Speed of cut is 20in/min. Downcut bit. 13,000 rpm on the Ridgid router. The chains slack out on one side and the whole sled jumps. I cannot figure out why this is happening! It’s a 4x8 sheet of 3/4" maple which wasn’t cheap.
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if the chains go slack and the sled jumps, then it is sticking. One of two
things cause this
-
the machine is tilted too far from vertical (10-15 degrees is good, 20
degrees is known to be a problem) -
the bottom of the sled is not slick enough, try to sand it, or wax it to
make it slicker
David Lang
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Thank you David! I was wondering about the sled itself not being slick enough since the bit is brand new and shouldn’t be causing this problem. I’ll check that tomorrow!
I think I might have the chains not parallel to the work surface as well, they looked out of wack but I didn’t want to try to change it on the fly.
chains not parallel to the workpiece can cause them to jump a tooth (or in the
worst case, fall free entirely) but not cause the sticking/jumping you describe
and the cuts show.
David Lang
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Okay, so its definitely the sled sticking. It was happening in the center of the sheet but the cuts were straight and not affected by the hopping/sticking.
How deep are you cutting with each pass?
Cutting at 1/4" depth per pass. It doesn’t seem like the bit/sled can’t keep up with the speed/movement but this is the first time I’ve had this problem so I’m also now wondering if cutting Maple at 20In/min is too fast, plus the sled sticking and causing the horrible jumps.
My guess is that it’s a combination of the bit and the wood and the speed. I would try a really shallow depth of cut like 1/16th and see how that goes. Most bits are happiest cutting less than 1/2 of their diameter so a 1/4 inch bit usually likes 1/8th or less passes.
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too deep a depth of cut can cause the cut to wander, but not to have the sled
jump, so it’s important to watch what happens in the bad cut area.
David Lang
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I think it was the cut depth that was doing it. Thinking back, the sled was being held up by the bit which would explain the chain slack and the jumping, not the sled sticking.
Last night I left the speed at 20, and reduced the pass depth to 1/8" and the cuts were super clean.
Greatly appreciate you and @dlang’s help! Thank you very much to the both of you!
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Is the chain ring up too high? is the sled lifting on the lower side as it tries to cut upwards? I’ve had mine set too high and the sled would do weird meanderings as it moved upwards because the chain was effectively tilting the sled rather than pulling it upwards. Chain ring too low and the top of the sled will lift off as it moves.
A down cut spiral bit will climb out of the cut if the depth of cut or travel speed exceeds the ability of the bit to clear a chip