8mm Router Bits?
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Crazyraceguy
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Cheese said:
Yes, 99% of people would never notice .003" or would attribute the difference to runout or flex.
9/32" seems like an odd size in the first place?
rmwarren
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Cheese said:
I was using it in Origin input as 8mm and the difference was enough that I had to add an offset when cutting 20mm dog holes. Finally dawned on me to tell it I'd been fibbing about the bit size and suddenly I didn't need the offset any longer. [doh] Sometimes I even amaze mtself...
RMW
Michael Kellough
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Coen said:
I always insert the shank as far as it will go, then pull it back out a mm or so.
Michael Kellough said:
???
Re: Tongue and groove bit set (and straight and dove tail bit set):
If i set the tongue bit all the way to the bottom and then adjust the depth of cut on the router, I can then switch to the groove bit, also setting the bit all the way to the bottom, and no additional depth adjustment is required.
What is the reason for not letting the shaft to bottom out in the collet? It cuts the setup time in half by letting the bits bottom out.
Cheese
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Packard said:
As you tighten the collet it puts a death grip on the router bit and it is actually pulling the router bit and collet further into the collet retainer. If the bit is already in contact with the bottom of the collet retainer, then the collet will not tighten up properly and will loosen up when the router is used.
Some people insert a small, undersized round rubber ball in the bottom of the collet retainer. Then when they place the router bit at the bottom of the collet retainer, the rubber ball will compress slightly allowing the collet to be properly tightened.
Michael Kellough
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[member=74278]Packard[/member] I’m not sure but I’ve read it many places. I’m guessing it has to do with giving the collet some space to seat down in the tapered hollow of the router spindle. Maybe it might not get tight enough? But I don’t think that’s likely in your case. (Thinking arms here) [wink]
Michael Kellough
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Cheese said:
Sommerfeld includes a half inch diameter rubber O-ring with his matched bit sets. You drop it into the router spindle before inserting the bit. It’s supposed to accomplish both what Packard wants to do (get matched bits at the same height without needing to move the router) and what the rubber ball does (making room for the collet to compress) at the same time.
Cheese
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Michael Kellough said:
Unfortunately, it appears that's no longer the case. [sad]
From their website on tongue & groove bits:
"The big key to this whole system is that both the Tongue & Groove bits are a perfectly matched pair in height. This allows repeated changing out of bits if necessary without adjusting the router. Every Tongue & Groove joint, no matter where it is used in the construction process, will automatically line up, fitting flush."
Yet there's no mention of an o'ring being included in the set and if you search for o'rings as an accessory, no results are returned.
Well, in the absence of any adverse effects from the practice up to now, I plan on continuing to allow the bits to bottom out to minimize setup.
I’m trying to picture in my mind how a collet would force the bit further down, but I’m only seeing squeezing going on. When I get home I will watch the action in my router.
In the meantime, I’ve been toying with using just mitered joints in the future. Switching back and forth between stub tenons and miters does not make sense to me. I’m comfortable with doweled corners. If I use miters, then only a dado blade is required.
But this is intriguing for dovetail joints. I’ll have to mull this over in my mind.
I’m trying to picture in my mind how a collet would force the bit further down, but I’m only seeing squeezing going on. When I get home I will watch the action in my router.
In the meantime, I’ve been toying with using just mitered joints in the future. Switching back and forth between stub tenons and miters does not make sense to me. I’m comfortable with doweled corners. If I use miters, then only a dado blade is required.
But this is intriguing for dovetail joints. I’ll have to mull this over in my mind.
Michael Kellough
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Cheese said:
Oh well, I never tried it anyway, the hole in the PC 7518 is too deep. Well, maybe I tried it. There is a 5/8” long piece of 1/2” diameter wood dowel in my Sommerfeld rail and stile kit so I must have at least planned to try it. [unsure]
Packard said:
It's a taper. That's how tapers work.
If your bit is bottomed out, then if nothing else you're forcing the collet against TWO friction surfaces, instead of just one. So your torque on the collet nut needs to be adjusted upwards. How much? That's the problem, right there.
Packard said:
Sooner or later you will find the bit jammed in the collet and unable to be removed without a bit if blunt force. Having been there and done that what I did was put a spacer between the under side of the bit and the collet nut and wound out the collet nut as a sort of press in reverse. From my memory it was this reason that the o'ring idea first came into use but I am going back many years and could be wrong.
To eliminate set up problems with matched sets such as tongue and groove get the heights correct then cut some samples and keep them as masters to avoid throwing the router and bits through a wall in frustration. [mad] [mad]
To avoid trying to buy hard to source 8mm bits it is possible to get a new collet made to suit the router, any decent machine shop should be able to do it.
Cheese
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Mini Me said:
1. I'll echo Mini Me's thoughts...just because you haven't been compromised...doesn't mean you won't be. You're a gun guy, and thus you take precautions with squib loads and hang fires seriously. This router bit bottoming thing is the same deal, you may or may not have an issue, but when it does come to fruition it's painful. When it goes wrong it can cost you the item you're working on, the time you've invested, a new router bit, a new router collet and hopefully not...a pile of bandages and some extra flesh.
2. I'd strongly suggest option 2. [smile]
