Linear Dado Cut on Tablesaw Help re Kick-back

[Lyndon Graham]

I am trying to make a 1" wide x 5/8" deep Dado cut in a 2x4 length wise (6' board and a 2' board)). Since the safety devices have to be removed for any partial cut, I am a little concerned about kick-back. Already had one come back at me. (and Yes, I was standing to the side so no harm was done. I was pushing it in w a push stick and apparently could not put enough pressure in the downward direction w a push stick. I could always use my router, but that will take forever and will have to buy a 1" bit.

I am thinking of buying some Woodstock Yellow W1104 Board Buddies. Thoughts on these?

Any other suggestions? Thanks

[John TenEyck]

Don't use a push stick. Use two of these: http://www.benchdog.com/push-bloc Look at the first picture.

John
(http://www.benchdog.com/push-bloc)

[Prashun Patel]

Can you cut it in shallow passes?

[Lyndon Graham]

Yes, Planning on making 3 passes.

[Lee Schierer]

Clamp a feather board to your table to hold the board against the fence. Clamp a second feather board to hold the piece down. Make three shallow passes. If the cuts were on my saw, I would be using my magnetic feather boards.328229

Or switch to a hand held router with a 1/2" dia bit and an edge guide to make the cuts.

[Michael Stein]

Don't use a push stick. Use two of these: http://www.benchdog.com/push-bloc Look at the first picture.

John
(http://www.benchdog.com/push-bloc)


Push block or not, I still wouldn't make the cut in that fashion. I was taught to never have your hand(s) above the TS blade, jointer knives, or router bit, no matter what the cut or how its being made. JMO.


How I would make the cut... Put 1/2" of dado stack on the arbor, raise the blade 3/8 or so high, make the first pass. Move fence 1/2", do other side, raise the blade to 5/8", run again, move the fence and cut out the remaining.

Really, I would probably cut the full 5/8" in two passes with 1/2" width dado stack.

[John TenEyck]

Push block or not, I still wouldn't make the cut in that fashion. I was taught to never have your hand(s) above the TS blade, jointer knives, or router bit, no matter what the cut or how its being made. JMO.




I make dados like that all the time, and never put my hands above the blade.

John

[Ben Rivel]

Push block or not, I still wouldn't make the cut in that fashion. I was taught to never have your hand(s) above the TS blade, jointer knives, or router bit, no matter what the cut or how its being made.
Man, if that were the norm Micro Jig would be out of business:

328233

[Lyndon Graham]

How I would make the cut... Put 1/2" of dado stack on the arbor, raise the blade 3/8 or so high, make the first pass. Move fence 1/2", do other side, raise the blade to 5/8", run again, move the fence and cut out the remaining.

Really, I would probably cut the full 5/8" in two passes with 1/2" width dado stack.


OK, I am fairly new at this. I understand not to go in depth wise all the way but rather make several passes. But why do a 1/2" width cut and then move fence? Why not make one pass at 1" at 1/4" depth, then raise blade by another 1/4 in and another pass?

Thanks

[Ray Newman]

"Why not make one pass at 1" at 1/4" depth, then raise blade by another 1/4 in and another pass?"
--L Graham

Quick answer: For safety reasons, the design of stacked dado blades limits the maximum width, usually between 13/16 - 7/8".

[Ben Rivel]

OK, I am fairly new at this. I understand not to go in depth wise all the way but rather make several passes. But why do a 1/2" width cut and then move fence? Why not make one pass at 1" at 1/4" depth, then raise blade by another 1/4 in and another pass?

Thanks
Also just to make sure, you dont have a SawStop do you? They cant do a full 1" dado stack due to the brake.

[Ray Newman]

Ben R.: the SawStop PCS & ICS manual state that due to the brake design, only install a 8" dado set and the width of cut can not to exceed 13/16"

[Ben Rivel]

Ben R.: the SawStop PCS & ICS manual state that due to the brake design, only install a 8" dado set and the width of cut can not to exceed 13/16"
Yep, exactly. Thats for providing the details. I was too lazy to look them up. ;)

[john lawson]

Depending on how precise you need it you could make tow passes with the rip fence and a regular blade, not using a dado. My son had to do this recently in his shop and the dado was too risky. The rip fence worked well.

[John Schweikert]

If the dado is centered down the board, with a 1/2" stack you set the fence once at 1/4" less than half the width of the board. Run the board once, rotate it end to end and run it again, then you have a 1" inch wide cut. Raise the dado stack and do again until you have the height you want. Using a scrap to test is always best. When I cut dadoes, the outer edges are my main concern. Cut those first, then work on removing any more inside the cut if needed.

I use jointer push blocks when doing dadoes on smaller pieces for down pressure, but use my Jessem stock guides for down pressure on larger pieces. Use a featherboard from the side to keep the wood against the fence.

