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Blades deform when tightened onto arbor

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Forum topic by JustLikeJames posted 05-05-2016 12:30 AM 709 views 0 times favorited 18 replies Add to Favorites Watch
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JustLikeJames

132 posts in 1022 days


05-05-2016 12:30 AM

Topic tags/keywords: arbor blade deform flex

This is kind of hard to explain in text, please bear with me.

All of my blades are flat, yet when I mount one on my tablesaw it deforms a little (becomes convex).

I’m not over-tightening the nut, only just past finger tight. I first noticed it while holding a straight edge against the blade to align the riving knife. The straight edge rocked slightly on the blade instead of laying flat against it. The center of the blade was slightly proud of the outer edge.

The outer edge of the fixed arbor flange is slightly proud of the center as it should be. The loose washer also seems normal. The two outer edges should squeeze against the blade as intended.

The only explanation I have is that when the arbor nut is tightened, the loose washer exerts just enough force on the fixed flange to flex it ever so slightly, and the blade conforms to that flex. That is hard to believe though because that flange is about 1/2” thick solid steel. It’s on a 3HP Jet cabinet saw with push button arbor lock. It seems like the thinner loose washer would be the weak link if anything was going to flex.

Like I said, hard to explain in text. Thanks for hanging in there.

Any ideas? Anyone have the same experience?


18 replies so far

View Mark Shymanski's profile

Mark Shymanski

5314 posts in 3172 days


#1 posted 05-05-2016 01:13 AM

A picture may help?

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

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conifur

955 posts in 611 days


#2 posted 05-05-2016 01:14 AM

Pics???

-- Knowledge and experience equals Wisdom, Michael Frankowski

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Nubsnstubs

826 posts in 1190 days


#3 posted 05-05-2016 03:51 AM

I don’t know a thing about you saw, but why is there a loose washer on the arbor????? What kind of blades are you using, and check them to see if that loose washer belongs to the last one you used. .... ............ Jerry (in Tucson)

-- Jerry (in Tucson)

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JustLikeJames

132 posts in 1022 days


#4 posted 05-05-2016 04:22 AM



A picture may help?

- Mark Shymanski

I though of that, but we’re talking thousands of an inch here, I don’t think I can get a pic that shows it.
Also, sorry for the delayed reply. I wasn’t getting emails about the thread for some reason.

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JustLikeJames

132 posts in 1022 days


#5 posted 05-05-2016 04:26 AM



I don t know a thing about you saw, but why is there a loose washer on the arbor????? What kind of blades are you using, and check them to see if that loose washer belongs to the last one you used. .... ............ Jerry (in Tucson)

- Nubsnstubs

Maybe it’s not called a loose washer. It came with the saw, it’s supposed to be there. I call it loose because it’s removable, not permanently attached to the arbor. Here’s the order of things from left to right to help you visualize:

Fixed arbor flange (has the the push button arbor lock)
Blade
Loose washer
arbor bolt

See what I mean? I’m sure that’s not the correct terms.

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MrUnix

4203 posts in 1659 days


#6 posted 05-05-2016 04:33 AM

Flange washer. Make sure you are putting it on the right way. Also, check the flatness of the arbor flange itself – and perhaps true it up if it’s out a little. Many ways to do it, such as this one by Matthias (which also shows how to true up the flange washer).

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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JustLikeJames

132 posts in 1022 days


#7 posted 05-05-2016 04:43 AM


Hopefully this helps.
This is an image from the manual and I have drawn a line showing which direction the blade bends. The line is very exaggerated for illustration purposes.

C = fixed arbor flange
B = loose washer (turns out “collar” is the correct word)
A = arbor nut

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JustLikeJames

132 posts in 1022 days


#8 posted 05-05-2016 04:54 AM



Flange washer. Make sure you are putting it on the right way. Also, check the flatness of the arbor flange itself – and perhaps true it up if it s out a little. Many ways to do it, such as this one by Matthias (which also shows how to true up the flange washer).

Cheers,
Brad

- MrUnix

Great article, thanks for directing me to it. Looks like a need to get a dial indicator to track down the problem. As I said, with just my straight edge, I can’t see any discrepancy. I’m afraid to do that procedure to a new saw but if that’s what it takes, that’s what it takes.

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Lee

49 posts in 338 days


#9 posted 05-05-2016 10:26 PM

Looks to me like the blade is not seating all the way on the arbor flange and when you tighten the washer it pushes the blade over slightly to the flange. You said it was a new saw, possibly the arbor is not machined enough to let the blade contact the flange.

-- Colombia Custom woodworking

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JustLikeJames

132 posts in 1022 days


#10 posted 05-06-2016 01:35 AM



Looks to me like the blade is not seating all the way on the arbor flange and when you tighten the washer it pushes the blade over slightly to the flange. You said it was a new saw, possibly the arbor is not machined enough to let the blade contact the flange.

- Lee

I really think the arbor is good. I get very nice cuts with all except for a very dull blade.

It’s definetely making contact, but that gives me an idea of something to check out. I’ll check to see “where” the washer is applying pressure. Maybe I can make an adjustment to correct the flex.

I may invest in a dial indicator anyways and check the arbor just to be sure.

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knotscott

7207 posts in 2835 days


#11 posted 05-06-2016 02:46 AM

I’m wondering if the diameters of the arbor flange and arbor washer are mismatched. Is there a way you can try a different washer?

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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JustLikeJames

132 posts in 1022 days


#12 posted 05-06-2016 02:54 AM



I m wondering if the diameters of the arbor flange and arbor washer are mismatched. Is there a way you can try a different washer?

- knotscott

You’re right to think that. The blade does exactly what it would do if the collar was larger than the arbor flange. However, they appear to be matched just like as shown in the manual. I don’t have another collar but I’m going to check and see if somehow the force is being applied too close to the outer edge somehow or if the edges that sandwich the blade aren’t as parallel with each other as they should be.

Good thinking everyone, we may be on to something.

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JustLikeJames

132 posts in 1022 days


#13 posted 05-06-2016 04:22 AM

Here’s a section showing what i think caused the phenomenon. Everything is exaggerated just for illustration purposes. Please excuse the drawing, I did that on my phone.

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JustLikeJames

132 posts in 1022 days


#14 posted 05-06-2016 04:31 AM

I suspected there wasn’t enough of a flat edge to not slightly flex the blade around the eased edge of the fixed arbor flange. (I’m talking thousands of an inch here).

So I put sandpaper on a flat surface and rubbed the collar around on it (being careful to keep pressure at the center) until there was a positive flat edge.

It looks like I sanded a bunch off, but that literally took 10 seconds.

Long story short, the blade doesn’t deform anymore so I’m happy.

Thanks to everyone that helped. Some of the things that were said made it dawn on me what was probably happening. Easy fix too.

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JustLikeJames

132 posts in 1022 days


#15 posted 05-06-2016 04:39 AM

FWIW, here’s the best pic I could get of the collar before sanding. It still doesn’t do it justice, but if you’re able to zoom in, you can see that the straight edge didn’t really touch except at the extreme outer edge. There was almost no flat spot at all.

showing 1 through 15 of 18 replies

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