# Forum Home Renovation Tools & Products  Advice on bore/arbor size on circular saw blade

## opinio

I have a DeWALT 7-1/4" circular saw bought in Australia that came with a DeWALT blade that fits a 20mm circular shaft bore (or arbor as some call it). The blade has "20mm" bore written on it. I am looking at new blades. I notice many blades online come with a 13/16" bore diamond knockout which according to my calcs is 20.6mm. I take it the 13/16" bore is essentially the 20mm bore give or take half a mm? And as such I can use the 7-1/4" blade with a 13/16" bore knockout? Or is the 'diamond knockout' and actual diamond shape once knocked out for a diamond shaped shaft? I am a little confused as I simply want a 7-1/4" blade with a circular 20mm (or very close to it) bore.

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## ringtail

Go to a decent tool shop and forget online.

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## opinio

That's really helpful.

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## METRIX

Get ones that state 20mm bore, there are heaps available search for 184mm blade.
I had some diamond knockout ones and they didn't quite fit, they had a slight wobble, and because of the diamond, were very hard to get centered. 
What type of blade are you after, how much do you want to spend, and how many do you need ? 
Diablo blades are fantastic to use, you would think there is no blade on the saw when cutting pine with these blades, they are Italian made by Freud, but don't last as long as some others.
I used to buy the IRWIN Marathon thin kerf blades directly from US very cheap a few years ago, this was when they were made in NZ, but now like most things they are made in China and the price is quite high which is not worth it. 
Bunnings usually have triple packs of IRWINS, for around $40, these work fine, and are cheap if you damage one.

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## opinio

Thanks Metrix. I was worried the knockout might not be precise as you said.

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## METRIX

I have some with diamond knockout and they work fine, but I found ones with a round hold for the stated size always work perfect.

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## PlatypusGardens

> Go to a decent tool shop and forget online.

   

> That's really helpful.

  
Usually when in doubt it's better to go to a shop and look at the product in real life rather than buying online hoping that it'll fit.   :Smilie:

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## David.Elliott

The Irwins I buy in in packs of three (coz I do a lot of recycled timber) for $20.00 are 20mm arbor...

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## opinio

Thanks Platypus, I really don't mean to be curt but I obviously picked up on all that and understand the availability of shops and their experts. I have noticed physical shops around in my many decades on this planet. I am simply looking for online help in relation knockouts and whether the bore size of 13/16 is the imperial equivalent to 20mm. Some forum members may know that. If the answer to an online query is 'go to a shop' then what is the use of the forum? I am a little puzzled about why two of the three comments so far relate to 'go a find the info somewhere else'? One thing I can say is that there is a hell of a lot more (and better) blades available in the US. I'd like to exercise my consumer right to look at those options.

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## Marc

> Diablo blades ..........are ... made by Freud

   :Eek: 
I thought he was more into incest and other things ...  :Smilie:

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## opinio

> The Irwins I buy in in packs of three (coz I do a lot of recycled timber) for $20.00 are 20mm arbor...

  Yeah I saw the pack at Bunnings. They are a really good price. I am looking for a 60T though or at least a blade that gives a really smooth finish on pine.

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## Marc

> That's really helpful.

  He can be such a bore sometimes ...  :Rolleyes:

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## PlatypusGardens

> Thanks Platypus, I really don't mean to be curt but I obviously picked up on all that and understand the availability of shops and their experts. I have noticed physical shops around in my many decades on this planet. I am simply looking for online help in relation knockouts and whether the bore size of 13/16 is the imperial equivalent to 20mm. Some forum members may know that. If the answer to an online query is 'go to a shop' then what is the use of the forum? I am a little puzzled about why two of the three comments so far relate to 'go a find the info somewhere else'? One thing I can say is that there is a hell of a lot more (and better) blades available in the US. I'd like to exercise my consumer right to look at those options.

  
I think we're on different pages... 
The way I saw it ringtail meant "don't shop online" and you took it as "don't ask questions online"
Not sure if that's what he actually meant, but anyway... 
Either way it seems you're getting the advice you need here.  
It's easy for things to come across the wrong way on forums.
Especially with one-line posts and messages.   
I'll leave it at that.   :Smilie:

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## PlatypusGardens

> He can be such a bore sometimes ...

  
Metric or imperial...?  
Ooopppssssss......drifting off topic again.
I'm outta here   :Shock:

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## johnc

Ringtail is quite capable of responding but I also think forget online and buy local. Assuming it is in stock you get it straight away and should be able to return it if they have given you something that doesn't fit.

