# Using Circular Saw Blades on a Table Saw



## CharlieM1958 (Nov 7, 2006)

This may be a dumb question, but….

This review happened to catch my eye, and it got me to thinking (usually not a good thing). Since probably more than 90% of my cuts are on material less than 1" thick, is there any downside to using a 7 1/4" blade in a table saw?

I'm not talking about for everyday general purpose cutting… I have a Forrest WWII that I'm quite happy with. But if I wanted a couple of special purpose blades (plywood, thin kerf, etc.) it would be cheaper to purchase the smaller blades.

I was just wondering if there was a particular reason *not* to do this, other than the obvious sacrifice in maximum cutting depth.


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## degoose (Mar 20, 2009)

Charlie… dont know for sure but I believe that the motors are set for max rpm for the diameter of the blade and if you reduce the diameter you have a different speed at the tooth… if that make sense.


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## PurpLev (May 30, 2008)

theoretically I would think that the depth of cut is the only factor, however. the larger blades are also heavier which contributes to a more stable cutter, which would result in a cleaner cut - theoretically speaking.

another thing to consider is the rotational speed - I'm not sure of the numbers, but I think that a TS turns faster RPMs than a circ-saw, which might shorten the life of the circ-saw blade if used on a TS. but I really am too lazy to look up the RPMs for the machines right now.

all in all - I think it's doable, but why not just use a good full size blade - there are some good ones out there that dont break the bank…


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## CharlieM1958 (Nov 7, 2006)

Larry, you're right….obviously the larger the diameter, the faster the tooth speed. I'm not sure how that would translate into cut quality.

Sharon, I hadn't considered different motor RPM's.


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## Alonso83 (Jul 14, 2009)

I've been using D0724X/A 24T from Diablo for a long time with no issues at all for some ripping and crosscutting, in fact yesterday I got D0760X/A "Ultrafinish 60T" to cut some venner plywood and I totally love it, like the review says, not much noise, less dust and cleaner cuts. I never thought I should not use a 7 1/4" blade on the TS


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## jeffreythree (Sep 15, 2009)

I use a classic Delta Homecraft TS and good 7-1/4" saw blades are a LOT cheaper than good 8". Thinner kerf too. I keep one 8" around for those times I need the extra cutting depth. I also used it on my previous Delta Shopmaster (all I could afford) and the smaller blade would breeze through what the stock sized 10" had no chance of cutting. Under a certain dollar amount, I think a TS should come with a smaller blade. They just don't have the power to run a full cut with a 10" blade.


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## DanYo (Jun 30, 2007)

go for it Charlie … I've used smaller blades many times and the only downside is depth of cut


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## webwood (Jul 2, 2009)

my dado head is 8"


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## Chipncut (Aug 18, 2006)

*I don't think going smaller should hurt.

I think a smaller thin kerf would be more stable than a large thin kerf.

Dado blades are smaller in diameter, so I don't see no harm.*


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## teenagewoodworker (Jan 31, 2008)

yep i use small blades all the time. go for it!


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## mark88 (Jun 8, 2009)

i don't personally understand the point in putting a 7 1/4" blade in the table saw. I understand for thinner cuts and cheaper prices but you won't get the height you want if you'ree cutting a thick piece or a long pitch angle. And those blades get so dull so quickly. I personally have the 10" freud (diablo i think its called [the red blade]) and i don't regret buying the beauty.


