Table Saw: non cast iron top, composites


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My brain was spinning last night rather than sleeping. This is what I was thinking about.

 

I know table saws and the basic design have been around for quite a while. So, it makes sense that cast iron is a handed down tradition, but I'm wondering why that's still so.

 

Seems that with all the lightweight and strong composites out there that non cast iron tops would be more common. I see them in videos every once in a while. They mostly look home made though - but I'm speculating on that. Router tables are made from all kinds of different materials - phenolic, MDF, baltic birch, etc...

 

My new Grizzly G1023 is a very smooth operator, so I'm not sure that the weight of the top really serves to stabilize much. 

 

The pros I see from my point of view are: does not rust, lightweight, dimensional  stability, non conductive, low thermal conductivity. 

 

What would be the cons?

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Lightweight is a pro and a con.  A heavy top will dampen vibrations.   generally speaking, the heavier the machine the smoother the performance.   Take the top off your grizzly and it might start bouncing around your shop.  

 

The only viable alternative I have seen to cast iron is granite and I dont' think steel city has made much hay with their granite tops.    

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The one aluminum top table saw I had got me be for home DIY stuff.  When I started getting into woodworking more seriously I found it more difficult to work with.  What finally made me switch to a saw with a cast iron top was the fact the aluminum table was extremely out of flat, with a hump running in such a way that a square cut was impossible.

 

For some machine types, aluminum tops work well.  My Ridgid OSS has an aluminum top, and function very well.  My previous bandsaw had an aluminum table, and functioned very well for many years.

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i'm not thinking aluminum, not plastics either. More along the line of carbon-fiber and other high tech composites. I don't think I would want granite. I have those int he kitchen and while they look nice I don't think it would make a great top for a machine - but I've never used one with one so...

 

The serpentine belt and trunion on the G1023 are super smooth. I bet some of the higher end saws are even smoother. I really doubt my machine would move at all.

I'm gonna put of glass of water on it to see what kind of vibration is revealed.

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i'm not thinking aluminum, not plastics either. More along the line of carbon-fiber and other high tech composites. I don't think I would want granite. I have those int he kitchen and while they look nice I don't think it would make a great top for a machine - but I've never used one with one so...

 

The serpentine belt and trunion on the G1023 are super smooth. I bet some of the higher end saws are even smoother. I really doubt my machine would move at all.

I'm gonna put of glass of water on it to see what kind of vibration is revealed.

The resin components of those are plastics.  Yes maybe kevlar filled nylon(plastic filled plastic!) might have pretty good wear resistance or glass filled plastics, but they are still plastics.

 

These can be very good in a lot of ways, but I don't know if as a saw top they would be good.

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Cast iron is heavy, relatively stable, moldable, machinable, can be made flat, magnetic, is strong enough to mount accessories to, and will generally withstand a lifetime of abuse.  Rust is a mostly manageable concern.  Most other logical replacement materials won't offer all of those attributes, but often eliminate the rust concern.  Granite has shown some promise because it's flatter, heavier, more stable, and doesn't rust.  Lighter materials have obvious appeal to the manufacturers, but so far, the composites and aluminum tops just don't seem overly marketable in the US marketplace for full size stationary saws.  

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  Lighter materials have obvious appeal to the manufacturers, but so far, the composites and aluminum tops just don't seem overly marketable in the US marketplace for full size stationary saws.  

That is a good point, and it is not limited to stationary saws.  Pretty much all stationary machines rely on a cast iron top or table.   I don't know what they use in Europe, but I'd guess other composites and alloys are more accepted.   If Festool were american a MFT would be made of cast iron.  You can certainly get good work out of lighter more streamlined modern tools.  We are pretty stuck on tradition over here.  

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That is a good point, and it is not limited to stationary saws.  Pretty much all stationary machines rely on a cast iron top or table.   I don't know what they use in Europe, but I'd guess other composites and alloys are more accepted.   If Festool were american a MFT would be made of cast iron.  You can certainly get good work out of lighter more streamlined modern tools.  We are pretty stuck on tradition over here.  

Festool doesn't make stationary workshop tools, but portable worksite tools.  Cast Iron is not a material of choice for workbenches of any variety in my experiance.

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Really, explain that please?

