Dado/Groover Tooling Decision

[Patrick Kane]

I recently sold my PM72, which was my primary dadoing/tenoning machine. I dont do much integral tenon work since i have a domino XL, but it was there if i needed it. Now i am left with my KF700 saw/shaper as my only saw and dado capable machine. I also have a work-in-progress Martin T17 to think about. Here is where the rub comes in. My shaper spindle is 1.25", my saw arbor is 30mm with pins, and the martin arbor is 1.25". Realistically, id like to have all the machines dado/groover capable. One, i dont see myself having the T17 up and running anytime soon, and some dados simply cant be performed on the shaper. I have a 3-4" tall rebate cutterhead for my shaper, which handles my rebate needs. Here is what i have as options, and i realize the best course of action might be, sell what i have and buy new/different tooling.

I have a 10" forrest dado king set with a 1" bore. This is too big to fit in my shaper hood. I think the max tooling diameter for my machine is 230-240mm. Waiting on Dynamic Saw quote on re-boring this set. I have no idea what the cost will be, which might make this better to sell instead of retrofitting.

I also have a smaller forrest dado king set, 8", with 5/8" bore. I dont know how far this would project above the table on the T17, but this would be a good size for the shaper because it fits within the fence/hood.

Finally, i have a 300mm diameter adjustable groover by Leitz. 40mm bore and adjusts from 8mm to 15mm widths. Easy enough to bush this down to 1.25", but i havent looked into 30mm. Im not sure how that would work, because the cutterhead doesnt have the Felder pin configuration. The pros for this piece are its a large enough diameter to be effectively used on the T17. Cons are it is too large for the Shaper hood.

Are groover cutterblocks better than dado blade sets? Should i work with what i have or sell the lot and buy new tooling? Im guessing i have $150-200 away from retrofitting the above tooling to fit my needs, 8" dado king for the shaper rebored, 10" dado king rebored for the saw, and bushing set for the Leitz on the T17. I cant help but wonder if thats throwing good money after bad?

[Tom Bain]

Patrick -- Does the KF700 accept an 8" stack? I know my older KF500 would only go up to 6".

[Patrick Kane]

The saw, definitely. I run a 13.75"/350mm blade. Curious how much an 8" stack would project above the table.

The shaper hood saws max tooling diameter is 230mm. Thats about 9" diameter. Anything above that i can technically mount on the spindle, but would have to run it without the fence. This is fine for tenoning work--i could fab up a hood guard for safety purposes--but i would lose the functionality of the fence to register off of.

[Andy D Jones]

I would confirm the maximum rated RPM on a dado set, before I tried to use it on a shaper.

Otherwise, does your shaper have a collet for dado router bits? But that might have the opposite problem (too slow).

-- Andy - Arlington TX

[Patrick Kane]

I have the router bit spindle that i believe goes up to 19,000 rpm; however, its kind of a pain to mount. Have to switch belt sets and spindles. Also, it always felt like i was putting eco tires from an old prius on a sports car.

That is a great question on the max RPM. I think the shaper spindle goes up to 10k RPM and maybe down to 4k RPM. I need to confirm that.

[Erik Loza]

One note: I talked to Ridge Carbide last year about the possibility of re-boring existing dado stacks (they are one of the few who offer in the Felder arbor) and the rep gave me a hard "no" on doing that. Too much liability, he stated.

Erik

[Jim Becker]

That doesn't surprise me, Erik...boring as part of manufacture is likely a bit easier to be consistent than reboring. Just a tiny, tiny bit off on something can really upset the balance.

[Jared Sankovich]

I would expect the low speed to be somewhere between 3k and 4k on a shaper designed to spin 9+" diameter heads.

[Patrick Kane]

Took a peak at the front plate of the machine after loading in a bunch of 14’ 8/4 Sapele. Looks like with the variable speed cranked down and on the lowest speed pulley, it will go down to 1700 rpm.

That is interesting on the refusal to bore a blade. I almost expect a BS number back, because I’m sure it’s more of a PITA to rebore something. That’s sort of what I was getting at in my original post. If it’s going to be $200+ to buy the bushing and have the blades bored, then I’m just better off selling them and starting fresh.

Does anyone have a preference between dado blade sets versus adjustable groovers?

[Jim Becker]

Patrick, if I owned a Hammer/Felder saw that was groover capable, I'd likely opt for the OEM solution, despite it being costly. I've watched a number of videos with it being used and the results were really nice. (I'm fortunate that my SCM/Minimax saw takes a standard dado if I want to use one, although I've never used one on the machine to-date)

[Rod Sheridan]

Hi, I use a dado stack on my Hammer B3 shaper, as well as a 250mm rip blade that I share with my saw.

I also have an adjustable groover that I use for grooving or cutting both sides of a tenon in one pass.

Most of the tooling in the world is metric, I always suggest that customers buy a 30mm spindle with their shaper....Rod.

[Patrick Kane]

Hi, I use a dado stack on my Hammer B3 shaper, as well as a 250mm rip blade that I share with my saw.

I also have an adjustable groover that I use for grooving or cutting both sides of a tenon in one pass.

Most of the tooling in the world is metric, I always suggest that customers buy a 30mm spindle with their shaper....Rod.

Hindsight, i think i should have gone with a 30mm spindle and bushed the 1.25" tooling down to 30mm. Assuming that is possible, that is. Its only a 1-2mm difference, so thats not much material for a bushing. Like you mention, its convenient to be able to swap groovers between the saw and the shaper. It would help me get over the cost of the groovers. Thats why i ask about their performance, because i would need two groover sets--1/4" to 1/2" and then 1/2-3/4"--when most dado blade sets cover that full spectrum in one set.

I cant say ive had complaints towards the forrest dados. On the older 10" set i sold with the PM, i would get slight differences in height between chippers and the outer dado blades. This would never be an issue on a hidden dado, but would definitely be a problem with exposed joinery. For example, the exposed mortise on a maloof joint. I dont know if that was the specific set of blades. Im guessing the bottom and sides are flawless with most high quality groovers. Whelp, i guess i have my answer, now its just a matter of money : )

[Jim Becker]

I cant say ive had complaints towards the forrest dados. On the older 10" set i sold with the PM, i would get slight differences in height between chippers and the outer dado blades. This would never be an issue on a hidden dado, but would definitely be a problem with exposed joinery. For example, the exposed mortise on a maloof joint. I dont know if that was the specific set of blades.

If you're referring to the "bat wings" at the very edge of the cut, that's by design in the grind of the outer plates so they shear cleaning at the edges of the groove/dado/rebate being cut. If there was a variation inside of the "bat wings", then it was a defective set.

[Patrick Kane]

Nope, not the ATB bat wing grind of the outter chippers, this was straight down the middle of the dado. We arent talking much of a difference here, but the dado would be "striped" along its length. Say i plowed a 5/8" wide dado, i would see 1-8 distinct lines that were 1/8" wide along the length where a chipper was a smidgen taller or shorter than the other chippers and outer blades. The reason i mention the Maloof joint is because that is exactly the situation i had where i discovered the discrepancy. I ended up having to alter the depth of the dado with a router plane to level it all out.

[Jim Becker]

Perhaps it's a fictional memory artifact, but I seem to remember something from long ago when there was a bad batch or something...but I could be wrong about that. The Dado King I owned back when I had my cabinet saw was clean, clean, clean and totally flat bottomed...other than the bat wings. I mean "really smooth" clean, too.