# Multiple Blades on Table Saw



## Deela40 (Dec 11, 2009)

Has anyone ever done multiple blades on a table saw with spacres between the blades? I am not talking about a dado stack, but need to cut three separate grooves as shown on the right:










There is about 5/32" between the grooves. I make and sell clothespins and am currently making three passes to make these grip gorrves. I am looking to cut down on production time, so I was wondering if it was safe to put two blades on my saw with spacers on between.


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## Clarkie (May 11, 2013)

Think about it, have you ever seen it advertised, "You can use 2 or 3 blades at one time on our table saw". Seriously, I'd say no to the idea, the arbor isn't designed for that. You may get away with it, but then again you may not, and it's the "may not" side you don't want to be on. I almost lost my thumb on a tablesaw a little while back, I can only imagine what may go wrong with trying what you are asking. Be safe, not always necessary to speed up production.


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## Deela40 (Dec 11, 2009)

Thank you Clarkie. I was leaning against doing it, but wanted to verify. I found a good bit about using multiple blades as a dado stack, but could not find any discussion about using two blades that are farther apart.


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## BenjaminNY (Jul 24, 2014)

They make machines that gang rip/score etc. I would not ad hoc it on a machine not designed for that application. It may work but it's too risky.


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## ClammyBallz (Apr 16, 2015)

What if you ground down the teeth on two of the chippers and used them as spacers? They would have to be perfectly balanced though.


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## jumbojack (Mar 20, 2011)

I would try it…...maybe. I think I would be more inclined to use spacers against the fence. Although in a production run you could groove a few boards and have a bunch of clothes pin blanks in no time.


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## pintodeluxe (Sep 12, 2010)

(5/32" space x 2) + (1/8" kerf x 3) = .6875"

Most arbors can accept a 13/16" dado stack, so I don't see why you couldn't. 
Those shallow grooves won't tax most tablesaws. Some woodworkers use double blades to cut tenons, so his isn't much different. Fender washers would make ideal spacers (5/8" I.D. for 5/8" arbor).

I would use the two outer blades of a dado stack, and one chipper in the middle.


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## MrRon (Jul 9, 2009)

The only thing I can see that could be a problem is; a change in blade spacing through vibration which might cause the work to bind resulting in uneven thickness and possible kick back. Maybe using smaller diameter blades would work. What you are doing is a job for a shaper or a planer/molder.


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## MrRon (Jul 9, 2009)

Duplicate post


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## splintergroup (Jan 20, 2015)

I also don't see any real issues. Dado set parts will work, but most outer dado blades have beveled grind teeth which would not give a very flat bottom cut. I think better results could come with a gang of three flat tooth rip blades.

Also consider that most large dado stacks are 8", not the normal 10" of a table saw. Although a typical 8" dado stack has greater rotational inertia than three 10" blades, you could/should stick to 8" (or more popular 7-3/4") blades (cheaper as well!).


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## SirIrb (Jan 12, 2015)

use steel spacers and keep the digits out of them and youll be fine. I would say that the reason you haven't seen saws advertised for that is because there arent too many people making clothes pins or need to score in that method, not because it is unsafe. I wouldnt rip through the board with a stack, though this is doable: google Gang saw.

go get em


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## Deela40 (Dec 11, 2009)

Thanks for all the feedback thus far. I may try these blades and see how it works.


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## JohnDon (Mar 14, 2015)

As an alternative to using washers as spacers, you might try using CD's. They conveniently have 5/8" center holes, are dead flat (washers might have burrs and deflections from the stamping), and they have a lot of surface area to bear against the blades, so they will more likely to stay parallel and not wobble. With the shallow grooves you're making, they wouldn't interfere with the cut, even with 7-1/4" blades. If they don't give you exactly the right distance between the blades, you can use them as patterns to cut shims from paper or thin cardboard.


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## knotscott (Feb 27, 2009)

> Thanks for all the feedback thus far. I may try these blades and see how it works.
> 
> - Deela40


I don't see why it couldn't work if your saw has the arbor length and the power. I do think you can do a lot better than those Irwin Classic blades though…you can get Freud Diablo 24T blades for the same price, or the 40T for another $5 ea…..much better blades.


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## splintergroup (Jan 20, 2015)

Watch out for circular saw blades, they usually are thin kerf, i.e. much less than 1/8" wide (if that is your target groove width).
Also look for FTG (flat top grind) if you want flat bottomed grooves.

