Piano Hinge ?'s

[BigTerp]

I'm planning on adding a stern deck that would run from my rear bench back to the transom. Been looking at piano hinges from here:

https://www.aircraftspruce.com/catalog/mepages/pianohinge.php

But not sure what size to get?? I plan to attach the hinge to my rear bench, and then to a piece of 1" x 1" aluminum angle. My deck (.125" aluminum sheet) will be attached to the top side of the angle. They list open width and thickness. I'm guessing the 2" open width would work good since I'm using 1" angle? What thickness would you guys reccommend?

They also have 2 grades:

MS20257P (supercedes AN257) hinge consists of two aluminum half hinges which mate and are held together by a hinge pin. Anodized finish. MS20257C is similar to MS20257P except made in stainless steel.

MS20001P aluminum hinge is extruded. The closed hinge loops cannot be pulled apart. Furnished with hinge pin. Anodized finish.

What is the difference, and which would work best for my application? I'm planning on "snipping" the hinge in the middle so I can independently open the port and starboard side of my deck. Looking to do something similar to what Jay415 did in his build.

https://www.tinboats.net/forum/viewtopic.php?f=21&t=22353&start=150

 

[panFried]

Haha, you are like a few steps ahead of me which is great for me. I was cruising the forum looking at past examples wondering about decking and hatches. Ill just follow your posts to get my answers. Thanks Terp!

 

[FerrisBueller]

Have you thought about using double-wrapped hinges?

 

[chevyrulz]

double wrapped hinges are for wood, they wrap around the wood so you can have a sturdier install & hide the hinge. they won't work on thin material like this aluminum sheet

the bigger the hinge, the sturdier the hatch will be for standing on & what not

the hinges i ordered from aircraft spruce were dinkier than i imagined based on the size listed so i'd say go w/ a step or 2 larger than you think you need. very good quality & super cheap, quick shipping, very well packaged (taped to a stick of wood to keep them from getting bent), they were just smaller than i imagined when i was reading the numbers on paper...

the ones i got were 1.5" x 0.040" so i suggest the 2" x 0.051"

with wood, you want to put the piano hinge on the edge which means you have to have a hinge that's the exact width (or a tad smaller) than your wood's thickness. but for aluminum sheet, you can't mount them like that (unless you add aluminum angle to the sheet) so the size of the hinge is not going to matter like it will for wood

now, the bigger the hinge, the bigger the pin inside it so if you're mounting the hinge underneath the sheet between 2 pieces of the sheet like on my build, then the bigger the hinge means the bigger the gap between the 2 pieces of aluminum sheet.

if you put the hinge on top, you can have a much smaller gap between the 2 pieces of aluminum sheet, but you do have to look at the entire hinge all the time then, and when you put weight on the hatch with the hinge on top, that weight is more supported by the fasteners than the structure itself in comparison with having the hinge on the underside. so underside mounting is more work & leaves a bigger gap, but it's going to be slightly stronger. you can always put a stick of angle underneath to add strength if you opt for the topside hinge mounting

now if you want hidden hinges, extra strength, and have the $ to use some extra aluminum angle then you will want to add aluminum angle to the bottom side of the sheet & then attach your hinges on the angle. that way your standing on the shaft of the rivet which is ideal. this also allows for the hatch to open 180 degrees to lay completely flat when it's open. the way mine are mounted on the underside, only allows about 130 degrees so when my hatches are open all the way, they are not flat on the deck. i am fine with that because i don't leave them open and i didn't have the extra angle to "do it right" so to speak

it sounded like you are saying you plan to sandwich the hinge between the deck and a stick of angle, but for a hatch that opens 180 degrees you'd want the hinge mounted perpendicular to the deck on the hatch side and then flat on the bench, rather than parallel to both like if you sandwiched it. that would mean that 1" angle should work perfect with that 2" open width hinge. you'll need to make sure you blind rivet with the rivet head facing the bow of the boat & mount the hinge on the bench a rivet head thickness back so the hatch closes all the way

 

[BigTerp]

panFried » Today, 9:48 am[/url]"]Haha, you are like a few steps ahead of me which is great for me. I was cruising the forum looking at past examples wondering about decking and hatches. Ill just follow your posts to get my answers. Thanks Terp!

HA!! Hopefully I lead you in the right direction. What are you doing for hatches? I was orginally planning on going with some aftermarket Tempress type hatches. But have decided to get some custom made ones from bassboy1 who runs FishOnFabrications. They are aluminum, can be custom made with or without drop in liners, can be blind riveted in place, are easier to paint than plastic and are comparable in price to something like the Tempress hatches. Check them out.

https://www.fishonfabrications.com/

 

[BigTerp]

Thanks Chevy!! I'm a bit confused as to how your saying to mount my hinges. I had orginally planned to mount the hinge to the vertical surface of the back of the bench and then to a piece of angle mounted beneath my sheet. When the hatch would be closed the hinge ends would "meet" at the back of the bench seat. Are you suggesting I mount the hinge to the underside of my sheet? So when the hatch is closed the hinge "arms" make a 90 degree angle? I'd also be ok with the hinge itself being exposed, I think. As long as it doesn't pose much of a tripping hazard.

