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Issues with Milling these large boards

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hey all -

i'm a beginner woodworker, and while the roubo is a big project, nothing seems super hard. So I took the plunge, researched equipment, waited for the right "big 4" to become available at the right prices. I have those, and I've been learning to use those tools (6" Grizzly Jointer, 12" DeWalt Planer, 10" Delta contractor saw with nice extended surface)., and finally started today with milling the boards for the bench top. However, before jumping right into the the maple boards I bought, I decided it would be best to walk through the process with a relatively cheap 2x4x12 SYP board. I worked as best I could all the way through a "glue up" of 2 boards 96" in length, 4 1/4 wide, and 1 1/4 thick (given they were 2x4, i couldn't get the actual thickness needed for the project). I'm glad I did, because when I finally glued stuff up, my boards were not super flush on the faces, and above all they just did't line up right across the top. One board was about 1/8" proud on one side of the "slab" and the other board was 1/8" proud on the other. Maybe it was a cumulation of errors. But I'm really having trouble handling these boards. I'm using infeed and outfeed rollers. My jointer walked on me a couple of times when I was passing boards over it. When I ripped the original board in half, I had trouble getting the jointed edge of the board to stay flush against the fence (which is a nice Biesemeyer fence). Now, I had used a magfence to keep the board relatively tight against the fence, but my table saw (@120 V) basically stopped ripping a quarter of the way through the board and the fuse in my garage blew (I had to reset it). ONly when I completely stopped using the magfence was I able to push the board across the table saw (again with infeed / outfeed support), but it was damned hard to keep the jointed edge against the fence.

So ... any advice out there with milling these boards? I have more SYP 2x4x12 to keep testing before I move to the "real deal" on the maple. I gotta get that jointer to stop walking on me. I should add that I used biscuits instead of dominos (as Marc uses) to line up the boards. I didn't just try to glue them up with out it. I was pretty accurate with those, but when it came to lining them up and putting them together it just wasn't lining up right.

[update: Pics uploaded here: http://imgur.com/a/g0jff ]

thanks for any help,

etienne

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Sounds like you have several problems there all at once. This is the one where I may have a clue what's going on:

Only when I completely stopped using the magfence was I able to push the board across the table saw (again with infeed / outfeed support), but it was damned hard to keep the jointed edge against the fence.

Assuming the jointed edge of your board is actually straight, this sounds like the fence on your table saw may not be parallel to the blade. Have you checked that?

-- Russ

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Assuming the jointed edge of your board is actually straight, this sounds like the fence on your table saw may not be parallel to the blade. Have you checked that?

Yeah I have. It's very very straight. I guess what I meant to say is that *I* am clearly moving a little bit left to right as I pass the board across the table saw without the mag fence there.

etienne

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It's very very straight.

No, what I meant for you to check is whether or not your fence is parallel to the table saw blade.

If it's not, one of two things is going to happen, depending on which way it's not parallel.

1. If the fence is closer to the blade at the back than the front, then the board will get jammed in between the fence and the blade and bind up. It may also try to lift up in the back and kick back. This is not good.

2. If the fence is closer to the blade at the front than the back, then the board will try to move away from the fence. This not good either.

If I had to guess, I'd say that #2 is your problem. That explains why it's "damned hard to keep the jointed edge against the fence." That also explains the binding up when you used the magfence to tried to use brute force to keep the board against the fence. In that case, the board gets jammed between the magfence and the blade with the same result.

Obviously I'm guessing here, but another possibility is that your SYP board has a bunch of internal tension that's making it warp when the tension is released when you cut it in two. When you were cutting the board, was the kerf (behind the blade) wider or narrower than your saw blade? If so, that's probably what was going on. Actually, this may be more likely than the saw setup. You said all these tools are new to you. Have you done much ripping with the saw so far? Have you had similar problems before with other boards?

Check the saw setup in any case, though, because it's important. Marc's video about setting up a table saw explains it all.

-- Russ

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hi Russ,

No, what I meant for you to check is whether or not your fence is parallel to the table saw blade.

Yeah in my original reply i meant that the fence is parallel to the blade. Just now I checked it. I placed a square against the fence and ran it up and down, checking its distance from the blade. It was true throughout - within 1/64" anyway. However...

