Machining Surfboards

[daniel]

Hey Guys, I'm trying to figure out the best way to line up a surfboard blank for machining. My concern is that it will not line up perfectly when I flip it to cut the other side. Somehow I need my reference marks to be at the front and rear of the stringer. I also need to figure out how to hold the board.

I have seen one or two low resolution pictures of the suction cups others have used. I was hoping to get some better pics and info.

I have been approached by a local surfshop owner that would like me to shape boards on the machine, so any information or resources would be greatly appreciated! Thanks

[chris_booth]

As far as 2D is concerned (flat-faced parts that will rest easily on the spoilboard when flipped) this topic is covered in several threads - search the forum for "registration" and the results are either talking about jamborees or the advice you need. Your "reference marks" or registration holes could be as few as 2, one at each end in line with the stringer, but e.g. 4 is perhaps better.

A number of similar techniques are detailed in a thread titled "Machining the "flip" side of a panel".

That advice should sort you out for position and orientation, but not for the fact that if you machine the whole surface of a surfboard then its no longer flat and so when you flip it over even with registration holes it will not sit in a way thats stable and flat as required to machine the other side - its 3D.

You need to plan-in extra support under the surfboard for after the flip.

One way is to leave a number of strategically positioned "flats" on the first side you machine - these would be small areas you don't actually machine off but leave there on purpose to provide support when you flip the part and which you later remove by other techniques (cutting them off and sanding).

Another way - and this technique lets you machine the whole of both sides - is to choose the areas you want to support after the flip, and make a "jig" that consists of a flat-bottomed support with an upper surface that is a "negative" of the surface you'll be making. 2 or 3 such jigs (although the more the better)will cradle the machined side in a stable manner if they're positioned and designed sensibly.

If you combine your registration holes and your clamping strategy with jigs based on these principles you'll make the task considerably easier and more reliable.

I wouldn't plan to use suction cups for hold-down of non-flat stuff. I'd start with a blank that's been surfaced by the ShopBot.