iSawitFirst Posted February 22, 2011 Report Share Posted February 22, 2011 I've read about arbor runout and have a few questions. First, what exactly is it? My impression is that "runout" means the arbor isn't parallel to the saw top but I've read other things that lead me to believe its something else. Second, how do you measure it. Third, how do you fix it? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
callyb Posted February 22, 2011 Report Share Posted February 22, 2011 Runout is the "wobble" you would see as the arbor spins. To measure it you'll need a machinist base and dial indicator. Set the indicator to a reference point (ex. - .005") and turn the arbor manually, nice and slow with consistent hands. Watch the dial for one complete revolution to identify the runout, actually the full indicated runout (F.I.R.). For example (set at .005"): dial goes from .007" to .004". This would give you a runout of .003". Lengthy answer, but I hope it helps. Best Regards. Quote Link to comment Share on other sites More sharing options...
jimmykx250 Posted February 22, 2011 Report Share Posted February 22, 2011 Runout is the "wobble" you would see as the arbor spins. To measure it you'll need a machinist base and dial indicator. Set the indicator to a reference point (ex. - .005") and turn the arbor manually, nice and slow with consistent hands. Watch the dial for one complete revolution to identify the runout, actually the full indicated runout (F.I.R.). For example (set at .005"): dial goes from .007" to .004". This would give you a runout of .003". Lengthy answer, but I hope it helps. Best Regards. I dont mean to hijack the thread but can this runout be fixed? How would you know if this was the arbor itself and not bad bearings? This is somkething i want to check on my TS as well. Thanks, Quote Link to comment Share on other sites More sharing options...
Ben H Posted February 22, 2011 Report Share Posted February 22, 2011 This is timely. I fixed my saw last night. Like said above, you'll need a few tools to get it done, but it's not hard, just tedious. You need: Dial Indicator, Magnetic Base, A fine cut file, Sharpie, A sharpening stone (or perhaps a DMT file), and patience. First set up the Dial to read your Arbor shaft not the flange that the blade rest against. Stay off the threads and measure the shaft. Place the tip of the dial indicator on the shaft and reset the dial to zero. Now turn the arbor slowly, reading the dial. You should have nil to very, very small about of variance. If you get more than 1 thou, stop now and order some new bearings. You may also have a bent arbor shaft, which basically means a new one is in order. Mine was between 0 and .0005, not bad for new bearings and a 50 yr old shaft. Now that you have determined your bearings and shaft are OK, move the dial indicator to the arbor flange (the big washer like thing that the blade rest upon). It may be easier to to tilt your saw to 45, the goal is to mount the dial indicator as close to 90deg to the flange as possible. Got in place? Good. Now DO NOT touch it, bump it, move it, or breathe heavy on it. IF anything moves at all during the next step, start over. First off, clean the flange with a scotch brite pad and some naptha or Mineral Spirits. Make 100% it's 100% clean. Small amounts of pitch and dust will skew you readings. You should now have your dial indicator in place ready to make the measurement of the arbor flange. Turn the arbor by your belt (small amounts of hand pressure against your flange could skew the results) don't touch it. If it's out, more than likely you'll see the dial jump from below zero to above it. Since you can't add material, slowely spin the flange (stopping every 1/16 of a inch or so to allow the dial to "rest") Find the lowest point on your flange, and make a small mark with your sharpie. This point is now your new zero. Now spin the arbor and find your highest point. Depending how off your flange is, it may be a rather large area (mine was over 60% of the entire thing) Found the high spots? Mark em. HINT: I used two differnt color sharpie. Red was material to be removed, black was good to go. File your high spots down file a flat fine cut file. Make sure you keep the file flat against the flange. If you don't, you could round the flange over, and then you'll be buying a new one. Also, keep a small brush handy to clean your file every few strokes or so. After you've filed away your marker. Set your dial up again, head straight for your zero mark. Reset the face of the dial, and check the arbor again. Rinse and repeat. Once you have your arbor within where you are happy (most say anything less than .002 is OK) Stone the whole thing to help feather out the whole flange. I was able to take my arbor from 8 thous, to less than 1 thous in about an hour. Good luck! Quote Link to comment Share on other sites More sharing options...
iSawitFirst Posted February 22, 2011 Author Report Share Posted February 22, 2011 Great info, Ben. Thanks much! Quote Link to comment Share on other sites More sharing options...
callyb Posted February 22, 2011 Report Share Posted February 22, 2011 File your high spots down file a flat fine cut file. Make sure you keep the file flat against the flange. If you don't, you could round the flange over, and then you'll be buying a new one. Also, keep a small brush handy to clean your file every few strokes or so. After you've filed away your marker. Set your dial up again, head straight for your zero mark. Reset the face of the dial, and check the arbor again. Rinse and repeat. Once you have your arbor within where you are happy (most say anything less than .002 is OK) Stone the whole thing to help feather out the whole flange. I was able to take my arbor from 8 thous, to less than 1 thous in about an hour. Good luck! I guess I could have included how to fix it too... By the way, great tip on the two different colors. I'm going to assume you have some vibration in your saw, which is what lead you to check the arbor. Keep in mind after you do this you need to check your blade after you reinstall it too. Quote Link to comment Share on other sites More sharing options...
Ben H Posted February 22, 2011 Report Share Posted February 22, 2011 I guess I could have included how to fix it too... By the way, great tip on the two different colors. I'm going to assume you have some vibration in your saw, which is what lead you to check the arbor. Keep in mind after you do this you need to check your blade after you reinstall it too. Well kinda. I've rebuilt a 1967 PM Model 66. Tuning the saw while assembly found the issue. Stay tuned, I have about 50 pics or so of the whole process. Large thread coming soon Quote Link to comment Share on other sites More sharing options...
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