Attaching Pattern Bit Template

[Val Kosmider]

I am making several small tables with a vertical curved/tapered support between the leg and the table top. I have created a pattern for this curve, and have rough cut the pieces on my band saw.

Now it is time to run the pieces through the router using the pattern and a pattern bit to smooth the curve to it's final dimensions (i.e., eliminate the rough edge caused by the band saw blade).

The question is how to attach the pattern to the support while it is going through the router. I have read about toggle clamps, which would require making a sled of sorts. I have also read about using carpet tape to attach the pattern to the top of the support pieces.

Is there a preferred way of doing this? Has anyone had experience, good and bad, with either of these methods? Is there a method which i am not considering?

I am thinking to go with the carpet tape, but the pieces taper along a 22" long curve from about 3" down to 1" and wonder if this gives me enough surface on the narrower end to get a firm hold. Will carpet tape slip at all--sort of the 'oozing' slide from heat and handling, or does it firmly attach with no movement?

Thoughts?

[Erik Christensen]

I have so much scrap plywood under foot in my shop I have never tried the double sided tape route. I also use a shaper, as I do not own a router table, and so I am even more concerned about things staying put while pattern routing. I have a couple of toggle clamps that I keep on the shelf just for this purpose, so all I have to do is - finish the plywood edge with the desired profile, position my rough cut piece, tack a few stop blocks for consistent positioning of multiple parts and then screw down 2 or more toggle clamps.

downside to this method - can only profile one or two sides before you have to re-position the piece and the pattern is on the bottom so the cutter is above and exposed

for what you are doing - a long thin leg - I would go the clamp route vs tape

[Robert LaPlaca]

I have used carpet tape and it has worked fine, BUT.. When I make the templates, I make the template longer than the finished piece for two reasons, one so that I can apply a strip of lumber to the right and left ends of the template that 'traps' the item being pattern routed, so essentially all the carpet tape is doing is keeping the template and the soon to routed piece temporarily laminated together, the strips of wood keep the piece indexed on the template. The second reason to make the template longer is there is somewhere for the template bit bearing to run against before the cutter hits the work piece.. Hope this helps

[Andrew Joiner]

I've used carpet tape for long narrow chair legs about the same size as you're doing. I was surprised how well the tape holds. I tested it first and found It easy to use to much tape. It held so well it tore up my pattern when it was removed. I ultimately used 3-tiny 1"x1" pieces of tape for each tapered leg. One at each end and one in the center. Worked great on 36 legs without destroying the pattern.

YMMV always test first.

[Stephen Cherry]

A sled and toggle clamps are a good way to do it, but you can run out of length on your router bit. I use the double sided tape from woodcraft with a pin router for this type of thing, and it works fine.

Of, you can screw the patturn onto the backside of the part, and remove the screws when done.

Here is a cheap implementation of a pin router:
http://www.amazon.com/MLCS-9061-Woodworking-Daisy-Router/dp/B001S2RAT8

[Bob Lang]

If the backs of the finished parts won't show when the piece is assembled, a few screws through the pattern work well. My preference in the last few years has been double-sided tape, but it needs to be a quality product. They aren't all created equal. FastCaps has some that can make a permanent bond and with good tape dis-assembly can become an issue. If you're buying locally, spend a few extra bucks.

Both the pattern and the work need to be nice and flat, and you'll get a more secure bond between the two if you bang on the parts with a rubber mallet after you connect them.

Bob Lang

[George Gyulatyan]

I always use double-sided tape for pattern routing. One trick is to make sure they hold strongly (and they're surprisingly strong) is to apply further pressure to the parts using wooden clamps. After that the hold is so strong that you may need something like a putty knife to pry them appart.

The other nice thing about using the double-sided tape is that you don't have to worry about adjusting the hold-downs, clamps, etc if you're routing a pattern all around a piece.