Unhappy Domino 500 Owner

Blackerty

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Joined
Jun 19, 2024
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22
Hi all, I've not posted in quite a while.

I bought a Domino 500 and accessories about ten years ago because of the promise of precise and uncomplicated loose tenon joinery from what was and still is pitched and priced as a premium tool. Illness and unexpected commitments meant that it was for a long time used only occasionally for very undemanding home carpentry type work.

Recent use in an attempt to accurately locate the edges of successive 40mm thick laminations in a bench top slab glue up in the same plane (by placing 8x22x40 dominos in the faces about 25mm back from the edges) threw up problems in use that should not have been present - it failed in the task. It's long out of warranty and consequently now a €1,500+ source of frustration.

This isn't just in hope of fixes beyond the usual work arounds (the usuals have been implemented) - it's also to ask does anybody have a data/measurement based overview of the big picture situation. As in (a) did I get a bad example, (b) are these problems present in current production and (c) does anybody sell a domino type insert made to decent tolerances?

The background is as follows.

The first discovery was that the dominos/inserts coming out of the very expensive systainer selection were several 10ths (around 0.3mm) below nominal thickness and fitted far too loosely in the slots cut in the laminations to be capable of aligning the edges - the potential misalignment/lamination was x2 the clearance.

The second was that the horizontal fence was moving in use - sometimes while cutting, at other times as a result of hand pressure on it while connecting a vacuum hose. It took a while, wasted good material and eventually required measurement to get to the bottom of what was happening - the initial possibilities were that the locking lever was not done up tightly enough, the fence was not set squarely or the tool was not properly seated on the work. (all were eliminated)

Getting back precisely to a lost horizontal fence height setting requires measurement with a height gauge or whatever - the scale is crude and useless.

Feedback on another forum established that neither the fence slippage nor the domino fit problem was unusual - but with some coming in (occasionally in a rather offended tone) to say that they had experienced no problems whatsoever.

The existence of a cottage industry in improved fences and of well known workarounds suggests however that the problems are in fact common.

I found that the two pads on the clamping block which bear on the back of the horizontal fence mounting frame were not seating properly - they were leaving only a line when the fence slipped. The pin comprising the third/inner leg (which seats in a drilled hole) was a bit too long/the hole not deep enough. Filing this back to length (very little material needed to be removed) so that the block tilted a hair and the pads gripped over their full area delivered some improvement, but it still wasn't enough.

The user recommended addition of extra length locking levers (a risky exercise given the only M5 stud and thread in the die casting - the originals are short for a reason) improved it further - to the point where the settings seem to stay put in use. It's not rock solid however - hand pressure on the top of the fence assembly when removing vacuum hoses can still cause it to move. The horizontal fence angle adjustment (useless scale apart) locks without problems.

The horizontal fence height adjustment and the associated angled seating face design (the primary locking mechanism) presumably worked in prototype form, so perhaps alignment error(s) were introduced in manufacturing...

The biscuit fit problem is still present. The tool seems to cut slots consistently on nominal size - despite the cutter being supported by a short and rather loose fitting bronze bushing. This looseness means that it's not possible to get back to a height setting by referencing measurements/a setting block off the cutter - measuring the height difference between the base and the horizontal fence does work.

Wetting the dominos/inserts causes them to go from being far too loose to being too thick to use. A more controlled humidification process might deliver a consistent interference fit, but setting it up would be a time wasting PIA and might anyway not be feasible if there is variation between batches of inserts.

The throw away excuse is that water based glues cause the inserts to expand, but that's not much use if using epoxy and/or if the requirement (as is the norm) is immediate and accurate location before clamping.

The commonly quoted work around (which is fine in situations where a loose tenon/insert to non standard dimensions may be required) is to make up your own strip. This however is a PIA and shouldn't be necessary. They if a large batch is made (one response to the PIA argument) presumably will also be subject to fit variations with changes in moisture content.

These fit problems leave the tool in similar territory to a budget biscuit jointer using mass market and normally loose fitting biscuits....

Might recent domino production by Festool or one of the others now offering inserts deliver the required light interference fit? I find myself looking at a close to €300 systainer full of undersize biscuits and struggling to find the motivation pony up more cash to buy alternatives to test....
 
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Sorry to hear about your frustration with what is considered a game-changing tool for many DF users. I may have missed some but the main issues you've experienced seem to be about the fence drift and tenon thickness.

Fence drift was reported in the earlier machines but has since been fixed; mine is 12 years old with no operating problems of any kind. If yours is younger, I presume it isn't one of the bad apples. And that leads to the fence height adjustable lever, which can be adjusted for grip. There's absolutely no need to replace it with a bigger lever as has been seen done by some for securing the fence. Simply unscrew it and reposition the handle and screw it back. The same can be done on the fence angle knob.

