Cedar

[erik_f]

Ok, so I should know some of this stuff, but I work with MDF all day long and haven't had to work with "real" wood in a long time. I have a customer that needs some sign blanks cut out...cross section wise they will look like a slab cut from a tree with the bark still on it...and then on the inside there will be an oval pocket hogged out...he wants it done out of 7/8" cedar...I've figured out that I want to use vertical grain cedar...even though I'm not sure what vertical grain cedar is or why I should use it...what is vertical grain as to flat grain...and why is one better than the other? Will I be able to cut these blanks without splintering...this is my major concern. Thanks

Erik

[gerald_d]

Link

[bjenkins]

Erik,

Gerald answered your question, but I just have to point out that by definition if you really take a cross-section of a tree you get both vertical and flat and all the gradients between. Do you mean you are actually using a slab with the bark on? Or do you mean that you are going to cut a simulated shape that is actually made of glued up vertical grain?

[erik_f]

it is going to be made from a board then the outside will be cut to look like a cross section...


Erik

[bjenkins]

Erik,

Good. Your sign will be much more likely to survive. If you pay attention to the way you glue up good vertical grain stock you can really minimize cupping and warping. Flat grain is notoriously prone to these problems.

[erik_f]

thanks...the learning never ends around here!!!

[ron brown]

Wood shrinks more in the "flat" grain than the "vertical" grain. Vertical grain material is more dimensionally stable and warps less than "flat sawn" material. My first attempt would be to use a "climb" cut. I might take the bulk off in two or three passes then make a "clean-up" pass of ~0.050" or so if a climb cut dodn't do it as smooth as I wanted.

Ron

[beacon14]

Sharp cutters, and slower feed speeds than you are probably used to for MDF. I second Ron's suggestion of roughing cuts and a light clean up cut. I've also had good results using a small cutter to "trace" the outline of a pocketing cut, then you can take the waste out a little faster without worrying about tearing out grain past the outline.
Did I mention sharp cutters?

[erik_f]

I tried a scrap piece for the signs and was able to run the file with no problems...I ran 2 passes to cut and a single pass for the pocket...no chipping or tearing...I ran everything at 13,000 rpms on the PC and 1.5" per/sec on pocketing and cutting...maybe beginners luck...but it was pretty easy. And I did make sure I had a nice sharp cutter in. Thanks guys.

Erik