Galley struts for a heavy & long Hatch

[Jerry Bleeg]

I could use some advice on ordering struts for my hatch. I have read many of the posts on this matter and understand there are basically two ways of mounting the struts.

The alternate way as above
OR

Grants way as above.
I have to give credit to andrew for the drawings.

I am thinking of using Grant's mount method. So I used a bath scale and prop stick to weigh my hatch at 5" from the hinge. I get a reading of 225 to 245 pounds depending where I place the scale on the floor. I still need to add about 10 pounds for the inner skin, latch rods, & galley light. That puts my weight at around 235 to 255 pounds at that 5" mark. I think it weighs in so heavy because it's a 5 wide and also long at 52" from hinge to the floor. (Gruman profile) My hatch framing is 1/2" Baltic Birch with 6 ribs including the doubled end ribs. I'm thinking of sistering some more Baltic birch at that 5" attachment point to beef it up some. There is a lot of stress at that point and don't want it to break. (comments welcomed)

My question is given a weight of 240+ should I order two struts Rated at 125# each? McMasters has a heavy duty strut that would be almost 20" long with the ends. They are available in 100, 125, & 150# increments

[planovet]

This is just me talking but I would recommend the top method. I used this method and it worked great. I completed my hatch before attaching it to the hinge and it weighed about 70#. I did not weigh it your way. I used 2 150# struts from McMaster-Carr and it was perfect.

There is also 2 schools of thought on how to orient the cylinders...up or down. Some say up to keep the seals lubricated, some say down so in case a seal leaks it won't make a mess. I placed my cylinders so they are up when the hatch is closed (which is 90% of the time).

[Jerry Bleeg]

Mark, thanks for the reply and advice. I think you way of mounting the struts may be better suited for Heavier hatches, and I may well fall into that catagory. I will say that there is a LOT of stress on that hatch mounting point at 5" from the hinge. It creaked and groaned when I was weighing it. 250 pounds is a lot of weight on the two 1" wide by 1.5" wide end ribs. Thats 125 pounds on each rib at that point. I'm not to good with the physics of all this, but you've got me rethinking the mounting method.

I would say my hatch weighs roughly 50 pounds. I never weight it and now when I try to weigh it mounted, the weight varies between 50 and 35 depending on where the prop stick is placed.

So if I mount my struts like you did, I can only guess as to how strong a strut to try. You mentioned you used two 150# struts. Can you remember the strut length you used? I figure I could use the same length you did but a lower strength (100 or 125). McMasters has all their struts listed on page 1186 of their online catalog.

BTW, I've always admired your T. Nice work.
Jerry

[planovet]

This is what I used:

9416K212 Gas Spring With Threaded Ends, 150 Force, 26.38" Extended Length, 10.24" Stroke
How did I come up with the 150# number? It was just a SWAG (Scientific Wild Ass Guess)

Thanks for the compliment!

[john]

check out the hatch struts on this thread. length baby.

http://www.tnttt.com/viewtopic.php?t=36521

[Jerry Bleeg]

John, those are some long struts. I ordered some 26.38" 125# struts from McMasters last night along with the hardware. It all comes in around 60.00, so I did not think the price was to bad. I'll post my results. Thanks for the tip
Jerry