Thread: Dovetail Tearout

Umm, cut them by hand?

What sort of jig are you using?

How fast are you moving the router? Maybe you need to slow your feed rate down.

Try cutting by scoring the outside of the cut with the spinning router bit before you plunge it in. Run along the entire cut first, taking a shallow cut all the way across, then gently cut in.

It's hard to explain but the technique is shown in the Gifkins Video, which should be on that DVD I made for you.

Thanks all,

Feed rate could be a problem and the idea of running across the fronts sounds good. I expected the Kauri not to be so brittle, but there you go.

Its a Leigh D4R dovetail jig (60cm) and I'm using a Festool OF2000 router with a CMT 1/4" shank, 19mm cut depth, 8 degree bit.

Unfortunately, my hand won't fit in the collet. and I don't have one of those beautiful Lie Nielson dovey saws like DPB

Thanks again,

Rob

Try some climb cutting (reverse cutting) taking small bites as you go. I use small arcs, working from right to left. Also backing up with a stiff timber is a good thing as long as it's clamped TIGHT against the work piece.

Problem is yer crappy router, send it to me and I'll swap fer a quality GMC one.

Rob,

Gumby and Major are on the right track. A little scoring, a little climb cutting and a gentle hand. I converted a large pile of scrap to firewood working on this problem. Tried tape on the outside of the wood, etc. etc.

Nowadays, I plunge the left side of the tail normally and climb cut the right side (Rockler Jig) which seems to work pretty well.

The DVD that comes with the Leigh jig shows the climb cutting technique, and recommends it to reduce tearout.

Tex

Hi all

Tex, do you reckon I could find that rotten DVD?!!

My plan of action is to do as you guys have suggested. Couple of things by the by.
1. I have been using a board tight up against the back of the workpiece, but I have been using sidegrain, which I believe does not give adequate support for the cutter.
2. I'm thinking of using a spiral upcut bit to remove the majority of stock, then use the dovetail to create the edges.
3. Yesterday was one hot day and seemed to affect the routing rather badly in other ways, such that a firmly seated bit would slip during routing and so my pin board has 22mm deep troughs as opposed to the 19mm I set!
I'll try again today and report back with visual aids.

Thanks very much guys,

Regards,

Rob

Have you thought about sharpening the bit, or giving it a clean.
My CMT did that after it clogged up with resin, quick clean and all was well.

Hi all,
Thanks Iain, that did cross my mind, but it was a new bit out of the box yesterday.
Normally, I would use an 8mm shank Leigh bit, but lately I've had problems with them falling out of the 8mm collet while running.:eek:

I've attached a pic of the last HB tails I ran and this is what I have found.

1. Drop Router speed to Mark 4 (not mach 4 )
2. The D4R uses plastic bridges between the fingers to ensure you don't route everything. If these are not precisely fitted, you end up with a raised profile in relation to the pins, which means you drop down into the trough rather than having a smooth entry. At high router speed this is a worry.
3. The backing board needs to be "taller" than the workpiece, otherwise you get the same situation as above,i.e. there is a chance for tear out at the face top of the tail.
5 While Leigh do not say as much, I believe that you need a finger to the right of the last cut. This gives stability to the router and allows an easier ride up cut.
The piece below had all of the above fied except for the extra finger and the wider backboard. This translates as the chip at the top of the face of tail #2 and the cutout on the left half tail, where the exr=tra finger would be used.
Its getting too hot now to continue as I don't widh to set fire to anything.

Thanks again and I'll show youse all the finished product with notes later.

Regards,

Rob

Cutters loosening can be caused by the cutter bottoming in the chuck. When you put the cutter in, lift it slightly off the bottom of the chuck before tightening. I suspect it's something to do with vibration being transmitted. Also, as Iain says, keep the cutters cleean. I use Mr. Muscle oven cleaner.

Hi everyone,
First, thanks very very much for the assistance. The beauty of these forumbulata is that you can show what a complete fool you are and still have people show patience in directing you back to the real world. Without all your suggestions I would still be making Fijian firewood.

I've attached a pic. I'm now looking forward to the finished drawer. Honey/pink of the Kauri against the Chocolate brown of the Walnut. There is one small nick at the top of tail #2, but this is surmountable with a new backing board. (The two angry beavers are due back to get theirs.)

I returned to using the 8mm shank, but using a 12.7-8mm reducer in a 12.7mm collet. Worked beautifully.
I took the router back to mark #2 and instantly got better results.
Interestingly, the 8mm collet ransomed by Festool has difficulties maintaning a grip on cutters. In one attempt this PM, the cutter dropped a full 2mm over a 120mm board:eek: . Chase this up I will have to!

Thanks everyone again.

Regards

Rob

Rob
what's with the Felder folder
you having a stealth gloat??