Table saw: Rip & Rabbet in one pass?

[Kent A Bathurst]

Any reason this will not work?

Mount 10" blade. Then, chippers and the outer blade from the dado set.

I would need enough spacers between the 10" and first chipper to offset the chipper's teeth from the 10" plate.

I am envisioning a situation where I would need a fair amount of boards - solid wood and/or ply - that are ripped to a specific width, and rabbeted. Seems like I can do it all in one pass, yes?

[James Phillips]

I would not do it for a couple of reasons

1- Tools are dangerous enough without using them in ways they were not designed
2- You would end up with (potentially) weird forces torquing the wood due to a through cut and a rabbet on a single pass. Does not take a lot of movement to create a violent kick back

[Kent A Bathurst]

Not sure I see that, James.........

The diameter difference means that the rip cut would occur ~~1" before the dado stack engages. The operations are basically sequential, not concurrent.

Plus - how is the 10" blade functioning different that the normal 8" dado stack blade that sits in it's place? I guess it is cutting more fiber than the individual dado stack blades.......


I can tell you this much for certain - a couple decades experience. Imagine this - you have an industrial operation making grooved 2 x 3 used for banding units of lumber [at sawmills]. You shove in a 2 x 8, and out come 3 pieces of 2 x 3 with a 3/4"W x 1/2"D groove down the middle of all three. They are split into thirds by larger diameter blades, and the outer edges are cleaned up and sized by larger diameter blades as well.

I grant you that there are multiple components in those industrial gang-rip saws, driving the boards and acting as anti-kickback devices, but a lot of that has to do with the low-grade lumber being run {"bark and better"} at > 100 LFPM. With that low-grade, you get breaks and knots that leave disconnected pieces, and you have to control those - make sure they move to the outfeed side of the saw, rather than returning at Warp 2 to the infeed side.

Thanks very much for your thoughts - definitely something I need to think about.

[Martin Wasner]

I knew a guy who would rip drawer parts and dado them in a single pass. I don't think what you want to do is much different. A power feed would be handy though.

[Mort Stevens]

When doing rabbets I usually bury the dado into a sacrificial fence so the board is free and can't be trapped by the fence. I also use a feather board to keep the board pressed down against the table.

When ripping, my splitter has pawls that prevent the board from coming back.

I can't see combining these operations safely.... yes, in industry they have machines that take a log in one end and you get a fully assembled chair out the other, but that's a machine designed for just that purpose.

My concern would be trapping the work piece between the blade(s) and fence. The board will have a tendency to ride up over the dado and with the rip blade installed has no where to go except a recipe for disaster (kickback!).

[John A langley]

I think it would be worth a try your outside blade should be no bigger than what you need and I definitely would use a power feeder and you have whole lot to do

[lowell holmes]

It appears your going to try it. However, I agree with James.

There is too much to go wrong. IMHO, it's not worth the risk to you nor the material.

Remember, never stand in the path of a potential kick back.

[Michael Peet]

It seems kind of limited to me - you want the rabbet at some specific depth (presumably), so your stock needs to be no more than an inch thicker than that, assuming an 8" dado and 10" rip blade. Even less when you leave room for the rip teeth to clear the top surface.

Mike

[Phil Thien]

The teeth on the chippers are wider than the blade plate. So you will need some sort of spacer between the last chipper and the 10" blade to prevent crushing the chipper's teeth into the 10" blade, and also bending the 10" blade plate somewhat.

In doing dados I like to apply some extra downward pressure over the dado stack, to make sure my depth is consistent. But you can't get too close because you have a 10" blade ripping through.

It seems like a tradeoff. You're saving a step, but possibly getting less than consistent dado depth.

[Kent A Bathurst]

The teeth on the chippers are wider than the blade plate. So you will need some sort of spacer between the last chipper and the 10" blade to prevent crushing the chipper's teeth into the 10" blade, and also bending the 10" blade plate somewhat.

Yeah - I noted that in me OP




In doing dados I like to apply some extra downward pressure over the dado stack, to make sure my depth is consistent. But you can't get too close because you have a 10" blade ripping through.

It seems like a tradeoff. You're saving a step, but possibly getting less than consistent dado depth.

There's a good point - maybe use a block of wood to offset a vertical featherboard so it is out near the dado................

[Kent A Bathurst]

It appears your going to try it. However, I agree with James.

There is too much to go wrong. IMHO, it's not worth the risk to you nor the material.

Remember, never stand in the path of a potential kick back.

All good points - thanks. Not sure that this project will ever come to pass - was just letting my mind roam through the materials/machining steps.

[James Phillips]

Not sure I see that, James.........

The diameter difference means that the rip cut would occur ~~1" before the dado stack engages. The operations are basically sequential, not concurrent.

Plus - how is the 10" blade functioning different that the normal 8" dado stack blade that sits in it's place? I guess it is cutting more fiber than the individual dado stack blades.......


