Author Topic: How much weight can the DF700 connectors hold?  (Read 1985 times)

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Offline aaduranh

  • Posts: 20
How much weight can the DF700 connectors hold?
« on: August 24, 2019, 03:51 PM »
Hi,

I need to attach heavy legs to a table top.  Each leg is 28" x 28 3/4, 3" 1/8 thick. It is in hard maple. Each leg is around 80 pounds. The top is 72" x 36" 1" 1/4 thick in maple too.
If i use around 6 DF700 connectors in each leg, would the connectors be strong enough to hold the legs to that top?

Thanks
Alex
« Last Edit: August 24, 2019, 04:37 PM by aaduranh »

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Offline tjbnwi

  • Posts: 6065
  • Cedar Tucky Indiana
Re: How much weight can the DF700 connectors hold?
« Reply #1 on: August 24, 2019, 04:26 PM »
I can't answer the question directly, but....

When I first got the 700 kit we did a few test mock ups, we could not pull the expanding piece out of the mock up after removeing the center post, we had to cut the wood away from it so we could reuse the insert (I'm to cheep to waste the pieces).

If you're wondering if 6 of the connectors in the leg will hold it to the top it when the table is lifted----my guess is yes they will.

Tom

Offline aaduranh

  • Posts: 20
Re: How much weight can the DF700 connectors hold?
« Reply #2 on: August 24, 2019, 04:29 PM »
I would have done the same thing:)

Let's hope someone put the df700 connectors to the extreme.

Offline mwolczko

  • Posts: 21
Re: How much weight can the DF700 connectors hold?
« Reply #3 on: August 24, 2019, 04:31 PM »
A while ago I looked but could not find any published specs on the strength of the connectors.  If anyone has a source I’d love to see it too.
In any case I went ahead and built an outdoor sofa using connectors and it feels solid to me (and has stayed solid for the ~2years it has been used).

For your table, are the connectors carrying the weight of the top, or is that being transferred directly to the material of the legs?  If they’re not carrying the weight, but being used to prevent racking, then I would think they will suffice. For my sofa I recessed the seat members into the armrests so that the connectors were not carrying the weight, just providing tension.

Also, be sure to consider any cross-grain wood movement that may occur.

Offline aaduranh

  • Posts: 20
Re: How much weight can the DF700 connectors hold?
« Reply #4 on: August 24, 2019, 04:37 PM »
The top would be seating on the end grain of the leg.

Let's say i would have to move table. The connectors would have to carry the weight of the legs attached to the top.

I know some people do beds with the connectors. They have to take the weight of two people. I imagine they are good enough. Does it make sense?

Offline mwolczko

  • Posts: 21
Re: How much weight can the DF700 connectors hold?
« Reply #5 on: August 24, 2019, 05:18 PM »
Should work fine — I would guess the pulling force needed to remove one of these connectors is measured in hundreds of pounds.

Offline Cheese

  • Posts: 6376
Re: How much weight can the DF700 connectors hold?
« Reply #6 on: August 24, 2019, 05:20 PM »
They always use wood Dominos along with the removable ones. Here's a photo from the printed Festool connector catalog. Read the TIP in the lower RH corner of the page. 

If you're going with 6 for each leg I'd probably do 4 wood versions and 2 removable versions.

Let us know how that works. [smile]


Offline tjbnwi

  • Posts: 6065
  • Cedar Tucky Indiana
Re: How much weight can the DF700 connectors hold?
« Reply #7 on: August 24, 2019, 05:44 PM »
They always use wood Dominos along with the removable ones. Here's a photo from the printed Festool connector catalog. Read the TIP in the lower RH corner of the page. 

If you're going with 6 for each leg I'd probably do 4 wood versions and 2 removable versions.

Let us know how that works. [smile]

(Attachment Link)

Their examples are in shear, the question posed here is for pullout.

I do agree, six is probaly over kill, I'd start with 2 connectors, one on each "inside face", 2 normal Dominos on the "visible faces".

Tom

Offline aaduranh

  • Posts: 20
Re: How much weight can the DF700 connectors hold?
« Reply #8 on: August 24, 2019, 05:48 PM »
I need to attach those legs to the table top. This not exactly my table. My table is in maple.

I am sorry i should have started with the picture ;D

« Last Edit: August 24, 2019, 05:51 PM by aaduranh »

Offline tjbnwi

  • Posts: 6065
  • Cedar Tucky Indiana
Re: How much weight can the DF700 connectors hold?
« Reply #9 on: August 24, 2019, 05:51 PM »
I need to attach those legs to the table top. This not exactly my table. My table is in maple.

Are the legs solid or hollow?

Tom

Offline aaduranh

  • Posts: 20
Re: How much weight can the DF700 connectors hold?
« Reply #10 on: August 24, 2019, 05:52 PM »
super solid hard maple!

