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[F4TCT]

Hi folks,

I'm currently building a Whitby coble from birch ply. Obviously the real ones had ribs installed last but I am breaking convention by pre notching the ribs (made from 4mm birch ply), first so they act as a jig/strong back and become an integral part of the build from the start. The planks will be 2mm birch ply, all sourced from SLEC ltd. The ribs were previously water jetted out from CAD drawings but were slightly incorrect. I am now in the process of renotching the ribs and form new planks as I go.

Now this is where my problem lies, the first plank off the stem is perfectly straight, the second is slightly bent and the third more so and so on... Now the planks are differing widths and my issue is how to cut the ply perfectly to the desired thickness. I don't have a band saw and my usual method is to roughly cut the planks out with a knife and then file to shape.

I need a better way of doing things as the odd 0.5mm here and there seems to exaggerate itself later on. The issue is the old question - do you cut before, on or after the black line. I do have a pair of digital calipers which I though I could set the width and score the sharp bit along the wood to be cut. I'm dead set on accuracy as I'm trying to eventually produce proper plans and possibly a kit.

And help and tips would be gratefully accepted.

Dan

[yorkiej]

Try making your planks out of good quality thin card first. Cut the card planks to fit and then draw around them on your ply.
Up to A2 good quality card is available from art shops. Huge sizes are available from printers.
Card can be cut cleanly with a good pair of scissors and is much cheaper than ply.
I've done this before. Its much cheaper. With your digital calipers, you can spile your frame landings onto a grid drawn on the card and get very close to where you want to be before wasting your ply.
Hope this helps.
Good luck
John

[F4TCT]

Hey John,

To a certain extent, I have been doing that. The card I used was from hobby craft and seems to work well.

I managed to create a perfect first plank yesterday, second one will be done today

Thanks

Dan

[Norseman]

Got a photo Dan? ........ the Coble not the plank 

Dave