DeWalt 7790/3431 12" radial arm saw parts?


Old 03-06-16, 06:40 PM
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DeWalt 7790/3431 12" radial arm saw parts?

I've browsed the web and the few outfits that troll as parts suppliers fpr old DeWalts show my needed parts as "discontinued". I've used a micrometer feeler gauge and am pleased to see that the 5/8 arbor on my motor shaft has zero wobble after more than 35 years of use. However, when I mount a dead flat 12" saw blade on the arbor, I get a wobble of up to 10 thousandths of an inch per revolution.
So I conclude that the arbor collars (which hold the blade on the shaft) are warped. I hoped to find some replacements, but no luck so far.
Any recommendations?
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Old 03-06-16, 06:49 PM
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How did you determine your blade is "dead flat"... have you had a machinist test the run out? Because it could be one or the other, or a combination of both.

You seem kind of techie, you might like this: Lee Valley Tools - The Importance of a True Running Blade
Old 03-06-16, 07:05 PM
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The arbor runout may not show unless there is a load on the bearings, so if you just checked the arbor with no blade.....

If the arbor collars are warped, you should see change in the runout as you rotate the position of the collars with respect to the blade and to each other. In fact, rotating them may be all you need to do if you can find the right position.

Failing all that, perhaps a couple of blade stiffners could stand in for the collars?

They are essentially large, well balanced and machined, washers.

Might have to have them bored out to fit the shaft.
Old 03-07-16, 03:30 AM
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You are measuring arbor runout at center mass. Extending even a 100/1000th run out to the edge of the blade will increase as it moves from center mass exponentially. My bet is on the blade not being "perfect".
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