Bandsaw - why a ribbed /corrugated top?

[Rich Tesoroni]

Didn't have time to play with the tracking I asked about in the other thread, but why is the top of the table ribbed?

http://img.photobucket.com/albums/v15/richtes/Centaurotable.jpg

I assume this is to reduce contact area like on a handplane.

Just curious,
Rich

[Bill Houghton]

probably to "reduce friction," although it doesn't actually, it just localizes it; or to give sawdust somewhere to go besides under the workpiece.

[Bruce Page]

Sure it reduces friction, that is why a lot of the higher end wood working machinery is made that way. I read a article awhile ago that said the ribbed surfaces were as flat and true as the ground surfaces, with a fraction of the drag resistance.

What kind of BS is it?

[Rich Tesoroni]

Centauro 600 (24") steel frame.

Rich

[Dan Forman]

I'm pretty sure that the ribbed table of my little benchtop Rikon 10" bandsaw was designed just to make my life miserable. It seems edges are forever getting stuck in the grooves in the middle of tight turns, just enough to take me well off the line.

Edit: Ooops, I went back to look, and your's aren't anything like the squared grooves in my table.

Dan

[Frank Drew]

The cast portion of my Ulmia table saw top looked exactly like that. I never had any problems with drag so I'll assume the friction was reduced.

[Barry Vabeach]

Rich, I am not sure, but from your picture, the table looks a lot like the jointer table on the Jet JJP-12 combo - I understand it is a different method of flattening the table ( not Blanchard ground ) I don't know whether it is designed to reduce friction or is just a product of that method of grinding.

[Simon Dupay]

It's from planing the table on a metal planer, it's a slower way of surfacing the table but it's more accurate because there's less heat. A lot of old and euro machines where/are planed.

[Jim Becker]

Most "non flat and shiny" grinds on cast iron tool tables assist with the workpiece gliding smoothly with out sticking. Try to push a wide board through a wide jointer sometime for that "last pass" when the board is essentially in a "vacuum" relationship to the table!

[Anthony Whitesell]

My father had an old (cheaper) model scroll saw with an aluminum table. He was getting black stains on his work pieces (the aluminum rubbing off, same thing happens with their router table). He sanded away the "grooves" on the table and found it was so smooth that the vibration of the scroll saw caused an air hockey table effect and the piece floated so smoothly and frictionless that he couldn't control the workpiece. He ended up epoxying a piece of formica to the table to prevent the aluminum stains. The family bought him a 18 or 20" VS Dewalt for Christmas a few years back.

P.S. Jim,: That's how I can tell when I'm done jointing. When I try to pick the piece of the table and it's "stuck" there due to the suction, I'm done.

[Pete Bradley]

I find that about 60 years of use gets a cast iron table to just the right surface finish. :D

Pete