Kent,
The cuts will be simultaneous, just maybe not in the same point on the board. For the majority of the cut both the 10 in blade and the dado stack will be engaged.

The 10in blade will put a different force on the board than the 8 in chippers and blade. It may not matter, but it does not take much to cause a kick back

[Peter Quinn]

How much are you ripping off? My first though was...shaper. We used to use a 30HP machine to do something like this en masse, I'm not saying it can't be done with a TS, I do wonder what surface quality do you require when its finished? Its an interesting idea. What is the product?

[Mike Henderson]

Seems to me that it would work. Give it a try and let us know how it come out. Just be very careful the first time you try it - maybe make a lesser cut and work up to what you really want to do.

Mike

[Regarding consistent depth, that's always a problem with dado cutters. You have to keep pressure down on the work to make sure it doesn't rise up over the blade and cut to a lesser depth. I'm not a big fan of dados, grooves or rabbet on the table saw with a dado cutter for that reason.]

[Kent A Bathurst]

.........Regarding consistent depth, that's always a problem with dado cutters. You have to keep pressure down on the work to make sure it doesn't rise up over the blade and cut to a lesser depth......

Very true.

Normally, my rabbet edge would be cut against a zero-clearance fence, with a vertical featherboard above it to ensure correct & consistent depth.

But, with this scheme, the rabbet edge would be away from the fence, and I would need to rig a featherboard out there - fingers will not do it with the larger dia rip saw on the far edge.

[Peter Quinn]

If you are doing enough of this for the saw/dado one pass concept to make sense this may be a good time to invest in a powerfeed. Solves the "where to put my hands" question.

[Peter Quinn]

Here's a pic of my set up, running about 1000lf of two different dados that intersect. Not doing this by hand and hoping for the best, featherboards are less reliable and put my hands too close to the blade. Power feeder solves all the problems.

[Rick Moyer]

I really am not sure if it would work well or not, but it will only work if you want about a 1" depth on the rabbet, correct? The depth being (1/2) the difference between the 10" blade and the 8" dado cutters?

[Steve Rozmiarek]

It's not a new concept IMHO, think gang saws and molders. They have power feed of course, I'd use a feeder too.

[Bill Adamsen]

Add in the jointer/planing/edging and it would really streamline the process.

[Yonak Hawkins]

Tools are dangerous enough without using them in ways they were not designed

No disrespect to the poster intended, but I feel I must say that avoiding such thinking is what will propel us forward and not be stuck doing things the same way, just because that's the way we've always done them.

[Ethan Melad]

The teeth on the chippers are wider than the blade plate. So you will need some sort of spacer between the last chipper and the 10" blade to prevent crushing the chipper's teeth into the 10" blade, and also bending the 10" blade plate somewhat.


This was my first thought, too.

[Kent A Bathurst]

I really am not sure if it would work well or not, but it will only work if you want about a 1" depth on the rabbet, correct? The depth being (1/2) the difference between the 10" blade and the 8" dado cutters?


Nope. Consider 3/4" thick material; 3/8" deep dado; 10" blade cutting height at 1-3/8" - more than enough to rip the 3/4 stock.

[Kent A Bathurst]

This was my first thought, too.



Fellas - re-read the OP. 3d line.

[Prashun Patel]

I just tried to goodle this. I JUST saw a video or read a blog about doing this exact thing. It was for cutting a whole bunch of shiplapped siding. Can't find it now.

I think it's been successfully done before (not on a Sawstop tho).

[Kent A Bathurst]

....not on a Sawstop tho......

Good to know. It won't be this time, either. ;)

[Brian Tymchak]

No experience with that kind of setup. Wouldn't even try it on my little 1.5hp saw. But I'm wondering - my feed rate for a dado set is significantly slower than the feed rate for a rip blade. (Which reminds me that I need to get my dado set sharpened..:rolleyes:) I wonder if a wood like cherry, which is subject to easy burning, will cut without a burn with that setup.

[Kent A Bathurst]

No experience with that kind of setup. Wouldn't even try it on my little 1.5hp saw. But I'm wondering - my feed rate for a dado set is significantly slower than the feed rate for a rip blade. (Which reminds me that I need to get my dado set sharpened..:rolleyes:) I wonder if a wood like cherry, which is subject to easy burning, will cut without a burn with that setup.

I'm sure it would. But, in my grand scheme of things, that operation would be cutting a rabbet/tenon to go in a groove, so NBD.

Brian - BTW - who you rooting for now? Badgers or Spartans?

Don't make me come over there...... :D

[Phillip Gregory]

It appears your going to try it. However, I agree with James.

There is too much to go wrong. IMHO, it's not worth the risk to you nor the material.

Remember, never stand in the path of a potential kick back.

