Workholding options for Routing tasks

[Mr Big]

Hi All,

I'm in the process of building a wooden Kayak (I've got a thread going in the wooden boat section) and have a minor issue to solve and was hoping I could get some feedback before my next time in the shop.

The issue: I've rough cut some templates in 19mm ply with a jigsaw, and given my previous experience with a jigsaw I left about 4mm of space between the actual line and the sawcut. It seems that this may have been a bit of a mistake as the blade drift for the cuts was almost non - existant (must be my technique getting better), this leaves me to reove the 4mm of excess from 18 seperate forms. Now I do have access to a belt/disc sander combo machine that I can use to clean up the cuts, but 4mm on all of the forms is alot of sanding, I was hoping to cut down on some time and sandpaper by routing down to around 1mm away from the line.

Potential solution: What I was thinking of doing was using a straight bit to take a shallow cut of around 4mm deep freehand to get close to the line and then coming back with a flush trim bit to cut through the rest of the thickness.

So firstly, does this seem like a reasonably sound approach? and would I be better off using my trim router or full size router for the initial and flush trim cuts?

Finally the crux of the problem is around workholding. the template forms I'm working on vary in size from about 50x150mm to 600x350mm. my current workholding options are, bench cookies, holdfasts, clamp to bench with f clamps. Given what I'm trying to achieve, which one is going to work best? and are the bench cookies enough on their own?

Thanks in advance for any input.

[Handyjack]

You may struggle to control the router to do what you want with your initial trim. The smaller items might be too small to clamp and then rout, the bigger items will not be a problem.

If possible consider using a scroll saw. Will be able to handle small items, and possibly you biggest ones. Can give accurate cuts with slow work and the correct sharp blade.

[Skew ChiDAMN!!]

+1 for scrollsaw or a fine blade in a bandsaw. :2tsup:

They're only templates, yes?

The smaller ones could be screwed/glued to, say, a pine stud offcut and the offcut held in a vise or clamped to the bench... you could also fasten other scrap pieces "around it" to give more support to the router platen. They don't have to be physically attached to the workpiece, so long as everything is fastened down tight relative to each other.

Me, I'd use a belt-sander/linisher to sand any curved sections down to the line then use a fence for guiding the straight cuts... but I suspect you don't have (m)any curves to do?

(If gluing, I suggest layering some brown paper (as from a brown paper lunch bag) in the joint. This makes it easy to separate later with a sharp knife and a few gentle taps. :wink:)

[Mr Big]

Thanks for the replys so far, it sounds like screwing the template to a backer is a good way to go for the smaller pieces and the bigger ones will be fine my themselves. And while a scrollsaw or bandsaw would be nice, they are not really an option as I don't own one or have acces to them easily, so I'll give the routing option a shot on a few pieces and see how I go.

Skew,

As for the templates they are almost entirely curved surfaces as it's for a strip kayak that doesn't tend to have to many straight lines.

I would still apreciate any feedback that people have on the bench cookies as a workholding option for routing tasks over other clamping options.

Cheers

[Mr Big]

So I tried the freehand routing option and it didn't seem to go very well, it was to difficult to get consistent results. I've decide to go back to the sanding option to bring things down to the line.

What I did find is that the bench cookies seem to work really well, at least for trim routing tasks, no issues with the work piece slipping.