Offline tjbnwi

  • Posts: 6065
  • Cedar Tucky Indiana
Re: How much weight can the DF700 connectors hold?
« Reply #11 on: August 24, 2019, 06:27 PM »
super solid hard maple!

Each leg weighs ~65-1/2 pounds (using the dimensions you posted).

I'd put 2 connectors on the long sides of each leg (4 per leg), about 3" in for the sides. Centered I'd place 2 Dominos, these will aid in alignment.

I suggested inside only in a previous post due to the covers for the set screw access mortices, there are covers that are very close to maple color. You could fabricate your own plugs for the visible side.

Tom

Offline aaduranh

  • Posts: 20
Re: How much weight can the DF700 connectors hold?
« Reply #12 on: August 24, 2019, 07:19 PM »
Thanks a lot for your help.

Just to make sure that I understood. you would install the connectors only in the inside of the leg, nothing on the outside?
Creating my own maple plugs is a great idea!

Thanks a lot

Offline tjbnwi

  • Posts: 6065
  • Cedar Tucky Indiana
Re: How much weight can the DF700 connectors hold?
« Reply #13 on: August 24, 2019, 07:20 PM »
Thanks a lot for your help.

Just to make sure that I understood. you would install the connectors only in the inside of the leg, nothing on the outside?
Creating my own maple plugs is a great idea!

Thanks a lot

For even load lift, install 2 inside, 2 outside.

Tom

Offline Jim_in_PA

  • Posts: 74
Re: How much weight can the DF700 connectors hold?
« Reply #14 on: August 25, 2019, 09:36 AM »
As in Cheese's reply in post #6, I used them for a Twin-XL over Queen heavy bunk bed setup recently and I have no concerns about strength. The connector plus two 14mm Dominos can support a whole bunch of weight and the design of the connector brings the joint in very tight. If the materials are cut true, that fully engaged surface to surface touch adds to the stability of the joint, too. Most of the weight of the joint is borne by the adjacent 14mm dominos...you don't often use "just" the connector in the joint.
----
ETS 150/3, Rotex 150, OF1010, OF1400, Trion PS 300, TDK-12, CT-22, MFT 1080, TS55, Domino XL DF 700, 8' track, (2) 55" tracks

SCM MiniMax S315WS, FS350, MM16, Camaster Stinger II SR-44 CNC

Offline tjbnwi

  • Posts: 6065
  • Cedar Tucky Indiana
Re: How much weight can the DF700 connectors hold?
« Reply #15 on: August 25, 2019, 09:50 AM »
Now I'm wordering if one on each end would suffice??? Regular Dominos on the long sides?????

The connectors are only there for when the table is lifted.....hummmm.

Tom

Offline Cheese

  • Posts: 6376
Re: How much weight can the DF700 connectors hold?
« Reply #16 on: August 25, 2019, 09:59 AM »
Ya, my thought was that any lateral loading to the table and consequently through the legs, would be transferred to and carried by the wood Dominos, while the D14 removable Dominos would maintain the tightness of the joint and facilitate lifting the table and moving it.
« Last Edit: August 25, 2019, 10:01 AM by Cheese »

Offline Michael Kellough

  • Posts: 4165
Re: How much weight can the DF700 connectors hold?
« Reply #17 on: August 25, 2019, 10:18 AM »
Straight withdrawal resistance is not the concern. A couple fittings per leg are sufficient for that.

The powerful leverage the non-aproned legs possess is what you have to resist. What happens when someone leans into the end of the table or the movers set one end down too abruptly?

I’d use a minimum of four per leg but probably twice that, placed close to the long faces of the legs.

If the mechanical fittings weren’t available your best joining method would be wedged through tenons (3 or 4 per leg) the full thickness of the leg (3 or 4 inches?).

This merits full scale testing. The mechanical replacement should be equally strong but I don’t know how many fittings that would require.

Offline Birdhunter

  • Posts: 2650
  • Woodworker, Sportsman, Retired
Re: How much weight can the DF700 connectors hold?
« Reply #18 on: August 25, 2019, 10:59 AM »
I’d worry a lot more about the table racking and snapping off the legs.
Birdhunter

Offline Bob D.

  • Posts: 1260
Re: How much weight can the DF700 connectors hold?
« Reply #19 on: August 25, 2019, 11:23 AM »
I’d worry a lot more about the table racking and snapping off the legs.

A single stretcher up high, maybe 5 or 6 inches tall, and down the center of the table
would mitigate that concern, and not detract from the look of the table, at least for me.
-----
It's a table saw, do you know where your fingers are?

Offline Michael Kellough

  • Posts: 4165
Re: How much weight can the DF700 connectors hold?
« Reply #20 on: August 25, 2019, 12:15 PM »
I’d worry a lot more about the table racking and snapping off the legs.

