Third-party Longer Mortise Bit for DF500

[ChuckM]

DF700 users can buy third-party cutters and use the 700 like a DF500. Is there anyone out there producing and selling longer cutters that we can use a DF500 with longer Dominoes like the 8mm x 22mm x 80mm, or even the 100mm?

Please share the source if anyone knows about such cutters for DF500. Thanks.

Chuck

 

[Birdhunter]

I would think putting a longer bigger cutter on the 500 could add more stress on the machine than what it was designed to handle. The adaptor for the 700 allows a smaller cutter to be used so the stresses would be lower.

 

[ear3]

I'd have to double check the machine, but I imagine there are physical limits imposed by how close to the front the arbor is.  In resting position, the standard bits are already near the mouth, so any longer and they would be poking out even without plunging.

 

[ChuckM]

Good point about the depth of the mouth.

I was thinking of a longer cutter used with the narrow (standard) setting for occasional projects. Recently, I completed a joinery by setting the max. of depth of cut and using 80mm cut to 56 or 57 mm long Dominos (5mm longer than the standard 50mm pieces, not much). But if we could use a cutter that mortises 65 mm or even 70mm, it would sure help.

May be I could attach a spacer at the front of the plate to keep the cutter from protruding?

I can't justify getting a DF700 and I also find it an over-kill for most of my projects.

Chuck

PS If I were doing just a joint or two, I could drill the mortises longer and use the 80mm Dominoes in their entire length. Too much work for regular joinery, though.

 

[Svar]

What is the maximum plunge amplitude (travel) on DF500? You can't cut deeper than that unless you do it with shorter cutter, replace the cuter with longer one and deepen the hole. Or am I missing something? Alternatively, install long cutter and place a spacer between the fence and the stock, cut, remove spacer, cut deeper into the same hole. Which pretty much defeats the purpose of this quick and accurate machine.

 

[Michael Kellough]

Svar is right.

If you could get longer bits for the 500 you couldn't use them
unless you replaced the posts (that the machine slides on) with longer posts.

However much longer the bit is, you have to back up that amount, unless you've already made a mortise in that location.

 

[ChuckM]

Alternatively, install long cutter and place a spacer between the fence and the stock, cut, remove spacer, cut deeper into the same hole. Which pretty much defeats the purpose of this quick and accurate machine.

I agree that method would undermine the speed and accuracy, which, even if the longer cutter were available, I wouldn't use in my day-to-day cuts. But that option would solve the occasional joinery needs that can only be met by a DF700. And it would still be faster and more accurate than drilling a series of holes inside the mortises.

Chuck

 

[Svar]

Alternatively, install long cutter and place a spacer between the fence and the stock, cut, remove spacer, cut deeper into the same hole. Which pretty much defeats the purpose of this quick and accurate machine.

I agree that method would undermine the speed and accuracy, which, even if the longer cutter were available, I wouldn't use in my day-to-day cuts. But that option would solve the occasional joinery needs that can only be met by a DF700. And it would still be faster and more accurate than drilling a series of holes inside the mortises.

Chuck

Actually you are right. This might not be too bad if the spacer is not just a piece of scrap, but well designed jig with reference marks and pins, etc.

 

[Bohdan]

A longer cutter would also give a wider cut. On a wide setting this could result in the cutter internally hitting the sides of the machine. You would also need to make custom length and width dominoes to utilize any benifit.

 

[greg mann]

What is gained by going deeper? The joints will most likely already fail by the adjoining wood coming apart, not the domino letting loose. Alternately, if you get more strength through depth, the wood holds and puts all stress on the domino, does it fail because it needs more cross-section? Seems like this is why the 700 was designed for bigger dominoes.

Rough analogy: If you put a fence post 2 feet deep and it will break at ground level when subjected to stress, what is gained by sinking it 3 feet?

 

[Mort]

If you only bury that fence post 6" it's going to tip over.

I'd like to have a deeper one for making extra wide mortises, and home made tenons.