Especially not with a reasonably-powered saw like most of us have here. That blade is not going to stall if it gets pinched, it will grab and launch the board. I guessed people used bandsaws for resawing 3-6" inch stock because it was faster when I used a 1 hp contractor saw to do so (bind up and you stall the motor and trip the 120 V breaker) but found out it really is because it's extremely dangerous due to kickback when I got a real 3 hp cabinet saw.


The teeth on the chippers are wider than the blade plate. So you will need some sort of spacer between the last chipper and the 10" blade to prevent crushing the chipper's teeth into the 10" blade, and also bending the 10" blade plate somewhat.

In doing dados I like to apply some extra downward pressure over the dado stack, to make sure my depth is consistent. But you can't get too close because you have a 10" blade ripping through.

It seems like a tradeoff. You're saving a step, but possibly getting less than consistent dado depth.

Stack dado sets have a set of spacers with them. Every one I've used has a pair of thick spacers to put inside the outer blades to prevent the set teeth of the outer blades from hitting the non-set teeth of the chippers (or the set teeth of the other outer blade if you are doing a 1/4" dado with only the two outer blades.) I suppose you could use the spacers with a 10" blade but I wouldn't try it unless you had a power feeder and were willing to risk ruining your piece of wood and the feeder if something bound up. I would under no circumstances feed that by hand. You can buy a shipping container full of SawStops for what it costs to put a finger back on and have even a tiny bit of function from it.

I'm a chicken but I've seen quite a few people lose fingers or parts of fingers doing woodworking (mainly construction.) I happen to like all 28 of my finger bones and wish to keep the entire length of all of them :D

[Brian Tymchak]

Brian - BTW - who you rooting for now? Badgers or Spartans?

Don't make me come over there...... :D

Kentucky... ;)

Actually, even though it pains me GREATLY to admit this in an open searchable forum, :(, I'm much more of an Izzo fan than a Ryan fan. In fact, MSU is the only team I'll tune in aside from the Buckeyes (which got almost unbearable to watch this year..). MSU is peaking at the right time and I'd love to see Sparty run the table, but I think that's a pretty tall order. I think they just might just get past Oklahoma but doubt any farther. Doubt that it matters though after the way KY mopped the floor with WVU last night.

[Rick Moyer]

Nope. Consider 3/4" thick material; 3/8" deep dado; 10" blade cutting height at 1-3/8" - more than enough to rip the 3/4 stock.
Guess I wasn't awake enough when I posted that. I must have been thinking about thicker stock. Doh!

[Pat Barry]

I don't have a riving knife on my saw and I don't usually use the splitter safety guard either so, for me, I would do this only as a trimming operation. I mean I wouldn't try to make the rip cut through the middle of a piece of BORG pine for example because that wood moves like crazy and would guarantee kickback. I think its a great idea otherwise though. Processing like this should reduce variation in board to board results thus helping to reduce assembly issues.

[Keith Hankins]

Kent,
The cuts will be simultaneous, just maybe not in the same point on the board. For the majority of the cut both the 10 in blade and the dado stack will be engaged.

The 10in blade will put a different force on the board than the 8 in chippers and blade. It may not matter, but it does not take much to cause a kick back

dont see that, as 10" will be out in front of the 8" and the dado cut would be on the part of the cut already made, and would clear the end of the cut and while the 8" stack finishes it's cut.

Extremely dangerous! would not advise, but then a lot of interesting youtube videos start with "watch this"

[Rick Moyer]

dont see that, as 10" will be out in front of the 8" and the dado cut would be on the part of the cut already made, and would clear the end of the cut and while the 8" stack finishes it's cut.

Extremely dangerous! would not advise, but then a lot of interesting youtube videos start with "watch this"
I'll agree that the 10" blade will cut first, but only a millisecond before the 8" cutters, same on the outfeed but opposite, but I would not characterize the operation as extremely dangerous! As someone else posted, it's done all the time with shapers. I think the safety considerations are valid, e.g., using a power feeder.

[Peter Quinn]

I'll agree that the 10" blade will cut first, but only a millisecond before the 8" cutters, same on the outfeed but opposite, but I would not characterize the operation as extremely dangerous! As someone else posted, it's done all the time with shapers. I think the safety considerations are valid, e.g., using a power feeder.

i make much bigger cuts all the time with a shaper, always with a feeder, often using a back fence so the accuracy of the fixed distance between cutter and fence is similar to a table saw. But one very big difference is the spindle/quill/bearings are quite a bit more stout on even a small shaper than even a decent cabinet saw. A I'm usually doing this on a big shaper with 1 1/4" bore and a quill assembly approaching more than 2' in height. My primary concern with dados on a TS is managing the speed carefully so the rest of the mechanism doesn't get over capacitated. If you compare the shaft on a tS to a shaper spindle it almost seems scrawny in comparison. All this plays back into surface quality, push a TS too hard and IME surface quality drops off fast due to deflection. Guess it depends on what the product is and what is required. If it's ship lap where both edges get milled it may be easier to split the rip and dado into two operations.