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Saw blade kerf

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  • Member since
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  • From: Harrisburg, PA
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Saw blade kerf
Posted by hbgatsf on Friday, November 4, 2022 6:55 AM

I know what kerf means and what it does, but I don't know how to choose it.

Specifically, I am looking at the Micromark 168 tooth blades for the table saw.  One has a .020 kerf and one has a .045 kerf.  Obviously the smaller one will make a narrower cut but why choose one over the other?  Is the thinner one more fragile?

I intend to use this for cutting styrene.  I have used the 80 tooth blade for this and was thinking the 168 might be more appropriate.  Before someone says to just score the styene and snap it I want to cut a number of pieces the exact same size and I will get better results using the fence on the table saw.  Also, score and snap doesn't work on columns.  

Rick

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Posted by Track fiddler on Friday, November 4, 2022 7:20 AM

Good morning Rick

First and most foremost, If available get a blade with carbide tipped teeth.

The reason being for different kerfs is gaining more relief from retention to less likely bind on or pinch the blade with a wider kerf.  Especially important with miniature saws that don't have as much power as the bigger ones.

When ripping Hardwoods, (some specifically more than others), have more retention that binds on the blade and hard on the motor.  Those are the rips that look like bananas when they come out the other end.  Pitchy Pine isn't the saws friend either.

Making sure your fence is parallel with the blade is also very important.  An (ever so slight) rake, wider at the discharge of the blade is beneficial.  Wider at the feed of the blade is nothing but problems.

Ripping styrene, I don't see you as having any problems as the material is consistent, manufactured in a controlled environment unlike wood.

In cutting styrene, the narrower .020 kerf blade will probably be easier on your saw motor as it's biting off less material to chew through on thicker columns.  Also provides you with less waste per pass is a plus when cutting many.

If it's a matter of expense and you want to get multi-use of cutting different materials with one blade, I'm sure the .045 will be fine as most styrene is soft.  One of my instructors always said, "Let the saw blade do the work".  My saw equipment has lasted many many years applying that rule.  Always using a newer sharp blade is also a rule of thumb.

 

 

TF

 

 

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Posted by wvgca on Friday, November 4, 2022 7:38 AM

a narrow kerf, while it may work easier, does / can have more of a tendancy to bend / wander, depending on the material  ..

a lot actually depends on the length of the cut , and how hard / heavy you feed it ..  the why commercial saws usually have a thicker blade, with less tendancy to wander with inexperienced operators ..

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Posted by hbgatsf on Friday, November 4, 2022 9:21 AM

Thanks.  I may have muddied the water a bit by referencing using the fence.  I will use it to rip pieces from 2' to 6" long.  I also use it for measuring on cross cuts by placing a spacer between the item to be cut and the fence to measure and then removing the spacer before cutting.  This works well when making identical columns that are 1/4" to 1/2" thick.

Rick

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Posted by NorthsideChi on Friday, November 4, 2022 10:13 AM

Is it possible to cleanly cut styrene on a table saw?  It seems like its melting point is too low resulting in raised or gummed up edges.  I've cut styrene with a fine tooth band saw in a rush and it was still pretty coarse.  Only plastic I could ever get clean cuts on a table saw or band saw was acrylic sheets.  

 

Styrene's low temperature stability would seem to make kerf dimensions negligible if the edges need additional sanding 

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Posted by SeeYou190 on Friday, November 4, 2022 1:07 PM

Kerf is from a combination of the width of the blade, and the offset of the teeth.

With what we do, my preference is for wider kerf when available. The blades last longer and it is easier to control the direction of the cut. Everything also stays cooler.

The additional loss of material is not a factor for my limited production of models.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by dknelson on Friday, November 4, 2022 1:48 PM

Unless you can control blade speed my experience is that cutting plastic, styrene or engineering plastic, with an electric saw is an invitation to melted plastic and a gummed up blade

Having said that, it may be that a very narrow kerf would be the better choice for plastic.

What I can say is that when cutting homasote with a jigsaw (not the ideal tool perhaps) I used the narrowest kerf blade I could find, one intended for metal actually, because it creates the least amount of homasote dust, which is a real annoyance.  Not NO dust mind you, just the least amount.  But it takes longer because the wider kerf really tears through the material which is why it is good for wood

Dave Nelson

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Posted by wrench567 on Friday, November 4, 2022 3:28 PM

  How thick is the styrene you are cutting? Good rule of thumb when cutting any material is at least three teeth across the thickness. Any less then there is a chance of tear out or in the case of plastic, shattering. I once tried cutting some plastic trim pieces with a skill saw using the finest blade I had and it didn't end well. I ended up scoring it and snapping it cleanly using a utility knife. I've scored and snapped styrene as thick as quarter inch.

