Bandsaw Blade Sharpener with Indexer
#18
  Re: RE: Bandsaw Blade Sharpener with Indexer by Willyou (I agree that we are ...)
(12-10-2020, 07:38 PM)Willyou Wrote: How will grinding the top change the gullet? Grinding a little on the underside will not change the gullet in any detrimental way.


The overall size of the gullet area.
Steve

Missouri






 
The Revos apparently are designed to clamp railroad ties and pull together horrifically prepared joints
WaterlooMark 02/9/2020








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#19
  Re: RE: Bandsaw Blade Sharpener with Indexer by Stwood_ ([quote='Willyou' pid...)
(12-18-2020, 12:36 PM)Stwood_ Wrote: The overall size of the gullet area.

...............................
That is true, but that isn't all bad..a larger gullet can carry more sawdust away...The important thing for me is I want to maintain the "hook" shape of the teeth..It's the very tip of each tooth that does most of the cutting..When you grind the tip only, you change the clearance angle by "blunting" the hook effect somewhat., but it is still sharper than the tips that are "rounded over" by wear....Grinding the entire gullet does not change the rake angle.....I consider a blade to be sharp when I can lightly drag my fingertips against the teeth and they "catch" the skin...if the finger tips just "slide" across the points, they are not as sharp as they "could" be...The way I do it by hand is the way shown in the last video..insert the burr into the gullet, then lightly "slide" the burr down the top of the tooth below. You can get pretty good at it by the time you finish just one blade.... Winkgrin
"If you don't read newspapers you're uninformed...If you do read newspapers, you're misinformed.....Mark Twain

Jack Edgar, Sgt. USMC Korean War 51/52
Get off my lawn ! Upset





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#20
  Re: RE: Bandsaw Blade Sharpener with Indexer by Timberwolf ([quote='Stwood_' pid...)
(12-18-2020, 01:14 PM)Timberwolf Wrote: ...............................
That is true, but that isn't all bad..a larger gullet can carry more sawdust away...The important thing for me is I want to maintain the "hook" shape of the teeth..It's the very tip of each tooth that does most of the cutting..When you grind the tip only, you change the clearance angle by "blunting" the hook effect somewhat., but it is still sharper than the tips that are "rounded over" by wear....Grinding the entire gullet does not change the rake angle.....I consider a blade to be sharp when I can lightly drag my fingertips against the teeth and they "catch" the skin...if the finger tips just "slide" across the points, they are not as sharp as they "could" be...The way I do it by hand is the way shown in the last video..insert the burr into the gullet, then  lightly "slide" the burr down the top of the tooth below. You can get pretty good at it by the time you finish just one blade.... Winkgrin

With respect to the gullet of the 1.3 tpi CT it's huge.  Grinding 0.002" off the back of the tooth does nothing to diminish the size of the gullet to a fraction of a percent.  I looked at the shape of the CT and both the tooth and the gullet form a curve.  Sharpening the front face of the tooth would require the use of a shaped wheel, like some sawmill sharpeners use, or the Dremel with a round diamond burr.  That's fine if you want to go that way; I chose not too because freehand is not for me.  

The 20 minute long video link above, which wastes 17 minutes to get to what's important, speaks exactly to your point about changing the angle of the tooth.  You could easily see how the Dremel was set up at too shallow an angle.  After grinding the tooth was substantially shorter and had a more blunt angle.  I was very careful not to change the angle on the back of the tooth.  The sharpened teeth look for all the world exactly like those on a new blade.  

I cut some bloodwood or something similar for a guy yesterday.  Whatever it was was hard as a rock.  The newly sharpened blade went through it with little effort and the cut quality was such that three passes through the drum sander at 0.004 - 0.005"/pass made them perfectly smooth, just like with a new blade.  

There are many clever people in the world.  It was interesting that those guys figured out how to index the blade at the same time the Dremel indexes forward, or backward.  I took the simpler approach.  It works well with the CT and I like the results.  It may not with even 3 or 4 tpi.  I'll worry about that when the time comes.  Those blades are so cheap that I may not bother.   