[Gerry Grzadzinski]

A 5/8" deep cut in a 2x4 is not deep at all for a reasonably sharp dado set.
I'd set up the blade about 5/8" wide, and make 2 full depth passes, one from each side of the board.

Just make sure you're using straight 2x4's.

[Ken Kortge]

This would be a easy to do and VERY safe using Eurekazone.com's Super Smart Router Kit (known by users as the SSRK).

There would be some investment, so it isn't a likely solution for your current need, but I thought I'd mention it.

You'd also need at least 6' of their guide rail (I'd suggest you buy a 64" rail and a 48" rail and two rail connectors so you can cut full length 4x8 plywood sheets as needed), two of their clamps, any router with a straight bit (you'd remove the stock base plate and mount it on the SSRK plate - even I can do that) , and any 7-8" long surface on which to put it on (needs to be shorter than the full length of the connected rails - for the clamps to be used).

Any width straight bit can be used, so long as its more narrow than the dado width. You just make multiple passes to widen the dado as needed. Stops on the SSRK are preset to define the dado width without moving the guide rail.

As with the router, you provide your own circular saw or you can buy one of theirs that has the guide rail base pre-installed.

There is a video here so you can see how the SSRK works: http://www.eurekazone.com/product_p/ezr2000.htm

BTW, I've been using their guide rails and other gear for a few years now. Just a very happy user.

Ken K.

[Lyndon Graham]

I have a Jet

[Lyndon Graham]

They will go through my jointer, then planar, then one edge thru table saw to get then straight as I can. and thanks

[glenn bradley]

A 5/8" deep cut in a 2x4 is not deep at all for a reasonably sharp dado set.
I'd set up the blade about 5/8" wide, and make 2 full depth passes, one from each side of the board.

Just make sure you're using straight 2x4's.

This is often the cause of kickback on a tablesaw. A tablesaw, by design, makes straight cuts. For rip cuts the feed path is a function of the fence and the table surface. The material passing over this (hopefully) true 90 degree perpendicular relationship must also be true and square. You don't have to ponder very hard to see what happens when a non-straight 2x4 is fed along a true table and fence. Irregularities in the board will foul the feed path and cause the material to contact the blade from the side. Presto; instant kickback potential. A hand held router would be my preferred method for this cut, especially if you do not have a jointer and planer that will allow you to properly prepare your stock for the tablesaw.

The small router base more easily follows the irregularities of ill-prepared or unwieldy stock:

328260

If you must use the tablesaw, I agree with Gerry's suggestion, a full depth pass running opposite faces of the 2x4 against the fence to achieve the desired width.

[Tom Ewell]

I am thinking of buying some Woodstock Yellow W1104 Board Buddies. Thoughts on these?

Any other suggestions? Thanks
Add on items like the Board Buddies are nice to have for table saw safety, I use another gizmo for the same function.

My gizmo and I assume the Buddies do the same, are a great aid in preventing kickback but also have the benefit of downward and sideways pressure (against the fence) to aid in making truer cuts. Downward pressure allows for more consistent grooves and dados, doubt that it'll do much for messed up 2x4 stuff tho.

Might also want to check your saw setup for parallelism, blade to miter slot, fence to miter slot and adjust as needed.

As mentioned, having your stock in good shape does make things go a lot smoother but setting up something like Board Buddies helps keeps things under control, if I am making a cut on less than optimally prepared stock quite often I can hear, feel or smell binding on the blade well before any chance of kickback.... I'll shut things down and clear the saw of the offending stock.

Even with lesser stock, most times you'll get a better cut with these aids assuming it does bind excessively.

[Cody Colston]

Don't use a push stick and you don't have to buy any gadgets. Use router push pads or a shop-built push shoe. I'm in the camp of making a full-depth pass, turning the board around and making a second full depth pass. The groove will then be centered in your 2x4. A 5/8" depth groove is not excessive and kick-back should not be an issue on a non-thru cut if you keep the board firmly against the table and fence.

[Shawn Pixley]

Horizontal featherboard to hold against fence. Vertical featherboard on auxiliary fence to hold against tablesaw top.

[Vince Shriver]

+1 with Shawn. However it is done - FEATHERBOARDS ARE ESSENTIAL

[Daniel O'Neill]

Clamp a feather board to your table to hold the board against the fence. Clamp a second feather board to hold the piece down. Make three shallow passes. If the cuts were on my saw, I would be using my magnetic feather boards.328229

Or switch to a hand held router with a 1/2" dia bit and an edge guide to make the cuts.

I have these (magnetic feather boards) and they work great for something like this. You get down and side pressure. then If you want you can put a second one after the blade for down only pressure. It helps keep the board from lifting. Then I use the bench dog push pads from another post and use that to push the wood through. I'm no expert so there may be a better idea mentioned. (Still reading the thread)