Planer Core Profile design

[ggardner90]

i have been searching this forum and reading alot of posts but i have one very basic question about using a planer to profile your cores. i saw the article on building the crib but it was only one sided so you would have to flip your core around to plane both tip and tail. i am wondering if there is any way to make one that is taller on both ends and short in the middle to accommodate the thick section underfoot. is this possible????

thanks

[MontuckyMadman]

http://www.skibuilders.com/phpBB2/viewt ... light=on3p

did you read this thread?

[ggardner90]

Yes I read that post which is why i have the question. i am just confused on who to design it because the concept does not make sense to me. if you have the crib with tip and tail i dont see how it could work. so maybe if someone could explain that to me it would all make sense.

Also how do you ensure that the core is flat on both sides not just parallel without the use of a jointer or a second adjustable planer jig to create the first side flat and not parallel

THanks

[twizzstyle]

It's hard to visualize core profiling with a planer until you just do it.

We have an adjustable crib that uses spacer blocks every 6" or so to set the height. You can also get a crib board CNC'd to the profile you want (I have one of these). Basically the crib (whether adjustable or CNC'd) is an upside inverse of the profile shape. Highest on the ends, lowest near the middle (or wherever your thickest part of your core is).

As the crib/core blank go through the planer, the planer rollers push the core down into the crib shape. You are effectively cutting a flat plate on a bent core blank (bent by the planer rollers). Such that when it relaxes, that "flat" face the planer cut becomes the profiled top surface of your core. It just works, and is the best method for DIY builders for accuracy and repeatability in core profiling.

If you're using plastic sidewalls it can be damn near impossible to keep the planer from ripping your sidewalls off and munching them to death though

[ggardner90]

how do you suggest installing the sidewalls if i am going to use the planer crib.

[vinman]

I disagree on the the plastic sidewall part. I was able to profile the core with sidewalls attached in the planer and they came out great. No snipe or chewed up sidewalls. Granted you must have good adhesion of the sidewall, sharp planer blades and your infeed table set up so there is no snipe.

If you do profile your sidewalls with the planer be sure to sand and flame them after to ensure proper bonding.

The idea of the planer crib is the planer will cut to a set height no matter what right... So by having a jig that is low in the middle, the planer will shave the tip and tail and leave the material in the waist of the ski thick. This is tough to imagine but the roller feed on the planer keeps the core pushed down on the crib to make this possible.