A single stretcher up high, maybe 5 or 6 inches tall, and down the center of the table
would mitigate that concern, and not detract from the look of the table, at least for me.

That works for me too.

Offline Svar

  • Posts: 1804
Re: How much weight can the DF700 connectors hold?
« Reply #21 on: August 25, 2019, 12:19 PM »
I’d worry a lot more about the table racking and snapping off the legs.
Exactly.
I'd put two dominos for registration and 4 or 6 connectors per leg.
Non glued wooden dominos are useless to prevent racking, which is the main issue for a table.

Offline Birdhunter

  • Posts: 2650
  • Woodworker, Sportsman, Retired
Re: How much weight can the DF700 connectors hold?
« Reply #22 on: August 25, 2019, 05:41 PM »
I’m very conservative when I build furniture that, if it fails, could hurt people. I’d use two stretchers for this design. I’d place them so people’s knees would not hit them, but far enough apart to provide stability.
Birdhunter

Offline aaduranh

  • Posts: 20
Re: How much weight can the DF700 connectors hold?
« Reply #23 on: August 26, 2019, 08:16 AM »
The customer of this table doesn't want to have anything but the legs under the top, even if you cannot see it.   [eek]

That's why i thought about the domino connectors. Tom had a great idea about making my own maple plugs.

Thanks
A


Offline Jim_in_PA

  • Posts: 74
Re: How much weight can the DF700 connectors hold?
« Reply #24 on: August 26, 2019, 09:23 AM »
Ya, my thought was that any lateral loading to the table and consequently through the legs, would be transferred to and carried by the wood Dominos, while the D14 removable Dominos would maintain the tightness of the joint and facilitate lifting the table and moving it.

Exactly.
----
ETS 150/3, Rotex 150, OF1010, OF1400, Trion PS 300, TDK-12, CT-22, MFT 1080, TS55, Domino XL DF 700, 8' track, (2) 55" tracks

SCM MiniMax S315WS, FS350, MM16, Camaster Stinger II SR-44 CNC

Offline Birdhunter

  • Posts: 2650
  • Woodworker, Sportsman, Retired
Re: How much weight can the DF700 connectors hold?
« Reply #25 on: August 26, 2019, 10:28 AM »
I just watched a video on making a huge conference room table from a large slab.

The builder routed a recess into the underside of the table and attached a steel  channels just short of the width of the table. The steel channel was attached using threaded inserts. The steel legs attached to the channel with short bolts. The structure looked bullet proof.

The steel channel probably would stop any cupping from the top. I seem to remember seeing more than two of these channels recessed into the table's underside.
Birdhunter

Offline ChuckM

  • Posts: 1191
Re: How much weight can the DF700 connectors hold?
« Reply #26 on: August 26, 2019, 12:19 PM »
Because of the massive weight, I would not feel comfortable with the two-leg design. In normal use, the table would be fine, but if racking happens (e.g. the table is pushed from one end in a moving attempt), the structure might not be sturdy enough.

I recommend that the customer be alerted of the safety caution in the absence of any stretchers. also consider orienting one of the dominoes along the grain direction of the top.

Offline Michael Kellough

  • Posts: 4165
Re: How much weight can the DF700 connectors hold?
« Reply #27 on: August 26, 2019, 12:58 PM »
Not an engineer but I don’t think the weight makes a difference. It’s the leverage of the legs that has the potential to rip out whatever kind of fasteners join the surface to the top ends of the legs.

I’d make a full scale model in construction grade softwood. Or, maybe just a full scale cross section like a 4x4 leg attached to the side of a 2x4. When an adequate fastening solution is found for the softwood it can safely be applied to the hardwood. I think the extra weight of the hardwood legs is accommodated by the flexibility of the tabletop.

Offline ChuckM

  • Posts: 1191
Re: How much weight can the DF700 connectors hold?
« Reply #28 on: August 26, 2019, 01:19 PM »
Not an engineer but I don’t think the weight makes a difference. It’s the leverage of the legs that has the potential to rip out whatever kind of fasteners join the surface to the top ends of the legs.

Snip

By weight, I was referring to the potential degree of damage or seriousness of injury if the table collapsed.

Offline Svar

  • Posts: 1804
Re: How much weight can the DF700 connectors hold?
« Reply #29 on: August 26, 2019, 02:10 PM »
Just put 6 connectors as in the picture. Each have at least several hundred pounds pullout strength, no different than a threaded insert or a screw. Alternative is a metal plate(s) wider than the leg screwed to the top of the leg to form flanges. Then recessed and bolted into the table top.
A table with this design (no stretcher) and weight is nothing unusual. I had similar one, just 4 threaded inserts per leg, that was all.