I just routed out the slot for a fins unlimited type box and found that the router bit seemed to bite the stringer very hard (even though it was sharp and i tried to plunge the router quite slowly). I kept thinking, as i tried not to shatter the stringer, that some sort of “burr” cut bit rather than blade would have been better. Any advice on the proper bit?
Thanks folks
I have always used a 1/2" or 1/4" double fluted straight shafted bit,on a standard router(non-plunge).
Here’s a tip…mine are carbide.
H
I only use the plunge function to set the depth and let me take off a little at a time not that whole depth of the bit in one go.
The ONLY type of bit I’ve used is a 3/8 inch, double fluted, CARBIDE bit. Many shallow cuts, moving slowly, produce a very clean result.
Mitchell, The key word you used was “bite” the stringer. That tells me that you are probably cutting along the side of the stringer instead of coming down on top of it. You’ll grab the grain, which is not always running in the ideal direction. If you grab enough of the stringer with grain going in the wrong direction, the router will jump sideways like somebody kicked it.
It will help the operation immensely if you make the first pass with the router down the middle of the slot, directly on top of the stringer. Go slow and easy, taking off no deeper than 1/16" to 1/8" on the pass. After that, the cut into the foam will be a snap. I assume you are using a router template with a pattern-cutting bit. (bearing on top) For the foam cutting, the bearing will run along the inside of the template, making a perfect slot.
The bit I use is a 1/2" diameter carbide, with a 1" tall two-fluted cutter. Because the cutter is 1" tall, I have to free-hand the cut at first; staying in the middle of the slot, concentrating on the stringer only. Once the cut is deep enough so the bearing will run on the template, I cut the sides which is all foam anyway, and easy to remove. The cutter height will give me a 1" deep slot, or slightly more: just right for a center box.
The whole operation from clamping the template to blow out with compressed air takes about 2 minutes.
Doug
I made a jig that the whole router fits into rather using the bits with the bearings. It works with our router using a 1/2" straight bit.
I found that sometimes when I use the bearing type bits you have to be careful or the router blade can go a little too high and cut into the template.
Our jig has tabs that we can use to hold it onto the board. Our friend has one that has a piece that runs under the board and it clamps the jig in place.
I use 3/8" redwood for stringers when I make a board with a stringer. I haven’t had many problems cutting the slot, but you do have to go slowly over the wood.
Very helpful Doug…yes as i was cutting the slot i frequently strayed into the foam and then came back to the stringer from the side…not vertically. So are you saying to cut the stringer down completely to the full 1" slot depth with many 1/16" - 1/8" passes before moving off into the foam?
By the way, my jig is like shark country’s…the entire router is down inside the jig. so the router plate is sliding on the board the entire time…its a plunge router, so i lower the bit down as i cut by slowly plunging it.
Mitchell, The key word you used was “bite” the stringer. That tells me that you are probably cutting along the side of the stringer instead of coming down on top of it. You’ll grab the grain, which is not always running in the ideal direction. If you grab enough of the stringer with grain going in the wrong direction, the router will jump sideways like somebody kicked it.
It will help the operation immensely if you make the first pass with the router down the middle of the slot, directly on top of the stringer. Go slow and easy, taking off no deeper than 1/16" to 1/8" on the pass. After that, the cut into the foam will be a snap. I assume you are using a router template with a pattern-cutting bit. (bearing on top) For the foam cutting, the bearing will run along the inside of the template, making a perfect slot.
The bit I use is a 1/2" diameter carbide, with a 1" tall two-fluted cutter. Because the cutter is 1" tall, I have to free-hand the cut at first; staying in the middle of the slot, concentrating on the stringer only. Once the cut is deep enough so the bearing will run on the template, I cut the sides which is all foam anyway, and easy to remove. The cutter height will give me a 1" deep slot, or slightly more: just right for a center box.
The whole operation from clamping the template to blow out with compressed air takes about 2 minutes.
Doug
Mitchell,
The type of template you use is a good one. Either one will work fine.
To answer your question: Yes, I do cut the stringer fairly deep before cutting the sides. It’s almost as if the sides take care of themselves after the center is cut out. Once or twice around the outside and the foam cleans up easily.
Everyone will find their own best way to do it within certain working procedures. I think the most important part of the process, besides having a sharp router bit, is the use of a template to insure a clean, exact slot for the box.
Doug