Jacob Reverb
05-23-2019, 11:09 AM
Hey, all,
Getting a strange phenomenon on my table saw, wondering if anyone else has seen this and might be able to suggest possible causes.
Several years back, I bought several 10" Irwin Marathon carbide 24T ripping blades (package labeled #14233, blade labeled #24233) at Lowe's because they were so cheap (I'm a sucker for bargains) and because I often use TS for rough/construction grade jobs.
https://i.ibb.co/XzbJtMy/IMG-3079.jpg
Anyway, when I use these blades for ripping 1" SYP or even 7/16" plywood, the blade seems to suddenly develop a wobble or chatter, almost like a percussionist's cymbal, and it makes a lot of noise when this happens (a growly SHHHHH sound like a cymbal makes), and the kerf widens by probably 50%.
This wobble or shimmy or whatever it is seems to be tied to both workpiece hardness and feed rate. Sometimes it does it when going through a knot, and sometimes it does it for no apparent reason. It seems almost like a harmonic vibration -- that somehow the blade might flex and start to get some runout in it, which then worsens due to harmonic feedback. If you stop feeding, the kerf width returns to normal and noise ceases. There's no burning of the wood associated with this when it happens -- just the sudden "cymbal" noise and widening of the kerf.
It does this with a fairly sharp used blade, and I just tested a brand-new specimen of the same make/model blade, and it does the same thing. FWIW, I have height set such that carbide teeth just clear the top surface of the workpiece, and the trunnion height and angle nuts are both tight. Also, fence is parallel to blade (or skewed maybe 1/32" - 1/64" away from blade at rear), the arbor bearings are new, and arbor runout/parallelism to miter slot seems to be negligible (1-2 mils). Arbor flange is smooth, arbor washer is flat, and the saw doesn't do this with other blades.
Has anyone else seen this and does anyone have any idea why it might happen? Unfortunately, I bought several of these blades 10 or 15 years ago because they were so cheap, and now I'm thinking I might have bought defective blades and there's nothing I can do with them, since I probably can't return them anymore...
Thanks in advance for any clues...
Jacob.
Getting a strange phenomenon on my table saw, wondering if anyone else has seen this and might be able to suggest possible causes.
Several years back, I bought several 10" Irwin Marathon carbide 24T ripping blades (package labeled #14233, blade labeled #24233) at Lowe's because they were so cheap (I'm a sucker for bargains) and because I often use TS for rough/construction grade jobs.
https://i.ibb.co/XzbJtMy/IMG-3079.jpg
Anyway, when I use these blades for ripping 1" SYP or even 7/16" plywood, the blade seems to suddenly develop a wobble or chatter, almost like a percussionist's cymbal, and it makes a lot of noise when this happens (a growly SHHHHH sound like a cymbal makes), and the kerf widens by probably 50%.
This wobble or shimmy or whatever it is seems to be tied to both workpiece hardness and feed rate. Sometimes it does it when going through a knot, and sometimes it does it for no apparent reason. It seems almost like a harmonic vibration -- that somehow the blade might flex and start to get some runout in it, which then worsens due to harmonic feedback. If you stop feeding, the kerf width returns to normal and noise ceases. There's no burning of the wood associated with this when it happens -- just the sudden "cymbal" noise and widening of the kerf.
It does this with a fairly sharp used blade, and I just tested a brand-new specimen of the same make/model blade, and it does the same thing. FWIW, I have height set such that carbide teeth just clear the top surface of the workpiece, and the trunnion height and angle nuts are both tight. Also, fence is parallel to blade (or skewed maybe 1/32" - 1/64" away from blade at rear), the arbor bearings are new, and arbor runout/parallelism to miter slot seems to be negligible (1-2 mils). Arbor flange is smooth, arbor washer is flat, and the saw doesn't do this with other blades.
Has anyone else seen this and does anyone have any idea why it might happen? Unfortunately, I bought several of these blades 10 or 15 years ago because they were so cheap, and now I'm thinking I might have bought defective blades and there's nothing I can do with them, since I probably can't return them anymore...
Thanks in advance for any clues...
Jacob.