table saw trunnion twisting

Hi -
I have a question regarding blade alignment on my contractor table saw. I have a Grizzly 1022ZFX if it matters.
Recently, I tried to align the blade on my table saw to make sure it's parallel to the mitre slot. I followed the instructions in the manual and I got the blade to be parallel within 0.002". However, when making the first cuts, I noticed that the wood would burn on the waste side. I measured again and sure enough the blade was out off alignment by about 0.030". I played around a little bit and I noticed that the blade would move back to being perfectly parallel when I would take the motor off. Apparently, the weight of the motor pulling on the arbor pulley made trailing edge of the blade move away from the fence by about 0.030". My question is, is it normal for a contractor saw that the trunnion assembly twists by this much?? It seems like a lot to me. Has anybody ever noticed this behavior on their saw?
I could of course account for the weight of the motor when adjusting the trunnion to make sure the blade is parallel to the mitre slot motor attached and all. However, given the stiffness of the trunnion assembly (or rather the lack thereof) I must wonder how much the blade is going to move under load.
If anybody has any experience with this problem (or is it just me???), I'd love to hear about it.
Thanks, Stefan
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Sounds like your arbor bearings may be bad.
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I don't know. I measured arbor and flange and both are within 0.001" of being perfectly round/flat. Also, the saw is running very smoothly w/o a lot of vibration. I assume that would not be the case if the bearings were bad.
Stefan
Leon wrote:

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On the Rockwell contractor saw I had, I found that you had to have the motor mounted when adjusting the blade to the miter slot due to the torque on the connecting bars. Theoretically, after adjustment, you should be able to get burn free cutting at 45. However, the weight of the motor is different at 45 and there is a different torque on the connecting bars. I could never get both 90 and 45 correct at the same time. This was done after making sure the connecting bars were in the same plane.
Preston

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I can understand the blade deflecting a few thousands of an inch. No trunnion/arbor is going to be perfectly stiff and given the way contractor saws are typically constructed there has to be some deflection due to the motor weight. However, 0.03" seems to be excessive, no?
Stefan
Preston Andreas wrote:

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I didn't measure it, but I do remember being surprised at the deflection I got due to the motor weight. There is a surprising amount of flex in the connecting rods. Fortunately, with my unisaw, it is one piece of cast iron.
Preston

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Preston Andreas wrote: Here's the latest update. I took the saw apart and I found that there was significant play in the arbor assembly. Not the arbor or arbor bearings, but in the hinge that attaches the arbor flange to the trunnion. When I apply light pressure to the blade I can clearly see the flange move. The saw is going back to Grizzly next week. Hopefully, they will be able to fix it, or exchange the saw.
Stefan

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Hopefully, someone will give you a better answer than this: On the Delta I got, the alignment of the blade to the miter slot changed over the range of heights I had the blade. Delta said this could not be fixed by me and I returned it. Their option was to repair or replace it (they replaced it).

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