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Ripping Blades explain?

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Forum topic by scribble posted 03-07-2017 08:41 PM 568 views 0 times favorited 7 replies Add to Favorites Watch
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scribble

146 posts in 2041 days


03-07-2017 08:41 PM

Topic tags/keywords: question oak walnut tablesaw milling

I read some one recently asking about ripping blades. I am curious about these as well. he one thing that really has my curiosity is that I have always in the past that the higher the tooth count of a blade the smoother the cut. What throws this out the window is these glue joint ripping blades in 42 teeth and such. I don’t currently have a ripping blade but after the last persons post about them and responses I am curiously looking into them as I have some new cabinet doors and drawers to make out of oak and some walnut projects as well coming up as soon as my joiner arrives.

-- If you can't read it Scribble wrote it!! “Experience is merely the name men gave to their mistakes.”


7 replies so far

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Jim Finn

2577 posts in 2762 days


#1 posted 03-07-2017 09:52 PM

I seldom cross cut on my table saw. I usually use my miter saw for that. I have a Diablo 24 teeth 10” saw blade in my table saw and it rips so smooth that the cut is good enough for a glue up without jointing. High teeth count is good for cross cutting and plywood low teeth count is better for rip or re-saw cuts.

-- No PHD, but I have a GED and my DD 214

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MrUnix

6017 posts in 2039 days


#2 posted 03-07-2017 10:10 PM

Saw blade selection information from Freud:

• The saw-blade’s projection (t) with respect to the work piece must be greater than the height of the blade’s tooth (fig. 18). Increase or decrease the projection of the saw blade to improve finish quality.

• The number of teeth cutting the wood simultaneously must be between 3 or 4 for ripping and ideally 5 to 7 for crosscutting. With less than 3 teeth cutting the sawblade begins to vibrate leading to an uneven cut. If you want to cut work pieces with increased thicknesses (T-fig.21), but wish to maintain the same diameter saw blade, then use a blade with less teeth. If instead you want to cut work pieces with a reduced thickness, but also maintain the same diameter saw blade, then use a blade with more teeth.


Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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knotscott

7789 posts in 3216 days


#3 posted 03-08-2017 02:04 AM

Fewer teeth tends to leave a rougher cut than more teeth, but it also leaves more room for larger gullets to clear away the larger chips caused by ripping, which in turn leads to less resistance, less heat, and less burning. A 24T FTG 10” rip blade excels at ripping quickly and effortlessly in thicker stock with little to no burning. Adding more teeth could lead to a smoother cut, but will also reduce the available gullet space, increase resistance, heat, and burning. It’s simple physics and there is always a trade off.

“Glue Line Rip Blade” is a clever marketing phrase, but you don’t need a blade that says those words to get a glue ready cut. Many blades are capable of a glue ready edge, and it’s important to note that the blade is only one variable in the equation. The saw, the material, and user technique are all contributing factors too….if any of those variables goes wrong, a special blade that says “Glue Line Rip” isn’t going to fix it. It’s also important to note that no saw blade will replace a jointer. If a saw is setup well, and material is flat and straight, a good sharp 24T rip blade will usually result in a glue ready edge…..that doesn’t mean glass smooth or finish ready, but it will usually be glueable as is. The 30T “GLR”s tend to have very tight side clearance to offer a more polished or burnished edge….the trade off is that those characteristics also increase resistance, heat, and tendency to burn, so they’re really only intended for materials up to 1” thick, which really leaves you with a blade that has a very limited operating range. I consider them an unnecessary luxury unless you do mainly ripping with your TS in materials up to 1”. A good 40T or 60T blade with a positive hook will also generally leave a very polished edge in materials up to 1” and even thicker depending on the material and specific blade, plus will be more versatile for many other tasks.

Look to a good 24T ripper for thicker ripping tasks. A good 40T to 50T blade for all around routine ripping and crosscutting, and a good 60T to 80T fine crosscut/ply blade for those times when you need an exceptionally fine cut.

Tips For Picking Saw Blades

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Rick_M

10645 posts in 2220 days


#4 posted 03-08-2017 02:54 AM

Roy Underhill has an episode about the difference between ripping and crosscutting blades. He talks about handsaws but it applies to circular blades. You can find it on PBS website.

-- http://thewoodknack.blogspot.com/

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mike02130

167 posts in 513 days


#5 posted 03-08-2017 07:22 PM

Hmm, I would’ve just googled it.

-- Google first, search forums second, ask questions later.

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bonesbr549

1445 posts in 2907 days


#6 posted 03-08-2017 08:51 PM

Friction is not your friend. Few teeth go through like butter but leave saw marks. High teeth smooth and great for cross cuts.

I use a combination blade the WWII its a great tradeoff between rip/crosscut and is a true sweetspot. I love my 40T ATB.

However when ripping large stock and speed is prescribed, I go to my 20T WWII and it cuts like butter. I use it mostly when cutting 12/4 or larger. It will not leave a glueline rip but cuts fast and does not burn.

-- Sooner or later Liberals run out of other people's money.

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Carloz

989 posts in 431 days


#7 posted 03-08-2017 08:52 PM

What throws this out the window is these glue joint ripping blades in 42 teeth and such.
- scribble

Which ones ? Most ripping blades at 10” have 24 teeth. Glue line as the name suggests sacrifice the ripping capabilities for the smoother cut but they have ~30 teeth at 10”
You probably are looking at the larger diameter blades where the tooth count is naturally higher.

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