Replies

1. 
   Badnewsz | Nov 16, 2019 12:16am | #1

   How do you do multiple passes with large router bits with guide bearings on a router bit? I am new to your forum and router technique. I am using a table and fence, but not familiar with how to do incremental cuts with bearings, and fence, without creating a hazard. Not much info on the net. I can try the whole cut but it is not a good idea for the bit or router. The bit is 1/2 inch with 1/2 inch shank.
   Many many thanks

2. 
   rob_ss | Nov 16, 2019 03:16am | #2

   Wise to ask advice. For all table saws get a lot of press, routers are potentially far more dangerous.

   It is not clear exactly what you are asking but I suspect you are using a half inch bit for flush-trimming. Half inch is not a large bit - they get way bigger than that! If you are following a pattern, then don't try to cut in multiple passes. Instead trim the piece as close as you can with a saw before you rout. You will get finer results if you are cutting off no more than 2mm (fat 16th) as trying to cut larger pieces will often result in splintering, especially in lighter woods. I had a bit of trouble with this using cedar to make the FWW adirondack chairs. The solution was a very accurate band saw cut first.

   The following may also be helpful:

   Generally, large bearing-guided bits are intended to be used in heavy duty routers mounted in tables, on larger work-pieces. They will often manage the job in a single pass if the machine is appropriately set up.

   You can of course use the fence to expose only part of the bit at a time, which will make the job easier if your router is under-powered. Just use an offcut of MDF clamped to your fence - cut out a slot that is just big enough to accept your bit. You can then keep uncovering more of the bit until the full depth is achieved. With some jobs you can also rise and lower the bit, though this can make it difficult to take advantage of the bearing.

   Try a test-piece first to make sure that your bearing has something to ride against.

   For safety - ALWAYS feed the work from right to left, pushing against the rotation of the bit, never with it.

   Keep the work-piece as large as you can for as long as you can. If you are cutting a profile on a moulding, rout the profile into the edge of a large board, then trim the moulding piece off, rather than trying to shape a smaller piece.

   Use guards where you have them.

   Feather boards are fabulous inventions - them ensure correct stock direction and a perfect position against the bit. Use them whenever you can. These can keep the work pressed down to the table as well as against the fence.

   If following a pattern, try to trim as close as you can before routing.

   Wear a dust mask, hearing protection and eye protection.

   Watch Bob Van Dyke's excellent series on FWW...

   https://www.finewoodworking.com/videoworkshop/2018/09/router-table-fundamentals-bob-van-dyke

   One other option is open to you - many router bit sets come with several different sized bearings. They are interchangeable. It is possible to swap the bearings round to achieve the same result as the fence moving, albeit on a fairly small scale.

3. 
   Badnewsz | Nov 16, 2019 07:35am | #3

   Many thanks, Rob I am using a triton in the table with a veritas fence . The bits I use are 1/2 shank bits. I was confused in that if I were to move the fence back away from the piece (wood) to expose more of the bit, which has a bearing it was unsafe because the router would grab the wood and take off!. If I attempt to route the piece on one pass with the bearing ( a 1/2 inch cut ) it would be to much for the bit and router. Many thanks for your quick reply. I will check out the recommended the video.

4. 
   geedubbee | Nov 16, 2019 01:56pm | #4

   First a terminology agreement, at least for the duration of this conversation. The width of the rabbet is the dimension across the face of the material from the edge. The depth of the rabbet is the dimension into that face. Others use different terms but, just to make the following make sense . . . bear with me.

   If I am using the bearing as the reference for my final width I will start with a full width cut 1/16" deep. I will then raise the router 1/6" to 1/8" at a time to reach full depth.

   If I am using the fence as the reference for my final width as in the case of a non-bearing guided bit, I will cut a full depth 1/16" wide initial cut. I then step the fence back in 1/16" to 18" steps to reach my final width.

   In each of the scenarios there are times when a whisper of a starting and ending pass can yield cleaner results. My .02.