     Pete.

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Posted by hbgatsf on Friday, November 4, 2022 7:24 PM

My table saw is variable speed and the blade I have been using has 80 teeth with a 0.07 kerf.  I can adjust the speed to minimize melting.

The first time I decided to use it on plastic was to cut the bottom out of the Walthers Coke Quench Tower to correct the design flaw of that structure.  It was already assembled when I discovered the problem, and to fix it I needed to make two parallel cuts.  I figured my best chance of making accurate cuts was to use the fence on the table saw.   That worked out perfectly and since then I have ripped and crosscut various thicknesses of different types of plastic successfully.  

The items I have cut this way have not been used with the edges exposed.  I am starting a project where I will need to crosscut Plastruct 3/8" rectangular tubes.  The joints made will be very visible and my thought was that a blade with more teeth would be more accurate.  

Maybe I should make a trial cut with the blade that I have to see how it looks before buying a new one. 

Rick

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Posted by DonRicardo on Friday, November 4, 2022 9:20 PM

The more teeth your blade has, the finer the cut will be. Allow room for sanding for a smooth finish. Check out panel blades.

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Posted by SeeYou190 on Saturday, November 5, 2022 1:02 AM

dknelson
What I can say is that when cutting homasote with a jigsaw (not the ideal tool perhaps) I used the narrowest kerf blade I could find, one intended for metal actually, because it creates the least amount of homasote dust, which is a real annoyance.  Not NO dust mind you, just the least amount. 

This is the best blade I have found for cutting Homasote.

No dust, and perfectly smooth cuts.

-Photographs by Kevin Parson

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by hon30critter on Saturday, November 5, 2022 2:01 AM

Hi hbgatsf,

My concern with using a blade with a narrower kerf is that the blade will be more likely to rub on the plastic which will create heat and lead to binding and melting. You could end up with a very messy cut.

You have already suggested what you need to do next which is to make a few test cuts, but my gut tells me that you should stick with the 80 tooth blade and the wider kerf. You may have to sand the edges a bit. For that I would recommend getting a sheet of glass and some fresh (i.e. flat) sheets of sandpaper.

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by rrebell on Saturday, November 5, 2022 9:05 AM

The proublem I see her is some are talking about a hobby saw, while others are talking 1-1 saw. 

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Posted by SeeYou190 on Saturday, November 5, 2022 9:51 AM

rrebell
The proublem I see her is some are talking about a hobby saw, while others are talking 1-1 saw. 

We took a slight detour into cutting Homasote with a jig saw.

The OP's question was well addressed.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by maxman on Saturday, November 5, 2022 1:02 PM

SeeYou190

 

 
rrebell
The proublem I see her is some are talking about a hobby saw, while others are talking 1-1 saw. 

 

We took a slight detour into cutting Homasote with a jig saw.

The OP's question was well addressed.

-Kevin

 

Yes, the homasote thing was a detour.

But I'd like to know what type table saw he has.  I wasn't aware that there were any variable speed full size table saws.

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Posted by hbgatsf on Sunday, November 6, 2022 5:25 AM

maxman

 But I'd like to know what type table saw he has.  I wasn't aware that there were any variable speed full size table saws.

 

 
Since I was asking about Micromark blades with a kerf of .020 or .045 I thought it was obvious I was talking about a hobby saw.  Specifically I have the MicroLux Mini Tilt Arbor Table Saw.
 

Rick

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Posted by maxman on Sunday, November 6, 2022 1:30 PM

hbgatsf
Since I was asking about Micromark blades with a kerf of .020 or .045 I thought it was obvious I was talking about a hobby saw.

Yes,it was obvious until "they" started speaking about cutting Homasote, and then someone else asked if it was 1 to 1 size.

I needed something similar for my projects, but chose a Proxxon chop and miter saw, https://www.proxxon.com/us/micromot/37160.php, instead.

I also cut tube and angles, so it is mostly cross cuts versus rips.  I personally would rather move the tool into the work, rather than the work into the tool.  But that is a matter of opinion.

So far as the blade goes, the number of teeth/inch was more important to me than the kerf.  The larger number of tpi seems to give a smoother cut, especially if cutting slowly.  I found that the smaller number tpi blades tend to grab the work as it approaches the end of the cut (tube wall for example), sometimes trying to rip the cut off piece from the main body of the work.

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