps trying to get the tension to tight?
The manual doesn't say WHERE to depress the blade with my finger to reach the .004" deflection. I was deflecting it between the upper and lower bearing guides.
Is there anybody that might be farmiliar with this type of saw, and the many small adjustments that have to be made, just to keep the blade on?
I just know that it shouldn't be this difficult, having used the saw for three years on metal, wood, plastic and even cutting up hunted deer.
I guess I shoudn't have played with the tracking, but there has to be some way of getting the tracking correct, and still maintaining the tension.
These saws seem to be very common; and I've seen more than a couple different manufactures, where all the components of the saw look identical to my saw.
Perhaps somebody out there owns a simular saw of a different make?
There is a picture of the saw in the tools forum posted by GregH.
It is found uder the "Metal cutting bandsaw" thread.
Please, if ANYBODY at all knows ANYTHING, about these saws, please post a reply!
I should have bought that chop saw back when I had the funding.............
THANKS ALOT!!!!!!
 
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Old 08-08-03, 05:40 PM
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Yes I have used these metal cutting bandsaws many times. Although as Greg says this particular model isn't a high quality machine. Some of Jets tools are marginal at best.
If I were you I'd get the tracking right first before I'd worry about the blade tension. By the way, are the wheels that the blade runs on rubber coated by chance? I'm guessing they are not.
Basically get the blade to track smoothly. Then tighten up the tension about as tight as you can get it by hand, don't worry they'll take alot. Now set your guide wheels on the sides and on the top of the blade to just about touching. Use a coolant/lubricant during your cuts. A water based coolant is by far the best because it disappates heat better. One thing I've learned is to not get too many teeth in the cut at one time as it will pinch the blade and either break it or knock it off the wheels. This actually may be where your problem lies. Even a high quality saw will do this. If possible tilt the piece in the vice so as to reduce the number of teeth in the cut. THere are other factors involved here also such as speed, feed, correct blade, etc. THis may give you a starting point anyway and we can work from here. Good Luck.
 
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Old 08-08-03, 08:32 PM
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jackmd
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Thanks Toni.
Just got home and read your post, so I'll try your method in the morning.
You guessed right; the blade wheels ARE NOT coated with rubber, or anything for that matter. They do have a flange to hold the outside edge of the blade.
The blade I'm using is an Olson 64-1/2"x 1/2"x .025"x 24 REG. The package says 24 teeth per inch will allow me to cut 3/32"+ stock size. I wanted that due to needing to cut some thinner steel also.
For the most part, I'm cutting 3/16" wall tubing, channel, and angle; with the 5"x 2"x 3/16" tubing the largest.
Do you think that it might be a good idea to turn the 5"x 2" tubing on end so the 2" side is resting on the cutting bed of the saw? It seems that not as many teeth would be in contact with the metal in doing this.
Before I knew that this saw was so touchy, I cut six pieces of 4" channel, without fluid, and without any problems at all.This was about 3 years ago, but I know the saw can do it.
As Greg advised, I'll cut with the slowest speed this time, and use lubricant. Does that sound ok to you?
Thanks again for your help, and I'll let you know how it goes. Please let me know if there is anything else that you think of.
 
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Old 08-09-03, 11:24 AM
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Yes, I would set the piece so as to have the least amount of teeth in the cut at one time. That alone may be enough to make the cuts that you are trying to do.
At 24 T.P.I ( teeth per inch ) I feel that this may be too fine of a blade. The ones we generally use are 10 to 14 teeth and they are a vari-tooth construction. In other words the teeth are offset every so many teeth back and forth. It cuts a wider kerf, but, the blade doesn't get stuck in the cut as often.
Do you have a feed/ speed chart with this saw? I would refer to that to determine what to set it at. The main thing to make sure that the blade is cutting all the time. If it isn't then it will be rubbing and the blade will dull eventually.
Beyond that I can't really say other than to be right there watching the saw making its cut. Is it possible that the saw has been tipped over and that the wheels that the blade run on have been damaged? It wouldn't seem like that would be the case but one never knows.
 
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Old 08-10-03, 06:01 AM
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You have two threads going on this but I'll answer here.

jackmd:

I would first check that the wheels are aligned as toni1595 suggested and have absolutely no sideways movement at all.
I would also get the 14 tpi blade, again as suggested. The wrong blade could be simply binding and is thrown when the cut gets a bit of depth. It doesn't matter how much tension or how well aligned, if the blade grabs its game over.