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## David.Elliott

The Saw Doctor I go to sources his blades locally, as in still made in AUS.
Just for fun he showed me the variance in the plate thickness of a 315mm chinese blade made that I paid $115 for against a $140 AUS made one.
The chinese had all the teeth set to one side too,(I shoulda picked that up)  meaning it cut one side and tore the other...

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## Marc

Out of curiosity ... what is a diamond knockout? I know of diamond knock off but not out. Also know of knockout but without a diamond in front, just a fist ...  :Smilie:

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## ringtail

Wow. Ok, firstly, I wasn't being rude or unhelpful. Merely stating that buying from a real shop would be beneficial to you. You can get the right blade first time with no dicking around. Also, trying to save a few bob online can be counter productive, particularly with power tools and accessories. Saw blades are as cheap as chips and really don't  warrant hitting the ebay tab.

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## Marc

Ebay is like buying MacDonaldoff (Mackers knock off) You must be very hungry to digest it.

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## ringtail

> Usually when in doubt it's better to go to a shop and look at the product in real life rather than buying online hoping that it'll fit.

  that's all I was sayin'

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## PlatypusGardens

> that's all I was sayin'

  
That's what I thought, and I did my best to clear up any possible misunderstandings until you got back   :Smilie:  
See post #13   :Wink:

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## METRIX

> Out of curiosity ... what is a diamond knockout?

  You knock the diamond from the middle to change the hole size, once knocked out, you cannot put it back in, actually it twists out and breaks the bits holding it in.

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## METRIX

> The Saw Doctor I go to sources his blades locally, as in still made in AUS.
> Just for fun he showed me the variance in the plate thickness of a 315mm chinese blade made that I paid $115 for against a $140 AUS made one.
> The chinese had all the teeth set to one side too,(I shoulda picked that up)  meaning it cut one side and tore the other...

  Wow, you paid $115 for a Chinese blade, they saw you coming, even Bunnings sells Italian made Diablo's for $97, you could have got these ones for $39. :Rolleyes:  Swarts Tools 305mm 12" 100 Tooth Tungsten Carbide Tipped SAW Blade 25 4mm Bore | eBay  Diablo 305mm 80T Mitre Saw Blade | Bunnings Warehouse 
The best blades I have ever used are the Diablo combinations, they cut quick and perfect, no tearing or damage.

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## ringtail

> that's all I was sayin'

  Thanks mate.  :Wink:

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## ringtail

The bosch blades at tradetools are hard to go past. Well priced and good quality.

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## opinio

> The bosch blades at tradetools are hard to go past. Well priced and good quality.

  I am not picking up much from trade tools apart from Irwin and their own home brand? 
Any suggestions on a 7-1/4" 60T with 20mm arbor/bore? Or a blade that give a super smooth finish?

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## Marc

> You knock the diamond from the middle to change the hole size, once knocked out, you cannot put it back in, actually it twists out and breaks the bits holding it in.

  That's not fair ...  :Frown:

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## METRIX

1: What are you using this in, a circ saw, or drop saw ?
2: What are you cutting with it
3: How much do you want to spend ? 
60t on a 184mm blade will usually be for cutting Aluminium, but you can get diablo 64T but 16mm arbour Freud Diablo 60T 7 1 4" 185mm Ultra Finish Circular SAW Blade D0760X Fine Timber | eBay 
I am using the 40t Makita Blumak blades in my little droppys', these cut clean and quick.  Makita 185mm BlueMak Circular Saw Blade | Bunnings Warehouse

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## opinio

> 1: What are you using this in, a circ saw, or drop saw ?
> 2: What are you cutting with it
> 3: How much do you want to spend ? 
> 60t on a 184mm blade will usually be for cutting Aluminium, but you can get diablo 64T but 16mm arbour Freud Diablo 60T 7 1 4" 185mm Ultra Finish Circular SAW Blade D0760X Fine Timber | eBay 
> I am using the 40t Makita Blumak blades in my little droppys', these cut clean and quick.  Makita 185mm BlueMak Circular Saw Blade | Bunnings Warehouse

  DeWALT DWE575-XE circular saw, cutting mostly pine and some ply. What do I want to spend? Well I prefer the best quality long lasting and the best price even if it is ultimatly an expensive blade, as opposed to elcheapos. I was trying to get hold of DeWALT because of personal preference hence my reason for looking in the US and the reason for this post. Most of the US arbors are 5/8" (16mm) like the Diablo you pasted above) not 20mm. 
The Makita though is a 20mm arbor but is not a 60T, but it looks good. 
I was looking at this blade, but as I said it has the 5/8" arbor.  :Frown:   http://www.amazon.com/DEWALT-DW3196-...dp/B0068XCZ4M/

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## METRIX

If it's in a circ saw then any semi decent blade will give you a good cut, in a fixed saw like a drop saw, the blade quality is very important because there is no play, in a circ saw, cuts are close but not what you would call accurate. 
The BluMak blades have performed well, but like any blade they will wear out with use no matter how much they cost.

