New DF500 domino: running hot and tenons too loose?

[charliefreak]

I recently bought a new DF500 and used it for the first time yesterday. I’ve been practising, but I have some issues and I’m wondering if the group can help me decide whether this is technique, or whether I might have a faulty unit.

In all the videos I’ve watched the tenons fit snugly into the mortises (even needing a hammer tap to seat properly). But mine are too loose. I’m pretty sure I’m plunging straight without movement (I’ve used many biscuit jointers), and I’ve tried multiple cutters and tenons... all the same... a fraction of play - too much for a good joint.

My unit also vibrates a lot (if I set it down on the bench running it walks) and gets *very* hot. After a minute or two of running, the metal parts on the body are too hot to touch and I can see it melting the lube on the runners. I am using good dust collection, the fence is tight, and my stock is square.

What do you think is going on? I'd be grateful if other domino owners could let me know whether their units get this hot after cutting a dozen or so mortises (the bottom of the bearing / gear plate on the unit is too hot to touch), or whether their units vibrate this much?

Here are three videos illustrating the problem:





Thank you!

 

[Svar]

[member=73125]charliefreak[/member]
Your video link does not show. It has to be in this format to work:http://www.youtube.com/watch?v= (video ID here such as QpHTkdPl39086)

 

[ChuckM]

Videos didn't load. I ran my DF without cutting or dust extraction for a minute or so non-stop. I took off the fence and felt the base with the back of my palm. Very mildly warm only, nowhere near hot.

The DF moved very slightly due to vibration, but didn't "walk" in any sense. Hope this helps.

 

[Birdhunter]

Your machine needs to go back to Festool for service.

 

[mrFinpgh]

Two thoughts on the too-loose mortise:

Bad bit?  Have you tried using a different sized cutter in a test piece? 

Is your fence stable? 

The hot motor - that sounds more concerning.  I'd probably send it in to be looked at.

 

[charliefreak]

Thanks ChuckM for testing your machine, and other posters for suggestions (and note about videos). I have updated the video links.

I thought it might be the bit, so I tried two different 5 mm bits and the 8 mm bit, and had the same sloppiness with all three.

 

[ChuckM]

The vibration is a lot lot more with your machine...mine probably moves less than 1/10 of yours.

 

[HarveyWildes]

I had one incident with a new Domino where the bit caught as I was plunging and torqued both the bit and the work piece.  It put a slight dent in the bottom of the base.  The dent affected a reference surface, so that was an issue, but it also had all of the symptoms that you are describing.  I sent it in for repair, got it back in beautiful shape.  Ever since I've been very careful to plunge slowly, make sure the work piece is held firmly, and keep a solid hold on the tool, and I haven't had any additional issues.

 

[Gregor]

Your machine needs to go back to Festool for service.

This.

 

[sancho57]

if you dont hold the domino near where the plug cord connects to it and push it from there very very slowly the domino will be tighter than if you just grabbed the body of the tool and pushed it.

from the photo it looks like the domino mortise is on the middle sized mortise. If its not and your getting  that large a mortise take it back to the dealer.

Could be the machines gears are stuck or not fully engaged which could cause the heat.

If they find a issue with it then swap it for another one.

You have 30 days in which to return it no questions axed.

 

[StevoWevo]

I’m guessing the shaft is bent.

 

[jeffinsgf]

I’m guessing the shaft is bent.

I thought the same thing.

I was just thinking about how to check this. It seems if you take the motor out of the base and turn the cutter by hand, it should be apparent or not whether the bit is turning concentrically.

 

[JimD]

If you are plunging slowly and smoothly then I think it is the machine.  But I would try plunging extra slowly, for you, before sending it in.  I have the XL but I have never noticed it running hot. 

There is a somewhat long thread on the CMT cutters where there where comments about oversize mortises.  Other comments were that they get oversize mortises when they plunge to quickly.

 

[jcrowe1950]

I recently bought a new DF500 and used it for the first time yesterday. I’ve been practising, but I have some issues and I’m wondering if the group can help me decide whether this is technique, or whether I might have a faulty unit.

In all the videos I’ve watched the tenons fit snugly into the mortises (even needing a hammer tap to seat properly). But mine are too loose. I’m pretty sure I’m plunging straight without movement (I’ve used many biscuit jointers), and I’ve tried multiple cutters and tenons... all the same... a fraction of play - too much for a good joint.

My unit also vibrates a lot (if I set it down on the bench running it walks) and gets *very* hot. After a minute or two of running, the metal parts on the body are too hot to touch and I can see it melting the lube on the runners. I am using good dust collection, the fence is tight, and my stock is square.

What do you think is going on? I'd be grateful if other domino owners could let me know whether their units get this hot after cutting a dozen or so mortises (the bottom of the bearing / gear plate on the unit is too hot to touch), or whether their units vibrate this much?

Here are three videos illustrating the problem:





Thank you!

Hi Charlie,

    Did you use dust extraction with your D500? I'll tell you what I have learned from training with both Festool and Greg Paolini. The Domino is essentially a router that waggles the bit. If you have loose dominos from too fast of a plunge, you will typically notice a sort of domed cut pattern on the top of the domino. There could be two reasons for this...first, when the cutter is waggling in one direction it's like a buried router regular cut but in the other direction it is a climb cut. A climb cut will tend to move the tool upward and that's why doing a slow plunge (count of eight when you are getting started) gives a cleaner mortise. The other factor that others have mentioned is that with the D500, the tendency to want to grab the barrel instead of pushing in directly from the very rear of the machine. This can cause issues because of basic ergonomics.....you want to move the machine in a direct line from your arm, sort of like cutting a dovetail with a handsaw, or correctly moving a tracksaw while sawing. In this respect, in my opinion, the XL 700 domino is much easier to use correctly. In any case, you have to use dust extraction on both models....not an option. Even with dust collection up full bore, the D700 can leave a bit of dust in the holes....failure to use dust extraction will cause the bits to clog and heat up......possibly damaging the bit and the tool. Just a few ideas.....it really sounds like you could use a visit to a competent dealer to do some diagnostics....FWIW, I (now) own both Dominos and they are excellent tools, but....like all Festool tools, they are best if understood in context of the system for which they were developed. Oh, one more thing....if nobody else has mentioned it, on the D500 you should only change the width when the machine is turned on. Oh, one further more thing...once you master the Domino, you will probably never use the third, extra loose setting. Sorry to be so longwinded and I hope this helps....best of luck in resolving your issues.

 

[jimmyboygr]

Hello,have you ever or someone else opened the bottom screws or even untightened them a little?I mean the screws with pin in middle 5 star.If so,the machine needs to be calibrated on a special machine in the repair shop

 

[Birdhunter]

New Festool product not running right = return it promptly.