bandsaws and dados

[Pete Martin]

Just following the bandsaw thread. NOTE: I'm a rank, but old, beginner!!

Grizzly and General seem to have a good following among the group. I've been looking at various ones and see that the aforementioned ones seem to have motors in the 1 1/2 to 2 HP range. Also prices around $700-$1200. Then, wondering why the 'other' similiar (17") size saws are priced around $2000-$3000, I see the HP rating is bumpud up quite a bit to 4 or 5 HP.

Now, from me (beginner) to you (gods), is this significant? HP that is. I've sure the rest of the machine as equal (I hope) improvements/quality.

That's the bandsaw part. Now the dado.

On my Ryobi 10" contractor style table saw (my wife bought it!), I've got a (cheap) dado to make it 1/4" wide. As I take the 3 1/2" wide poplar board over it to create a (?? tenon for a rabbet?), I see the width change even thou I holding down very hard. See below.

/ / 3 1/2" wide / -------------- |

[Stephen M]

A $2K machine will have more iron, less flex & vibration and a sexier guide mechanism. As the owner of a $1K 2HP bandsaw I think that you have to be doing some really serious sawing (Volume and intnsity) to justify more HP than 2. The speed with wich I can cut is limitted by blade geometry not the motor.

There is a limit to the "buy the best..." logic. Nobody's 1st car is a Porche. (If they did, who's to say that that would not find that they should have bought the Hummer for the same money)

Don't be. Look at the fence systems (for instance) and you'll see a big difference. CI vs Aluminum.

Either the board is not a consistant thickness or something is flexing/moving during the cut.

That's why they make tennoning jigs. I find it's a more accurate way to make that cut.

-Steve

[Pete Martin]

Thank you! Another poster mentioned the same thing. That's a good savings in cash too for other stuff!

Stephen M wrote:

[TWS]

from your description I think you are trying to cut a rabbet which is

1/4 x 1/2". I am not sure which 1/4 inch dimension is the one you are having trouble with (the 1/4 inch deep rabbet or the 1/4 that is left over after you cut 1/2 deep). Since you seem to think holding down the board harder should help I am thinking that your problem is with the 1/4 inch left over from your 1/2 deep cut. Let me know if this assumption is not correct.

One possibility, especially with an inexpensive saw, is that there is backlash in the height adjustment mechanism and the depth of cut is varying as the blade changes height slightly. Are you sure you have locked the height adjustment? For your rabbet I would cut it with a regular rip cut blade rather than a dado. Set your fence so that there is 1/4 inch to the opposite side of the blade. Make sure you measure to the tooth, not the kerf of the blade. Set your blade height to slightly less than 1/2 inch (7/16 would be good). Lay the board face down and cut the slot. Do all your pieces.

Next set your fence so that the fence is exactly 1/2 inch from the opposite side of the blade and set your depth slightly less than 1/4 inch (3/16). It is best if you use a feather board to hold the work piece against the fence, This cut will be on the edge of the board and will cut away the waste piece. Do not stand directly behind the board as you push it through as the waste piece might catch on the saw and fly backward. In setting up the cuts this way you are using the fence as the reference point for your critical dimensions rather than relying on the blade width or height. I suggest that you get a beginners Table Saw guide book as this will give you tips on cutting rabbets, dados, and safety.

Let us know how this works out.

TWS

[TWS]

CORRECTION! I had an error in my reply last night. My reply was based on the assumption that you had a 'zero-clearance' insert in your saw but I realized this morning that is probably a bad assumption and the order of the cuts is incorrect.

Without a zero-clearance insert you should make your edge cuts first and then the face cuts. The reason is this: on every cut you need to have support for the work piece after the cut is made. On the face cut this is no problem but with the edge cut you will only have 1/4 inch material left if it is the second cut. That 1/4 inch could easily slip inside the standard insert on your saw. If you cut the edge cut first you will have the full thickness of the board for support throughout the entire cut.

I prefer to make the shallower cut last because it gives less of an edge on the waste piece for the saw to grab and throw back but I also have a zero clearance insert so 1/4 inch material is still enough to support the work piece through the cut.

I apologize for the error.

BTW, cutting the deeper cut second increases the chance that the waste piece will be thrown back so be sure to stand off to the left of center as you feed the work piece.

TWS

[Pete Martin]

Correct. The 1/4" at the top was the problem. Next time I'll make those cuts as you suggest. I did it that way as the other boards (it's a drawer btw!) have a 1/4 X 1/4 dado 1/2" in from the edge. Those are all right! And these were the first peices, so it's starting to make sense.

Thank you!

TWS wrote:

[Pete Martin]

Very good point! I'll have to make up a zero-clearence insert for my regular blades.

TWS wrote:

[TWS]

Pete, you're welcome.

Note that the way I suggested you set up your cuts any mistakes are on the 'safe' side. In other words, if you don't have the work piece solidly against the fence the cut will drift into the waste area, not your good piece. To fix you simply run the piece through the saw once more. This is why I didn't suggest setting the inside of the blade

1/4 inch from the fence. If your work piece drifts from the fence then your tongue is irrecoverably too thin. It pays to plan your cuts this way.

You will be able to make very fine furniture with your saw as long as you learn its strengths and weaknesses and design your work to capitalize on the strengths and avoid the weaknesses. IME the biggest contributors to quality work are: patience, persistence, and learning how to hide mistakes... Inexpensive tools challenge all of these but, in most cases, you can persevere over all of them.

Have fun!

TWS