Bandsaw Techniques, Templates?

[Timo Christ]

Creekers,
I dreamed up a project which requires sawing a curve in a thick (12") laminated blank and later regluing the sawn surfaces. Do you think this will work without unsightly gaps? The radius is big, about 40". A veneer layer with the thickness of the kerf could be used to eliminate this problem..

I'm wondering if someone has experience with the Veritas Bandsaw Duplicator, it is a little guide pin attached to the upper blade guide.
In the Bandsaw Book by Lonnie Bird he shows another template technique with a stick to guide the saw, clamped to the table above the workpiece. This is shown in the link below:
http://www.woodcraft.com/articles.aspx?articleid=410

As my workpiece is thick, i would prefer having the template below the piece, on the table. I think Mr. Bird's method would be easily adaptable, and the Veritas jig could also be adapted. How about fastening a pin on the zero clearance insert. Provided the ZCI can be fixed at the same position, a higher
repeatability would result vs. the clamped stick. Could a rare earth magnet be used? IOW is cast iron magnetic?

I don't have the bandsaw yet, so i can't just try it out now :( .

The search function didn't turn up much for bandsawing with templates, so i'm hoping for some feedback from experienced creekers :o Thanks!!

Regards,
Timo

[Ian Barley]

Timo

I have tried using templates with the bandsaw before and have never had any degree of success. I suspect that it can be done but if your need is for a simple radius rather than a collection of curves you would probably be better off to construct a swinging arm jig of some sort.

Tell us a bit more about what it is that you are trying to achieve and there may be some other (better) ideas from the bright folks here.

[Doug Shepard]

I think I understand what you're trying to do. LIke Ian, I think a trammel arm setup might work better if it's just a simple arc. Assuming it's a simple arc, I also think you'd get better results using a router mounted on a trammel arm. You could rough cut to a line first with a bandsaw or even jigsaw to make the routing easier. I think what you're describing is pretty similar to cutting male and female bending forms for making bent laminations. Except in your case the thickness of the lamination between the forms is 0". Cutting the 12" thickness is going to pose a problem regardless of whether you do it on a bandsaw or a router. Can you cut the shapes before laminating or is this something that's already glued up? If you can put a couple of small holes in each piece for alignment pins (brass rod or dowels) it should be pretty easy to get all the layers cut to the same shape then lined up for gluing the laminations.

[Mike Cutler]

Timo.
Depending on how close the tolerance need to be, it is achievable.
I think that it would require 2 seperate templates and guides. One on the top and one on the bottom to keep the blade perpindicular.
I do believe that you will end up with some form of a transition piece during the glue up process in the space that was the kerf of the blade though. Some pretty fine work can be done on a bandsaw but that may be asking too much.
This cut will also require a pretty powerful bandsaw, and some form of an adapted table to give you more work area. It sounds like an interesting concept though. Let us know more, we may be able to tryout the technique for you and isolate the shortcomings.

[Timo Christ]

Thanks for the help guys.
I think a guide on top and bottom would be hard to align..

The attached sketch shows what the piece looks like from the top. All the black lines are bandsaw cuts. The piece is 12" thick. The curved cuts have to be re-joined to the center piece later.
There is one simple arc cut, but this isn't the hard one anyway.
The idea of cutting and reglueing was born because i want to avoid minor inaccuracies from screwing up the glue joint later, as could happen with lots of separately routed parts which are then assembled.
The bandsaw will be > 3HP and probably 20" (not purchased yet).