Dado Blades?

[conwaygolfer]

I need a stackable dado blade set to fit the BT3. My question is, will the 8" blades work? It seems people migrate towards the 6" set and I am wondering why?
I have an oportunity to get a set of 8" Forrest stackable blades and wondering if they will give me good results?
Any help will be appreciated. I used to use an adjustable dado with mixed results. And it will not work on the BT.

Thanks,
Conwaygolfer (Glenn)

[LCHIEN]

Hi, the BT3 FAQ (see my sig line below ) has a complete explanation of dado blades for the BT3.

8" stack blades need an extra 1/4" spacer between the blade set and the motor housing that the 6" don't need. As a result, on the 8" sets, a stack greater than 5/8" will have some chippers and blades riding on the threads of the arbor and the left blade washer won't fit. The blades sittin on the arbor threasd sit a bit lower than those on the unthreaded part and this causes an uneven bottom as these blades are offcenter by a few thousandsths. everything fits and works better with the 6" except you can't get a 3" deep dado, only 2" which should be deep enough for most things. Saves money too, there are good 6" dadoes like the Freud SD206.

[Uncle Cracker]

In wider configurations, an 8" stack will have clearance issues in a BT. A 6" stack will cut a dado deep enough for almost any application, and is free of the clearance limitations. EDIT: Sorry about the duplicate info, Loring... We posted together...

[conwaygolfer]

Thanks

for answering my questions so quickly. I will stick with the 6 in. and look into the Frued SD 206.
Thanks again,
Conwaygolfer

[Uncle Cracker]

I will stick with the 6 in. and look into the Frued SD 206.

That's a good one...

[conwaygolfer]

More Help?

I checked out the SD206 and find that some have 10 teeth and some have 24. Also one has 20 degree and one is 15. Now I am really confused. Which is best ?

Thanks again in advance for your answers.
Conwaygolfer

[Knottscott]

I checked out the SD206 and find that some have 10 teeth and some have 24. Also one has 20 degree and one is 15. Now I am really confused. Which is best ?

Thanks again in advance for your answers.
Conwaygolfer

More teeth typically means a cleaner cut (if all other parameters are equal). Is the angle you're refering to the bevel angle across the top of teeth of the outside cutter? If so, steeper will generally have lower tearout characteristics. Also, I suspect one is the SD506 and the other the SD206. The 506 is the 6" version of the 508 (8" set), which has twice as many teeth as the 206/208, and is a step up from the 206/208 for sure, but more money also.

As an in between low cost option, the Oshlun 6" gets very good reviews for value and performance. Probably not quite in the league of the SD506 but is < $70 and should more than hold it's own against the SD206. Use the "BT310" discount code with Holbren to get 10%...orders of $75+ get free s/h too.

[LCHIEN]

Freud makes SD20x, SD30X, SD40X, SD50x where x = 6 or 8 (inches) models, with increasing number of teeth and chipper teeth and increasing price along the range. The upper end ones (SD508) off the top of my head are around $250.

The SD206 I think is 10 teeth, and the SD208 are 12 teeth, the SD306 and SD308 are in the range of 22-24 teeth. more carbide teeth are one one thing increasing cost buys.

I don't think you can really tell much difference at all between one level and the next. I think you will get great, smooth, clean dadoes from the SD206.

I myself have SD308 and SD306 sets; I learned firsthand about the 6" vs 8" problems and eventually broke down and bought the 6" because of them.

Good luck to you.

Corrections:
Amazon descriptions:
SD208 has 12 tooth and 2-wing chippers for $ 95
SD308 has 22 teeth and 2-wing chippers for $142
SD408 has 40T outer blades and 2-wing chippers for $230
SD508 has 24T outer blades but has 4-tooth or four winged chippers @ $199
the 6" versions have a couple or so less teeth and cost somewhat less

[conwaygolfer]

Once again

I want to thank you both. What you both say is very helpful. I will continue to try for the Freud with the Oshlun as a backup

Thanks,

Conwaygolfer

[SARGE..g-47]

Morning Conway Golfer. At the moment Amazon has the Oshlun 6" set that Knotscott mentioned for $54.74 with free shipping. The Oshlun has more teeth than the less expensive Freud 6" and is less money invested on a tool you will use sparingly compared to a regular blade. A lot of folks on the 3 forums I visit daily are picking up the Oshlun and I haven't seen one yet that found any concerns as the more teeth give a cleaner cut.

I have an Oshlun 40 T blade that is excellent for $25. It is well made and has plenty of carbide to re-sharpen. Is it the calibre of my Infinity General $100 + blade? No.. but it is much more blade than the $25 price tag and I will not hesitate to rotate it with my other 2 more expensive blades.

Frankly I much perfect to do dadoes with a home-made adjustable router dado jig as I can dial in exact dadoes in under 10 seconds without all the fiddling regardless if my stock is 3/4'.. 13/16".. or any thickness between 1/2" and 1". You cannot gaurantee exact milling to say 3/4" as you will be off several .000 usually. If the dado is not exactly the size of the stock to be inserted you will get gap when the insert stock is under-size and have to trim when over-size. That is eliminated with an exact adjustable jig and you can also cut stopped dadoes which I almost always do personally. Thats a major task with a stacked dado set.

But.. if I were to use a stacked dado blade I would go with the Oshlun as IMO it has more teeth.. good quality.. etc. Just my take on your scenario.

Good luck...

[LCHIEN]

question re: the Oshlun...
Formerly the Avenger, any Oshlun complaints had been about varying plate thickness.
With my Freuds, I can use the two 1/8" outer blades plus (say) 2 1/8" chipper and 1 1/16 chipper and get precisely 9/16ths on the nose. That is, the nominal values always stacked up exactly.

