Why do table saws still use naked cast iron?

[Michael Gantz]

Why do table saws still used naked cast iron tables? Is it just a cost issue? The firearms industry has a plethora of metal treatments that could be used to prevent rust and corrosion on equipment. Some of these treatments are a coating and probably wouldn't be appropriate because of scratching. But other treatments actually change the surface of the material at the molecular level. And in the firearms world these treatments are exposed to much harsher environments and use than most table saws.

[johnny means]

Why do table saws still used naked cast iron tables? Is it just a cost issue? The firearms industry has a plethora of metal treatments that could be used to prevent rust and corrosion on equipment. Some of these treatments are a coating and probably wouldn't be appropriate because of scratching. But other treatments actually change the surface of the material at the molecular level. And in the firearms world these treatments are exposed to much harsher environments and use than most table saws.

I think a better question is, why not?

[Cary Falk]

Well since Steel City introduced a Tinitride coating(among other things) and they went out of business, I suspect that there isn't a market for it.

[Brian Holcombe]

Cerakote with a additive to reduce surface friction would be awesome.

[Mel Fulks]

Cast iron is stable ,affordable, quiet ,and slick. Platinum is good too....but expensive.

[Bob Jones 5443]

Michael, I suppose you’re asking about rust. We do need to be vigilant to keep our surfaces rust free. In some shopping environments that’s harder than in others. I’m in California, and even through the winter I don’t get rust. I probably wax the tables of my saw, jointer, and bandsaw maybe once a year. That seems to keep me rust free.

[Mike Wilkins]

Likely a cost issue. Bluing and other firearms coatings sound and look nice. But would you want to pay for all that real estate to be coated likewise?
Cast iron is relatively inexpensive to cast and machine into a saw top, and easy to keep shiny with a periodic waxing.
Besides, it is a tool, built for use.

[Curt Putnam]

Cast iron adds mass, which reduces vibration. Consider also why modern, premium hand planes are made from ductile cast iron.

[Michael Gantz]

Michael, I suppose you’re asking about rust. We do need to be vigilant to keep our surfaces rust free. In some shopping environments that’s harder than in others. I’m in California, and even through the winter I don’t get rust. I probably wax the tables of my saw, jointer, and bandsaw maybe once a year. That seems to keep me rust free.

Yes, rust was my primary reason for asking. I realize in some places it's not much of an issue. In my area of Michigan the temperature and humidity swing around like crazy and one must be very vigilant. I was waxing the table saw and was thinking "Man, wouldn't it be nice if this thing had something like the old Glock Tenifer finish." And yes, one would still have to care for the equipment properly. But the chances of serious rust damage would at least be greatly reduced.

I think Tenifer would at least be a possibility. Cerakote would give some interesting options, but that process changes the dimensions of the final product and I'm not sure how consistent its thickness would be across a saw table.

[Michael Gantz]

Well since Steel City introduced a Tinitride coating(among other things) and they went out of business, I suspect that there isn't a market for it.

I wasn't even aware this was once available, interesting.

[Michael Gantz]

Cerakote with a additive to reduce surface friction would be awesome.

Considering all the colors that Cerakote is available in, it would certainly add some style to a few shops I'm sure. Though I wonder how many would object to such "outrageousness".

[Micah Puscheck]

Harvey sells them with a Titanium Nitride top specifically marketed for rust prevention.

https://www.harveywoodworking.com/products/alpha-hw110lc-36-10-2hp-cabinet-table-saw

[Eric Arnsdorff]

I think this is a great perspective and comment. It is industry status quo to offer raw uncoated cast iron that rusts easily. This is true of the market based on history. However, if you were designing the first shop equipment today I'm sure that this would be a critique of the product.

I see some comments about cost and such. It is true that it would add some cost but when you consider the premium sawstop gets for it's safety feature (this isn't a jab at them and it is a great feature - just a comparison of the cost) there seems to be a place in the market for a cost adder that the customers may be willing to absorb. Additionally, the higher end saws aren't priced based on cost but on market segment offering. But just the same it would give them another feature to charge an additional adder.

Personally, if the cost were reasonable, I'd pay the extra if I were buying a new piece of shop equipment even though my shop conditions do well keeping rust down. It isn't worth the premium sawstop gets for it's safety feature obviously.