Most people complain about the tenons being too tight to pull out due to humidity. Is the storage area particularly dry that the tenons have shrunk in thickness over the years? Or is it a bad batch from the supplier?

I have handled several different DF500s, but by and large, they were all problem-free in use.

Could you post a couple photos of your machine levers when the fence is in the "secured" position?
 
Thank you for coming back so quickly Chuck. Fence drift and domino/tenon thickness are indeed the two major issues.

The tool promises a lot, but to deliver in fine work it needs to be able to place dominos accurately enough to precisely align faces.

My Domino is older than I thought - checking says that it was bought in the UK in September 2009. 16 years ago.

Do you have any idea what the cause of the fence drift in early machines was caused by?

I'm not sure what you mean by adjusting the locking levers for grip. They (both the originals and the aftermarket items currently fitted) to my understanding are small versions of what are sometimes known as Kipp levers - they have a splined hub which permits lifting and repositioning of the lever so that the clamp can be tightened in a tight space/if the lever is about to foul something. There's no question of my levers fouling anything/not bottoming out properly - unless you have something subtler in mind. It's bedtime here so pics would require waiting until tomorrow.

The 8x22x40 tenons/dominos came out of a previously opened pack. Our RH year round tends to be around 70%, equilibrium moisture content is around 17%. The workshop is lightly heated in winter to prevent it getting much below about 10 deg C but not by very much. If I had to guess I'd say it's unlikely that they had shrunk - the opposite in fact.

The question I suppose is whether or not buying more dominos might fix the fit problem - are bad batches common or might Festool (as seemingly do the makers of budget biscuit jointers) sacrificing fit in favour of avoiding the possibility that some given the inevitable variation in what may be a less than sophisticated manufacturing process) will be too large to use? Does anybody else do a better fitting variant?

It seems that some use a press or roller system to get a consistent fit in the case of biscuits. Might this be possible with loose tenons?

Achieving a consistent light interference fit is a matter of quite fine tolerances - a situation that requires both cutting the slot precisely on size (my machine is to within a tenth or so cutting pretty much on the nominal mm thickness dimension - is this normal?) and coming up with a means of delivering dominos/loose tenons which despite the tendency of beech to move are kept to a similarly tight tolerance.

The latter might require a bit of lateral thinking - the ridges on dowels are presumably there for this reason as well as to allow air to vent etc...
 
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I make my own wide tenons for the DF500 and I did fairly comprehensive testing on the sizes of the tenons, and found that 10mm tenons for example had a variance of -0.3mm to +0.2mm. Pretty much the same for the 8mm, 6 and 5mm were slightly less. But even if they feel loose when inserted, they are compressed so once glued in they will be a tight fit. If it really worried you give them a tap with a hammer on the side's edge.

So far as the fence moving, as said by others simply unscrew the locking lever and reposition it one click anti-clockwise which will allow more torque when tightening. If that's not enough to stop it moving, adjust it another click.
 
Thanks guys.

The fibre grip looks useful S but why if the fence does not grip reliably (a fundamental problem) did Festool not recall the affected product?

The range of thicknesses you found LMT sounds very possible - mine as above are about 0.3mm under nominal. It depends a bit on what the tool is being used for but reliance on glue swelling the dominos for the reasons above is not practical in some situations and shouldn't anyway be necessary.

Has Festool actually done anything to fix the tenon thickness problem?

These are huge difficulties - they destroy the key selling proposition of tool (i.e. fast and trouble free precision loose tenon joinery) and dump it into the same space as budget biscuit jointers. Why would anybody in their right mind pay a premium price for a tool which does not deliver/requires a string of work arounds to function?
 
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Picture of the aftermarket horizontal fence locking levers now fitted (they help but don't resolve the underlying grip problem) :

pic domino 500 with amarket levers 21-5-25.jpg
 
The way you plunge and the type of timber used will also introduce a very slight variance in the finished mortise, so the variance in thickness is a moot point as they make zero adverse impact as they swell when glued.

So far as the torque on the handle to stop movement under load, it would make absolutely no sense for Festool to recall the Domino's, as that's why the locking levers have adjustability built in as opposed to being a fixed knob with no adjustability. And as others have pointed out, while a nice looking "bling", there is absolutely no requirement to upgrade to the new spring loaded levers as the existing ones perform very adequately. I've never needed to adjust my levers after the initial adjustment some 10 or so years ago despite very heavy usage as evidenced by my latest batch of extra wide tenons made!
 