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## davidmicraig (Nov 21, 2009)

Not a stupid question at all Charlie. Before posting my comment to the review, I tried finding any info I could online. I guess my concern was the RPM, the depth of cut, and the stability of the blade. Kind of like routers. If I have a table mounted router, my preference is a 1/2 inch shank because I am pushing the wood into the blade, not the other way around. When you run wood into a cutting surface, the stress is much greater. To me, that is one of considerations taken into account when they design the size and shape of the blades in question. Yes, a dado blade is smaller in size than some circular saw blades, but look at the thickness and the quantity of the cutters. They are substantially weighted. I personally do not see much gain in going with circular saw blade even with a price savings of 10-15 bucks. Wood magazine had quite a list of tablesaw blades with a lot of life and quality for around a thirty dollar purchase. The blade would last longer and the cuts would be more precise, and you wouldn't be limited to a cutting depth of just over an inch. Just my humble opinion


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## Alonso83 (Jul 14, 2009)

I think is very simple, if you need the thin kerf but height is not a problem go with a small blade, if height is an issue, then go with the standard 10", I second *Mark* I do also have the 10" Diablo full kerf, it is a great blade.


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## Beginningwoodworker (May 5, 2008)

I have try it, but I rather use a 10'' blade.


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## mark88 (Jun 8, 2009)

Good choice for a blade alonso  the diablo is worth the cost


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## knotscott (Feb 27, 2009)

Charlie - The teeth on smaller diameter blade make a tighter arc than those of a 10" blade, which translates to the equivalent of a steeper hook angle. It should be fine for ripping, but I suspect it'll be a mixed bag for ultra fine ply cuts. Most plywood blades have a fairly low hook angle. Smaller blades will work, and may even be easier to spin, but I doubt they'll cut as cleanly on a critical fine cut. Keeping the height on a smaller diameter blade low should help some, but I don't think it's worth passing up a good blade for.


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## CharlieM1958 (Nov 7, 2006)

I'd like to thank everyone for all the input.

It sounds like the bottom line is that there is nothing wrong with using a smaller blade in certain situations, but it's probably not a huge money-saving idea either. And it could be frustrating for that one time out of ten when I need the extra depth of cut.


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## JKC (Jul 25, 2009)

Recently at the Woodworkers Show in Sacramento, the fellow demonstrating the Grip-Tite Magnetic Featherboard system showed some very, very thin veneer type pieces he cut using the Grip-Tite product and a Diablo 40 tooth 7-1/4" circular saw blade mounted on his table saw.


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## Julian (Sep 30, 2008)

I use 7 1/4 blades in my 8" portable tablesaw all the time since they are cheaper and easier to find than good 8" blades. I only use 10" in my shop ts though, with the exception of dado blades.


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## rustedknuckles (Feb 17, 2008)

Just one more observation on this, I once put a 7 1/4 blade on my TS and had very bad results. Have you ever noticed those circular saw blades that have like a diamond shape embossed around the arbor hole? Ever wondered what it's for? Well I didn't, until that small blade broke on my TS right there; just like that shape was punched out with a die. Very frightening event and one I will never experience again.


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## russv (Sep 21, 2009)

next time you go to a woodshow, look and see how many demo booths are using 7-1/4" blades. i've seen alot of them. i was thinking of using 2 of them to make a 1/4" dado set-up. would be alot less than I paid for my dado set and i do alot of 1/4" dado's. a 7-1/4" plywood blade is alot less than a 10" any day.

russv


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## Dusty56 (Apr 20, 2008)

Hi Charlie , I've not had any issues using the 7.25" blades on either my benchtop Delta or my JET 3hp Cabinet TS…..I use to use them for the thin kerf aspect to try to save as much of my exotic woods as possible when ripping , but that was before I got my bandsaw. I actually had one reground to a FTG style instead of the ATB style to make flat bottom grooves on a few projects as well as some tiny box joints (finger joints). 
Long story short is if the specified blade RPM isn't exceeded , you should be fine. I haven't had any issues with the diamond pre-punches giving out in the past 15 years….I must be doing something wrong ; ) LOL

Happy Thanksgiving Charlie !!


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## Kindlingmaker (Sep 29, 2008)

I use 7 1/2" blades in the TS (General 650) to cut the first part of the kerfs in zero clearance plates.
...also, dado blades are smaller in dia. than the normal 10" TS blade…


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## frostwood (Sep 3, 2009)

Charlie, I just wanted to say thanks for bringing this up. I am new to woodworking and have wondered about this. I thought all the responses were helpful. I especially thought that the technical response from Knotscott made particularly good since. At least now I would fell comfortable in using a 7 /12 " blade in a pinch .
Thanks again!


