Warped cast iron table saw wing - Woodworking Talk - Woodworkers Forum
 
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post #1 of 9 Old 06-14-2019, 01:55 AM Thread Starter
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Warped cast iron table saw wing

Hi


One of the webbed cast iron wings for the Craftsman 10" table saw I'm rebuilding is warped in the center, it sags about 1/32". Is there any way to un-warp it, other than taking it to a machine shop to get flattened? I have read that cast iron is a little bit flexible and I might be able to use some force to get the wing and table to line up by bolting the center into place first and then pulling the front and back down into place. If I am unable to get the wing to level out properly, which side would it be better to mount it on so the warp does not interfere with the table saws normal operation? Just so you know these are the lighter webbed cast iron wings.
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post #2 of 9 Old 06-14-2019, 03:56 AM
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Metal warps as internal stresses in its structure even themselves out. Anything you can do to force the warp out will just re-introduce stresses to the metal, and itll warp back over time.

The 'proper' way to do this would be to take it to a machine shop and have it re-ground to get it flat. The improper way to do it would in fact be to force it back into flatness and then brace it to keep it that way. Be warned though, itll take a fair bit of force to get things to bend, and cast iron is not flexible, not safely anyways. Steel or aluminium you can bend pretty well, for the most part, but cast iron will tend to fracture long before it bends to an appreciable degree. Personally, i wouldnt bother with the wing unless it causes issues with use, and if it does create problems, have it re-ground or get a new one

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post #3 of 9 Old 06-14-2019, 04:32 AM
where's my table saw?
 
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Look at it this way ....

If it sags 1/32" in center, you could remove 1/64" on either edge by laying it on the main saw table with two strips of 100 grit sand paper.
It may take a while, but it would reduce the problem by half.



I would use it on the left side where typically the off fall from the rip goes. Cross cutting would be more effected on the left however. I'd just fix it. Draw filing will remove metal faster than sanding and leave a clean surface. A few strokes with a 14" file and you would be done.



I don't know your means of checking for flatness, but possibly a feeler gauge under the main table would work. Ebay has older/used takeoffs if you want to gamble a bit. I have 3 webbed extensions sitting on a shelf somewhere in the shop myself, I'll probably never use. Never checked them for warp/flatness ....... I'd just use another main table because I don't like the holes in the webs. Garage sale have older saws for parts also. I am really spoiled by have a wide saw table from multiple saws bolted together.

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #4 of 9 Old 06-14-2019, 10:36 AM
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I just assembled a refurbished table saw. It has a cast iron table and two cast iron wings. The first time I attached the wings, I was not satisfied with flatness, so I called the company (SawStop) and also posted a thread asking for advice here:

https://www.woodworkingtalk.com/f12/...6-inch-212929/

My problems were an order of magnitude less than yours. So much so that I cannot recommend the same straightening methods that worked for me.
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post #5 of 9 Old 06-14-2019, 12:21 PM
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Best way to get perfectly flat cast iron is to have a machine shop surface grind it. Cast iron is full of internal stresses when it is first cast and needs to just sit for 6 months to a year before being machined. Even then, much like wood, the internal stresses may cause it to change shape as it is machined. The original manufacturer of it likely didn't age the cast iron piece sufficiently before machining it. Re-surfacing it now that it has aged should produce a very flat surface.

Charley
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post #6 of 9 Old 06-14-2019, 03:03 PM
where's my table saw?
 
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Yes, but ..... $$$$$$$

Quote:
Originally Posted by CharleyL View Post
Best way to get perfectly flat cast iron is to have a machine shop surface grind it. Cast iron is full of internal stresses when it is first cast and needs to just sit for 6 months to a year before being machined. Even then, much like wood, the internal stresses may cause it to change shape as it is machined. The original manufacturer of it likely didn't age the cast iron piece sufficiently before machining it. Re-surfacing it now that it has aged should produce a very flat surface.

Charley

I can equate machining a cylinder head off a car to the surface size of a table saw wing, more or less. So, here's a video on a DIY process for much less than a machine shop would cost:

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #7 of 9 Old 06-14-2019, 04:58 PM
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If it's only warped a 32nd I can't see how that would affect anything. If it was the saw top itself maybe but not the extension. It probably came from the factory like that.
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post #8 of 9 Old 06-14-2019, 07:22 PM Thread Starter
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Hi


Unfortunately I don't have the money to have the wing machined, but I did try the bending trick and it worked quite well, I didn't think the cast iron would flex that easily.
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post #9 of 9 Old 06-15-2019, 08:28 AM
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Glad you got it fixed. I was going to say put some Bond-Do on it and sand it down.

Don in Murfreesboro, TN.
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