Pattern routing grief

[Brian Holcombe]

Afternoon gents. I'm doing to pattern routing for chair parts and running into a bit of trouble here and there. I'm getting catches where I have not expected them and I can't quite understand it. I'd appreciate any insight.

The arrows show the direction I have been feeding when successful, but what confuses me is why the inside curve wants to be routed against the grain. I don't recall it having such preference last time I performed this operation (which was with walnut and ash) but for some reason it seems to prefer it here.

The catches have been completely unnerving and so I want to better understand what I'm doing here to prevent any kind of injury.

[andy bessette]

Prior to routing, trim as close as possible to the line. Then pattern route only about 1/4" deep. Finish with full length bearing follower.

[Tim Bueler]

Since I see a router table in the picture I assume you're using that and not a hand held router. Judging by your arrows it looks like you're feeding into the grain, on both inside and outside curves, which does lead to catching, tearout, etc. Try flipping your set up over and feed your work piece into the bit in a counter-clockwise rotation all the way around. If my brain is working the way I hope that will put you feeding with the grain, so no grabbing. If I'm upside down I'm sure someone will correct me. The point I'm trying to make is you'll have better results feeding with the grain.

[Jon Grider]

What Tim said.

[johnny means]

Looks like you're climb cutting that inside curve. So your cutter is biting in and trying to pull the piece in.

[Brian Holcombe]

Andy, I trimmed very close, within 1/16"

Since I see a router table in the picture I assume you're using that and not a hand held router. Judging by your arrows it looks like you're feeding into the grain, on both inside and outside curves, which does lead to catching, tearout, etc. Try flipping your set up over and feed your work piece into the bit in a counter-clockwise rotation all the way around. If my brain is working the way I hope that will put you feeding with the grain, so no grabbing. If I'm upside down I'm sure someone will correct me. The point I'm trying to make is you'll have better results feeding with the grain.

Tim, what you're describing is exactly what I was doing when the bit caught, both times feeding into the grain. That's my reason for this post is that I can't quite understand why it worked successfully feeding against the grain.

[Brian Holcombe]

I know to avoid climb cutting, that's not my question. The arrows note the successful attempt, not the times when It grabbed. That is why I'm wondering what the problem is, as they're often breaking the rules of cutting with the grain and yet the bit cut nicely in those directions and did not when I was doing as I should be doing.

I should be going the opposite direction of those arrows on the inside curve, and yet when I did so it grabbed terribly.

[Mel Fulks]

A shaper with steel knives would be better. The raggedy saw cut edges of the material make tear out worse. Try using sandpaper to quickly remove those square rough corners before the trimming. It can keep the sweater from unraveling.

[Mark Hennebury]

brian.jpgFlip your wood and pattern over.

[Brian Holcombe]

Given some after-hours contemplation and another attempt this morning, I figured out what I was doing wrong.

I'm a bit of a chicken when it comes to pattern routing so I had been taking small bites, then getting out of the cut, backing up and taking more. I was thinking that making short cuts rather than one long continuous cut would allow me to regroup at the end of each cut but it was instead making it so the bit had a chance to grab as I re-entered the cut.

So, to those following my folly, don't take this stupid approach.

[Tim Bueler]

brian.jpgFlip your wood and pattern over.

Marks picture is what I was trying to describe.

[Brian Holcombe]

I'm certainly understanding what you guys are saying. I have a feeling that the short-cuts approach was what was causing the issues, rather than direction of the cut.

I had the same problem on the back side, but I think it has more to do with the pattern on that side of the arm. The pattern doesn't have a lead-in and I think that is also causing issues, so I'm working on that now also.

Appreciate the insights.

[Brian Holcombe]

On the backside of this arm, I was getting a grab at the outside corner. I'm thinking this was due to the lack of a lead-in, so I set the tool fence to limit depth of cut and that seems to have cured the issue. This is what I'm talking about:

[Ken Fitzgerald]

Given some after-hours contemplation and another attempt this morning, I figured out what I was doing wrong.

I'm a bit of a chicken when it comes to pattern routing so I had been taking small bites, then getting out of the cut, backing up and taking more. I was thinking that making short cuts rather than one long continuous cut would allow me to regroup at the end of each cut but it was instead making it so the bit had a chance to grab as I re-entered the cut.

So, to those following my folly, don't take this stupid approach.

No offense Brian but you don't have the patent on using stupid approaches.


By the way, while pattern routing I turned off my plunge router, flipped the router over releasing the depth lock as I flipped it. I looked across the shop at my telephone where I'd received a phone call just a minute earlier joyfully announcing the successful surgery of a dear family member. I pushed the router down another 1/4" while looking at the phone. My wrist happen to be over the bit which hadn't quite stopped yet. My wife was at lunch at the elementary school from which she's retired. Luckily for me neighbors were at home and took me to the ER. 14 stiches later things were better. Eventually the minor nerve damage resolved itself and the numbness in the area between my thumb and the palm of my hand went away. No sir. You don't have the patent on stupidity.

[John M. Smith]

Whiteside makes an excellent bit fir doing this. Pricey, but I've gone any way towards the grain with no catching or tear out.