 

[bobfog]

The short answer here is if you can afford it, people need both the 700 and 500 if they want all their bases covered through the use of dominos. No matter how many adapters or third party gizmos you have none are a true replacement for having both machines.

I wonder if Festool will ever bring out a Domino XXL?

 

[rvieceli]

[member=60286]bobfog[/member]

They already have one.
https://www.festool.com/Products/Pages/Product-Detail.aspx?pid=769536

 

[bdiemer]

It's just bad math to extend the domain of any machine. I should know, I'm bad in math.

 

[ChuckM]

I was thinking that if someone could come up with an after-market set of cutters for DF700 to be used as a DF500 (that actually did extend the domain of the DF700), may be something could be done to benefit the DF500 users.

I mentioned about using only the standard setting with a longer cutter. Why deeper? To add strength to a joint, for the same reason why Festool has the 8 x 22 x 80 mm & 100 mm Dominos.

In a recent project, with the DF 500, I cut my mortises to the max. (57 or 58mm?) and then cut a batch of 80mm Dominos to an hair shorter than 58mm. I then drilled a deep hole into each mortise for the excess glue. Did 8mm longer matter? I don't know but that was all I could do -- unless I borrow a DF700 from a buddy (that would have quite delayed my project).

I knew owning a pair of the DF500 & 700 would be the best option, but I would not use the DF700 enough to justify it, as a hobbyist. Between the two, I would prefer to have DF500 for its ease of handling.

The making of custom Dominos is my least concern even if I don't want to modify Festool stock (probably the 80mm or 100mm ones). I can cut floating tenons of any size and length with ease in my shop.

May be someone could study this in depth and explore if it is technically feasible to extend the capability of the DF 500 a bit. Yes, on the surface, it is un-doable, just like many other inventions -- the SawStop is an example until it came to the market.

Chuck

 

[greg mann]

If you only bury that fence post 6" it's going to tip over.

I'd like to have a deeper one for making extra wide mortises, and home made tenons.

You are turning my example upside down to argue against a point I did not make. Where did I imply going shallower was even part of the equation?

 

[Mort]

Easy there, bro-tato chip.

With a longer tenon the force of stress on a joint would be distributed on a longer area.

Your fence post analogy implies that it doesn't matter how far in you sink it as long as it sinks. If you sink that post in 3 feet you have another foot of material holding it laterally. Stability is this enhanced. If you go shallower, stability decreases. Simple physics.

 

[Bohdan]

I think that the real question is, if you break the joint, exactly what breaks.

Will it be the domino or will it be the surounding wood. If the domino breaks then a deeper one would have made no difference. If the surrounding wood breaks then a deeper domino may have helped but if the domino pulls out then maybe you didn't use enough glue or it wasn't long enough.

Has anybody seen any tests that tested domino joints to destruction.

 

[greg mann]

Easy there, bro-tato chip.

With a longer tenon the force of stress on a joint would be distributed on a longer area.

Your fence post analogy implies that it doesn't matter how far in you sink it as long as it sinks. If you sink that post in 3 feet you have another foot of material holding it laterally. Stability is this enhanced. If you go shallower, stability decreases. Simple physics.

You missed my point. If there is only so much inherent strength in the mortise (or post) sinking it deeper will not help. In my analogy I pointed out If the post snaps off at 2 feet sinking it to 3 feet won't help. Raising it to 6 inches will save the post but there will be a different failure, of course. I never advocated shallower mortises. I just pointed out deeper won't make it stronger if you surpass the inherent strength of the domino.

 

[greg mann]

I think that the real question is, if you break the joint, exactly what breaks.

Will it be the domino or will it be the surounding wood. If the domino breaks then a deeper one would have made no difference. If the surrounding wood breaks then a deeper domino may have helped but if the domino pulls out then maybe you didn't use enough glue or it wasn't long enough.

Has anybody seen any tests that tested domino joints to destruction.

My point, said more elegantly. [not worthy]