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## russv (Sep 21, 2009)

one thought about the diamond knock out. I have a blade stabilizer (really just an extra large washer) i use on my 10" blades to do fine cutes. it can be used on the 7-1/4" blades and would cover the knock out totally. I would think the standard washer covers the knock out anyway, but i haven't looked closely yet. the 7-1/4" blades are use in a much harsher condition when on a circular saw (at least mine is), so i think the would think it's on vacation when working in the tablesaw environment.

the plywood blade (7-1/4") i would think would work good also, cause it works on the circular saw. the speed of the teeth is the main difference. but cutting faster i would think would give a cleaner cut.

anyone know the rpm's of a tablesaw vs. the circular saw?

FYI, the Freud 7-1/4" 40T blade is about $15.00 and the 10" version is about $50.00!

russv


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## Dusty56 (Apr 20, 2008)

Charlie , you may be interested in this fine Shop Asset ; )


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## SUPERDOG683 (Nov 3, 2009)

no doubt, smaller blades are fine and in some cases better.

the cut depth is 95% of the reason for larger blades.

you can buy 7.25 for 1/2 to 1/4 cost of 10 inch.

and you can focus on quality ie buy higher quality 7.25 for less$$ than medium quality

10 ich. most dont want the hassle of blade changes etc. but if you dont cut thick stock

you dont need 10inch blade. and dados and other specialty blades are far less
and when using shapers and dados who cuts deeper than one inch???
maybe when doing some mortise and tenon.

if you do high vol. cutting of thin stck this will save a decent amt of $$ over time.


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## mmax (Dec 9, 2008)

Thought you might be interested in these comments.

http://woodgears.ca/shop-tricks/skillsaw_blade.html


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## Dusty56 (Apr 20, 2008)

mmax…nice link …thank you : )


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## CharlieM1958 (Nov 7, 2006)

Yes, thanks for that link, mmax.


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## vegeta (Mar 10, 2009)

thanks to all who participated in this post i learned something new today


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## Roz (Jan 13, 2008)

Man, you guys are impressive! There is so much information here I am going to have to read this again! Great question Charlie, I never thought of the blade swap.

It seems to me the smaller diameter blade would allow the teeth to pass through the material more often than a larger diameter blade with the same number of teeth turning at the same speed. That might make some improvement in the smoothness of the cut.

There is a lot of points here that never occurred to me. You guys and girls are awesome. I learn something here every day. Thanks to all of you. all of you.


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## russv (Sep 21, 2009)

Guess what? this month's Woodsmith's magazine (issue 186) has an article about inlay banding (page 14). In the article, they suggest using the thin kerf 7-1/4" circular blade. They say it will waste less wood when cutting the inlay (page 15).

russv


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## PASs (Dec 1, 2009)

If it fits I'll run it. 
I did it with my TS. 
I've done it with my Radial Arm.
And the blades are a little cheaper.
Interesting about the blade failure on the diamond shaped hole.
Any mechanical engineers that want to speculate on the reason the slight difference in speed might have caused a catastrophic metal failure at the hole.

And from mythbusters lumberjock annex.
My dewalt 364 skil saw has a no-load speed of 5,800 rpm.
At a diameter of 7.25" thats a tip speed of (pi x diameter x rpm / 60 [seconds per minute] / 12 [inches per foot]=fps)...are you ready for this…183 feet per second.
A dewalt 746 table saw has a no-load speed of 3,000 rpm. 
At a 10" diameter the tip speed is…130 fps.
Put the 7.25" inch blade on the TS and your tip speed is…95 fps. 
However, a quick comparison of a Hitachi and Skil saw (thank you Lowes) shows 5,000 rpm which would give a 7.25" tip speed of…158 fps…still slower than a 5,800 rpm skil saw (p.s. high-torque skil saws….like worm gear drive…are less than 5,800 rpm.)