The idea is that the material on either side would shrink. Of course so would the material under the miter slot. As it is all one piece I would expect a slot to shrink in chilling though I can not think of any exact example of this being used unlike say heating where a bearing will be inserted to expand it to let the bearing fit in better.

 

I would expect it to be more of an issue if you are using two miter slots for your sled, then you have the whole distance between them for relative differences in expansion and contraction with temperature change to build up into more significant displacements.

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I think woodworking is a craft heavily based on tradition. Even if a superior product came out that outperformed the cast iron counterpart, there will still be the vast majority saying, "But we've always done it this way."

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All miter slots wear even cast iron, plane and simple. Plastic I would assume would wear even faster. 

I had thought the original reference was to the slots growing or contracting with temperature change not wear over time.  Though of course all materials will wear, and more wear resistant materials are probably not economical to make the tops out of.  Slides and bearings an other moving machine parts are not made out of cast iron because it is not all that wear resistant for a ferrous metal.  But a saw top made out of tool steels is going to raise the price of the saw a lot.

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I had thought the original reference was to the slots growing or contracting with temperature change not wear over time.  Though of course all materials will wear, and more wear resistant materials are probably not economical to make the tops out of.  Slides and bearings an other moving machine parts are not made out of cast iron because it is not all that wear resistant for a ferrous metal.  But a saw top made out of tool steels is going to raise the price of the saw a lot.

 

Miter slots get wider as they wear even cast Iron. I don't have a clue if it would have seasonal movement. I would think saw dust along with a steel miter bar would wear the plastic pretty fast, just a guess. I know that even hard surfaces like phenolic wear pretty fast even with just wood sliding across. I wouldnt  want any sort of a plastic top. The top also adds rigidity, the base of saws like cabinet saws are not very rigid without the top. Not saying it can't be done but not anything I would consider an option I would entertain.

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Miter slots get wider as they wear even cast Iron. I don't have a clue if it would have seasonal movement. I would think saw dust along with a steel miter bar would wear the plastic pretty fast, just a guess. I know that even hard surfaces like phenolic wear pretty fast even with just wood sliding across. I wouldnt  want any sort of a plastic top. The top also adds rigidity, the base of saws like cabinet saws are not very rigid without the top. Not saying it can't be done but not anything I would consider an option I would entertain.

But this thread was about the sleds sticking when it got cold.  So this response doesn't fit into the thread well.

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But this thread was about the sleds sticking when it got cold.  So this response doesn't fit into the thread well.

The response fits just fine. The thread is about alternative tablesaw top materials. I originally stated the miter slots would grow. You then posted something about expansion and contraction to answer a question that was directed to me. My original comment was not going down that line of thinking.  My comment was a wear concern and that the slots would get wider with wear. I should have been more specific.

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I agree that they will widen over time with wear (to what degree of course depends on your setup/use), and they also contract with cooler temps and expand when warm (that's just basic physics).

 

  1. Composite materials (also called composition materials or shortened to composites) are materials made from two or more constituent materials with significantly different physical or chemical properties, that when combined, produce a material with characteristics different from the individual components.

So, we are not really talking about plastic, per say. We are talking about plastics plus. It depends on the type of fibers, resins, etc... Composites can be made to look like just about anything these days. They can be shiny and in any color, they can be textured in any pattern. They can have multiple colors and just about any degree of gloss to no gloss. You can even have it made with your name or logo in it. You could get all hippy and embed hemp fibers in it for tensile strength too. Make it look like a natural fiber material.

 

Some airplane fuselages are made of composites these days. Boeing is doing it. Cars too. I would not be surprised if some of the next generation military aircraft are made of it.

 

My cousin is all into the stuff - manufacturing and engineering side of things. He was over for a visit and we got to talking, and well you know how that can go. Ideas started flowing. So, this is really just a brainstorm kind of thread.

 

I know that solutions for the wear could be easily found. The miter slots could be filled with an aluminum t-slot, or lined with something, or even impregnated in that area for a more durable material.

 

I think it really it comes down to the weight. If you get a 5hp motor humming at >3,000 rmp, and there is even a little imbalance then well the machine might just try to walk away. But if it is tuned well and running smooth, then why not?

 

There is also the whole cost side of things, but with manufacturing volume and shipping that could lower the price point.

 

To defy the laws of tradition, is it only a crusade of the brave? (who knows that reference?)

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