The same thing coincidentily happened to me last winter.
I revived an old Delta wood cutting bandsaw and had some grief with blade set-up. After much frustration realized the bearings were worn and the adjustment device was loose.
After repairing it I tried resawing a 6" log to make some boards but only had the fine tooth blade that came with the saw. The blade kept jamming and would pop off the wheels.
Went out and got a few different blades and now install the correct blade to match the job at hand.

If the saw is in good repair then maybe spending a few bucks on the right blade would be the ticket.

Good site for troubleshooting:http://www.bandsawblade.com/chart.htm

<img src="http://www.bandsawblade.com/images/bldbrkg.gif">
 
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Old 08-10-03, 06:28 AM
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jackmd
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Ever wonder why things have to be so difficult?
I tried for about 3 hours yesturday to set the tracking, and just get the blade to stay on the wheels.
I even took apart the tracking assembly, to see if I could find out how it operates.
I am a mechanical engineer/designer; so I do understand clearances, tolerances, and tooling to some degree; but this one has me stumped.
The manual states that the blade must be at full tension before any tracking adjustments are made. Then you must loosen the two screws that hold the blade wheel and blade tension sliding plate, in order to turn a setscrew which tilts the wheel at various angles.
All this is done with the saw running to observe the tracking of the blade.
Every time I do this, the blade becomes very loose and works its way off the wheels. I tried making small adjustments to the set screw with the machine off, then running it, but the blade just won't stay on.
The saw has been treated with great care since the time I purchased it new, so I'm sure it hasn't tipped over or sustained any damage.
There is a material/speed chart in the manual, that states mild steel @120 FPM; but that does me no good without a blade on the wheels.
I just wish I knew of a starting point for the set screw, that got me closer to the correct tracking.
Jet Tools does have a website, and a technical service phone number, so I'll try calling Monday.
The website does have my manual online in pdf form @ www.jettools.com
It's listed under Manuals/Metalworking/HVBS-56, if you care to take a look.
Thank God for the trusty little hacksaw that I've been using since yesturday, when I gave up on the other one.
I've already cut the 5"x 2" tubing, 4" channel, and some stl. angle, without a problem at all! This took about three hours, but I'm finally getting somewhere, and I'm getting a great workout!
I have to get this steel cut, so I can start welding this project together........
Thanks once again for your time, and if you can think of anything else, please post.
I should have bought a chopsaw............
 
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Old 08-10-03, 07:21 AM
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A couple more things,

If the blade came off while in use it is possible that it twisted or distorted making straight tracking impossible.

I'm not directly familiar with your saw but on the wood bandsaw I have I am able, while unplugged of course, set the tension and then spin the wheel by hand to get initial tracking. Once in the ballpark I will bump the power to fine tune the setting.

I can't say if this is possible on your's but you must have the covers off to see what's going on.
You have to be extremly carefull when doing this. Stay out of harms way and if unsure of anything don't do it.

The manufacturer I'm sure will be able to help you out. A factory repair depot may not charge or wouldn't charge much to check the saw and either find a problem or show you how to set it up.
 
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Old 08-10-03, 06:26 PM
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I guess I'd disagree with the tension needing to be at full tightness in order to track the blade. It "should" stay on the wheels just being snug enough to adjust it...... THe more I read this post the more I'm getting the feeling that the problem is the alignment of the wheels. Is there any way you could get a straightedge onto the wheels to check it? Probably not, because of the various parts of the saw being in the way.
THis is kind of tough to troubleshoot without being at the saw. All I and Greg can do is give you some suggestions and let you take it from there.
What I would try is to get the blade on tight enough to hold it on the wheels and keep tweaking the adjustments until it is running perfectly true. Once you have that, then bring the blade up taut.
If you can't keep the blade on long enough for that, then you will have to find a reference point on the frame that is the same as the opposing wheel and try to set at the same plane.
 
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Old 08-11-03, 11:44 AM
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Another thing:

Toni is right in that you don't need a lot of tension on the blade.

Within reason you only need enough pressure to minimize the deflection from the amount of force you are placing on the blade.
I would only give it enough tension to keep it tracking straight.
You could try to set it up using wood as a test media and then if ok gradually add tension while compensating with very delicate alignment adjustments.

One way to check wheel alignment is to get the blade installed and under medium tension. After running it for a couple of minutes without comming off, stop the saw before making any cuts.
Look at the position of the blade on both wheels. They should be in exactly the same spot on both wheels. If not then one wheel is not aligned with the other.