Sooo, calculator studies would show that a skil-saw blade on a table saw spins slower, has a slower tip speed, and would therefore probably not cut as fast as a 10" blade. But the blade is unders less centrifical force and is less likely to fail than in it's original tool. Which could be an indication of the failure mentioned in an earlier reply…if you put the work into the slower tip-speed blade you might tend to over stress it. I think feeding stock into the TS gives you less feel for the blade load than when you are pushing the skil saw over the stock. 
But then again, if you mount your skil saw in a table you loose that feedback as well.

They are called face shields…I ALWAYS wear one…AND goggles.


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## Lip (Apr 25, 2007)

I started out with an old Sprunger Brothers TS that I thought was an 8" model … turns out it wasn't … could only use the 7 1/4" blades on it … so I got used to buying them … when I upgraded to an 8" and eventually a 10" table saw … I had two choices … either scrap the blades I had or use them … so I used them. While there are a good variety of affordable TS blades on the market, most of the my local shops only stock the expensive brands or the bargain basement blades … so to get a good reasonably affordable blade, I've either had to order them online or though the store … but they do stock a fairly decent supply of reasonably priced 7 1/4" blades … if I have a situation where I don't have time to wait for a blade to be sharpened or for a new blade to be shipped … I'll pick up a 7 1/4" with no hesitation.

One consideration for the star shaped knockout that's already been mentioned is the blade stiffener … the washer on my table saw is not flat and only it's outside edge touches the blade … leaving very little support for the knockout in the middle … so I do use a stiffener to make sure that it is firmly supported on both sides and doesn't have any room to move … the stiffener does limit your depth of cut … but if you're only trying to cut veneered plywood, that shouldn't be a problem and the stiffer blade should provide a cleaner cut.

I don't have the link … but I know somewhere over on the Old Woodworking Machines site they had a chart or little App that would allow you to figure out blade RPM based on the size of your cutter, pulleys, and motor … I've been able to use the 7 1/4" blades on my TS without having to reconfigure anything … but if your interested in finding out what the difference in RPM is … or if you run into issues … I'd go ask those guys … I've restored more than a few pieces of equipment and know that simply changing the pulley can make a world of difference and is often a lot more cost effective than replacing an entire motor … after all, if the whole idea is to use a save a few bucks … replacing a motor seems like it would defeat the purpose!


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## GaryK (Jun 25, 2007)

Without reading everything above, I'd say "try it", if you like, you like it.


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## Tom22 (Jun 5, 2011)

Hello guys great info! I do have a question, although it might be obvious, but based on all replies I still feel the need to ask. Worst question is the one you don't make right?
Would the same apply to a miter? I mean using the 7.25" blades sometimes instead of the 10"?

Thanks,
Tom


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## BuyoMasilla (Jun 5, 2011)

New here and trying to get unbloked to ask my own question and hopefully get valuable input and thoughts like it has been the case here. If Tom is talking about what at times is called a "chop saw", seems to me the smaller diameter will make a difference. The width and height of cut will be compromised, especially if the saw is not a sliding miter saw. It is possible that the square stop on the back may have to be moved forward for a better fit to this smaller diameter blade.

Just an opinion from a very green woodworker.


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## ferstler (Oct 5, 2008)

It sounds workable. I do not think the diamond knockout issue is a big deal, provided the thing has not been partially removed and the table-saw's own large washer clamp covers it completely and holds the blade in place.

On the other hand, my hand saw is a Skil Mag 77 and the knockouts on all of my 7.25-inch blades have been, well, knocked out. So for me the issue does not exist. I DO have a diamond adaptor that allows such a blade to be installed in a regular circular saw, but I have never tried it and probably never will.

Howard Ferstler


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