deflection in router bits

Great cor cutting dado,s with a router and template/straight edge guide.

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Not always true.

Look, I am only trying to help you out. If yo want to get into a pissing contest, you win.

Then you have a defective bit or it is not properly mounted in the router.

Reply to
Leon
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the most wood you can cut is the diameter of the bit plus the depth depth is limited by top and bottom bearings

material was 1/8x1/8 a smidgeon

no to both I tried in two routers I still need to try it with the end bearing and allen screw removed

Reply to
Electric Comet

it's a 1-1/4-inch x 1/4-inch shank

I've never used any bits longer than 3/4-inch with 1/4-inch shank so first time I'd seen it

as mentioned will remove bottom bearing & allen screw just to see of there's an imbalance

Reply to
Electric Comet

right, that's the point

right that was the point, more an exercise or example that I intentionally exagerrated to make the point

you say should but I say wouldn't find some 4-inch x 1/4-inch diameter stiff rod and rev it up

Reply to
Electric Comet

now I know, just hadn't seen them as another poster pointed out too

it is, a partial truth is a full lie but I just figured your reply was meant to be polite instead saying I was full of it

Yay! wait what'd i win

settle down is rec.woodwroking

I'm leaning toward a poorly engineered bit but I still have a couple of tests to do with it

so possibly defective by design but still a chance that it's defective in materials although it appears fine

Reply to
Electric Comet

Electric Comet wrote in news:mc22gu$k7o$2 @dont-email.me:

After reading Bodger's comment, I realized what the problem is here: you don't know what the word "deflection" means.

from thefreedictionary.com: "deflection - the movement of a structure or structural member when subjected to a load"

(the "structural element" in this case being the router bit).

What you are talking about is (as Bodger said) runout. He explained the causes of runout. If it changes with the speed of the router, it could be an unbalanced bit, or it could be bad bearings - more likely the latter. If it doesn't change with speed, it's most likely a bent bit.

John

Reply to
John McCoy

I've stayed on the sidelines but this thread has gone on so long I finally thought I'd see what was going on... :)

...

You're reading it wrong, yes methinks... :)

He's saying the shaft isn't stiff enough but what the mass on the end causes flexure when at high speed. The case where he goes on to later to mention the 6" long shaft is clearly what he's speaking of. Now whether that's the actual mechanism can't tell w/o actually seeing it or measurements, but seems clear what he thinks is happening.

Iff'en as he says it occurs in two separate routers I'd judge not the collet/router runout but associated with the bit. It could be there's sufficient imbalance to cause the problem if it were an inexpensive bit that didn't muster quality control checks that a more expensive would have failed at the manufacturer. Or, given the fact it has double bearings it may just be that indeed the mass is too much for a 1/4" shank and with _any_ imbalance is an issue. If this is an issue, I'd put it back in the toolbox and never get it out again in anger--a flying router bit head from a fractured shaft is too spooky to venture a chance...

I'd venture the solution would be to set the bit deeper into the collet if have that much exposed shank that flexure is an issue and use the router depth adjustment to control the depth. If the shank is so long that even set a full depth it causes this, see above.

If it were a decent manufacturer and the bit is fully inserted in a collet, I'd contact them with the symptoms; some Chinese import thru eBay or whatever source, "not so much"...

ADDENDUM: Perhaps it's hitting a critical axial moment--at that point bending resistance magically becomes much less and all kinds of bad things can happen. Once't upon a time in a former life with centrifuges for a casing of approx. tractor-trailer length and feet in diameter, operating speed was at roughly router rpm's. To get up and down from rest required passing through 5(yes, five, count 'em!!!) criticals; early on the failure rates were quite the issue...

Reply to
dpb

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