DF700 cuts too deep

[smorgasbord]

My DF700 cuts about 1.2mm - 1.4mm deeper than the depth setting.

Is this within normal spec?  Seems like it might be a problem when working with certain materials, coming closer to cutting through than I’d like.

I could not figure out if this is adjustable. Happens with different stock cutters, too.

 

[bertv]

That is within specs, I think. If you need exact depths you could use tube materiaal cut to size to shim the 'pillars'. If I remember correctly these are commercially available or can be 3-d printed.

 

[Birdhunter]

Both my 500 and 700 cut slightly deeper than the setting. I think this allows for tenon variation and room for glue to ooze into.

 

[squall_line]

Because the bit cuts an arcing path, it's likely that the depth setting is for the "shoulders" of the cut on the narrowest setting rather than the center of the cut, to allow the domino to actually seat in the mortise.

This is an educated speculation on my part based on absolutely nothing other than my brain's neurons firing and coming to that conclusion just now; I don't think it was ever described as such in the documentation or anything on Youtube.

 

[Michael Kellough]

Those are some good neurons squall line!

 

[smorgasbord]

Because the bit cuts an arcing path, it's likely that the depth setting is for the "shoulders" of the cut on the narrowest setting rather than the center of the cut, to allow the domino to actually seat in the mortise.

That's not what I'm seeing. On the DF700 the effective bit length is over 150mm and the swing is just a couple/few degrees. I measure at most a third of a mm difference between center and ends, depth-wise.

Anyone know how to adjust this?

 

[smorgasbord]

OK, does anyone know how to get access to the depth slide?
There are two torx screws for the plastic cover, but after removing them, the cover still seems attached. Do I have to take the DF700 apart further?

What I want to do is put some thick tape on the depth slide to reduce the depth at which the tool plunges.

Here's an exploded view with parts ID:https://www.mtmc.co.uk/Festool-DF-7...cD6bQKs-mYjdaLCC1Ri1lDgSFNZqAELoOIG-GR4LPHOuy

The part I want to modify is #96, and it's $3.69, so cheap to repair back if needed.

The cover plate with screws and such is part #100. That's a bit more money if I mess that up.

 

[smorgasbord]

Here's a photo showing the two screws that can be removed, but the cover plate is still trapped at the right and bottom:

[attachimg=1]

Here's my first attempt at depth reduction: putting two strips of tape on the stop:

[attachimg=2]

But, here's the (almost) final solution: double-stick tape a washer onto the end of the rod:
[attachimg=3]

I say "almost" because that washer is almost a mm thick and with the double-stick tape's thickness I'm getting just about exactly 15mm depth on the 15mm depth setting and I'd rather it be about 15.25mm-15.5mm deep. I have some 0.5mm thin washers coming from Amazon tomorrow, so will try that.

I know this may seem OCD to some, but cutting 16.5mm deep into the face of 18mm plywood is kind of scary for me.

 

[Crazyraceguy]

I say "almost" because that washer is almost a mm thick and with the double-stick tape's thickness I'm getting just about exactly 15mm depth on the 15mm depth setting and I'd rather it be about 15.25mm-15.5mm deep. I have some 0.5mm thin washers coming from Amazon tomorrow, so will try that.

I know this may seem OCD to some, but cutting 16.5mm deep into the face of 18mm plywood is kind of scary for me.

Agreed 100%, and I wouldn't waste a second trying to get that close. Back the stop up to the 12mm point and be done with it. Getting closer than 1/4" (6mm) to the outer face, is just asking for problems. You can very easily get hydraulic blow-out, from the glue, when assembling this joint.

 

[smorgasbord]

Agreed 100%, and I wouldn't waste a second trying to get that close. Back the stop up to the 12mm point and be done with it. Getting closer than 1/4" (6mm) to the outer face, is just asking for problems. You can very easily get hydraulic blow-out, from the glue, when assembling this joint.

Well, for the connector, I gotta go at least 15mm deep. At that depth I can tap the connector in to be exactly flush, maybe a hair under.

And for my DF700 there is no 12mm depth. Just units of 5mm. I do have the 3D printed snap on depth thingies to get 5, 10, and 12mm depths though. But again, 12mm isn't deep enough for the connectors.

 

[luvmytoolz]

I always thought the ideal way to get repeatable oddball depths, was to cut the plastic circular protective piece on the guide the Domino ships with into various sizes to give a hard stop.

