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Blade wobble - runout stumper Delta 36-725

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Forum topic by TBennett posted 02-19-2018 03:42 PM 1634 views 0 times favorited 10 replies Add to Favorites Watch
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TBennett

9 posts in 313 days


02-19-2018 03:42 PM

Topic tags/keywords: blade wobble blade runout delta 36-725

Hi everyone. I recently picked up a used delta 36-725 off of CL and was taking some time to tune it when I got home. I first aligned the blade to the miter slots and then I was evaluating blade runout. I got an TIR of .015”. I then measured the arbor on the shaft and there was pretty much 0 in that. I then took a reading on the flange that contacts the blade. I had about .005” TIR.

Ok, that must be it. I got the router out with a stone attached and proceeded to lightly touch up the flange with the saw running. I got the flange to be pretty flat – “.0005” TIR. I re-attached the blade and was still in the .010”-.012” TIR range. I tried the same blade in my old 113 series Craftsman and had about .007”-.008” TIR. I was just trying to rule out the blade. I also tried a few other blades. I suppose they all could be bent but it seems doubtful.

I then laid some 400 grit sandpaper on my cast iron top and ran my armor nut and flange washer over it. They both looked really flat based on the even wear pattern.

I’m stumped here as to why I am seeing so much blade wobble still. There doesn’t seem to be any play in the blade. The wobble also seems to get worse the more I tighten the blade nut. I just snug it down lightly but it makes me think something is there that is explaining this.

Any thoughts?


10 replies so far

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WhyMe

1074 posts in 1764 days


#1 posted 02-19-2018 03:52 PM

If the blade wobble gets worse as you tighten the arbor nut tells me the flange washer surfaces are not parallel. So tightening the nut puts more pressure on one spot of the blade than another. Running the arbor flange washer over sand paper will not parallel the sides.

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Sark

82 posts in 564 days


#2 posted 02-19-2018 04:06 PM

Given that you’ve ruled out bent arbor and flange, I suspect that the bearing(s) is showing signs of wear. If so, then you would get wobble regardless of how flat all the component pieces are. There could a slightly flattened space in the bearing arbor which would cause wobble. Others far more expert than me could chime in on other possible causes such as loose motor mounts, pulleys, belts, etc…

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TBennett

9 posts in 313 days


#3 posted 02-19-2018 04:21 PM

Thanks for the responses. The thoughts of the washer surfaces not being parallel crossed my mind. I figured if both surfaces contacting the box was flat, I’d be good. I do see how uneven pressure would be applied to the blade. I’ll have to set up the indicator again tonight and check the washer out. Any tricks on how to true the one side relative to the other?

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WhyMe

1074 posts in 1764 days


#4 posted 02-19-2018 04:33 PM

Sometimes we can get obsessed with trying to get things aligned perfect on a table saw, I’m guilty of it. I find in most cases it’s not worth chasing a few thousands of an inch. What level of fine word working are you trying to achieve? Checkout this video… https://woodgears.ca/saw_arbor/index.html

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TBennett

9 posts in 313 days


#5 posted 02-19-2018 04:57 PM

I’m not going for absolute perfection but .015” seemed excessive and I could visibly see the wobble. I knew didn’t want that much. I build projects around the home. Heirloom quality hardwood furniture is not my goal at the moment. But hey – it would be nice if my tools were up to the task if I decided I wanted to. The article was helpful. I couldn’t think of a better way that an iterative process (other than machine shop).

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Sark

82 posts in 564 days


#6 posted 02-19-2018 06:29 PM

.015 is excessive, I think. One easy thing to try is to buy a blade stabilizer. There are lots for sale on the internet. I use 3” diameter one, and I think its 1/8” thick. It’s always surprised me how small the flange washer is relative to the size of the blade. Some of the blade stabilizers are totally flat, and some are slightly grooved so the force of the nut is distributed out away from the shaft (Woodcraft). This might help to overcome slight non-parallelism.

Next question, could it be that the blade stops its wobble when its spinning? Which you could tell by the size of the curf. Does the curf measure exactly what it should or is it .015 large? If it’s spot on, then you can put your mind at ease. In which case, its not worth spending more time on a problem with no consequence. You can also run this test with and without the blade stabilizer.

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patcollins

1687 posts in 3069 days


#7 posted 02-19-2018 07:20 PM

I would check to see of the arbor nuts face(s) are totally parallel to each other and possibly out of perpendicular to the screw threads on the shaft.

View Woodknack's profile

Woodknack

12431 posts in 2584 days


#8 posted 02-19-2018 08:23 PM

It sounds like you know what you are doing but I have to ask, how are you measuring? If your flange is flat and your washer is flat, then they aren’t introducing wobble. It’s also possible to double check with feeler gages. You already mentioned tightening too tight, they just need to be snug – finger tight + 1/4 turn roughly. When measuring blade runout, are you measuring the same tooth front and back? If your bearings are bad, I think you can check for that with the DI.

Here is how I check flange runout. I’ve never checked the arbor itself because I don’t know how or if it even makes a difference. You should be turning the blade by touching the belt only, if you touch any part of the mechanism you will get false readings.


View on YouTube

-- Rick M, http://thewoodknack.blogspot.com/

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TBennett

9 posts in 313 days


#9 posted 02-19-2018 09:28 PM

Thanks for the input everyone. I have a few things I will chase down tonight and report back.

Unfortunately I can’t turn the motor shaft with the belt or pulley as they are not accessible in this hybrid saw. I am checking runout with a dial indicator. I made a rig that attached to my miter gauge. I set the indicator up to touch the blade and then rotate the blade a full revolution. To evaluate my blade is square to the miter slot, I use the same tooth/spot in the blade though.

I plan to do the following tonight, time permitting.
I’m wondering if I could just use a regular washer just to evaluate if anything changes by doing.

I will also make some cuts and evaluate the kerf width. Maybe this is only happening at slow speeds – something I didn’t consider until the feedback fro earlier.

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TBennett

9 posts in 313 days


#10 posted 02-20-2018 04:38 AM

Update. I checked the washer. The sides were pretty parallel around .001” TIR. I did have a stabilizer that I tried and just using that dropped the sawblade runout to around .007”-.008” range. The nut must be the culprit here but I’m not sure why. I think I’ve landed in a decent spot though so I’m not sure I will spend much more effort tracking it down.

I really appreciate the suggestions and input. Thanks everyone.

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