Wooden Hinges

[Burkhardt]

You may have seen my project thread about the watch display/winder and I am in the process of making Winder 2.0 because the first one worked but not smoothly.

That gave me a chance to re-do the lid hinge that I had to patch together after breaking in version 1.0. Came out quite nice and I thought to share the method of making such a fully wooden hinge. I did use a brass pin, though because it can not be seen anyway.

Given the Bamboo plywood with changing grain directions I can not really call it an "invisible" hinge but the same method can be applied to solid hardwood with the hinge barrels cut from an end grain strip. Then it would be barely visible.

1. Hinge barrel grooves cut into mating parts (I used a 1/2" ballnose) going 1/2 diameter deep
https://lh6.googleusercontent.com/--STGI0SeleQ/VRxrO_7HTGI/AAAAAAAAFpg/c33zp-w3pe0/w640-h853-no/DSC03029.JPG

2. Hinge barrel layout in VcarvePro. If you look closely you can see the radius of the barrel is a tiny bit larger (0.01") on one side. That gives the moving parts a bit of play later. Left two barrels are not completely drilled through as end caps.
https://lh3.googleusercontent.com/-xTT_qvxWnlk/VRxryIFTsWI/AAAAAAAAFq4/K7_2dgV2rWA/w1587-h712-no/ScreenHunter_01%2BApr.%2B01%2B15.05.jpg

3. Hinge barrels with tab for alignment
https://lh4.googleusercontent.com/-nmkScHjUlt8/VRxrQbK0SZI/AAAAAAAAFpo/n1L-_PODqI4/w1137-h853-no/DSC03030.JPG

4. Barrels threaded onto 2 brass rods with thin PE film back and forth as glue release
https://lh3.googleusercontent.com/-qLAvMG1vE6c/VRxrT40-QoI/AAAAAAAAFp4/XCY1YlRfyfw/w671-h852-no/DSC03032.JPG

To be continued.....

[Burkhardt]

5. Another picture of the threaded barrels
https://lh3.googleusercontent.com/-lmZUXYWxsnA/VRxrVVwGxzI/AAAAAAAAFqA/U7HAnCPNM2A/w492-h853-no/DSC03034.JPG

6. Barrels glued in (Titebond)
https://lh4.googleusercontent.com/--nSBvQ13w0E/VRxrXBG5amI/AAAAAAAAFqI/Y3-gEEh6cyo/w1502-h853-no/DSC03035.JPG

7. Pins removed, hinge speparated, film removed, some minor glue voids filled with CA glue, re-assembled with a pin of proper length. Cutting such a hinge into the end grain for this plywood is not a good idea as the edge ends up a little jagged. This would not be a problem for a normal box where the grain is parallel to the hinge.
https://lh3.googleusercontent.com/-0K-Wv5WYamw/VRxrY2q5DBI/AAAAAAAAFqQ/cNHPwXkIKfA/w1592-h853-no/DSC03036.JPG

8. End cap barrels (not completely drilled through) glued in, protruding parts cut off (band saw) and sanded flush (belt sander)
https://lh4.googleusercontent.com/-ZpUCYxI6XQc/VRxraHJ9FwI/AAAAAAAAFqY/txj5IzwjJnA/w1461-h853-no/DSC03037.JPG

[Burkhardt]

9. Hinge inside open
https://lh5.googleusercontent.com/-qezVqRFDk_M/VRxrdGywk5I/AAAAAAAAFqo/ZJi9QTN66PM/w1439-h853-no/DSC03039.JPG

10. Outside open
https://lh4.googleusercontent.com/-6J2qj2ilNAg/VRxrfD_KMrI/AAAAAAAAFqw/AISppgDwJoY/w840-h853-no/DSC03040.JPG

[David Iannone]

Great job. That is a good looking hinge.

[Kyle Stapleton]

:)I think it is a grass hinge.

[scottp55]

Looks Great Gert!
Looks like you left enough materiel on second iteration. 20/20 hindsight is wonderful...Ain't it:)
Got a lot of Teak/Maple end grain cutoffs from slabs.
You willing to to share a .crv/.eps in exchange?
Good work!! Looking forward to seeing the new gears with guides!
scott

[Burkhardt]

.........You willing to to share a .crv/.eps in exchange? .....