 

[smorgasbord]

If someone with a DF700 would cut a few mortises at different depths (say 15mm, 25mm, 40mm), measure them accurately and report back the actual depth, I'd appreciate it. Just for comparison purposes I think it would be good to know what depths the units are cutting at and if my unit is in fact cutting deeper than others.

And maybe a DF500 owner or two as well? Again, it would be interesting to see/know. I got my thin (sub-mm thick) washers and will put one on today and see what my depths of cut are. Maybe at 15mm I should target an actual 16mm at center of mortise and just under at the ends?

Remember, with the dominos themselves being shorter than the nominal length, even at exact cut depths there's room for glue. Here's an older glued-up edge to edge joint (8 x 80mm tenon) I cut through:
[attachimg=1]

You can see:
A) The domino isn't centered, probably because I pushed it in one of the boards first and then assembled.
B) There is plenty of glue space in the right side board, including an air gap at the end, so no hydraulic pressures (I'm assuming air was able to escape as I assembled)
C) Overall, the joint looks good and solid.

 

[luvmytoolz]

[member=77266]smorgasbord[/member] If someone did do that test they'd also need to do it with each of the cutters, as the ratio of the actual size to the stated nominal size of the tenon varies, so I would assume the cutters are designed specifically to allow a predefined variance on the mortise depth.

So you'd probably need to do at least 3 test depths for each cutter, on each Domino to get a meaningful result to then compare across machines in the same class.

 

[smorgasbord]

the ratio of the actual size to the stated nominal size of the tenon varies, so I would assume the cutters are designed specifically to allow a predefined variance on the mortise depth.

I don't think so, as long as the cutters are the same length, which they are, any effect from a couple mm's of diameter difference will hardly matter given the small arc they move within.

 

[Neil Lickfold]

Im new to the DF700 and Festool in general. Being a toolmaker, just had to measure the length of the set of cutters that I got with the machine, 8mm to 14mm and their corresponding Domino box sets to start with. I was surprised at the length variation of the cutters, up to 0.7mm from the longest at 90.0mm Measured digital caliper, to the shortest at 89.3mm over all. In the hand booklet , it mentions that they are intended to make a deeper slot by about 2mm for glue relief to prevent hydraulic of glue and Domino. I noticed that it arrived with a plastic spacer. So any 22mm ID plastic tube would work as a limit stop spacer if required. Or rings cut from the thickness of sheet for the required limit. I also got the DF500 set, and the 4mm cutter on the adapter is only 80mm long. It cuts the correct width for the 4mm Donino's, which suggests that they made the 4mm donino thinner to compensate for the shorter tool. All the tools work well with their corresponding domino's width despite the length variations.
Another option of you want the depth to be very close, is to buy the lengths of Domino stock, and then cut to fit what you have created. Not measured the accuracy of the  domino stock block lengths, but they are shorter than the the nominal length on the box labels.
Neil

 

[smorgasbord]

[member=83033]Neil Lickfold[/member] , could you measure the depth of the produced mortises?

My concern is blowing through stock in face mortises. With, say, 18mm plywood, a 15mm mortise that is really 16 & change deep gets scary.

 

[Neil Lickfold]

So I measured the 8mm cutter. It is actually 89.99 mm long overall. The test cuts on the 15mm depth settings are 15.89mm deep and15.85mm deep. Looking at the stop arrangement, a 3/16 fibre washer is 1.0mm thick. Than can go over the 4mm pin. I am going to make some spacers up so that with my 4mm cutter,  the 15mm depth setting becomes 5mm for the 4mm cutter. Then keep a 1mm spacer in there.  With a 4.1 or 4.2mm (tapping size drill for M5 ) hole and a 13.9mm
od will work well. I will make mine from some 14mm Delrin rod and will skim the od to look nice.

 

[smorgasbord]

Thanks. I ended up with these 0.5mm thick washers:https://www.amazon.com/dp/B0C3TV2QDX

And with the double-stick tape's thickness I ended up with a DOC just slightly greater than 15mm deep, which is what I wanted. Not ideal, but works OK.

 

[Neil Lickfold]

I remeasured the depth of the pockets, in the centre is correct as reported. The outer edges are shallow by about 0.1mm , that will be due to the arc of the tool and the radius it is on.
Neil