Domino DF 500 in red oak

[jt42]

I'm on my second project using the Domino DF 500 connected to a CT 26 E dust extractor.  My first project used 4 mm and 5 mm tenons.  One problem I frequently had was the tool would "grab" or "jerk" when plunging.  I know I need to plunge slowly, and I do.  I also apply as much pressure as I can on the front knob to hold the tool firmly on the work piece, but despite this it seems every 3rd or 4th plug I get the grab / jerk thing which ends up causing some tear-out (annoying, but generally not an issue since it will be covered by the joining piece), and sometimes causes the tool to move off my line.

Today I started my second project with the Domino, this time with the 6 mm cutter -- first use of this cutter.  I made test mortises in two pieces to confirm alignment, using the same material as my project (again, red oak).  Both of those went well.  Then I started making mortises in my work piece.  The first one went very well.  The second one did the grab / jerk thing.  I stopped the tool, moved it back to my line, and tried again.  This time I noticed more resistance when plunging.  When I got done, I discovered the mortise was thinner than the previous one and the two test mortises.  I tried two more times, and they, too, were too thin.  Upon inspection of the bit, it appears to have suffered some minor damage at the tip.  So I got three excellent mortises from the 6 mm cutter before it broke.

Any thoughts on what I'm doing wrong?  Or any hints for using the tool with red oak?  I'm plunging slowly.  I've confirmed the dust extractor is working.

 

[luvmytoolz]

I do loads of oak with mine but I've found the "grab" to be an issue mainly when using the DF500 in vertical mode to cut slots in the face of a board. For normal edge slotting I always reference from the top and hold the front fence with a death grip while slowly plunging, and it's only when I accidentally push too fast I feel it give a fraction of a jerk.

However I can't see how the cutter would have been damaged pretty much immediately by just the third slot, even if you were plunging aggressively. Very strange, I wonder if the cutter was defective to start with, or had been dropped?

 

[Crazyraceguy]

Although it is possible that your 6mm cutter was damaged, either straight out of the box or from dropping, I have never had that issue. I have even used aftermarket cutters from Amana and they work equally well.
I'm thinking that this must be a technique thing. You really shouldn't need a "death-grip" or exceedingly slow feed rate. The initial contact needs to be smooth, you should almost not feel it, then proceed steadily.
I use mine in White Oak all the time, with zero issues. You may experience a slightly different feeling in end grain, taking slightly more force, but it shouldn't be a big deal.
The tip of the cutter is very close to the fence. It takes very little movement before contact is made, so be smooth there.

 

[ChuckM]

Like CRG, I haven't experienced any issues using the 6mm cutter from Festool, which is still the cutter I have for my projects.

Is it possible that when you did the third or fourth cut, you unintentionally moved or lifted the machine before the cutter stopped spinning and was fully retracted? The cutter might have suffered some damage when its corner hit the wood. I once broke my 4mm cutter because I tilted the machine before the cutter was fully retraced.

 

[ear3]

[member=81866]jt42[/member]

This is unusual behavior for a normally functioning domino (even in very hard woods), which is why the suggestions have been technique.  If you have those capabilities, you could always upload a video of a you doing a plunge if you wanted some specific guidance or troubleshooting in that area.  Another possibility might be the stock you're working with, viz. whether it is truly square and flat.  If your edge is not true 90, then there will be a slight gap either between the fence or the machine face side, which would provide enough play for the sort of jerking you are describing.  Even when you do have a true edge, it can happen sometimes (especially when trying to hold the machine against the board with too much pressure), that you elevate the fence slightly above the face of the board, which will also lead to the jerking.

I'm on my second project using the Domino DF 500 connected to a CT 26 E dust extractor.  My first project used 4 mm and 5 mm tenons.  One problem I frequently had was the tool would "grab" or "jerk" when plunging.  I know I need to plunge slowly, and I do.  I also apply as much pressure as I can on the front knob to hold the tool firmly on the work piece, but despite this it seems every 3rd or 4th plug I get the grab / jerk thing which ends up causing some tear-out (annoying, but generally not an issue since it will be covered by the joining piece), and sometimes causes the tool to move off my line.

Today I started my second project with the Domino, this time with the 6 mm cutter -- first use of this cutter.  I made test mortises in two pieces to confirm alignment, using the same material as my project (again, red oak).  Both of those went well.  Then I started making mortises in my work piece.  The first one went very well.  The second one did the grab / jerk thing.  I stopped the tool, moved it back to my line, and tried again.  This time I noticed more resistance when plunging.  When I got done, I discovered the mortise was thinner than the previous one and the two test mortises.  I tried two more times, and they, too, were too thin.  Upon inspection of the bit, it appears to have suffered some minor damage at the tip.  So I got three excellent mortises from the 6 mm cutter before it broke.

Any thoughts on what I'm doing wrong?  Or any hints for using the tool with red oak?  I'm plunging slowly.  I've confirmed the dust extractor is working.

 

[smorgasbord]

Upon inspection of the bit, it appears to have suffered some minor damage at the tip.  So I got three excellent mortises from the 6 mm cutter before it broke.

The Domino bits are carbide tipped, which is quite brittle. Still, it's extremely unlikely it got chipped in wood, even a hard wood like red oak. That would come from hitting a nail or screw or dropping the tool, etc. Also, if the resulting mortise isn't 6mm thick, then the damage to the bit is more than "minor."

 

[jt42]

Update: I purchased another 6 mm cutter and tried again.  First I re-did the three thin mortises from yesterday and that went well.  Then I did about 30 more and they also all went well.  There was almost no grabbing this time, too.

 

[bobtskutter]

You need to plunge the machine without tipping it.
If the machine is being held horizontally with your left hand on the fence and right hand on the motor body, you need to push the motor body WITHOUT lifting it - it's not easy to get the proper way to move the motor.

Try holding the motor in your right hand as close to the end of the machine as you can, at the very end close to the power connector.  Push the motor from the end trying to use your elbow as a pivot.

It also sounds obvious but make sure the adjustable fence is sitting SQUARE to the work piece.  If it's a small work piece the fence with handle can "tip off the back" since the design is almost a pivot.

Regards
Bob