My 520 started singing today.

[dusty]

I called Shopsmith and they said they will probably replace the rear trunnion so I'm waiting on a call back.

Today I am going to the shop and get out the tape and compare the results with Dusty's pictures. Since this takes the trunnion hole size out of the picture because the table is not mounted. I should get the same results in theory.

Michael

The only variables are the width of the rubber bumper and the length of the saw arbor. Make sure the arbor is firm against the knurled knob and lock all the locks.

This setup sorta confirms design characteristics. This shows how the pieces fit together with respect to one another.

I believe there maybe another variable. The newer tables have trunions with just three holes for adjustment. The fourth hole at the outfeed left side is just big enough for the bolt which allows no lateral adjustment of the table. You can align it parallel to the blade but can not center the blade. I think that is the reason shopsmith started to use the larger bumpers. My old 1990 vintage table had all large holes in the trunnion so you could also adjust it laterally.

Can you date the table? Are you the original owner (could someone else have drilled out "one" hole?

[dusty]

The table I have has 518348 engraved on the back. I don't know the exact date because I bought it on the grey market but it appears to be in new condition, no detectable scratches or normal wear.

If you look through all the discussion on this issue someone mentioned that some trunnions had only one hole drilled out to 1/2" and they were supprised that none of mine were drilled. The hole thing was a vendor issue. Some of the bad trunnions got out to production. Shopsmith will replace the bad trunnion.

Michael

The blue painters tape tests tell the entire story. It does not rely on the trunnion holes and it verifies the carriage position with respect to the blade (which in turns validates or invalidates the rubber bumper dimension).

[JPG]

For those 'decimally challenged', the spacers are 1 3/8" and 1 7/16".

[dynabase]

I got the new trunnion from Shopsmith installed today and that did the trick. The blade is much closer to the center and all is good. I got the table aligned. Tomorrow I will check the fence alignment and we should be good to go.

Word of advice if this happens to anyone else "Check the trunnions first". I didn't have a clue where to start when I addressed this issue but with the help of some great folks on this forum WE got it done. I have had this off center blade issue since day one and now it is gone.

Thank you ALL

Michael

[JPG]

I got the new trunnion from Shopsmith installed today and that did the trick. The blade is much closer to the center and all is good. I got the table aligned. Tomorrow I will check the fence alignment and we should be good to go.

Word of advice if this happens to anyone else "Check the trunnions first". I didn't have a clue where to start when I addressed this issue but with the help of some great folks on this forum WE got it done. I have had this off center blade issue since day one and now it is gone.

Thank you ALL

Michael

And how many YEARS ago was 'day one"?

[Ed in Tampa]

I got the new trunnion from Shopsmith installed today and that did the trick. The blade is much closer to the center and all is good. I got the table aligned. Tomorrow I will check the fence alignment and we should be good to go.

Word of advice if this happens to anyone else "Check the trunnions first". I didn't have a clue where to start when I addressed this issue but with the help of some great folks on this forum WE got it done. I have had this off center blade issue since day one and now it is gone.

Thank you ALL

Michael

Great! What about the singing what was that?

[JPG]

When you say replaced the trunion, are you referring to the part that has the holes for mounting to the table? If so, front or back or both? Is the hole location different?

[dynabase]

JPG - I got the 520 in early 2013. Yes the trunnion is the part that mounts to the table. I replaced the back trunnion. The old one had holes the same size as the bolts and it should have 1/2 inch holes. The small holes did not allow any table adjustment.

ED IN TAMPA - The singing is some sort of vibration/harmonic probably caused by a overheated bearing or a slightly bent quill shaft. I still haven't figured out that one but it doesn't seem to affect the cuts. The blade sounds like a tuning fork when I finish a cut. I am not going to do anything about it now because it doesn't hurt anything. I am going to let the get worse so that I can track it down easier. Right now I don't have a clue what is causing it. Since I was raised in the south I am use to singing saws. I just might get a banjo and play along with my Shopsmith. If I run into someone around here that has a Shopsmith I might temporarily swap quills to see if that makes any change. I want to know what the problem is before I start throwing money at it.

Michael

[sehast]

I got the new trunnion from Shopsmith installed today and that did the trick. The blade is much closer to the center and all is good. I got the table aligned. Tomorrow I will check the fence alignment and we should be good to go.

Word of advice if this happens to anyone else "Check the trunnions first". I didn't have a clue where to start when I addressed this issue but with the help of some great folks on this forum WE got it done. I have had this off center blade issue since day one and now it is gone.

Thank you ALL

Michael

I guess that debunks my theory that my rear trunnion which only has one 1/2" hole is a new standard. Once I got the new larger (1 7/16") carrage spacer my blade is exactly centered with the the single 1/2" hole in the rear trunnion. Having one of the holes in the rear trunnion with no slop actually helps me in aligning the table so I don't think I will try to change it out. By the way was it very difficult to change out the trunnion?

[dynabase]

Changing the trunnion is very easy. Just take the table off and remove the two bolts that attach it to the table. After you change the trunnion just watch the sawdust session #1 on table alignment.

Michael