 

[chevyrulz]

BigTerp » 10 minutes ago[/url]"]I had orginally planned to mount the hinge to the vertical surface of the back of the bench and then to a piece of angle mounted beneath my sheet. When the hatch would be closed the hinge ends would "meet" at the back of the bench seat.

ah ok that's fine, well on mine, i can't easily mount hinges to the back of the bench because it has a lip & is not flat. so if yours is flat, then you can definitely use the back of the bench as the bench side mounting surface for the hinge.

BigTerp » 10 minutes ago[/url]"]Are you suggesting I mount the hinge to the underside of my sheet? So when the hatch is closed the hinge "arms" make a 90 degree angle?

I would wanna mount the hinge to the underside of the aluminum sheet deck for looks & so it doesn't stick up above the deck

BigTerp » 10 minutes ago[/url]"]So when the hatch is closed the hinge "arms" make a 90 degree angle?

exactly

if when the hatch is closed, one hinge side is @ a 90 degree angle to the other hinge side (perpendicular), the hatch will open 180 degrees. if you mount the hinge so that when the hatch is closed the hinge is flat, by flat i mean open to its full width, then the hatch is only going to open to 130 degrees or so & not lay flat when it's open.

your plan will allow 180 degree hatch motion. my hinges lay flat when my hatches are closed & my hatches don't open a full 180 degrees. i like to hide my hinges so i wouldn't mount it on top like you're planning. but mounting it on top is a little easier for installation & it will still look & work fine. it's not going to stick up enough to trip over. conceptually, i wanted to be able to look across my deck & it be perfectly flat so i did lot of extra work to make that happen. funny thing is though, my hatch handles still stick up about the same amount as my hinges would have lol

i wanted no hinge sticking up AND the smallest gap possible around my hatches, so my hatches were not noticeable & didn't trap leaves, mud, sand in a big gap. well it turns out you can't have both. if you want the gap small on a hatch in the middle of the deck, you have to have the hinge stick up, or the hatch won't open. and if the hinge doesn't stick up, like i did, then you have to open up the gap in order for the hinge to be able to open or the hatch hits the deck before you get the hatch even 1/2 way open. now if the hatch is not in the middle, you don't have that problem. i haven't yet gotten around to making my rear deck, but i plan to do it exactly as you're doing. full deck from bench to transom, that has a seam in the middle so the left & right open indepently, so i'm kinda figuring mine out in my head by replying to your thread, sorry if i'm too wordy

 

[BigTerp]

Thanks again Chevy. That all makes sense, mostly. It's just hard to picture what someone says and also to explain what I'm thinking in my head. I'm sure I'll get a better understanding once I get my hands on a piano hinge and can mess with it.

Of the 2 grades aircraft spruce offers, which did you go with? Whats the difference between the 2?

 

[chevyrulz]

I bought 2 of these but still haven't used them:

MS No. MS20257P4-3
Spruce PN 03-00050-3
Open Width 1-1/2"
Thickness .040"
Price $4.75


i ended up getting a smoking deal on a full stainless hinge, which I then cut into 3 pieces to make my 3 hatches.. a local boat dealership i get some parts from had 1 in the back of the shop that they had cut like 2' off of for some job & it had been laying around for a long time apparently, & there was like 4' left of it. sold it to me for $5

the 1.5" wide ones i got r perfect for edge mounting to 3/4" plywood, but if you're mounting to a big flat surface like alum sheet or a flat bench surface then go big, get the 2"

well there's 3 types they have @ aircraft spruce. they have 2 types of aluminum, & then stainless.

of the 2 aluminum ones, the 20257 is not as strong as the 20001 because the 20257 is created by bending the aluminum to hold the hinge pin, whereas the 20001 is extruded without a gap to open up under stress. the aluminum ones end in P1 P2 P3, etc... & the stainless ones end in C1, C2, etc...

so the 3' long x 2" wide alum 20257 is only $6.50

the 3' long x 2" wide alum 20001 is $30.00!

& the 3' long 2" wide stainless is $16.50

the $6.50 ones are plenty strong though. go stainless if you have the $, they're stronger

the purpose of the $30 ones is to be super strong & super light, which is paramount on an airplane, but not so vital in a jon boat

from their site:

MS20257P (supercedes AN257) hinge consists of two aluminum half hinges which mate and are held together by a hinge pin. Anodized finish. MS20257C is similar to MS20257P except made in stainless steel.

MS20001P aluminum hinge is extruded. The closed hinge loops cannot be pulled apart. Furnished with hinge pin. Anodized finish.

 

[panFried]

BigTerp » Today, 10:18[/url]"]
HA!! Hopefully I lead you in the right direction. What are you doing for hatches? I was orginally planning on going with some aftermarket Tempress type hatches. But have decided to get some custom made ones from bassboy1 who runs FishOnFabrications. They are aluminum, can be custom made with or without drop in liners, can be blind riveted in place, are easier to paint than plastic and are comparable in price to something like the Tempress hatches. Check them out.

https://www.fishonfabrications.com/

I checked out BassBoy's work, which looks really nice. However, its probably out of my budget. So I am planning to go the route of Rubbermaid or plastic reservoirs for tackle boxes below a deck door (piano hinges ).

 

[BigTerp]

Thanks Chevy!!

Yeah, I hear ya panfried. I've already probably tripled what I paid for my boat in materials to do this build. There are several things that I had to decide between which one gets the budget parts and which one gets the more expensive ones.