My wood saw was in pretty rough shape and I had to reinforce the bearing area so it didn't flex under tension.
Mine would do the same as yours in that the blade would pop off if I pushed the wood too hard.
It now works flawlessly.
 
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Old 08-11-03, 09:48 PM
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jackmd
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Thanks!

I wish both of you could see the saw so you could see what I was talking about.
To date I still haven't got the tracking straight, but I didn't put much time into it either.
The manufacturer just reads to me out of the same manual that I own already; or I can ship the saw back to them to adjust it.
I agree with the idea of not tightening to full tension. I'll try that next.
I can turn the blade wheels by hand, by turning the belt from the motor pully, to turn the blade wheels slowly, to monitor the tracking.
When I took apart the tracking assembly, I was suprised to see that the shaft that the blade wheel is mounted to, fits into a much larger oversized hole, to allow the blade wheel to "wobble" in any direction it needs to. The thing that's confusing about this, is that when there is different amounts of tension on the blade, the blade wheel tilts in different directions. As soon as the tracking bolts are tightened, I can watch the blade wheel move into a completely different atitude than what I had it adjusted to. At the same time, the blade tension increases, which tilts the blade wheel, until the bolts are tight.
I've lost you, I'll bet!
In other words; the bolts have to be loosened to turn the setscrew, that adjusts the tracking, making the blade wobble.
ANYWAY, thats why I will try to get the blade wheels both level and tight, and then work my way from there. At least that way, I think I'll be closer to true tracking.
Thanks to both GregH and Toni, and I'll let you know how it comes out.
 
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Old 08-15-03, 04:20 PM
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hmm.. your oversized hole got me thinking.

I had a junky no name horizontal saw that i used to
cut a lot of metal. fairly reliable. one day the blade
jumped and jumped and jumped again.

finally realized that the metal shavings had worn down
a very hard to see bushing, causing one wheel to wobble.

i replaced the bushing and all was good.

so, once you've set up your wheels, they should not
wobble! the blade will definately jump if they do.

look carefully and see where it is wobbling. could be
a worn part, not a design feature.
 
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Old 08-16-03, 12:04 PM
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OK let me give my two cents.
On my band saw before I put my blade on I use a mic and feeler gages to set the guide wheels so that it holds it straight up and down, ( .001 ) gap.
The next bad imformation I heard was that there are to many teath setting on the part at one time, you want to lay the pc. flat to maximize the amount of teeth on the part at one time.
When using a new blade the teeth a very sharp and you need to Knock some of the edge off. I do this by getting a pc. of 1/2" x 4" pc. of flat bar, lay it flat and make about 3 cuts before trying to cut the tube.
Next, make sure the part does'nt get loose, this will break the blade every time.
Next, keep your front and back blade guides as close as possible on each side of the part.
Next, Tracking your blade, put the blade on, properly tension it first, then quickly turn the saw on and off to see what way the blade is walking, and then there will be an adjustment that will **** the wheel one way or another, keep turning the saw on and off untill you get it. Remember to wear gloves and a face shield just in case it pops off.
If this doesnt work go to your local welding shop and ask the guy that puts the new blades on if he will come and show you what your doing wrong. It would be $ 50.00 well spent.
 
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Old 08-16-03, 01:06 PM
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that's some pretty good advice from portable welder.

also, if you have a local do-all shop (the folks who sell
big metal bandsaws and bandsaw blades) see if you
can get the rep to come out and look at it. you can
tell them your problem, and perhaps they can send
a service person. same deal as portable welder's advice.

still, i'd check for broken parts. I've never had that many
problems setting up a bandsaw, they are fairly easy, even
with slightly wrong adjustments the blade dosen't jump
and break that much.
 
  #14  
Old 08-21-07, 02:32 PM
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john1443

I purchased one of these saws from a dairy where I worked several years ago for $5 and it had been sitting in my shop for several years before I decided to start using it. The reason they no longer wanted it at the dairy was for the fact that it wouldn't cut straight and they couldn't keep the blade from jumping off. I dismantled it and found loose bushings and the roller bearings in the wheels to be a little rough. I purchased the bearings in a local bearing house and new bushings from Home Depot. While it was torn down I decided to make sure that the blade wheels were aligned properly and needed to shim the top wheel out to the same distance as the bottom wheel. About 1/4" to align properly. With no more play in the bearings and bushings and proper wheel alignment, I use it as a horizontal as well as vertical and it cuts everytime perfectly straight and the blade has never jumped off. It may take some time but you may want to take a look at the wheel alignment. I invested about $30 dollars in bushings and bearings and about three hours of time to align everything.
 
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