Jumping DF 500

[Naildrivingman]

I've noticed that my DF likes to jump from side to side when plunging into hardwood. It seems that no matter how hard I bear down, it still can jump. I make every effort to plunge straight in with my hand gently grasping the barrel at the extreme rear. My bits are nearly brand new. I have not noticed this in softwood and my hardwoods have been hickory and red oak.

Thoughts?

Thanks,
Chris

P.S.  What is the reason for adjusting mortise width with the machine running?  Can I damage the machine if I switch between width when in the off position. I try to follow directions, but that is one I seem to forget. I don't really want to wreck an expensive machine. Thanks again.

 

[flair woodworks]

I'm not sure that I've mortised stock as hard as hickory. Have you tried slowing down your plunge rate as slow as possible?

The reason to switch mortise widths while the machine is running is to ensure the gears mesh cleanly. When shut off, you may notice that sometimes it is easy to turn the dial and other times it's not.

 

[HarveyWildes]

I've noticed that my DF likes to jump from side to side when plunging into hardwood. It seems that no matter how hard I bear down, it still can jump. I make every effort to plunge straight in with my hand gently grasping the barrel at the extreme rear. My bits are nearly brand new. I have not noticed this in softwood and my hardwoods have been hickory and red oak.

Thoughts?
...

The oscillating motion of the bit gives the tool some sideways momentum.  I put a dent in the base plate once when I was holding the tool loosely and it jumped with a fair amount of force.  If you think about how the blade moves, it would take a lot of jerk to be able to force the blade housing into the base like that.  Festool fixed the base on warrantee, but it still concerns me - I don't want to do it again.

To minimized the tool movement, I've adopted the following technique
*  I always make sure that the work piece is securely clamped to a workbench. Clamping elements are your friends.
*  I always make sure that I have a firm grip on both the fence and the barrel.  I'd be a bit leery of a gentle grasp.
*  I try to plunge slowly enough to keep the natural vibration of the tool at a minimum.

I don't think I've used my Domino on softwoods at all - primarily cherry and oak, with a smattering of other woods like sycamore, jatoba, ganadillo.  If I keep to my technique, it works just fine in all of them, though the harder the wood, the more I feel the oscillation vibration.

 

[Stone Message]

I do most of my Domino work with oak, maple and mahogany. The only time that I clamp a work piece is if I am putting a slot on the flat face near the end of a piece. The rest of the time I either react the piece (no clamps) or have the piece between a pair of Parf Hats but again no clamps at all.

The other contributors are right - a slow plunge rate is important (2-3 secs with the DF500 and 3-4 sec with the DF700). You must use a dust extractor and whatever you do never put your hand or fingers on the opposing side of a slot whilst cutting in case you have bished up the depth setting.

You will see all sorts of Domino work in this video showing the main construction of my mobile bench:


Peter

 

[bdiemer]

The domino 500 will also jump if you try to plunge before it is up to full speed.

 

[Birdhunter]

I've done mortises into endgrain Ipe which is extremely hard without seeing any jumping. I do clamp firmly and have a firm grip on both barrel and front handle. A slow entry into the wood is crucial. An abrupt entry can cause the Domino to jerk and/or break the bit.

 

[Sparktrician]

It will lurch side-to-side if you're plunging too quickly.  Slow down!  Take your time plunging.  Listen to the motor.  If the motor slows down significantly when you plunge, you're plunging too quickly. 

 

[Cheese]

Just to bring the Big Green Egg discussion back to life...just remember the words, Low & Slow.

Use a Low initial entry feed speed and maintain a consistent and "relatively" Slow feed rate.

FWIW...conventional 10/8/6mm twist drills are recommended to rotate at 1500 rpm in hard woods. In the Domino, those same sized bits are being spun at 24,000 rpm. So when they contact the surface of the wood, they will bite with much enthusiasm if the entry feed speed is high.

I've found it best to be very prudent when first contacting the wood surface, after the initial bit contact, a faster feed rate can be generated as it has less impact 

 

[Naildrivingman]

Thanks all. I thought I was plunging slowly enough, but I will go even slower next time. To date I have done all my mortises on the middle setting. I use the domino for alignment of planes and not edges. I'd better develop good technique soon, because eventually I will want to be able to create framework with even corners.

The reason I put more pressure in front vs rear is because on my first attempt, I badly misaligned planes because I tilted the cutter up due to too much down pressure on the barrel.

 

[Stone Message]

Thanks all. I thought I was plunging slowly enough, but I will go even slower next time. To date I have done all my mortises on the middle setting. I use the domino for alignment of planes and not edges. I'd better develop good technique soon, because eventually I will want to be able to create framework with even corners.

The reason I put more pressure in front vs rear is because on my first attempt, I badly misaligned planes because I tilted the cutter up due to too much down pressure on the barrel.

I only use the narrow setting unless allowing for movement. The wider setting will give more lateral force.

Peter

 

[Cheese]

...I badly misaligned planes because I tilted the cutter up due to too much down pressure on the barrel.

That's the reason I grip the end of the Domino very lightly, just enough to hold and control it. I also found out that when I put the death grip on the Domino, I have a difficult time feeding the Domino slowly...the feed rate becomes uneven and jerky which results in the cutter grabbing.