Alternatively you could use a single FTG rip blade and make up a set of spacers (or even carriers) you place between the workpiece and the table saw fence. This would require a pass for each groove, but there would be no extra setup or fence moves, just make a pass, switch to the next carrier, another pass, rinse, repeat.


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## Deela40 (Dec 11, 2009)

> I don t see what it couldn t work if your saw has the arbor length and the power. I do think you can do a lot better than those Irwin Classic blades though…you can get Freud Diablo 24T blades for the same price, or the 40T for another $5 ea…..much better blades.
> 
> - knotscott


I will check out the Diablo blades. I was just looking for some cheap ones see if it worked.


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## Deela40 (Dec 11, 2009)

> Watch out for circular saw blades, they usually are thin kerf, i.e. much less than 1/8" wide (if that is your target groove width).
> 
> - splintergroup


The groove width isn't critical, but I will see what the blades kerf is before I purchase any to make sure it is close.


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## wormil (Nov 19, 2011)

> Think about it, have you ever seen it advertised, "You can use 2 or 3 blades at one time on our table saw".
> - Clarkie


Yes, on literally every saw that can use a dado blade.

To answer the question, it works fine but the cutter quality is poor.


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## splatman (Jul 27, 2014)

I would see no problem. Use 7-1/4" blades, as already suggested. Make an insert, and raise the blade, just as you would to make a 0-clearance insert, and you'll have a triple-slot 0-clearance insert for your triple-blade setup.
You are basically cutting a dado w/o removing all of the material in the middle. Using a chipper to cut the middle groove would very likely give a rough cut. A chipper is really just a 2-tooth blade (Or 3-tooth, or 4-tooth, depending on the dado stack model).

If the grooves turn out to be too narrow, slide the fence a 1/32" or so and make another pass. Now all your grooves will be wider. Or use a thin piece of material on the fence that you remove for the second pass, to avoid having to move the fence.

As far as safety goes, you just follow all the same precautions as you would when using a dado stack.


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## SirIrb (Jan 12, 2015)

I'm not going to give you the pathos-(or is it ethos) I don't care to look now, I think it's ethos-of "I'm a design engineer, trust me". Because look at all the places that has gotten us: Tacoma narrows bridge, Challenger, Colombia, Ford pinto, 3 mile island, chernobyl….
(We keep a running list at work on a white board, it's called the "don't be 'the guy')
So again, I'm not going to pontificate about how I should be trusted. I shouldn't. It's your life. Don't even take your Dr. at face value. Make him convince you and earn his money.

Here's what I want to pass along and then I'll let you get back to grooving.

You have a model to compare to: Dado.

You have a mental model of the amount of torque a Dado set to 13/16 (average max width) would require; would a 3 blade stack exceed this?

On your model (dado) how does it connect to the saw? Can your 3 blade stack replicate this? I promise you the stack (and, God help us, the wobble) Dado have much more time being tested in a lab than you have running them. Match your model.

Only difference between you and a Dado is you are turning 10" and stacks are 8" usually. So there's a bit of difference. Again, compare the mass of what you want to spin to that of your model. A big stack has more mass than your 3 blade stack.

These are the types questions that go through my mind in a when I encounter a design question.

Though I am specifically a plastics and composite designer let me throw some thoughts around.

Yes, I would bet that a cd would do what you want. 99.9% chance that you don't become "that guy". But if the lexan that the cd is made from (polycarb) cracks and flies out during operation then the formally tight nut is no longer cinched down. Sure, it's natural tendency is for the nut to tighten due to the rotation. And the O-rings are supposed to seal during cold weather. Would the nut come off? No, I doubt it. But this is a business venture, Google blade stabilizers. They are huge 4 or 5" washers. Space your blades that way. http://www.toolstoday.com has them for $20.

Just don't end up being "that guy".

Steve
Who awaits the NASA engineers on LJ to chime in and school him on whose fault it really was.


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## Deela40 (Dec 11, 2009)

I ended up buying some 3" blade stabilizers to use as spacers and three cheap blades to test it out with really good results.





































This new setup resulted in slightly smaller grooves than I previously had, but the difference is minor. It also reduced my production time to by 350%.


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## ADHDan (Aug 17, 2012)

Apologies if someone suggested this (or if I misread your post and it just won't work), but could you possibly rig an adjustable box-jointing router bit to the right spacing, and then run your material over it vertically using a tall auxiliary fence?

I'm thinking of a bit like this - http://www.toolstoday.com/p-4947-box-joint-set.aspx.

Edit: never mind, I see your last post resolved the issue. Nice work!


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