[Michael Gantz]

Harvey sells them with a Titanium Nitride top specifically marketed for rust prevention.

https://www.harveywoodworking.com/products/alpha-hw110lc-36-10-2hp-cabinet-table-saw

Well, I learned something new today! How did you find this? Or were you already familiar with their product?

[Michael Gantz]

Personally, if the cost were reasonable, I'd pay the extra if I were buying a new piece of shop equipment even though my shop conditions do well keeping rust down. It isn't worth the premium sawstop gets for it's safety feature obviously.

Exactly! I have to keep a constant eye on the furnace in the winter and the dehumidifier in the summer otherwise disaster will strike. It's a constant struggle in the summer to reach 50% humidity around here.

[Mel Fulks]

In well run shops the machine tables have rules for use. Like no drinks on them. No gluing on them. No naps on them. And there is one
product used by all to keep them slick.

[Bill Dufour]

Who had a granite tablesaw? they have made multi-ton machine tools from concrete with metal embedded for accurate ground and scraped wear surfaces.
Bill D.

https://www.americanmachinist.com/archive/features/article/21892630/rocksolid-machine-bases

[Andrew Seemann]

Based on what my old Unisaw top looked like, I suspect wear could also be an issue for a coated top. Most places of that top you could no longer see the Blanchard grinding marks, it was just smoothly worn iron, and 1/32" - 1/16" thinner than it started in some places. I think it originally was in a production shop that worked with particle board before I bought it.

[Micah Puscheck]

Well, I learned something new today! How did you find this? Or were you already familiar with their product?

I was in the market for a saw and Harvey came up here several times, so I browsed through their offerings. Had never seen another saw with that option.

[Bob Jones 5443]

A few years back I had to store my equipment in a garage with no climate control, right in the fog line from the bay. I wasn’t able to use the machines for about a year. After that, when I moved into their present (and permanent) location, they had so much rust on them I was in despair for a little while. So I had to rehabilitate every surface. Now that I’ve done that, I guess I’m a little more vigilant. Plus, I’m well inland now. Paste wax is all it takes.

[Rick Potter]

I wonder if that new ceramic wax they sell for cars would work?

[Steve Eure]

Hmmm. Bluing a firearm isn't going to prevent rust. Where I live, because of hard use and high humidity, we have to oil our firearms to stave away the rust. It will rust on you before you get home from use if not careful.. I suspect a table saw or other cast iron tool would do the same. Something I have learned, is to keep a low wattage light bulb on constantly in my safe to scare away the rust. Works great. I suppose if you kept heat of some sort on cast iron. it would do the same thing.

[Doug Dawson]

In well run shops the machine tables have rules for use. Like no drinks on them. No gluing on them. No naps on them. And there is one
product used by all to keep them slick.
I love it! if you’re going to have a nap on the table saw, unplug it first. Unless you have a SawStop, then it’s just a wakey wakey.

[William Hodge]

Why do table saws still used naked cast iron tables? Is it just a cost issue? The firearms industry has a plethora of metal treatments that could be used to prevent rust and corrosion on equipment. Some of these treatments are a coating and probably wouldn't be appropriate because of scratching. But other treatments actually change the surface of the material at the molecular level. And in the firearms world these treatments are exposed to much harsher environments and use than most table saws.


One reason that machines aren't waterproof is that it is expected that people would use them in a wood shop. If the shop is so humid that water condenses on the tools, the stored lumber and work in process must also be being subjected to unacceptable humidity.

It's like buying milk, the seller assumes you will store it properly, instead of selling it in a heat proof container. If your tools rust, dry out your shop. The wet wood will thank you by not moving so much.

[Michael Gantz]

No naps on them.

Interesting story time? This has to be a good one.

[William Hodge]

Interesting story time? This has to be a good one.

I used to work in a millwork shop.

I built a 2' wide by 6" long outfeed table for a 10" saw. We made a lot of long narrow stuff, no plywood.

The foreman drank a lot. By the 2:00 break the alcohol from the night before would be pretty well worn off, and he would go to sleep on the outfeed table I built. He wore these big white basketball sneakers, with big soles. One of the young guys that worked there would let said foreman go to sleep, then grab a screw driver and 2" sheetrock screws,sneak up, and try to screw his feet down to the outfeed table. The foreman would wake up fast.