John
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#21
  Re: RE: Bandsaw Blade Sharpener with Indexer by jteneyck ([quote='Timberwolf' ...)
(12-18-2020, 01:54 PM)jteneyck Wrote: With respect to the gullet of the 1.3 tpi CT it's huge.  Grinding 0.002" off the back of the tooth does nothing to diminish the size of the gullet to a fraction of a percent.  I looked at the shape of the CT and both the tooth and the gullet form a curve.  Sharpening the front face of the tooth would require the use of a shaped wheel, like some sawmill sharpeners use, or the Dremel with a round diamond burr.  That's fine if you want to go that way; I chose not too because freehand is not for me.  

The 20 minute long video link above, which wastes 17 minutes to get to what's important, speaks exactly to your point about changing the angle of the tooth.  You could easily see how the Dremel was set up at too shallow an angle.  After grinding the tooth was substantially shorter and had a more blunt angle.  I was very careful not to change the angle on the back of the tooth.  The sharpened teeth look for all the world exactly like those on a new blade.  

I cut some bloodwood or something similar for a guy yesterday.  Whatever it was was hard as a rock.  The newly sharpened blade went through it with little effort and the cut quality was such that three passes through the drum sander at 0.004 - 0.005"/pass made them perfectly smooth, just like with a new blade.  

There are many clever people in the world.  It was interesting that those guys figured out how to index the blade at the same time the Dremel indexes forward, or backward.  I took the simpler approach.  It works well with the CT and I like the results.  It may not with even 3 or 4 tpi.  I'll worry about that when the time comes.  Those blades are so cheap that I may not bother.   

John
...........................
I'm not knocking the use of jigs or indexers, John...nobody likes machines, jigs etc more than I do, I have made quite a few myself........There are some very clever designs out there..and seeing them causes some people to think of ways they might be improved by some simple modification. I welcome that...I got the idea of hand sharpening BS blades 15 years ago because I had a dremel, a chainsaw burr and dull BS blades plus I hated spending money for new ones....The chainsaw burr just happened to be the correct size for my dull blades.....I always had the idea that if a tool was sharpened in a factory somewhere, I could "re-sharpen" it when it got dull. I enjoy it...But I will leave the handsaws to folks that like it...They are too "tedious" for me these days.
"If you don't read newspapers you're uninformed...If you do read newspapers, you're misinformed.....Mark Twain

Jack Edgar, Sgt. USMC Korean War 51/52
Get off my lawn ! Upset





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#22
  Re: Bandsaw Blade Sharpener with Indexer by jteneyck (After a gentle prod ...)
I'm fully aware that taking 2-3 thou off the top does not change the gullet.
It does change the angle of attack.

I am talking sawmill blades, and usually I didn't get down into the gullet until about the third sharpening.
If you keep taking off the top only, you loose your tooth height, and also the gullet *area* that carries the dust/chips out.
And yes, you use a formed wheel to sharpen those blades with. Formed easily with a stone.
To me these bigger bandsaws (I have one) that run basically the same tooth pattern, set, thickness, etc, should be, need to be, sharpened like the band mill sharpeners do.
And yes, that my opinion, which is the common theme with bandmill manufacturers and their blades.
Steve

Missouri






 
The Revos apparently are designed to clamp railroad ties and pull together horrifically prepared joints
WaterlooMark 02/9/2020








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#23
  Re: Bandsaw Blade Sharpener with Indexer by jteneyck (After a gentle prod ...)
I think it looks great.

And as the saying goes, "the proof is in the pudding."
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#24
  Re: RE: Bandsaw Blade Sharpener with Indexer by Phil Thien (I think it looks gre...)
(12-18-2020, 04:45 PM)Phil Thien Wrote: I think it looks great.

And as the saying goes, "the proof is in the pudding."


Yes I agree. Except I would index the tooth that is being sharpened.
Steve

Missouri






 
The Revos apparently are designed to clamp railroad ties and pull together horrifically prepared joints
WaterlooMark 02/9/2020








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