Rockler Torsion hinges

[cwarner]

With shop time spiking in light of current events, I've been finally getting to build the Greene and Greene blanket chest from FWW 243.  I had ordered up some of the rockler torsion hinges.  I used their calculator based on some weight estimates and weighing some rough milled boards.  The calculator recommended 4- 60 in/lb hinges for the job. 

I just took the lid out of the clamps and proceeded to weigh it... 3lbs less than estimated.  Ok, go back to the torsion calculator and now it recommends 2- 60 In/lbs and 2- 40 in/lb hinges.  It says I need a total of 201 in/lbs for this job.  

If I put all 4 that I currently have on the chest I will have 240 in/lbs and if I go with 3 I'll have 180 in/lb.  Are there any ramifications of going with all 4 other than the lid being stiff to open and close?  If I choose 3 am I looking h basically at a "soft close" vs hold any angle the lid soft at?

I am mortising these into the top of the chest side so that there is no gap the thickness of the hinge so I only get one shot at this.

[cputnam]

One of the chests I've built using 4 torsion hinges had one hinge break. I suspect that a lack of perfection in the alignment of all 4 caused it to break.

[AHill]

Err on the side of being too strong. Install all 4 and then you know you can't overload it.

[Bill Holt]

No real help here.  I've used their calculator and hinges three times and very happy so far.  Just like you, I could only estimate the weight of the lid.  In two of my cases, "soft close" was not an option; they had to stay open.  What ever "over-engineering" I did was not an issue.

Good luck, give us some photos.

[cwarner]

Thanks Allan,  

I'll go with all 4, no sense in having a single hinge leftover, especially at the price point!.

Photo attached at current project status.  I'm using some cherry slabs that have taken up room for 10-12 years.  They were riddled with pitch pockets which I think gives some character.  I've resawn all my boards from the 2-3" thick slabs that I started with.

[David G]

I built that project with three 60lb hinges and it has worked fine for several years.  Just finished a smaller scale box with a two 60 lb hinge lid.

[GeeDub]

Looking good Chris. I look forward to a report back on the hinge performance.

[cwarner]

Ok, so I 've got the 4 hinges installed, mortised  into the back of the chest so it will close without a gap.  The issue I'm having now is I am getting a little spring back from the hinges.  I tried swimming the hinge depth to be a tad shallower (1 or 2 thicknesses of a business card) with little to no change. I can see a small gap along the hinged side so I know the lid is not binding on the case.  I've worked the hinges past fully closed 25 or so times each and still getting spring back. I've taken them off now and pushed them as far as I could past "fully closed" and am leaving over night hoping the spring may relax a bit.  

Anyone have any other ideas on what may be at play here ?