Freud SD208 Chippers Confusion

[LCHIEN]

Thanks Loring. You explained it so my kindergarten mind could understand. ;-)

You're very welcome.

[LCHIEN]

I'm not sure I understand how that price list works... It says "add up all the pieces..." Are the side blades of a dado stack also considered "chippers"? So what's the extra $4.50 covering then?

Not sure if this is true of all Rockler stores but ours has a local guy that comes around and picks up sharpening. I've used them for other blades and they seem to do a good job. That would be my first choice for the dado unless someone warns me away from it.

All the pieces means the number of chippers plus the two outer blades.
THe outer blades typically have 24 teeth and the chippers 2 teeth. A set usually goes 13/16th inches which is two 1/8 outers plus 4 1/8 chippers plus one 1/16th chipper
So for a stack dado its like the charges add up like this:
two outer blades Minimum of $10 each or $6+$3, so $10 each
CHippers $4.50 each (total 5 x 4.50) = 22.50
Additional $4 charge for a stack dado (not sure, maybe its just a charge for the extra trouble) on top of the charges above listed
total: $46.50

It's also possible the "complicated" blade charge applies for the outers... Not sure what a complicated blade is but it may include things like ATB blades where you have a series of 5 teeth with a raker plus two each beveled teeth. A outer blade for an high quality dado like the SD208 has each outer I think from memory with some really sharp bevels and some rakers.. Extra 5 cents per tooth.

As complex as a Dado is, you'd better call or e-mail the guy for help before being surprised. It's not cheap.

As for when to sharpen, I would think if you started to get tearout on the vertical edges then its time to sharpen. I might even shaprpen the outers once or twice before sharpening the chippers.

[atgcpaul]

As for when to sharpen, I would think if you started to get tearout on the vertical edges then its time to sharpen. I might even shaprpen the outers once or twice before sharpening the chippers.

I would think that's the wrong thing to do. When you sharpen the carbide, you will lose some material and your blade gets smaller in diameter (just like when you sharpen a chisel, it gets shorter). Sharpening just the outers wouldn't give you a flat bottom groove anymore.

A properly sharpened blade should come back no thinner (carbide-wise) than when it left the factory. THey should hone the carbide across the face, with the sharpener working on the face thats perpedicular to the sawblade body, not on faces parallel to the sawblade body!!! Any experienced sharpener should know that.

I think this depends on the existing grind of the teeth. If you have a rip blade with carbide teeth that are exactly parallel to the side of the blade body, then it's reasonable to expect that your kerf would be unchanged (but your blade will still get smaller in diameter with each sharpening), but with most carbide tapering down from top to bottom, you're not only going to lose blade diameter, but also kerf with each sharpening.

http://www.carbide.com/sawshop/serviceFAQalt.htm
http://www.dynamic-saw-blade-sharpen...h-designs.html

Honestly, I didn't measure the width of the teeth when they came back from sharpening, but I know I had to use more shims than before. I measured the teeth this morning and my side chippers and the 1/16" chipper measured 0.139" and the 1/8" chipper measured 0.262" in width which is less than what Ken reported on his new blades. I'd be curious what other owners who haven't had their SD206 (or SD208) measure. The kerf change on the dado stack doesn't really bother me, though, because almost all the sheet stock I use would require it anyway because it's all undersized.

Paul

[capncarl]

I can't speak for all of them, but most saw sharpening shops do not touch the sides (kerf) of a blade. When they sharpen they just polish off the front of the carbide to whatever angle it might be. This makes an nice clean cut on the kerf side. Sometimes they will to touch off the top or outside of the carbide and may reduce the outside diameter of the blade by several thousands of an inch. This may be necessary because the amount that they cut off the front is not enough to remove the wear because this is where the wear shows up, not on the sides.

[tfischer]

Honestly, I didn't measure the width of the teeth when they came back from sharpening, but I know I had to use more shims than before. I measured the teeth this morning and my side chippers and the 1/16" chipper measured 0.139" and the 1/8" chipper measured 0.262" in width which is less than what Ken reported on his new blades. I'd be curious what other owners who haven't had their SD206 (or SD208) measure. The kerf change on the dado stack doesn't really bother me, though, because almost all the sheet stock I use would require it anyway because it's all undersized.

Paul

My SD206 is 10 years old, never sharpened, and not seen tons of use over the years, and is closer to your measurements than Ken's: .1385 & .2665

[LCHIEN]

I would think that's the wrong thing to do. When you sharpen the carbide, you will lose some material and your blade gets smaller in diameter (just like when you sharpen a chisel, it gets shorter). Sharpening just the outers wouldn't give you a flat bottom groove anymore.

...
Paul

Assuming that the blade had a hook angle of 0 degrees which means a radial line from the center of the blade could lie on the face of the tooth, then sharpening the face a few mils would not reduce the radius of the blade in any significant way.

In reality most blades used for table saws have slightly positive hook angles, but in the range of 10-15 degrees.
If you remember your trig of small angles then a hook angle of 15 degrees is very steep so that reducing the face by grinding off say 5 mils ( a lot) would reduce the radius of the blade by only 0.17 mils.



And it won't make much discernible difference in the flatness of the bottom of the dado.

And yes, you are correct the sides of the carbides are also tapered, but also at a fairly steep angle. Again, taking off a small amount will shorten the blade by a few percent of the amount faced off, and the reduction of the tips will take a few percent of the top reduction off the width of the carbides due to the taper. But if we're talking tip height reduction of .17 mils then a 15 degree side taper on two sides will take off about 8% of .17 mils or .015 mils kerf reduction.

and kerf reduction is not even a problems for these chippers we've been discussing.