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Issues with Delta table saw 36-670 bearing replacement

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Forum topic by Beuford posted 02-28-2021 06:12 PM 289 views 0 times favorited 3 replies Add to Favorites Watch
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Beuford

19 posts in 45 days


02-28-2021 06:12 PM

Ok, long, detailed post… Sorry!

I recently purchased a used Delta table saw marked 36-670. The arbor bearing sounded a bit noisy, so I pulled it apart to replace the bearings. As I took it apart I realized that it wasn’t the bearing causing noise, but instead the movement of one of the spacers (#206 in the parts drawing).

Reviewing the parts list and the actual parts, it looked to me like the inner bearing races should be coupled under pressure via the blade support, bearings, spacers, pulley and finally the pulley nut (see my top hand drawing). But under that assumption the long spacer (#206) should not be loose. I reassembled the bearings and shaft and low and behold I had the same condition as before – the long spacer was slightly loose. Didn’t seem right…

I investigated further and realized that the slightly wider part of the shaft where the pulley-side bearing seats – diam 0.669in – was a little longer than the inner bearing race. Further, I found that the short spacer (#211) – which I assume sits against the pulley-side bearing inner race – has an inner diameter of only 0.625in. The result is that the short pully-side spacer (#211) seats not against the bearing race but instead against the bearing seat in the shaft (see the second hand-made drawing). Thus the long spacer is never compressed between the two bearing inner races.

The saw looks all original, so I doubt that the short spacer has been incorrectly replaced. So I’m wondering: has anyone else seen this on a Delta 36-670 series table saw when replacing the bearings?

Part list:

My drawing(s):

Thanks in advance,

Beuford


3 replies so far

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MrUnix

8503 posts in 3250 days


#1 posted 02-28-2021 06:28 PM

Are you sure of the model number? All the parts diagrams I find for a 36-670 show it as a pseudo direct drive machine and does not have anything like what you show in your diagram above.

But beyond that – are you sure you got the right bearings? You may have needed bearings with an extended inner race. If you let a parts guy pick them for you, there is a good chance that they wouldn’t have even noticed the difference and just gone on bore, O.D. and width at the outer race. Seen it happen way more than once.

Cheers,
Brad

PS: Measure the dimensions in metric. The bore may/may not be in metric (it may actually be 5/8” as indicated), but the rest should all be metric.

-- Brad in FL - In Dog I trust... everything else is questionable

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Beuford

19 posts in 45 days


#2 posted 03-01-2021 01:18 AM



Are you sure of the model number? All the parts diagrams I find for a 36-670 show it as a pseudo direct drive machine and does not have anything like what you show in your diagram above.

Yep – clearly marked on the saw. But this is the base saw model; it was typically sold in a configuration that gave it another model number, like 36-649, 36-675, 36-678, or 36-679.


But beyond that – are you sure you got the right bearings? You may have needed bearings with an extended inner race. If you let a parts guy pick them for you, there is a good chance that they wouldn t have even noticed the difference and just gone on bore, O.D. and width at the outer race. Seen it happen way more than once.

Original bearing are clearly marked with part number 6203 RS – very standard bearing.

I chamfered the inner diameter of the shorter spacer just enough for it to clear the small projection of the shaft bearing seat, and now it all tightens up correctly. I believe that this is how it was supposed to be built; otherwise there would be no lateral support for the shaft. Now, the pulley-side bearing – which is captured using a bearing nut that holds the outer race – provides lateral thrust support. The bearing shaft could move on the pulley-side bearing inner race a few millimeters without the adjustment I made to the short spacer. Note that the long spacer has a larger inside diameter to avoid this problem.

I’ll finish assembling the saw tonight and test, but I am confident that this is how it was meant to be built. I think that the short spacer was incorrectly spec’d for this particular lot. However, it is equally plausible that the long spacer was simply made just a bit too short. There is sufficient lateral clearance available in the positioning of the saw blade side bearing to allow a slightly longer “long” spacer to correct the problem, too.

Steve

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Beuford

19 posts in 45 days


#3 posted 03-01-2021 09:00 AM

Additional note: The pulley did not always sit perpendicular to the shaft before this modification to the short spacer. When the assembly was tightened the pulley would randomly be slightly out of square. I attribute this to the random position taken by the spacer depending on how it contacted the extended bearing seat on the shaft. By chamfering the inside of the short spacer I avoid this and the pulley is now square each time the assembly is tightened.

If you have one of these saws, check to see if the long spacer is “loose”; if it is you might want to investigate.

Steve (aka Beuford)

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