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Router bits + O-rings + bottoming out question

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Forum topic by Holbs posted 01-30-2019 04:57 AM 702 views 0 times favorited 7 replies Add to Favorites Watch
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Holbs

2349 posts in 2830 days


01-30-2019 04:57 AM

About to do my beginners attempt at the nicest cabinet I can make (surely will not be heirloom quality but better than my usual utilitarian look) using tongue & groove router bits. Was watching the Sommerfeld video with Marc S about placing an O-ring inside the collet shaft so that the matched router bits are at the same height during changing of the bits. What a great idea! I then did more research about router bits, o-rings, dowels, and bottoming out. I’ve always pulled any router bit up 1/16”-1/8” as you are suppose to but didn’t know why. The more I know :)
My Milwaukee 5625 router has a spindle shaft of nearly 2 3/4” from top of the collet down to the shaft bottom. I looked at some existing 1/2” router bits and they all vary in shaft length (I have not yet received the t&g router bits to see what lengths they are). Most bits I have are over 1” and less than 2” in shaft length. I know with a 1” collet, a minimum of 80% of shaft is required for safety purposes to be inserted into the collet.

Here is the snag: if my spindle shaft depth is 2 3/4” and avg 1/2” shank bit has a length of 1 1/2” inch… how is a o-ring dropped into the spindle shaft suppose to help? I’m thinking… it shall not. I measured the depth of my Bosch 1617 router and that had a 2” depth. Maybe Marc S had a shallower spindle shaft router. My existing 10-20 1/2” bits are no where close to bottoming out, even if an o-ring was sitting down there. Along my quick research, I read that some folk put wooden dowel down the shaft. That could work too except for the varying shaft lengths of router bits. Of course, I am assuming the o-ring or dowels stays down the shaft forever. Or do folks take them back out once done with certain bits?
I’m just afraid if the incoming t&g bits are 1 1/4” in shaft length and I put wooden dowel in the spindle shaft to keep same bit height for changes, what happens when I need to insert a 1 1/2” bit?
Or do I have this all wrong. That an o-ring does not go to the bottom of the spindle shaft itself of 2 3/4” down, but instead to the bottom of only the collet?
He does say “at the bottom of my collet for my o-ring”, does not say spindle shaft. Hmmm…. I thought collets are not tapered enough to hold an o-ring in place. And would leave cutting head so far away from the collet.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"


7 replies so far

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Rich

5687 posts in 1390 days


#1 posted 01-30-2019 05:40 AM

Marc Sommerfeld’s techniques all revolve around his quick setup ideas. He has the dial-in jigs and more. The idea with the matching bits, whether tongue and groove or rail and stile, is to have you drop in the bit and make the cut knowing it will be perfect. Does it work perfectly every time? I don’t know.

I always want to do a test cut before I commit to my good wood. Even my blog posts about flawless setups — and they are flawless — aren’t enough for me to ignore economy and just jump in with a cut on expensive hardwood without testing it.

While I strive for repeatable setups, I’ll always do test cuts.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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Holbs

2349 posts in 2830 days


#2 posted 01-30-2019 05:45 AM

The more I’m reading…the more I think I am wrong. You are not suppose to put o-ring down the spindle shaft but instead actually in the bottom of collet. But then, I read about using dowels. Surely, dowels would land on the bottom of the spindle shaft.
PS: took longest shaft router bit I had (in the picture way above on the left). If there was a o-ring or washer at bottom of collet, cutter head would be over 1/2”-3/4” above collet. Unsafe. Also, re-reading internet posts about the subject, I think there is confusion with vocabulary between bottom of spindle shaft (aka bore) and bottom of collet.
Yes Rich…I would strive to do as accurate repeatable setups as possible while always doing a test cut in the end.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

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Rich

5687 posts in 1390 days


#3 posted 01-30-2019 06:05 AM

I’m sure there’s something to the concept of setting the bit perfectly in the collet. How I work is to measure the height of the bit with a gauge when it’s set properly. I guess that takes more work, and Marc is definitely a seasoned pro, but it’s what I’m comfortable with.

The bottom line is to have a system that you’re comfortable with such that you’re not starting from scratch every time, wasting time doing that.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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Holbs

2349 posts in 2830 days


#4 posted 01-30-2019 06:09 AM

Rick…oddly enough, I actually have the Wixey and iGuage height jigs I forgot all about :) Thanks for reminding me.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

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shawnn

152 posts in 2165 days


#5 posted 01-30-2019 02:03 PM

I use my Wixey gauge to set bit heights then write down the height for the duration of the project to ensure I can get back to the same cut easily.

View Fred Hargis's profile

Fred Hargis

6303 posts in 3294 days


#6 posted 01-30-2019 04:23 PM

I’ve never seen that advice, but a good way to use the O rings is to put them on the shaft of the bit to support it up from the collet. Of course they have to fit snugly on the shaft….I’ve done this quite often, but not always.

-- Our village hasn't lost it's idiot, he was elected to congress.

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Holbs

2349 posts in 2830 days


#7 posted 01-30-2019 04:41 PM

Fred… yea. I’ll start adding o-rings to my router bits on the shaft right below cutter head to keep the collet far enough away from the flange (where shaft meets cutter head) and to give that little gap to tighten collet with both hands.
Putting o-ring/washer in collet to keep matched router bits at same height for changes … seems unsafe to me since the cutter head would not be 1/8” from collet but instead could be 1” or even more above the collet. At least, I believe the whole point of pulling a router bit up 1/16”-1/8” up from collet is to keep cutter head close as possible to collet.
I do like the idea of putting wooden dowels down the spindle shaft to keep matched set router bits even height. Would have to be 1”-2” type of dowels depending on the bit shank length.
For now, I bought the Wixey and iGauge initially for table saw blade height (don’t much care for the plastic housing on the Wixey) but can be used for router bit height as well that I’ll give a shot.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"

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