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## Gaza

Masters have good range of Bosch blades, I been buying 160mm for my Frstool track saw from them lately about $30 bucks for 48t blade vs over a hundred from Festo, 
60t in circular saw is kill unless doing some very detail cutting there is not like there is a zero clearance insert / splinter guard to prevent tear out   
Sent from my iPhone using Tapatalk

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## ringtail

> I am not picking up much from trade tools apart from Irwin and their own home brand? 
> Any suggestions on a 7-1/4" 60T with 20mm arbor/bore? Or a blade that give a super smooth finish?

  Yep, they had a website upgrade recently and it's pretty retarded. They only list 1/10th of what they actually stock. As far as a 60 T goes, Bosch do one but I don't know if trade tools stock them. Sydney tools do though. 20 mm bore and comes with a 16 mm reducer as well. They are good to deal with too I've heard.  https://sydneytools.com.au/bosch-260...material-blade

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## Marc

That diablo blade looks the part. I like that depth notch thingy they have every 5 teeth, a bit like the chainsaw, prevents the teeth from dig in and break off. Actually I just noticed the Hilty picture you posted has it every tooth.  
I like Sydney Tools, good prices and good service. In fact I think they have the best prices most of the time.
I heard Masters is closing down some of their stores.

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## opinio

I think Sydney Tools is the go. They have excellent prices. They don't have a huge variety of blade brands but they about 6 Bosch blades that suit my DeWALT. I wish Diablo made a blade to fit though. It does look well engineered.

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## METRIX

> Masters have good range of Bosch blades, I been buying 160mm for my Frstool track saw from them lately about $30 bucks for 48t blade vs over a hundred from Festo,

  How are these blades performing, the original Bosch blade 2 608 642 384 for the Bosch railsaw is also over $100, these were made in Italy but are now coming from China, I suspect the Italian ones are made by Freud, as Bosch purchased Diablo and Diable is made by Freud.   

> 60t in circular saw is kill unless doing some very detail cutting

  Agree, that's why I asked what it was being used in, and as it's a circular saw, then any blade will work fine, as you cannot achieve the accuracy with a circ saw that would justify a very high tooth blade, if it was a track or drop saw different story.

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## METRIX

> I think Sydney Tools is the go. They have excellent prices. They don't have a huge variety of blade brands but they about 6 Bosch blades that suit my DeWALT. I wish Diablo made a blade to fit though. It does look well engineered.

  They do make blades to suit a 184mm saw with 20mm, I use them all the time in my one, you can get them from Bunnings 40t which is plenty of teeth to give a fine cut. Diablo 184mm 40T Circular Saw Blade | Bunnings Warehouse

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## opinio

Thanks for the comments on not needing a 60T. You're right. It was a theory I had on getting a finer saw for a better finish but the 60T will probably make no difference.  
Thanks Metrix for the lead on Bunnings having the Diablo. I'll check it out.

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## METRIX

Bunnings is not the cheapest for these blades, but it's about what you will pay for them in AU. 
Last ones I bought were in lots of 20 from the US via ebay  :Biggrin:  cost was about $9.95 including shipping, I still have a number of them left, they are a very nice blade, but $40 is not justified for site use, as you are bound to damage the blade on something, this is where the cheap IRWINS come into their own around $10 they work well, if they get damaged you just toss them. 
Also take a look at the Makita blade, this is also very nice, cuts smooth and clean.

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## METRIX

> Thanks for the comments on not needing a 60T. You're right. It was a theory I had on getting a finer saw for a better finish but the 60T will probably make no difference.  
> Thanks Metrix for the lead on Bunnings having the Diablo. I'll check it out.

  If you want a better finish buy a track saw, a circular saw is limited in what it can produce, admittedly it can produce good results but there are to many factors which won'' allow an exceptional cut like a track saw will give you..

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## r3nov8or

> That diablo blade looks the part. I like that depth notch thingy they have every 5 teeth, a bit like the chainsaw, prevents the teeth from dig in and break off. Actually I just noticed the Hilty picture you posted has it every tooth. 
>  ...

