measuring plywood for bulkheads

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cormorant

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I seem to remember that there was a method for drawing out complicated bulkhead shapes etc onto ply where no pattern exists - except that I don't remember it! Anyone know the best method or can point me to a website please?
thanks!
 
Try this

It's much easier than it appears at first and you'll be most impressed with yourself when you do it. /forums/images/graemlins/wink.gif
 
Cut your ply roughly to shape , measure the biggest gap and cut a bit of wood 5mm bigger than the gap , put a pencil on the top of the wood and let the bottom follow the shape .
If there are still small gaps get a penny washer and put your pencil in the hole and let the washer roll around the shape , a perfect scribe . As said above use cheaper boards if you dont think you can do it first time .
P.S I can sell you a Marine penny washer for £30.00 + postage /forums/images/graemlins/grin.gif
 
As stated above. /forums/images/graemlins/confused.gif /forums/images/graemlins/laugh.gif

PS Those special washers sound great. May I order a couple? Can you guarantee that they really are marine grade? /forums/images/graemlins/laugh.gif
 
Yup if you buy a pack of 100 now i will send you more if they rust . They are for Marine scribing only and not to be used for anything else mind !
 
Yes, but it doesn't say "Marine Grade" on it so it can't be any good for boats! /forums/images/graemlins/smile.gif

I must try and get another Trend catalogue. I haven't seen one for ages. Good stuff. Not cheap.
 
I use the CMT ones from Axminster for production work and they are good quality. I also use the cheaper Dakota ones from Rutlands for some of my less commonly used cutters.

Good cutters aren't cheap but using several cheap ones for a one off job can be cheaper than buying one good one.
 
You guys are obviously professionals but I'm strictly amateur.

When I first got a router I used it, scared myself witless and never touched it for a year! I've used it a lot since then but it's a tool which I respect more than any other! SWMBO is under strict orders, if she comes down to my workshop, to do nothing to distract me when I'm using the router.

When I bought my cutters I got most of them from a company in South Wales (Griffiths?). They imported them from Australia and they were still considerably cheaper than Trend. Good cutters. I don't know if they are still in business.
 
You need a "joggle stick". Ideally 4mm aluminium plate - cut a wedge about 500mm long, and 60mm or so high, but "notch" the long leg with say 10 "teeth", and number these starting at the pointy end. You'll now have something that resembles a very coarse saw, and usefull on smaller bulkheads.
To use, clamp a stout piece of "reference" material (say 19mm thick, but wide enough that it's less than 500 to each point the bulkhead will touch) so that it's on the same plane as the bulkhead will be.
Now lay the joggle stick so that the point touches a point that defines the bulkhead and then use a pencil to trace the body of the stick on the "reference" board. Repeat for a swag of points. Take the reference board, place on the to be cut bulkhead material, and reverse the tracing procedure, laying the joggle stick onto the reference tracings, and mark the point on the bulkhead material. Join up the dots, cut it out, and it will fit like a glove. Sand the reference board to remove the pencil marks, and you're ready for the next one.
 
Joggle stick is the best method for large bulkheads or an old stout cardboard box and cut it to fit and if you over cut anywhere (like notchings etc) you just measure and draw it on the pattern! easy peasy!
 
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