how do I account for blade kerf when ripping a board in half with a table saw?

[Travis Conner]

It seems my blade takes out about 1/8'' of material when it cuts. I tried ripping a 1x4 in half so I set the fence at 1.75" It cut the first side right where I wanted it but the other side was 1/8'' narrower so I had to run the board through again and make it slightly narrower. So to avoid that, should I divide the width of the blade in half and just move the fence in that amount? So in this case I would move the fence in 1/16'' and that will make both sides the same width? Am I right? So I guess when I want to rip a board in half i'll always lose a little bit to the blade kerf?

[Peter Quinn]

Total width minus kerf divided by two. So 3 1/2" - 1/8" divided by 2= 1 11/16". So yes, you need to subtract 1/2 the blade kerf from each piece, or bump the fence over 1/16".

[Michael Heffernan]

What Peter said. But if you want them to be exactly the same width, bump the fence narrower by 1/64" to 1/32", rip in half and then rip the off cut board to match the first rip.

[Justin Ludwig]

What Peter said. But if you want them to be exactly the same width, bump the fence narrower by 1/64" to 1/32", rip in half and then rip the off cut board to match the first rip.

+1 (or 2?)

I'll run it a bit thin then shave the outboard piece as well. Depends on how picky you want to get.

[Loren Woirhaye]

I use a marking gauge to divide a board. Set it by eye to near-center and mark from both sides. Then make a pencil mark in between the two gauged lines. This method is accurate enough for most work and there's no measuring to mess up. With experience you'll be able to eyeball distances better and split narrower boards to within 1/16" by eye alone.

[Yonak Hawkins]

I'll measure half the board width from the fence to the middle of the blade (the body of the blade, not the cutting tips) then, as Michael does, tap the fence a hair narrower and cut both halves.

[Jak Kelly]

If you have a zero clearance throat plate then I go off of the cut line of the throat plate.

[Joe Kieve]

What Yonak Hawkins said, "just measure to the center of the blade".

[Mike Henderson]

I measure as the others have said above. Then, I push the board into the blade just enough to get a nick. Then turn the board over and do the same. You can see if the nicks line up. Adjust if they don't.

Mike

[scott spencer]

I find it easier if I can start with a board that's slight wider, set the fence for the desired width, and rip two pieces. No dividing, no experimenting.

[Rich Engelhardt]

I find it easier if I can start with a board that's slight wider, set the fence for the desired width, and rip two pieces. No dividing, no experimenting.I feel better now knowing I'm not the only one that does it that way.

[George Bokros]

I find it easier if I can start with a board that's slight wider, set the fence for the desired width, and rip two pieces. No dividing, no experimenting.


I feel better now knowing I'm not the only one that does it that way.

Another one here


I measure as the others have said above. Then, I push the board into the blade just enough to get a nick. Then turn the board over and do the same. You can see if the nicks line up. Adjust if they don't.

Mike

I have been known to do this also.

George

[Don Huffer]

It seems my blade takes out about 1/8'' of material when it cuts. I tried ripping a 1x4 in half so I set the fence at 1.75" It cut the first side right where I wanted it but the other side was 1/8'' narrower so I had to run the board through again and make it slightly narrower. So to avoid that, should I divide the width of the blade in half and just move the fence in that amount? So in this case I would move the fence in 1/16'' and that will make both sides the same width? Am I right? So I guess when I want to rip a board in half i'll always lose a little bit to the blade kerf?

The problem usually lies in the strange number you get when you measure your saw kerf. Blade width will be a little less than the kerf. If it doesn't have to be perfect, do the math and cut.
When I need perfect I use a test cut. Set it cut it. Flip it cut it again. Fudge the fence as needed.

[Don Huffer]

What Peter said. But if you want them to be exactly the same width, bump the fence narrower by 1/64" to 1/32", rip in half and then rip the off cut board to match the first rip.

I do this too.

[Pat Barry]

It seems my blade takes out about 1/8'' of material when it cuts. I tried ripping a 1x4 in half so I set the fence at 1.75" It cut the first side right where I wanted it but the other side was 1/8'' narrower so I had to run the board through again and make it slightly narrower. So to avoid that, should I divide the width of the blade in half and just move the fence in that amount? So in this case I would move the fence in 1/16'' and that will make both sides the same width? Am I right? So I guess when I want to rip a board in half i'll always lose a little bit to the blade kerf?
Yes - this last point is a vital aspect of physics that cannot be avoided.

[Chris Padilla]

Yes - this last point is a vital aspect of physics that cannot be avoided.

I'm working on a thingamagig that counteracts this small, inconspicuous area of physics.... ;)

[Lee Reep]

Yes - this last point is a vital aspect of physics that cannot be avoided.

My 8th grade woodshop teacher claimed you could fix slight mistakes with the "board stretcher". But we were not allowed to use it. Heck, he never would even show it to us ... claimed we needed to learn to cut things correctly in the first place.