  They are dual purpose cross-cut and ripping blades. My Metabo 18v circ saw came with one very similar to the Hilti, but smaller at 165mm. The tooth design means you get less teeth but (usually) a narrower curf and (IMO) a more flexible saw.

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## David.Elliott

My sliding table saw has a 30mm arbor, which in my experience, limits my options a bit...

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## METRIX

> My sliding table saw has a 30mm arbor, which in my experience, limits my options a bit...

  I hate how they have no standard for such a widely used tool these days, circ saws, drop saws etc, why can't all the manufacturers agree on a standard, you could try the ones below for a start.   Tungsten SAW Blade 305mm X 30 MM X 60TEETH FOR Wood Irwin Professional | eBay  Bosch 305mm X 30mm X 100T TCT SAW Blade Ultra Fine Precision FOR Wood Laminate | eBay  Clarke 60 Tooth 305mm DIA Tungsten Carbide Tipped SAW Blade 30mm Bore TCT308 | eBay  Trend CSB CC305108 Craft SAW Blade Crosscut 305mm X 108 Teeth X 30mm | eBay  Freud PRO LP60M Circular SAW Blade 305 MM X 30 MM Bore X 96 Teeth | eBay

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## David.Elliott

Gee Metrix,
Thanks for all the effort. So what I see there is that the $140 for a locally made stacks up well...the saw will take a 315mm blade as well, which I can just tell, with my luck I will need once I don't have that 10mm

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## METRIX

> Gee Metrix,
> Thanks for all the effort. So what I see there is that the $140 for a locally made stacks up well...the saw will take a 315mm blade as well, which I can just tell, with my luck I will need once I don't have that 10mm

  If you can get a locally made one, I would take that any day.

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## METRIX

Just to show you how good the 40t Diablo blades will cut, below is a piece of 100x50 Blackbutt I was cutting down today to 70x50, cut one with the Diablo, and the other with the track saw, the cut from the Circ saw would be considered very good, the tracksaw would have been better but the current blade hit a screw last week, plus it was cutting a lot of Yellow Tongue as I thought the blade was stuffed might as well get the most out of it. 
Cutting 50mm Blackbutt is a test for any saw to get a decent finish, the one on the left is Diablo 40t, right tracksaw (blunt)  :Rolleyes:  so you can see a few blade marks as it was working hard to get through the timber, the Diablo blade ate through it like a piece of pine. 
Irrespective of how the saw cuts the timber needs further finishing, although with a new blade the tracksaw will give a finish that need no further work, result is the last picture.

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## ringtail

How do you find the bosch circ saw Metrix ? I hate my makita. Rubbishy base is bent like a banana. Plenty of power for what it is but it's just not accurate enough for my liking.

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## METRIX

> How do you find the bosch circ saw Metrix ? I hate my makita. Rubbishy base is bent like a banana. Plenty of power for what it is but it's just not accurate enough for my liking.

  The Bosch one is nice, I have a Makita 184 with the alloy base, the Makita is 1800W and is powerful, Bosch 1400W but does not lack any power, the Bosch, is lighter and better balanced.
The Makita is heavy to one side, which makes doing any semi delicate stuff with one hand difficult, the Bosch seem to have it's weight evenly spread, I like the Makita LED light, this is good if in a darker situation,  
The Bosch only has a pressed metal plate which is fine,, I like the height adjustment on the Makita better, it is more robust than the Bosch.
 I find myself always going for the Bosch now, and the Makita just sits there as it feels clumsy compared to the Bosch.

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## ringtail

All I need to hear. Another bosch to add to the collection  :Wink:

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## phild01

After trying to buy a blade today I'm resigned to looking on-line as well.  Seems my Hitachi _216mm_ is a bit hard to get a replacement for. Bunnings didn't help, neither did Masters though they had the size but only a very ordinary Bosch blade with an undersized bore.  Not up to the challenge to go far in Sydney traffic.  _edit...oops eight and half/216mm_

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## opinio

> After trying to buy a blade today I'm resigned to looking on-line as well. Seems my Hitachi 184 is a bit hard to get a replacement for. Bunnings didn't help, neither did Masters though they had the size but only a very ordinary Bosch blade with an undersized bore. Not up to the challenge to go far in Sydney traffic.

  What size is your bore?

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## Marc

Sydney traffic, your bore ... are we still talking circular saw blades?

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## phild01

> What size is your bore?

   Thought I might get asked, just measured it as 29.92, so 30mm. 
....also made a mistake with blade size, it's a 216mm 8 1/2"

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## phild01

> Sydney traffic, your bore ... are we still talking circular saw blades?

   bore problem with both :Wink:

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