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The fibre grip looks useful S but why if the fence does not grip reliably (a fundamental problem) did Festool not recall the affected product?

Honestly, metal on metal friction is pretty high. But grease/lube that gets in there can dramatically reduce it. Some people like to spray lube the rods and don't take care to mask that guideway. So... user error I guess. Grubby paws can also do it as well as a dirty shop. They should probably put a maintenance bit in the troubleshooting section of the manual - but old Festool probably assumed everyone was a machinist.
 
I'm at a loss LMT - please read the above.

I know very well that the tool needs careful handling so that the cut is not disturbed when plunging - that this can displace slots and see them misaligned. So could stock planed out of square, debris under the fence, the fence not set square ete etc etc

I'm as above however talking about horizontal fence slippage proven by measurement of the change in it's height above the base using a vernier height gauge.

I'd appreciate it if you would explain precisely how the 'adjustable' levers solve this problem - tell me what I'm missing.....

Making extra wide tenons is great but it does nothing to resolve the stock domino/tenon thickness issue...
 
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My original background was machine shops and tool rooms WF.

Just for the record - grease has never been used on the tool. The slideways were washed with solvent while it was apart - it still slipped....
 
It looks to be that your machine is one of those early machines that suffered from the fence drift problem that was eventually fixed by Festool in the subsequent releases of new machines.

If you send it in to repairs, maybe Festool would replace whatever (fence, base?) that would fix your fence slippage problem.
 
It sounds worth a try Chuck.

Do you happen to know whether or not Festool have been (presumably quietly) fixing tools with the slippage problem?

My best guess is that there's a misalignment in the machining of the slideways - that perhaps surfaces that are supposed to be meeting face to face when the clamp is done up are making only line contact.

I have some limited machining capability and if it comes to it will strip the tool again and check it out in detail. It'd be a lot better if Festool would just fit good parts - if nothing else I'd resent the prospect of having to put the time into fixing the thing
 
Here are a couple of prior posts that may shed some light on your situation. They cover both the slipping issue and the Domino fit issue.


 

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Thank you very much Cheese. There's a degree of mixing of issues, defensiveness and some hocus pocus in the threads, but it's clear as day that as Chuck said that at least a significant proportion of the earlier machines had a genuine fence slippage problem. Also that Festool (in the US at least) accepted its existence and changed out fence assemblies.

Overtightening/using long levers in an attempt to overcome the issue as some said is looking for trouble.

I had to give up on the Domino and use plastic wrapped clamping battens to align the laminations in the project where the problem came to light.

I've following the suggestion by Chuck (i'd not considered the possibility given the age of the tool - even if it's had only minimal use) contacted our local Festool service (in Ireland), explained the fence situation and requested an out of warranty free of charge rectification. It's a long shot but based on the information from here there's precedent. Thank you. Will update when I get a response.

There unfortunately seems to be no clear answer to the domino/tenon thickness variability problem - just more confirmation that it exists. The DIY tenon route at least provides an alternative and effective solution.

My feeling regarding OEM tenons is that some sort of synthetic or at least treated and much more stable material to a relatively tight tolerance matched to the seemingly pretty consistent width of the slots cut by the machine is required. Deformable ridges and/or grooves might have a part to play too.

Festool can't have it both ways on the domino/tenon fit problem - as in pitch the Domino as a premium priced precision joinery tool but not deliver on the promise. They need to figure out a way to deliver this...
 
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can you go to a shop and do a demo on one of their store machines? That would eliminate both the machine and user error, with a person present for a hands on demo
 
Thanks UN1. It's not an option here but the fence slippage and tenon thickness problems are anyway pretty clearly not down to user error...
 
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I am not certain and I have not read every post on FOG regarding Domino tenon thickness. But this is the first time I recall a problem with them being too thin. Generally people say they are too thick / tight and have trouble getting them into the mortise or trouble getting them pulled out when doing no glue test fits. Many users keep a sanded set ( to make them thinner) for test fits.

A big factor in the tenon tightness is the moisture content. It does not take much difference in humidity to alter the fit by a fraction of a mm.

When I have trouble with being too thick / tight to get them into the mortise, I microwave them spread out on a plate or tray for 60 seconds or so. Shrinks them a tiny bit.

Maybe put them in a humid environment or steam them to make them thicker?

Seth
 
Lamello has solid surface biscuits for that expansion problem... So it's definitely an "engineered for use case thing". For festool, we're pointed to the DV connectors which does the same thing. The only people left out are those using epoxy for DF700 applications like exterior doors, but somehow they manage.
 
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