With the Avengers, and later the Oshluns, the rap had always been that the plates were not exact and you got some other stack up other than the nominal values.

We're talking .005 or maybe .010" (much less than 1/64") total stack up error for the Freuds vs. many 10-thousandths like .050-060 for the Oslun; that's about 1/16th".

Precisely predictable widths makes a stack Dado much more convenient to use. Not that you can't get an exact width, but saves a step of trialing. Some people who use the Oshlun said they just made a table of which plates to use and how many shims were required to make a cut of such-and-such width, but that also seems inconvenient to me.

Anyway, is that still the case?


Is this still true?

[SARGE..g-47]

question re: the Oshlun...
Formerly the Avenger, any Oshlun complaints had been about varying plate thickness.
With my Freuds, I can use the two 1/8" outer blades plus (say) 2 1/8" chipper and 1 1/16 chipper and get precisely 9/16ths on the nose. That is, the nominal values always stacked up exactly.

With the Avengers, and later the Oshluns, the rap had always been that the plates were not exact and you got some other stack up other than the nominal values.

We're talking .005 or maybe .010" (much less than 1/64") total stack up error for the Freuds vs. many 10-thousandths like .050-060 for the Oslun; that's about 1/16th".

Precisely predictable widths makes a stack Dado much more convenient to use. Not that you can't get an exact width, but saves a step of trialing. Some people who use the Oshlun said they just made a table of which plates to use and how many shims were required to make a cut of such-and-such width, but that also seems inconvenient to me.

Anyway, is that still the case?


Is this still true?

I can't personally say Loring as I don't have the Oshlun dado set. But.. I can tell you that with a Freud set I had years ago for the BT when I had one... making my own chart from experimentation was how I had to go as the blades on that did not match up with the chart that Freud supplied on my set. The micro-meter proved why at that time. Could Freud have up-graded that latter as you state yours is precise... I simply don't know?

But the fact still remains that you have to mill the stock to exact thickness of your given set-up's or.. you have to re-shim the set-up to be precise or trim the insert stock. If you cut the insert stock too thin you have a problem of gap and you either start over or shim the dado from the bottom on the actual carcass and hope it's not seen.

That is very in-convenient to me. A waste of time and effort when I can dial an adjsutable jig in in under 10 seconds using a piece of the already milled insert stock.. lock it in with two twist of knobs and I'm ready to cut the dado the exact thickness of the stock. And I have the advantage of stopped dadoes done with only step left or squaring the one rounded end.

So.. for me personally.... "all" dado stacks are in-convenient from the point of precise match of dado and insert.. a major pain to cut a stopped dado.. and just takes too long to set up on the TS. Again.... that's just my take and I opt for the router jig.

[LCHIEN]

sarge we're going a bit off topic here on router vs dado blade.

Let me first say i respect your POV greatly and can see how you like router cut grooves over dado cut on the TS.

MY preference is often (not always) for TS cut dados.
1. speed of cut is much higher esp. for deep and wide, altho setup can be a little longer. Deep dadoes with a router can take multiple passes.
2. Cut always seems cleaner with dado for me, I guess that's personal experience YMMV sort of thing.

I frequently need precise fraction dadoes, I like to build jigs and tools and toy and stuff - i need tooling slots and such to fit hardware. Whereas you like to build furniture, so you need to fit milled stock of indefinate dimensions.

If I need to cut precise dados to nonstandard stuff, say .453" then I'll take a 3/8" stack (two outer plates and one 1/8" chipper, an easy decision when you can rely on the dado width) and cut the slot. Then I'll use my rip fence microadjuster and move the rip fence over 0.078" (.453-.375) which at 1/64th (0.016") per tick is about 5 ticks and make a second pass. It's not that hard. Without measuring anything but the original item I would expect to get within .010" of my goal, often better. Of course I do usually check along the way, I check the 3/8 groove and the final mostly to make sure i haven't made any boo-boos.

Not saying you're wrong but that there's more than one way to skin this cat.

[cgallery]

If I need to cut precise dados to nonstandard stuff, say .453" then I'll take a 3/8" stack (two outer plates and one 1/8" chipper, an easy decision when you can rely on the dado width) and cut the slot. Then I'll use my rip fence microadjuster and move the rip fence over 0.078" (.453-.375) which at 1/64th (0.016") per tick is about 5 ticks and make a second pass. It's not that hard. Without measuring anything but the original item I would expect to get within .010" of my goal, often better. Of course I do usually check along the way, I check the 3/8 groove and the final mostly to make sure i haven't made any boo-boos.

That is the same method I use for my router bits.

I have a small wood block with a knob that goes into a t-nut that rides the top t-slot of the front fence rail. I can move this anywhere along the length of the front rail and lock it down. Handy for when you're going to need to remove the fence, but want to later replace it in that exact same position.

Also handy for how I make dados.

I can take a 1/2" router bit and make my first pass on the router table (extension on the BT3K, so using the BT3K fence). I then hold a 1/2" gauge block between the fence's front block and my clamping block and tighten my clamping block down. Now I loosen the fence's lock and insert a piece of scrap of the material I'm trying to match the thickness of between the fence's front block and my clamping block, and I lock the fence.

Now when I take a second pass with my router bit, my groove with be the exact thickness of the scrap material I used.

It is so close, in fact, that if you can put them together, you'll have a difficult time pulling them apart. Adding a folded dollar bill to the scrap provides some play and room for glue.

Same trick can be used for dado stacks.

[SARGE..g-47]

You are correct Loring.. he did not ask what our opinion of the best way to approach precise dados was.. simply about which dado stack to cut them. I apologize to the original poster for heading the thread in a different direction other than the original intended. I should have not replied at all considering I no longer use dado stacks therefore don't even have one at this point other than a box joint set which could be used for dadoes but again.. that is straying from the original path.

My bad....