Problem With Spiral Upcut Bit

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Forum topic by gfadvm posted 04-17-2012 04:07 PM 1940 views 0 times favorited 32 replies Add to Favorites Watch
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14940 posts in 2927 days

04-17-2012 04:07 PM

Topic tags/keywords: upcut router bit problem

My Woodcraft 1/4” solid carbide upcut router bit will not stay chucked in my collet. If I start to route a 1/4” deep slot, it will creep to over 3/8” within 3” of routing. This is a 1/4” shank but I have no problems with ANY of my other 1/4” shanks. I have tightened it tighter than the other bits to no avail (but I haven’t tried torqueing it down REALLY hard as I’m afraid I’ll ruin my collet). Any suggestions? Edit: This is a new bit and I have cleaned collet and shank.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

32 replies so far

View a1Jim's profile


117417 posts in 3814 days

#1 posted 04-17-2012 04:12 PM

Have you used a Micrometer on it to see if it’s undersize.

-- wood crafting & woodworking classes

View gfadvm's profile


14940 posts in 2927 days

#2 posted 04-17-2012 04:17 PM

a1Jim, I don’t have a micrometer but that’s a good thought. I assumed that buying a quailty bit would give me an accurate shank diameter. Maybe not.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Monte Pittman's profile

Monte Pittman

30142 posts in 2575 days

#3 posted 04-17-2012 04:17 PM

I have one that does that also. Not sure why though. Ruined a couple pieces because of it. Causes some definite noise pollution to occur :-)

-- Nature created it, I just assemble it.

View a1Jim's profile


117417 posts in 3814 days

#4 posted 04-17-2012 04:22 PM

If Woodcraft is not far away you might have them mic it for you ,if nothing else they should have calipers to check it.

-- wood crafting & woodworking classes

View Sawkerf's profile


1730 posts in 3306 days

#5 posted 04-17-2012 04:25 PM

If you’re using a reducer to accomodate a 1/4” shank, make sure that it’s lined up right before you tighten the collet nut.

My reducer has a narrow slot that runs the full length of it. That slot needs to line up with a similar slot in the 1/2” collet or the bit will move. When the slots are lined up right, it’s rock solid.

-- Adversity doesn't build reveals it.

View Loren's profile


10477 posts in 3885 days

#6 posted 04-17-2012 04:45 PM

I would take it back or measure it to make sure the
size is accurate. Carbide shanks tend to smoother
than the steel ones. It may be worthwhile to rough
up the shank.

Collet reducers do vary in size. So do bit shanks.

View DS's profile


3045 posts in 2658 days

#7 posted 04-17-2012 04:55 PM

There is a high likelyhood that your collet is worn.

Router bits, especially solid carbide bits, are manufactured to a very tight tolerance.

Though it may be possible to get a size mismatch, (never, ever have I seen this), the worn collet is the most probable cause, IMHO.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View KenBee's profile


109 posts in 2873 days

#8 posted 04-17-2012 05:00 PM

I agree with Loren about collet size. I just bought a new DeWalt 611PK and the collet must be undersized, because even off the router it is a struggle to insert a 1/4 inch bit into it. I tried 3 or 4 different bits and all were the same.

I also have a Spiral Upcut bit that will work its way out of the collet in 3 of my routers that I have tried it in. That one bit is the only one of my 1/4 inch shank bits I have used that will work its way out though.

-- If it won't fit get a BIGGER hammer.

View Dallas's profile


3599 posts in 2724 days

#9 posted 04-17-2012 05:22 PM

Sounds like a metric shank on a SAE/Imperial collet. Metric: 6.000mm, Imperial 1/4”: 6.35mm

.35 mm is 0.01377952755905511”

-- Improvise.... Adapt...... Overcome!

View longgone's profile


5688 posts in 3546 days

#10 posted 04-17-2012 05:58 PM

andy…it seems as if this a common issue with several people and I have had the same problem with my 1/4” shank bits. I use a 1/4” spiral upcut to cut the channels for my box bottoms and noticed creeping with the 1/4 shanks. I switched to 1/2” shanks and have not had a problem since. I guess it grabs tighter on 1/2 shanks due to greater surface area. I use the whiteside router bits and have been extremely happy with them.

View gfadvm's profile


14940 posts in 2927 days

#11 posted 04-18-2012 12:31 AM

Thanks for all the input guys. My collet is a 1/4” (not an adapter) and note that this is the only bit I have ever had problems with. I tend to think that the upcut configuration tends to pull upward on the bit. The next time I go to Woodcraft, I’ll see if they can measure it but it is a 60 mile round trip so I’m waiting until I have to go for something else. Greg, I bought this one to cut the channels for my box bottoms. I may see if they’ll exchange it for a downcut.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View mcase's profile


446 posts in 3366 days

#12 posted 04-18-2012 12:50 AM

Sixty miles? Well that makes for an afternoon trip. Why drive sixty miles to pay Woodcraft prices? You may be better off ordering online from a reputable router bit manufacturer. Try Whiteside, Better prices, better quality and American made.

View NiteWalker's profile


2738 posts in 2814 days

#13 posted 04-18-2012 01:27 AM

A great place to get whitesides.

-- He who dies with the most tools... dies with the emptiest wallet.

View jumbojack's profile


1685 posts in 2861 days

#14 posted 04-18-2012 01:44 AM

Andy when you chuck your bit do you back it off a bit? That is do you send the bit to the bottom and then tighten. If so that could be your problem. when you chuck your bit, back it up an 1/8” or so. Some bits have a bit of a shoulder on them where the base meets the cutter. Give it a try.

-- Made in America, with American made tools....Shopsmith

View gfadvm's profile


14940 posts in 2927 days

#15 posted 04-18-2012 02:21 AM

Did that Jumbojack even though this type bit has no shoulder. Still creeps up.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

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