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Author Topic: Slab saw blade is bending while cutting  (Read 245 times)

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jalapeno333

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Slab saw blade is bending while cutting
« on: October 02, 2020, 04:43:58 PM »

My slab saw is cutting slabs with one end thicker than the other.

How can I resolve this issue?

I’m spinning the blade BEFORE placing the stone inside and noticing minor wobbles.. so I straighten the blade manually by pressing it into the opposite direction as I rotate the blade. 

Then I place the rock and turn the saw on.

After 20 minutes I return and see this (image included). Blade is crooked and pinching to one side... it’s an old blade, should I just buy a new “sharper” one?  THANK YOU EVERYONE :-)




Sent from my iPhone using Tapatalk
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lithicbeads

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Re: Slab saw blade is bending while cutting
« Reply #1 on: October 02, 2020, 05:30:02 PM »

This seems to go beyond normal blade deflection. Stating on a relatively square portion of the stone will help prevent deflection of an undamaged blade as will slowing the saw down. What type of blade, size and make ?
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Ryaly2dogs

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Re: Slab saw blade is bending while cutting
« Reply #2 on: October 02, 2020, 06:17:10 PM »

I've seen this happen when the jaw vise slips and the rock moves during the cut.  Can you rule this out?
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irockhound

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Re: Slab saw blade is bending while cutting
« Reply #3 on: October 02, 2020, 09:21:33 PM »

I agree that it looks like the piece shifted however if your saw is normally cutting thick to thin there are multiple possible issues.  Dull blade, bad arbor bearings allowing the shaft to change position with pressure, blade alignment being off which over time warps your blade and the deflection keeps getting worse.   Although it is hard to tell from a photo, a feed that is moving faster than the cutting action can also cause this which can be caused by motor issues or even a slipping belt.

As for dull blade a common problem is not keeping the blade dressed.  Segmented blades and most continuous rim blades can be flipped direction which you can do to lessen warp over time from blade wear and also exposes new diamond edges during the flip.  For sharpening the blade there are a ton of different viewpoints out there.  Some saw red bricks that I find ruins the oil but most people do it right before an oil change,  Some use old Silicon Carbide grinding wheels like I do laying them flat and making 3 or 4 cuts across them, Cutting Obsidian or other glass, or using of all things the blade sharpening stones sold by many companies.  Dressing the wheel often saves a lot of headaches for sure.  Some people also swear by hammering the cutting edge of the blade to flatten it before sharpening.  As the blade wears it gets rounded on the cutting edge and then can meander more is the philosophy.  One of the blade vendors in Quartzsite recommends this and says many of his commercial customers do this.
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55fossil

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Re: Slab saw blade is bending while cutting
« Reply #4 on: October 04, 2020, 10:30:07 AM »

   Two questions:
1.  Is your arbor running true?  A quick check with a straight metal ruler to see if the vise travels true from the front of the blade to the rear is a must know item. If there is even a little bit of run out from front to back this will start the saw blade digging in or traveling out from the rock and give you slabs that are thicker at one end.
2.   Is your rock vise and table locked in tightly?  If the vice has any wiggle to it at all again you will get pinching or run out of your slab. If the saw table has any loose areas that allow it to lift or feel loose on the rails the whole table can be forced to travel out of plane and again you get slabs that are not true.
   Bent blades do cause this most often. But out of true rock vises are often the cause of blades warping and locking up as the rock cuts untrue.   from my personal experience.....
    I am sure there are some good table / vice alignment threads here on the forum you can search for.
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Slabbercabber

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Re: Slab saw blade is bending while cutting
« Reply #5 on: October 06, 2020, 05:58:09 PM »

Looks like an alignment problem.  Put an indicator in the vise and run it up to the blade.  A pencil will do.  Now push the vise past the blade.  The indicator should stay right on the blade surface all the way through.
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catmandewe

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Re: Slab saw blade is bending while cutting
« Reply #6 on: October 06, 2020, 08:53:09 PM »

Looks like a dished blade to me.

As it gets dished it starts in the wrong place which makes it cut on an angle, as it progresses the angle gets worse and worse until it actually wont cut anymore. You can fix it by flipping your blade occasionally BEFORE it gets dished, but that dish is bad enough that you can only fix it by hammering or pressing it out or getting a new blade that is not dished.

Tony
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