I cut a 12" disc with my BS, leaving the finished cut about 1/8" to slightly under 1/4" oversized. I was not worried about the acuracy as I would be trimming the disc down with the MFS template and straight bit chucked into my OF 1000. I have done this before using a plastic circle guide mounted to bottom of one of my PC routers with a pin for center point. I never had a problem.
Yesterday, i decided to leave the PC where it is doing very well at collecting lots of dust. Every bit of dust that lands on it is one less grain of dust going thru my Delta air cleaner
Besides, i wanted to try the circle cutting process with my MFS
Anyhow, i set up the MFS with that circle cutting guide mounted exactly where i wanted it located. I was going to cut about 1/4" depth all around the perimeter and flip the disc so I could finish off the oposite side useing a bottom bearing pattern bit. To go any deeper, i would not clear the bench dogs and clamping element as I trimmed the disc.
I made one complete 360? pass with no problems. I decided to make a second pass to clean up the fuzzy edge left with the first cut. (I do this all the time when i trim with my WoodRat and even when straight cutting with the MFS and/or MFT with guide plate and either OF 1000 or 1400. Never had a problem.
This time, as I made the second trip around, I suddenly noticed the bit had traveled inside the original arc just a tad. At about the instant I noticed the problem, the bit took off towards the center of the piece. now is where I really got stupid. Insted of shutting off router and waiting for it to quit (the damage had already been done to the wood) I shut the router off and without waiting, just picked it up out of the circle guide. there was like a minor explosion.
The MFS jumped, the router jumped and a corner of the MFS parted not quite a mm. not damage to the template, but that circle guide looks like it has been attacked with a wood rasp, coarse grade.
NOTE: The festool bit was not even scratched.
What i determined to have happened is that the circle guide had come loose. As it came loose, even tho contained by the MFS template, it wandered inside of the first cut. Before the router had stopped, I, evidently withot thinking, picked the router up out of the cut. Instead of coming stright up in the air as I cleared the circle guide, i must have moved sidewise a little. The corners of the bit tore into the guide and tried to move all out of the way. The MFS parted a little at one of the corners and scooted an inch or so away from me. With only a 16mm bit, there was not enough force generated to sent things flying, but enough to create a lot of surprise.
The MFS corner that came apart is not damaged. The circle guide is pretty scarred up but the bit still looks like brand new. I found out that "snug" is not enough to hold the circle guide in place. It must be TIGHT.
Before going back to trimming the disc with the router/MFS setup, I decided to just setup with the Bandsaw and make a precision cut and then sand the edge all around. I could not find the centering pin I use for Bandsawing of circles (A temporary victim of shop reoganization) I just put the MFS to use. The hole was already in the disc to accept the 8mm centering pin that was already mounted in the MFS. I finished so quick, i will probably use BS & MFS method many more times.
The wood disc (a lazy susan) was just redesigned to be a little thinner than originally planned. I did not even have to set it aside for another project. That is the first time i have made that sort of mistook in quite awhile. i guess it was just to keep me humble ???
Tinker
Yesterday, i decided to leave the PC where it is doing very well at collecting lots of dust. Every bit of dust that lands on it is one less grain of dust going thru my Delta air cleaner
Besides, i wanted to try the circle cutting process with my MFSAnyhow, i set up the MFS with that circle cutting guide mounted exactly where i wanted it located. I was going to cut about 1/4" depth all around the perimeter and flip the disc so I could finish off the oposite side useing a bottom bearing pattern bit. To go any deeper, i would not clear the bench dogs and clamping element as I trimmed the disc.
I made one complete 360? pass with no problems. I decided to make a second pass to clean up the fuzzy edge left with the first cut. (I do this all the time when i trim with my WoodRat and even when straight cutting with the MFS and/or MFT with guide plate and either OF 1000 or 1400. Never had a problem.
This time, as I made the second trip around, I suddenly noticed the bit had traveled inside the original arc just a tad. At about the instant I noticed the problem, the bit took off towards the center of the piece. now is where I really got stupid. Insted of shutting off router and waiting for it to quit (the damage had already been done to the wood) I shut the router off and without waiting, just picked it up out of the circle guide. there was like a minor explosion.
The MFS jumped, the router jumped and a corner of the MFS parted not quite a mm. not damage to the template, but that circle guide looks like it has been attacked with a wood rasp, coarse grade.
NOTE: The festool bit was not even scratched.
What i determined to have happened is that the circle guide had come loose. As it came loose, even tho contained by the MFS template, it wandered inside of the first cut. Before the router had stopped, I, evidently withot thinking, picked the router up out of the cut. Instead of coming stright up in the air as I cleared the circle guide, i must have moved sidewise a little. The corners of the bit tore into the guide and tried to move all out of the way. The MFS parted a little at one of the corners and scooted an inch or so away from me. With only a 16mm bit, there was not enough force generated to sent things flying, but enough to create a lot of surprise.
The MFS corner that came apart is not damaged. The circle guide is pretty scarred up but the bit still looks like brand new. I found out that "snug" is not enough to hold the circle guide in place. It must be TIGHT.
Before going back to trimming the disc with the router/MFS setup, I decided to just setup with the Bandsaw and make a precision cut and then sand the edge all around. I could not find the centering pin I use for Bandsawing of circles (A temporary victim of shop reoganization) I just put the MFS to use. The hole was already in the disc to accept the 8mm centering pin that was already mounted in the MFS. I finished so quick, i will probably use BS & MFS method many more times.
The wood disc (a lazy susan) was just redesigned to be a little thinner than originally planned. I did not even have to set it aside for another project. That is the first time i have made that sort of mistook in quite awhile. i guess it was just to keep me humble ???
Tinker
