Replacing cast Iron Planer bed

[Clarence Martin]

From a purely rust preventative design, I can't see why the manufacturers have not switched to all aluminum planer beds . So the idea came to me!! I checked out the price on Aluminum flat stock of the same width and thickness as is on my Jet 13 inch Planer Moulder with the cast iron bed . The price is not that bad. So, why haven't they switched out the cast iron for aluminum ?

[Mark Wooden]

Aluminum is too soft for a planer bed ; it will wear un-evenly and not plane to the same dimension one side to another. Being soft, it won't feed as well as cast iron. Aluminum will also leave black marks from oxidation on the stock unless cleaned constantly- which will wear the bed too.

Best is to clean your cast iron bed well and protect it with a coat of paste wax periodically. If you just can't stand doing that, screw a piece of stainless steel to it

[Jim Andrew]

Simpler way to stop rust than replacing the table would be to use some spar urethane on it. I tried some on my tire machine as the tires I repair often are wet. The CI top was rusty after about the first week. So I cleaned it up and tried some spar urethane, Varathane brand. Worked like a charm. Just one thin coat, much tougher than wax.

[Judson Green]

I think aluminum can leave black marks on wood, probably not big deal if you're gonna sand or whatever. But you're not alone thinking of using aluminum for machine tables; google "Barton machines jointer".

http://www.sawmillcreek.org/showthread.php?87996-Aluminum-Black-Marks

[johnny means]

Clarence, machinery surfaces are subject to a lot of abrasion, after only 5 years my cast iron tablesaw top is already showing grooving in the area closest to the blade. Aluminum would have yielded an unusable surface already.

[Loren Woirhaye]

Some lighter European machines have anodized aluminum tables. I have a little Kity 5" benchtop jointer/planer with an anodized planer table. It's really meant for hobby use but for me it' an installation tool.

You can lay phenolic over the planer bed if you like. It will wear pretty well and I don't think it will mark the wood the way unanodized aluminum will.

[John Downey]

Why so much worry about rust? It will take far longer to develop serious pitting from atmospheric moisture than to wear out an aluminum bed under normal use. Brush off the rust before use and wax it if you feel so inclined. I have an old jointer with fairly deep pitting (left in the rain at some point in it's life) and it doesn't affect use at all.

Add to that, aluminum is less stable than cast iron (at least properly seasoned cast iron), and most alloys are more flexible than cast iron. I would imagine that you would need at least +1/3 in thickness to get close to the rigidity of cast iron, perhaps more.

[John Sanford]

One more consideration, vibration dampening/absorption. Aluminum, having less mass, won't absorb the vibration as well as a comparably sized cast iron bed.

[Clarence Martin]

Well, it looks like I got bigger problems than just plain old rust on the bed. The crank handle to raise and lower the bed is stiff as a board. been about 3 years since I used the machine and it has been sitting in the basement. Looks like a lot of crud piled up in the threads on the rod that raises and lowers the bed.

[Loren Woirhaye]

You can soak the threads with a degreaser like WD-40. I've taken to using mineral spirits brushed on with a glue brush. I acquired a sander loaded with metal dust and cleaned it that way. I also used mineral spirits in a spray bottle. A brass or nylon brush can be used to excavate grime from threads. After they're clean, put some oil in there and try to get the table moving.

[Jim Andrew]

The hydraulic oil used in tractor transmissions absorbs water. I use it to soak frozen threads, because it works. Let it soak overnight.