Table saw blade question

[Pat Barry]

Lets say I have an old blade, maybe carbide, may not, but I want to dress the teeth to create a flat bottom cut for splines. Could I re-grind the teeth to create that profile? Here is a what if - why not put the blade in the machine backward, start it up, then carefully run a stone up to the blade edge and grind the tips down. Afterward I could remove the blade and file the burrs off the teeth. I think this could work. How about you?

[Ken Fitzgerald]

I'd be worried about the teeth coming off.

You are spinning their physical support in advance when you reverse the direction of the blade so the pressure would be placed on the tooth with just the weld/bond/braise to hold it and nothing physical behind it.

[Ben Hatcher]

If you did this the blades would be flat on the leading edge. You would then need to grind a bevel on each one. A blade can be reground to make a flat bottom, but I'm not sure this technique is going to save you much time in getting there.

[Jerrimy Snook]

This is NOT a good idea.... the result, provided there is no injury involved, would not cut well if at all. Usually splines are cut near the end of the project. An improperly modified or ground saw blade will likely ruin the project. Glenn Bradley, a fellow creeker, shares some experience with splines here: http://www.sawmillcreek.org/showthread.php?161965-Review-Carbide-Processors-1-8-quot-Groover&

[scott spencer]

I would never put a carbide tipped blade on backwards because it's no longer supported by the steel shoulder and relies completely on the binders to hold the tip in place.

Edit....basically +1 on what Ken said! ;)

[Harvey Pascoe]

Plus, the carbide will just cut a groove in your stone.

I assume you're trying to get around the problem of a V cut for corner splines. There are two ways to deal with this. Buy a flat top tooth blade or send an old blade to a sharpener, who can regrind it for you. I did both because I use two sizes of splines, 3/32 and .060.

[bob hertle]

Don't even think about it! Not only is it extremely dangerous, if it worked at all, it would produce a "circular ground" blade, which by definition has zero clearance, and would not cut--it may push material out of the way, but not really cut. A good saw shop can alter the blade for you.

Bob

[Peter Quinn]

Sounds crazy to me on every level, and not highly effective at least. The cost of a decent diamond stone capable of grinding carbide outweights the cost of a basic FTG blade on most models, so it's even a bit foolish economically. I use a 30 th rip blade with FTG and it works fine. Spline keys are generally a ripping cut anyway, and usually involve a full backer in the form of sled or jig. That said if you try it be sure to video tape it and put it on the web, because you may beat that Brazilian luthier who resaws with a TS blade on a shaper sans guards in the most dangerous category.

[Sam Layton]

Wayne Hendrix just recently posted a title of, Pay attention to the little voice inside your head, that voice went off when I read your post... It said DANGER... A new blade with the grind you want would be far cheaper that the ER bill, and the long lasting effects.

Sam

[Dave Zellers]

Wayne Hendrix just recently posted a title of, Pay attention to the little voice inside your head, that voice went off when I read your post... It said DANGER... A new blade with the grind you want would be far cheaper that the ER bill, and the long lasting effects.

Sam

Word Up.

Don't do it.

[Chris Fournier]

Extremely dangerous and the results would be poor even if you were unharmed - botched geometry. Take your blade to a sharpening shop in your area and have them do what you want.

[Jamie Buxton]

When I need a flat bottomed cut, I use a rip blade that already has flat teeth. Mine, which works very well, is a Freud that generally costs $50 or so. http://www.amazon.com/Freud-LM72M010-Industrial-10-Inch-8-Inch/dp/B00004T78V/ref=sr_1_5?ie=UTF8&qid=1315614802&sr=8-5

It also does a fine job of ripping solid lumber.

[Chris Kennedy]

I really don't care if this method would give you the perfect grind or not -- it sounds incredibly dumb. You're going to try to hold your stone against the power of your tablesaw motor? Really?

All the luck to you. You're going to need it. By the way, whatever opinions come out of here, I would check with your homeowner's policy and also the ins-and-outs on your major medical.

Chris

[Greg Peterson]

No need to pile on. Just a +1 to Ken and Scott. False economy in trying to modify a saw blade. Let the professionals with the proper tools do this for you.

[Glen Butler]

I would wager that you couldn't even grind the teeth. When they hit the stone running backward they would shatter immediately, especially if you didn't have a ridgid setup, in both the stone and blade and something feeding the stone in a slow and controlled manner.

[Tom Walz]

Jerrimy Snook (above) and his father, Dave, run Snooks Saw and make some of the finest, if not the finest, custom blades in the country for a very wide variety of applications.

We use him as a consultant and supplier and I don't believe we have ever stumped him with a question and I know we have never gotten a bad blade from him.

Even if the blade is run backwards the tips should stay on. Blades are accidentally run backwards on a fairly regular basis.


Tom

[Pat Barry]

Thanks all for the feedback. I appreciate your advice and, after this feedback and further considerations, have decided NOT to try it.

[glenn bradley]

$20 or less at the sharpening shop. Let them do it right.

[Bill White]

If you're gonna do this, call the emergency room in advance. Make a reservation.
Bill

[Trent Shirley]

Pat, as others have said it would not be safe to perform this act the way you described. However, you could do it far more safely making yourself a little jig of MDF with a dowel in the middle to rotate the blade on and use an angle grinder with appropriate material on it for cutting down the carbide. Clamp your jig down so it does not move and so you get consistent positioning of the teeth to the grinder. Take off material slowly and keep the teeth from overheating and you are not running much risk of knocking off the teeth.
The trick will be getting the angle just right to have a truly flat bottom and keeping all the teeth at the same height but if your blade fits the dowel well you should be able to get consistent depth as you rotate all the teeth.
Wear eye protection of course and a mask to keep out the carbide dust.

There is always more than one way to accomplish a task. Doing this on the table saw would be unsafe but doing it manually apart from the table saw and taking it easy with the amount of material you remove at a time it is not that big of a risk. Whether the results will be usable is a different story but if you wanted to try, this may be the way to go. Sometimes it is more about the trying out something and learning than it is about saving money and although it is good that people jump in and tell you when something is dangerous it is also good if alternatives can be suggested.

Good luck.

[Kevin Presutti]

I read that post Sam and I couldn't agree with Wayne more. If you really feel the need to ask that question you probably already know the answer. The TS is without a doubt a dangerous piece of equipment (do I have to say anything about the NON-EXISTENT guard)! I buy freud blades on Amazon they are the cheapest vendor I have found. $59.00 - $79.00 for the industrial blades and they can be resharpened and cut great, and you with caution and safe practices will continue to have the ability to count to ten. If you feel you need a $200.00 Forrest then buy one, I can buy 2 Freud blades (I prefer the Ice coated), lunch, coffee and still have change in my pocket and 2 sharp blades in the grind I need. Whatever way you go get the right tool for the right job. BTW did I mention the TS is a dangerous piece of equipment. All the grinds are out there, get what you need, use caution, and when you hear that voice in your head.............listen to it!

Kevin

"The Safe Way Is The Best Way!"

[phil harold]

Lets say I have an old blade, maybe carbide, may not,

hmmmm
"maybe carbide, may not" makes me wonder if you have a clue to what you are doing

I have freshened up some hole-saws by chucking in a drill press and running in reverse on some slate
so
running them in a table saw in reverse by theory could work
start with the blade below the surface and raise the blade slowly up to a secured diamond stone may work

that being said I would just buy a blade with the proper configuration, a stack dado blade or a freud LM74R010 would do the task