Chatter along Y axis during profile cuts

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Ryan Richardson
Posts: 17
Joined: Mon Nov 18, 2013 9:31 am
Location: Brighton, CO
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Chatter along Y axis during profile cuts

Post by Ryan Richardson »

As the title says, I’m getting a lot of chatter along the Y axis when my Black Diamond is doing profile cuts. It happens when doing straight cutout profile cuts with a 0.25” end mill and when doing chamfer cuts using a 0.5” 90 degree V-bit. The material I normally use can be anywhere from 0.5" to 0.8" thick.

The end mill is an up-cut spiral bit and I’m mainly cutting hardwoods like European beech, Maple, Oak, Cherry, etc. I take shallow cuts of 0.125” or less with each pass, and I’ve played with feed rates from 60 ipm down to 25 ipm, same results. I’ve tried router speeds from 23,000 RPM down to 16,500 RPM.

I end up spending a lot of time sanding and sometimes cannot quite get all the chatter marks out. Does anyone have any ideas for reducing or eliminating this? I’ve already added the aluminum gantry upgrade kit and aluminum angle brackets under the table to stiffen it.

Thanks.
Ryan Richardson
Brighton, CO USA
http://www.etsy.com/shop/dragonflywoodcrafts

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bill z
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Joined: Fri Sep 25, 2015 9:09 am
Location: Spring, Texas USA

Re: Chatter along Y axis during profile cuts

Post by bill z »

This may not be your issue but it did work for me.

I use a light coating of penetrating oil on the Y axis bars and screw when my machine starts chattering. Same on the Z axis. After applying, the chatter goes away.

Also, I have read on this forum, a well used router will develop an eclipsed bearing because of pressures on the same side too much of the time. This assumes the bearing is of the bushing verity.

Ryan Richardson
Posts: 17
Joined: Mon Nov 18, 2013 9:31 am
Location: Brighton, CO
Contact:

Re: Chatter along Y axis during profile cuts

Post by Ryan Richardson »

bill z wrote:This may not be your issue but it did work for me.

I use a light coating of penetrating oil on the Y axis bars and screw when my machine starts chattering. Same on the Z axis. After applying, the chatter goes away.

Also, I have read on this forum, a well used router will develop an eclipsed bearing because of pressures on the same side too much of the time. This assumes the bearing is of the bushing verity.
Thanks for the tips. I use the Dupont teflon silicone spray from Nextwave on the bars and screws for each axis, would the penetrating oil be a better option?

The router I'm using is a Porter Cable 892 that I purchased with the machine a couple of years ago. Is there any way to check for bearing wear without tearing the router apart, like measuring for runout at the collet or something?
Ryan Richardson
Brighton, CO USA
http://www.etsy.com/shop/dragonflywoodcrafts

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bill z
Posts: 342
Joined: Fri Sep 25, 2015 9:09 am
Location: Spring, Texas USA

Re: Chatter along Y axis during profile cuts

Post by bill z »

Try the penetrating oil once to see.

To check your router, you can cut along the inside of a 2 inch square and outside of a 2 inch circle using scrap. The circle should be perfectly round and just fit in the square. Listen to where the noise comes and goes.

Try and let us know.

Ryan Richardson
Posts: 17
Joined: Mon Nov 18, 2013 9:31 am
Location: Brighton, CO
Contact:

Re: Chatter along Y axis during profile cuts

Post by Ryan Richardson »

Sorry the delay in responding.

Today, took some time to remove the aluminum bed and thoroughly clean the machine and tighten all the fasteners I could get to. I was able to tighten some of the bolts on the Y axis carriage. I haven't gotten any penetrating oil yet but I did clean all the rails and screws and then lubed them well with the silicone lubricant.

I ran the test on a piece of European beech and here are the results. With my digital calipers, the circle measures 1.9965". The square measures 1.9815" along the X axis and 1.9670" along the Y axis. Obviously, the circle doesn't fit. Also, the circle actually tapers out as you measure down from top to bottom. Meaning, when I measure it at the top, it is 1.9965" in diameter, at the middle it is 1.9985" along X and 2.0000" along Y and the at the bottom it is 2.0045 along X and 2.0090 along Y. You can also see tool marks along the sides of the circle. I'll attach pictures to the post. The cuts were made with a 2-flute spiral upcut bit. I tried listening for noises, etc., and it did seem like the pitch changed a bit when it was cutting the square, each time it was at the lower right corner of the cut.

I still need to do some larger cuts to see if any of the tightening has helped with the chatter marks.

Also, using a dial gauge I'm measuring about 0.002" of runout at the collet and then about 0.004" of runout down at the bit.
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Ryan Richardson
Brighton, CO USA
http://www.etsy.com/shop/dragonflywoodcrafts

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