Sure, no Problem, here it is (https://dl.dropboxusercontent.com/u/29562014/INVISHINGE.crv). There is really not much to it. Just a stepped circular barrel with an unsymmetrical extension attached

Couple of hints:
- This is for exactly 0.75" blank
- The groove is exactly 0.25" (6.35mm) deep and the center is exactly 0.177" (4.5mm) from the edge for a 90 degree opening angle.
- If you cut this from an end grain strip/slab, make sure it is milled or sanded flat and parallel. You will also need to increase the thickness of tabs (or use other holding technique). The holding tabs in the file are not strong enough for end grain.
- The unsymmetrical extension helps stacking the alternating barrel sides. Test fit the drilled holes with the pin and make sure each one moves freely but not loose. If too tight, ream with a drill until it fits.
- I used approx. 1 mil PE film (a.k.a. sandwich bag). It is thin enough to conform and strong enough not to rip.
- When going left/right/left/right around the barrels make sure the film is on the side of the barrel with the smaller radius
- The brass pins are long enough to clamp in a vise, polished with steel wool and sharpened to better penetrate the film. Put a tiny dab of white grease into each barrel hole and distribute with e.g. a needle. Do not smear the grease onto the barrel outside.
- Stack up the barrels one by one on both pins and penetrate the film as you go. Do not try to push one pin through when everything is lined up, the pin tip will snatch the film and jam in the hole.
- Do a test fit with the grooves before gluing. The hinge stack-up should sit snugly. If both sides are spaced too far, you must cut the grooves deeper (may be difficult after the fact). If the hinge is moving a little, you can put a small strip of electrical tape on the barrel over the film as spacer. If the hinge is very loose you may better start over with the grooves.
- Mask the body and lid of your box inside and outside along the hinge with thin tape (e.g. Scotch Tape) to avoid glue on non-hinge surfaces. Painters masking tape may be too thick.
- The stack-up should leave 1/3 to 3/4 of a barrel length free at both ends to put the end caps on
- Brush wood glue sparingly onto the exposed sides of the barrel (larger radius). Assemble hinge, align carefully and clamp. Scrape off squeeze-out before it gets tough. Let dry well, e.g. overnight.
- Remove the pins and take the assembly apart. Remove the film including small slivers that may get stuck.
- The glue may not have perfectly filled all crevices. A few careful drops of medium viscosity CA glue can fix that. Wipe off all excess CA before it hardens.
- Re-assemble the hinge with a new pin cut to the the length of the stack-up plus approx. 0.5". De-burr the pin ends.
- Attach the end caps (their center hole must be deep enough to accommodate the pin sticking out). The glue must be applied very carefully here to not jam the whole thing. The end caps are anyway more cosmetic. Let dry completely.
- Saw off all protruding extensions with a band saw and don't screw up now cutting into the box.
- Sand everything flush. An oscillating band sander works very well for that.

[chiloquinruss]

One of the perks of owning a bot', this great group of fellow sharing botters. Thank you for taking the time to followup on ver 2.0 and the very complete tut on making the hinge, very cool! Russ

[barrowj]

Thank for the link Gert,

I will update when I get to a project that I can use the hinges with. I think we should have a new area dedicated to sharing our project files.

Joe

[David Iannone]

G. Thanks for the instructions and file. I saved the instructions and the file in my dropbox for tinkering one day. I would like to make some kind of a small wooden trinket box for my wife with a nice 3d relief cut into it. Whenever I get around to playing with it, I will give your hinge a try. I am not a woodworker at all, but am always inspired by the fellows like yourself who do such top notch work, and are willing to share their success and failures. It makes me try to think outside the box.....ha
Hats off to you Sir.

Joe,
I agree, an area for sharing project files would be cool.

Dave

[scottp55]

Thanks Gert!!!
For a "Non-ShopBotter:)" You've contributed enough so you should have a REAL USPS "Dropbox" for us folks to send YOU stuff!!!:)
If only too get you away from "Fenceposts" and Bamboo:)
It would be interesting just to see how YOU would deal with "Scrap" thin rips and cutoffs!
Probably an "Endgrain Tesseract" or "Quilted Klein Bottle" :)
Thanks once again,
scott

[Joe Porter]

I am jealous of that bamboo, I wish it was available on the East coast where I could go and buy it in person...joe

[scottp55]

Pretty much "Razzing" Gert:)
But also a "mass flowering event" is starting on several species in China at the moment(every 60-120 years).http://en.wikipedia.org/wiki/Bamboo
And if G's species is involved, it may be time to start hoarding:)
scott

[Burkhardt]

I am jealous of that bamboo, I wish it was available on the East coast where I could go and buy it in person...joe

Maybe not in your town but you can get it from places in Durham, Charlotte or Fuquai Varina if I can believe Google.

Mind it is not cheap. Nowadays I pay some $200-230 for a 3/4" 4x8 sheet.