When you were cutting the board, was the kerf (behind the blade) wider or narrower than your saw blade?

It was narrower. Much narrower but only after a few inches or so. I'd say that after about 18" of board had passed through the blade, the far / back ends of the board were touching. What I mean is that the kerf narrows to the point where the ripped ends of the board are touching.

You said all these tools are new to you. Have you done much ripping with the saw so far? Have you had similar problems before with other boards?

It's a very new saw for me - and my first table saw, period. The guy I bought it from was very nice. He was old, retiring, and selling everything in his shop for very cheap. But it was clear he took his work seriously, took care of his tools, and would not have sold anything that sucked (but you never know).

So it looks like maybe - maybe - the issue was tension in the board released by the ripping? The SYP has been in my garage for ... two months I'd say.

Check the saw setup in any case, though, because it's important. Marc's video about setting up a table saw explains it all.

Will do. I've seen that video once before, but I'll look at it again.

thanks Russ,

etienne

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When ripping long boards on a table saw there is another "trick" that I have learned.

Let's say you want to end up with a 4.25" width - make your first rip at 4.5" - this will allow for a little movement, burning, etc. you can go real slow since you don't care about the burning. Then make a second pass at 4.25" - much easier.

Also, when using a featherboard make sure the feather board is in front of the blade NOT beside it - if the feather is beside it things go wrong very fast.

If you have access to a band saw (or even a jig saw) the initial rip done there and then cleaned up on the table saw works great.

Hope this helps!

-Tom

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Hope this helps!

-Tom

That... helps... enormously. Thanks so much Tom. Especially about the magfence / featherboards. The magfence I used was exactly beside the blade. I think I might buy a couple of featherboards since they are small in size than the magfence, meaning that I could place one on each side of the blade. Super duper helpful. Thanks again!

etienne

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meaning that I could place one on each side of the blade.

Not sure what you mean by "each side of the blade" but in any case you definiately don't want to do that - kickback wating to happen. I think Russ's diagnosis of released tension during the cut is what happened given your description.

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Not sure what you mean by "each side of the blade" but in any case you definiately don't want to do that - kickback wating to happen. I think Russ's diagnosis of released tension during the cut is what happened given your description.

See the attached picture. When I tried ripping the board yesterday, I was using a magfence. I had the magfence positioned as you see it positioned in the picture -- in a position I understood Russ to mean "beside" the fence. The featherboards in the attached pic are on "each side of the blade" as I understand it. What I heard Russ saying is that it's better to have your magfence / featherboards to the front and back of the blade as opposed to "beside" it. Does that clarify what I mean?

etienne

post-7083-0-53251100-1342973638_thumb.jp

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Feather board/ mag fence should only go on the infeed side of the blade. Putting them on the outfeed side pushes the kerf closed- binding the blade = kickback.

What he said. A feather board is not necessary on the outfeed side.

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What Beckycrum said... If you think about the function of a riving knife or splitters and what they're designed to prevent, you'll understand why having anything potentially pushing the stock into the back of the blade is very dangerous. So where the magfence and the featherboard are currently positioned in your illustration is NOT GOOD and isn't keeping the board flush with the fence anyway - the featherboard in front of the blade is fine.

If you have a bandsaw or access to one, I would follow Tom's advice especially when ripping long boards in half. And don't get discouraged. Your instincts on doing a practice run are spot on. SYP is a different animal than hard maple but it's better to make mistakes and learn on stuff you can sacrifice than the expensive stuff.

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I didn't mean to say or imply anything about the position of featherboards or the magfence. But I definitely agree with all the others that if you use something like that, it wants to be on the infeed side of the blade.

Also, it sounds like the board is definitely closing up on you. The suggestion to make the cut in two passes is a good one, as is using a bandsaw for the rough rip (if you have one) instead of the table saw.

-- Russ

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If this is your first table saw I recommend getting a book (orDVD) in the vein of "The Complete Table Saw." I found this very helpful, as well as a basic woodworking course I took at Woodcraft. At least for me, a table saw wasn't something I wanted to experiment with. I'll also suggest a thin kerf rip blade, or even better, a band saw. Take care, but this project is worth it.

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