I have a problem with my 12 year old, Jet Cabinet saw that’s driving me nuts! It hasn’t seen lots of hard service since I’m a low production, one man shop. For the past few months I’ve noticed that the blade would rub against the sides of the zero clearance throat plate on initial start up and also when coasting to a stop. I’ve modified my zcp so that I can use inserts that are made out of 1/4″ MDF. The image attached is of one I just cut for my rip blade. You can see the initial cut from raising the blade to full height at the far right side. I’ve only made a dozen cuts or so but already the sides are getting chewed up. It seems too that on some of my rip cuts, when I joint them (hand plane) the cut is concave!
So far I’ve used a dial indicator to adjust the miter slots to the blade, then aligned the fence to the slots and all is within +/- .002. Hard to believe that the arbor bearings would be shot after this relatively short period of time but is there anything else I’m missing? Would it be wise to crawl around the trunnion, motor, etc. and just tighten every nut and bolt I can find? Has anyone out there ever had an experience like this — is so I’d sure appreciate hearing from you.
If worse comes to worse, how difficult is it to replace the arbor bearings if that’s what the problem is? Thanks in advance for any words of wisdom you pass my way!
Replies
Bearings
If you are having that much blade wobble that the blade is touching the sides of your zero clearance slot you should be able to wiggle the blade and see a lot of deflection if you check it with a dial indicator. Also if the bearings are worn out you will hear a noise indicating so. Check the mounting flange for something stuck to it , you may have a blade that is not mounting flush with the mounting surfce, this will cause the blade to be angled and you will see the runout at start up and slow down. At operating speeds the blade will appear to be running steady .
Try this to check the saw arbor and bearings:
Raise the blade as high as it will go. Take a strip of 1/2" or 3/4" mdf as if you were going to rip it, but cut only about 1/2" or so into it and then back out being careful to keep it tightly against the rip fence going and coming. Stop the saw and set the cut in the mdf back around a saw tooth. Check with a feeler gauge to see how much wider the kerf is than the saw tooth. This method eliminates several sources of error in measuring runout.
If the kerf is no more than 0.015" wider than the saw tooth, I'd say your saw is spinning true. If it is wider than that, check the saw collars for nicks, the arbor shoulder for the same, whatever fastener holds the arbor from shifting side to side. If those are all good, then change the bearings. They aren't jet engine bearings, and it isn't rocket science. A hammer, some end grain blocks of hard wood, short pieces of pipe of different diameters, and a couple of heavy C clamps should be all you need.
Throat Plate
That's what I would have thought too but not the case. I took the outer flange and laid it on a piece of sandpaper and checked for any runout or foreign objects stuck to it, has me puzzled so I'll do a thourough cleaning of everything in there. No unusual noises even after taking the blade off and running motor. I suppose it could be the blade (Amana rip) but I'll just keep scrathing my head to try and figure this thing out!
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