Help using router trim bit

[Dave Carey]

I need some help using a straight trim bit. I have a 1" bit with the ball bearing on the top in my router table and am trying to trim around an irregular shaped pattern fastened to a piece of 3/4" MDF with double sided tape. No matter how I feed the piece into the bit it grabs and kicks back. Do I need to use a slow speed? Is there some other secret I'm missing? Appreciate any tips!

[Ed Kowaski]

I think you need to supply more details about what you are doing.

How big is the piece.
What shape.
How much are you tying to take off
How and where are you starting the cut
Apparently.... We like pictures! :)

That type of stuff. Something is not right, recommend you stop for now.

Ed

[Russ Massery]

Also what direction are you feeding the workpiece into the bit?

[Dave Carey]

Ed,
I've definately stopped until I figure this out. The kick back is just too scary. The piece is about 3" x 5" with two relatively staight sides and two curved sides. I've attached the pattern to a piece of 3/4" MDF and cut out the blank with the band saw leaving about 1/8" "extra" outside of the pattern. If I use the router table fence to trim the straight sides I can control the kick back somewhat, but on the curved sides the bit will bite in and kick the piece out with a noise and action similar to trying to make a climb cut. Don't know that a picture would help (or that my photographic skills are up to the task!) Dave

[Dave Carey]

Russ,
Using the router table i'm feeding the piece from right to left with the bitspinning clockwise, ie the same set up I've used for every other bit without a problem.

[Corey Hallagan]

It sounds to me like the biggest problem is the work piece is pretty small with a good sized cutter and doesn't allow you to get a handle it to control the kick back and feeding. Small workpiece with big cutter usually leads to some kickback and can be dangerous. DAMHIKT :) Can you affix the piece in something like a hand screw or some other clamp to lay it flat and give you more leverage to control the kickback?

Corey

[Ed Kowaski]

Dave the bit spins counter clockwise as viewed from the top in any router table I've seen. Clockwise when hand held.

As Cory said the piece is very small. His idea is a clamp idea good one.

Ed

[Doug Shepard]

In addition to the hand clamp suggestion, I'd also try cutting closer to the line. Like 1/16 or 1/32 oversize instead of 1/8". Also, do you have one of those starter pins? Those usually make a world of difference.

[Dave Carey]

Got that northern hemisphere, southern hemisphere thing going for me tonight re the spin direction! I'll try again tomorrow with less waste to remove and with the piece clamped securely (and even give the pin a try.) Appreciate the tips and everyone taking the time to help. Cheers.

[Norman Hitt]

Dave, one other thing that would help considerably would be to have the pattern board longer on one side, to give you a starting point, so that using the starter pin, AND the longer pattern at the same time, it would allow you to have the pattern solid against the starter pin, and the Bearing of the cutter BFORE the cutter started it's bite into the workpiece. This method, however would not allow you to go completely around the workpiece in one operation though.

Hope this makes sense.

[Jerry Todd]

Dave,
After a minor mishap on my router table I ordered this item they call the "Finger Saver". It has not arrived so don't know that much about it. Try this link for a picture: http://www.eagleamerica.com/product.asp?pn=420-1010
EAGLE AMERICA sells it for about $15.00.

[Rick Shelton]

Dave,

When routing small pieces like that, I have better luck using a handheld router and a router pad. I would never try what you're doing with a router table. Too many things can (will) go wrong. I cringe just thinking about it.

[pat warner]

"I need to use a slow speed? Is there some other secret I'm missing? Appreciate any tips!"
_________________________________

The problem is lousy clamping. For max safety and workpiece to templet rigidity, toggles & fences are required. They'll block in the work and it will not slip.
Note that cutter traction goes way up in end grain and overcomes the tack in the carpet tape. The work often flies away just when you start cutting end grain, usually right at the transition.

To reduce the traction, cut the work as close to the templet dimension as possible. To keep the process risk free, rout in stages with a plunger and no temporary glues or tape. 1/10 the full thickness cut reduce the traction enormously. 5 or 10 cuts with a fast plunger and a small workpiece goes pretty fast. I'd bet on success with light plunge cuts.
Routers (http://www.patwarner.com)

[Dewayne Baker]

I agree with what Norman said. I do a lot of pattern routing and the only time I have had a problem with carpet tape not holding securely is when I tried to reuse it. I try to make my template longer than the work piece to provide a place to stop the bearing on the template before contacting the work piece. If that's not possible you need to use a starting pin. You place the piece against the pin and ease it in to the bit. This gives stability and control.

I always use safety push blocks as well. Pic below illustrates starting pin.

31692

If you RT table is not so equiped you can drill and tap a hole and thread a machine screw. Hope this helps.

[Dave Carey]

Again thanks to everyone for the tips and suggestions. It's what I love about this forum. I just wish I had asked the question BEFORE I tried to use the bit. Fortunately no permanent damage done. Jerry - $15 sounds like a bargain to keep my fingers safe. My next act is to order one. You guys have been very helpful. Cheers