[Burkhardt]

Pretty much "Razzing" Gert:)
But also a "mass flowering event" is starting on several species in China at the moment(every 60-120 years).http://en.wikipedia.org/wiki/Bamboo
And if G's species is involved, it may be time to start hoarding:)
scott


No idea about the species. I just buy from a local hardware/plywood specialist and I guess (not sure) this is from Plyboo (http://www.plyboo.com/products/category/plywood-veneer), one of the major importers. Just keep in mind when buying bamboo, the pretty amber or dark brown stuff is heat treated and much more brittle/splintery than the natural bamboo that is very hard and tough. Example of a scrap piece after cutting out (keep in mind most of the cross-section is end grain). You can not do that with most hardwoods:

https://lh4.googleusercontent.com/-mRGEK6srAV0/TxZcAOB8cjI/AAAAAAAAFEM/KZEzl1GwaF0/w1024-h768-no/DSC00414.JPG

https://lh6.googleusercontent.com/-lzWXT-EGkbE/TxZcC7nj7zI/AAAAAAAAFEQ/CvYrwekbEPc/w640-h853-no/DSC00415.JPG

[scottp55]

Gert, Permission to backpedal enough to remove my foot from mouth, SIR!!
Never meant it was "Cheap"!
Should have remembered the ancient Chinese adage;
"A closed mouth catches no foot".
Got sticker shock when you mentioned price---and then remembered what 2 faced Marine grade Teak 3/4" was when I tried to price it to match 2 sheets I bought in '96 for the bathroom for a project(scrapped that idea!!).
Looking at the site was interesting! In the "Dimensional Lumber" section they said "100% moso bamboo" and it looked a lot like your interior plies.
Interesting about the "Heat treated". Sounds a lot like the "Torrified" Ash we use. Makes it extremely brittle (at C-90...the MOST heat treated grade...also available in C-30(light amber),50(med), 70(dark amber), 90(chocolate)) , but very dimensionally stable and VCarves like butter.

Thanks for posting pics, especially the end-grain "Arch" :)
The thickness of the face "Veneer" is great and would give a lot of options:)
scott

[Joe Porter]

Thanks for the info, Gert. Durham is not too far away. I have to travel that far or further for any hardwood or special ply. I will look them up....joe

[larry_high]

Joe I am in chapel hill and know of no suppliers of any ply in Durham
you may want to try Horizon Foresty Product 919 719-0877 , McEwen/Hood,919 772-7550 or Wurth 919 231-6620 all are in Raleigh
Good luck
Larry

[larry_high]

Joe just remembered Atlantic veneer in Beaufort may have it, they are the best supplier in your neck of the woods.
Call Jack he is the manager, 252 728-7620

[Burkhardt]

Maybe this business in Windsor, $233 for an 18mm sheet marine grade. That looks anyway like a candy store.
http://www.worldpanel.com/#!product/prd2/3369524261/solid-bamboo-marine-plywood-4%27x8%27

[tri4sale]

Joe I am in chapel hill and know of no suppliers of any ply in Durham
you may want to try Horizon Foresty Product 919 719-0877 , McEwen/Hood,919 772-7550 or Wurth 919 231-6620 all are in Raleigh
Good luck
Larry

Thanks for that info, I live right outside Raleigh and drive past McEwen/Hood 3 or 4 times a week and never knew they were there, not much signage at that location telling what they are!

[Joe Porter]

Thanks, Larry and G. I found Wurth in my Google search, but I don't know if I want to go in there or not. They probably check your bank balance before entering, lots of high end machinery in there...I have heard of Atlantic veneer and I will go and visit them...thanks for the directions....joe

[EricSchimel]

For those of you looking for gear plans, check out "www.geargenerator.com" You can get free gear SVG files.

[Burkhardt]

For those of you looking for gear plans, check out "www.geargenerator.com" You can get free gear SVG files.
Got to try that sometimes. So far I have used Matthias Wandel's Gear Generator software (http://woodgears.ca/gear/index.html).

However, both tools produce "ideal" gears like you would cut them on a gear hobbing machine. For a 3-axis CNC-cut gear with an endmill of reasonable diameter (I use 1/8") this must be tweaked.
I create the gears first with maximum addendum setting, import into CAD, cut out a single tooth and "file" or "fill" in CAD until no radius is smaller than my endmill and no interference happens when turning the gear pair. Obviously, the active surfaces of the involute tooth flank must not be touched.

That works but is quite cumbersome and I wish there was software that calculates a well working tooth outline so that it can be cut directly on CNC. I sent an email to Matthias Wandel a while ago and asked if he might consider that but he is not into CNC and had no interest in that.