At least the kid didn't hit the power switch in the saw.

[Ole Anderson]

Kicking myself for not taking a picture. I was in my local Lowes a few weeks ago and noticed they has a bandsaw and drill press on display, both had cast iron tops that were heavily rusted way beyond repair. Looked like they had been the subject of a salt spray test. I think they may have been Porter Cable. Why they would put them on display was totally beyond my comprehension.

[Erik Loza]

As a manufacturer, my answer: "COST"

Erik

[Richard Coers]

Why did it take generations of table saws to have a decent blade guard and a useable splitter? And why do low end table saws still not have them? COST Why is the only dust collection on a table saw a 4" hole in the base when 1/4 of the dust comes off the blade. COST

[John TenEyck]

I had an Inca J/P. Great machine made with hard anodized pressure cast Al tables. That coating is incredibly durable but after 25 years of pushing wood over it was worn really thin in some spots. My point is you can put any coating you want on metal but if you run enough material over it it will wear through. The benefits could still outweigh its inevitable demise, however. But apparently, almost no manufacturer thinks it offers a competitive advantage to offer something.

John

[Brian Holcombe]

Manufacturers are still in the mindframe of ‘you’re doing woodwork so why does it need to be flat!?!’ So I can’t imagine this actually moving forward but coatings are not expensive in mass manufacturer so cost is nonsense.

There is a manufacturer of welding tables who has them nitride coated, so it’s possible.

[Ray Newman]

Another issue might be wear marks from the miter gauge and the nylon pads on the fence. Soon leading to complaints about the scratch/wear marks on the anti-rust coating. On my old Uni-saw and now on my SawStop ICS, I can seen where the miter gauge and the nylon fence pad ride/slide on the table.

[Warren Lake]

one thing that fascinates me about cast iron is how cold it gets. Machines in a garage when its really cold are brutal. If i lean on a table top its so damn cold it feels like it burns you, it sucks all the heat out of you in seconds. Ive tested with the Raytek and it always feels way colder than what the meter shows.

[Travis Conner]

Kicking myself for not taking a picture. I was in my local Lowes a few weeks ago and noticed they has a bandsaw and drill press on display, both had cast iron tops that were heavily rusted way beyond repair. Looked like they had been the subject of a salt spray test. I think they may have been Porter Cable. Why they would put them on display was totally beyond my comprehension.

That's because everyone walks by and touches it. I use paste wax and I can wax it once a year. I dont use my tools though so if I'm running wood through them then you Probably have to do it after each use

[johnny means]

I've had a couple of 80s era Centauro saws that actually did have blackened table tops.

[Michael Gantz]

Lots of great comments in this thread. I noticed two important things:

1) Several people remarked that there wasn't much demand and that's why we don't see such a thing, along with price issues.

2) Several people made references to existing/past products that have/had corrosion resistant tables.

I was actually surprised to find out that some of these products exist because I've never seen then before. I'm wondering if some of the demand issues might really be a marketing issue. It doesn't seem to take long to find out about SawStops safety features when looking for table saws. That safety feature is marketed and visible everywhere. But until yesterday I wasn't even aware that saws was rust resistant tables existed.

I definitely learned something in this thread.

[Wes Grass]

Glock's coating is their in-house version of Melonite, salt bath nitriding. Molten salt. Hot. I'd be concerned a cast iron table would warp from it. And then there's no flattening it without removing the coating . They *should* be stress relieved already, but my guess is they really aren't, at least not properly. As already noted ... cost. It takes a lot of energy to heat cast iron to 1000+ deg and hold it there for an hour, minimum. And it has to be cooled in the furnace.

Throwing them outside to sit in the snow and sun for a couple years does nothing.

https://apps.dtic.mil/sti/pdfs/AD0620556.pdf

My Felder bandsaw table is a horseshoe magnet. I can run a piece of steel over it, and it doesn't stick until it gets to the gap for the blade. Stress relieving should have demagnetized it, but it could have picked it back up from grinding. Of course I'm never going to cut steel on it, so ...

And why does every woodworking bandsaw I've seen have an alignment pin to flatten the table out? Likely because the casting wasn't stress relieved, and it's not heavy and stable enough to have the slot cut before grinding the surface. A good metal cutting bandsaw, like a Grob, doesn't have an alignment pin, and the table is flat and stable. Also damn heavy ...

