Metal cutting bandsaw

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  #1  
Old 08-05-03, 06:13 AM
jackmd
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Metal cutting bandsaw

I'm in the process of cutting mild steel, the largest of which is 5"x 2"x 3/16 tubing. I'm using a HVBS-463 Jet bandsaw that has a 1/2"x 0.025"x 64-1/2" blade.
I just replaced the blade, which I broke cutting the tubing. The new blade is hard back with a larger amount of teeth per inch.
I do have the manual, and finally through many tries, I've managed to keep the blade on, and tracking straight. (IT WAS DIFFICULT TO SAY THE LEAST!)
My big question is, how tight should I be getting the new blade?
The manual says .004 deflection with finger pressure! I can't get it that tight, and even if I could, I would'nt be able to see it!
Could this be a mistake on the manufactures part?
Does anyone out there have any experiance cutting metal with bandsaws?
Are there any basics that I should know about tensioning or cutting metals?
I'm new to this type of cutting, and don't wan't to keep replacing 18 dollar blades.
Can anyone HELP.
Thanks alot.
 
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  #2  
Old 08-05-03, 10:39 AM
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jackmd:

Although the tubing size you are trying to cut is in the range of what the mfr says it can cut this is a light duty machine.

The blade speed should be set to the slowest, a lubricant should be used and a minimum amount of pressure applied to the arm would likely give you the desired results.

That is one chunky piece of steel and I think you are likely trying to go too fast.
A band saw is a slow and steady machine.
An abrasive chop saw does not make as pretty a cut but is faster.
<img src="http://www.southern-tool.com/store/media/HVBS-56M.gif">
 
  #3  
Old 08-07-03, 06:46 AM
jackmd
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Thanks Greg!
Sorry about being late on my reply.
Just before reading your post, I broke another blade on the same tubing, on the first cut! Thankfully the store that I purchased it from let me replace it for free. So here I am, about to try the whole thing again for the third time.
Honestly, I'm very nervous about trying this again!
While I was trying to do the last cut I had the saw speed set @ 120 SFPM, and I wasn't using any lubricant.
As far as using to much pressure; I honestly don't think I was. I was afraid that the blade might break again, so I was carefully watching it, and using just the weight of the saw arm to slowly cut, while holding it, trying to FEEL for any snags or slowing down.
I will now try what you suggested, but I can't find anybody that sells lubricant out in the rural area that I live.
I was wondering if there was anything else I could use in place of the cutting lubricant?
Do you think that perhaps a motor oil, or a type of grease, might work temporarily?
If I do use a lubricant of any kind, will I still be able to weld the metal at the cut point?
I did notice that the blade seemed to have broken, where the tubing weld bead started.
If I were to turn the tubing on edge, with the 5" side running vertically, and the 2" side resting on the horizonal cutting bed, do you think that might help?
The blade guides would then be closer together, giving more support to the blade.
Is the tension on the blade as critical as getting it down to .004"; or will I be ok just getting it as tight as I possibly can?
Could I infact, be tensioning the blade to tight?
I only have a couple of cuts left to do on the large tubing, with the remainder of the approx. 70 cuts, being on smaller stock. The largest stock left is 4"x 3/16" channel, needing 8 cuts.
Do you think a blade will last long enough to do 70 cuts?
I apologize for being SO long winded with all these questions, but I really want to learn and understand what I'm doing.
Thanks very much for your time and any more information you may be able to forward me!
 
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Old 08-07-03, 10:33 AM
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jackmd:

It might be usefull to check the owners manual for the correct usage of the saw.

I would like to get one but don't own a small bandsaw like yours.
I have used a larger industrial one and with those you don't apply pressure yourself.
On the one I used there is a crank that is set so the arm just comes down on it's own and then you crank it slightly to apply a little bit of pressure. Maybe yours has this feature.
A bandsaw is not a fast way of cutting and perhaps you need a little more patience.
In the absense of cutting fluid I use anything I can get my hands on. Motor oil would work fine. Just be aware that there is a potential for fire so you should do this in a safe manner.
One small band saw I looked at had a resevoir, pump and nozzle for bathing the workpiece in fluid.
 
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