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Trouble Routing Sharp V Grooves

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Forum topic by pkunkel5 posted 01-03-2009 09:59 PM 1219 views 0 times favorited 23 replies Add to Favorites Watch
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pkunkel5

18 posts in 3381 days


01-03-2009 09:59 PM

Topic tags/keywords: router v-groove v groove shaping

I’m getting a small amount of apparent wobble in my router bit that is causing the tip of my V-groove to be wider than desired (getting a consistent 1.5mm valley). The bit is sharp, new, and of high quality. The router is high quality, and almost new. The table/insert is cheap, and light-weight, but I can not find any source of movement here. I tried turning the bit (in router) by hand to see if it carverd a sharp hole in a test piece—it did. So I think the wobble is coming from the high speed action of the router. I’m actually running a little above the bit’s spec’d max. Any suggestions? I’m considering trying to slow the RPM’s with a voltage regulator—bad idea?


23 replies so far

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ChicoWoodnut

904 posts in 3720 days


#1 posted 01-03-2009 10:02 PM

Does it vibrate? How big is the bit and shank? Is the collet clean?

-- Scott - Chico California http://chicowoodnut.home.comcast.net

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lew

11941 posts in 3660 days


#2 posted 01-03-2009 10:09 PM

What is the brand/number of the bit?

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

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pkunkel5

18 posts in 3381 days


#3 posted 01-03-2009 10:50 PM

The bit is an Amana 45deg, 1/2 shank, insert type. Yes, I’m using a router table—good fence, but the rest is crap. Wood is a hardwood. V-groove is only about 5mm deep. I’m not noticing any vibration. Other questions? Ideas? Thanks!

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ChicoWoodnut

904 posts in 3720 days


#4 posted 01-03-2009 11:08 PM

Hmmm,

If there is no runnout and the bit is running true then I’m out of ideas. As for slowing the RPM with a voltage regulator, can’t help you there either; my Bosch has variable speed. IME slower speeds are for bigger bits.

-- Scott - Chico California http://chicowoodnut.home.comcast.net

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Scott Bryan

27251 posts in 3726 days


#5 posted 01-03-2009 11:35 PM

One thought I had was are you using a featherboard to hold the stock tight to the fence? I have found that this improves my pieces when I make molding, especially on longer pieces where I am having to reset my grip on the piece to keep it moving.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

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pkunkel5

18 posts in 3381 days


#6 posted 01-03-2009 11:39 PM

Regarding dadoe at 45deg suggestion… the groove I need is 45deg, not 90 deg (two 45’s). I’m thinking your idea would cut a 90deg groove (layed over on a 45). Or did I miss something?

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lew

11941 posts in 3660 days


#7 posted 01-04-2009 12:13 AM

Have you tried this- do a stationary plunge cut. Don’t move the work piece. Shut off the router. Check the bottom of the hole. Is it a point or is it “flattened”?

The reason I ask is, even though the router bit comes to a point when it viewing from one position, if you turn the bit 90 degrees and view the “point” it will be wider due to the thickness of the carbide cutter. This may be causing the problem.

Just a thought.

Lew

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

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ajosephg

1880 posts in 3465 days


#8 posted 01-04-2009 01:37 AM

If the bit comes to a point, if there is no run out, then it seems to me that it boils down to vibration.

Vibration could come from:
1. The router to table connection
2. The whole table or parts thereof. You mentioned that it is cheap table. May be that the “flat” surface is “oil canning.”
3. The stock.

Even though every thing seems solid at rest, things change a lot with a bit spinning at 20K rpm. Even though you can’t feel it, there could still be some vibration.

My guess is that the stock is vibrating due to the action of the bit on it. I’d try the following in the order listed.:
1, Evaluate how you are controlling the stock.
2. Feed at a faster rate
3. Slow the rpm down with a speed control.

Another experiment would be to make a cut on a piece of scrap with a handheld router. (Different router or take the one you have out of the table..) If the problem goes away, then wouldn’t it have to be the table and/or stock control?

-- Joe

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jeffthewoodwacker

603 posts in 3709 days


#9 posted 01-04-2009 02:52 AM

I would agree with Joe. There is probably some slop in where your router base attaches to the router table.

-- Those that say it can't be done should not interrupt those who are doing it.

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pkunkel5

18 posts in 3381 days


#10 posted 01-04-2009 03:14 AM

Thanks for all the thoughts. I still believe it is some form of vibration either in the tool or in the table. I’ll try some of the thoughts provided. Some more info… I believe that I can see the wobble when the bit is spinning free at speed (mounted in the table). For note, it’s a porter-cable router turning at 27K and the bit is rated to 25K. Does anyone know a way to slow this down to 20K i.e. like via a rheostat? One test I’m thinking of is to run some thicker stock through it. Thanks again.

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ajosephg

1880 posts in 3465 days


#11 posted 01-04-2009 03:26 AM

Rockler has a speed control for $50.00. (If your PC doesn’t have a soft start.) Don’t try to use a rheostat even if you could find one with enough wattage.

PS – With all due respect I don’t think you can see a bit wobble at 27K.

-- Joe

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pkunkel5

18 posts in 3381 days


#12 posted 01-04-2009 07:47 AM

Thanks Joe. Maybe “wobble” is the wrong term. I can see that the tip, though a blur, is rounded over, like the cut I’m getting.

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lew

11941 posts in 3660 days


#13 posted 01-04-2009 08:07 AM

As mentioned above, I think it is impossible to get a perfect “V” groove with this type of bit.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

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ajosephg

1880 posts in 3465 days


#14 posted 01-04-2009 03:22 PM

The more I think about it, I think Lew is right.

-- Joe

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pkunkel5

18 posts in 3381 days


#15 posted 01-04-2009 09:52 PM

OK. I did a couple of tests, and seem to have confirmed my need to slow the rpms. When I feed thicker stock, I get the same flat tip or valley in my groove. However, if I feed it really fast, enough to noticably slow the router, the valley narrows. Anyone disagree?

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