[Alex Zeller]

Most coatings are just that, coatings. They will only last so long before wearing off and the process to apply them aren't always the best for a machined cast iron surface. The process for titanium Nitride is usually PVD or CVD. That involves heating a machined surface that once coated can't be machined again since the thickness of the coating is a tiny fraction of what we woodworkers normally measure the flatness of a surface. Yes it can be done but I suspect that doing it could get pricey depending on the type of coating. In the cast of Harvey it's $560 extra for that coating. Any cast iron that's not coated, say possibly inside the T-slot, would still rust and most likely propagate under the coating. Other materials could be used, say stainless steel or solid ceramics. Other products like granite have been used but never really took off. It comes down to what people will pay for it.

[Mel Fulks]

Interesting story time? This has to be a good one.

Well, it used to be pretty common to nap at lunch time. Especially in the large old two or three story mill-work places. One place I worked
had a large conveyer belt that some used. Once in while it would get turned back on before every was up. I just wish I could convey the
story to you as well as that old rolling magic carpet did .....( copy right 1964)

[Marc Fenneuff]

Kicking myself for not taking a picture. I was in my local Lowes a few weeks ago and noticed they has a bandsaw and drill press on display, both had cast iron tops that were heavily rusted way beyond repair. Looked like they had been the subject of a salt spray test. I think they may have been Porter Cable. Why they would put them on display was totally beyond my comprehension.


I saw the exact same thing last year in my Lowe's (you're in MI too so could've been the same one). Honestly it's depressing looking at stationary power tools (floorstanding or benchtop) at the big box stores. A lot seem to have marginal capability and the displays are not maintained. The powered hand tools though, it's like a bazaar, what with the branded zones for Dewalt, Craftsman, Milwaukee etc.

[Brian Holcombe]

My comments aside, I don’t feel a coating is necessary. Rather I think that the surface prep should be more suitable to the work being done. A planed surface is ideal for most woodworking machines. The surface ground finish, especially a very fine surface ground finish builds a lot of friction.

Surface ground is ok for tools where the part is stationary but pretty much everything else is better off planed.

[Malcolm McLeod]

... if you kept heat of some sort on cast iron. it would do the same thing.

All you have to do is keep the tool's surface temperature above the dew point of the surrounding air. Or, keep the dew point of the air below the tool's surface temperature.

The first requires heat, as you suggest. The second requires de-humidification, generally by cooling the air below the dewpoint.

So everybody needs to install a PLC with an analog input for a thermocouple attached under the T/S top, then another input for the dewpoint. And for outputs, either time-proportional discrete (relay) output to a heater, or an analog output to a variable-rate heater. Then an HMI to view status, and ... errr, wait. Oh, this was about coatings. Never mind.;)

[Andrew Seemann]

Surface ground is ok for tools where the part is stationary but pretty much everything else is better off planed.

Until the customer sees the added cost and the manufacturer the added time of planing, then everyone suddenly is okay with grinding, fly cutting, and end mils:)

[Dave Cav]

Glock's coating is their in-house version of Melonite, salt bath nitriding. Molten salt. Hot. I'd be concerned a cast iron table would warp from it. And then there's no flattening it without removing the coating . They *should* be stress relieved already, but my guess is they really aren't, at least not properly. As already noted ... cost. It takes a lot of energy to heat cast iron to 1000+ deg and hold it there for an hour, minimum. And it has to be cooled in the furnace.


I think this is it. Some years ago I toured the Genie Lift factory in the Seattle area. They had an in-house nitriding line for all of their pivot pins and high wear items. The parts had to be kept in the molten, red hot salt for some time then cooled under controlled conditions. I don't think this would be economical or practical for larger cast iron parts.

[Brian Holcombe]

Until the customer sees the added cost and the manufacturer the added time of planing, then everyone suddenly is okay with grinding, fly cutting, and end mils:)

That’s why you only see it on top end equipment. Fly cutting or a large shell mill is fine, I assume that’s how SCM does it, I like the surface finish on their jointer tables. Usually it’s not so smooth as to become high friction.

[Brian Holcombe]

Dave, check this out:

https://weldingtablesandfixtures.com/blogs/the-welders-blog/what-is-a-plasma-nitrided-welding-table