Thread: My first attempt at a working wooden padlock

Time to start on the centre lamination. First it needs to be accurately marked out. After marking, I cut over the lines with a thin blade, for easier trimming right to the line. When sanding, the last bit peels away, indicating the centre of the line.: -
Attachment 221413


And the centre lamination again, cut out and cleaned up a bit. Great fun trying to cut this with the 1/2" bandsaw blade, but I was too slack to mess around putting the 1/4" on, so had to do lots of shaping with a chisel. The spindle sander was useful for cleanup. I left the spring slot slightly thin for now, at about 1.3mm. I can widen it later to fit the spring. : -
Attachment 221414


A temporary 1.4mm Camphor Laurel spring in place for testing.: -
Attachment 221415


It's time to glue dowels in the three 6mm holes that I drilled earlier in the rear lamination.
Top hole is the spring stop, the middle one is the lever pivot and the bottom one is the key pivot.
The top of the key pivot is rounded a bit to make key insertion easier.: -
Attachment 221416


It seems like a good point to check that everything aligns OK, before going further: -
Attachment 221417 Attachment 221418

So far so good. Now onto the latch bolt.
It will be made from a piece of Jarrah, nice and hard for low friction, 75mm x 17.5mm x 8mm.
Attachment 221419


Latch bolt partly shaped. It needs to be free enough to slide smoothly and easily.
At this stage, it's a good idea to check the fit before continuing.
I had to file the top edge of the spring stop flat for the latch bolt to slide freely.
I also lightly filed the right-hand-side of the spring stop, where the spring will rest: -
Attachment 221420


The business end of the latch bolt: -
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And now with the notch cut for the end of the spring. (It's supposed to be half-dovetail shaped.): -
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A quick trial: -
Attachment 221423


The next thing on the agenda, tomorrow, is the actuating lever.
The key rotates the lever, which in turn presses on the spring, drawing back the latch bolt to release the end of the shackle.

I forgot to say, I haven't decided on the final timber for the spring yet. I'll be testing some Yew, Tallowood, Pecan, Ash, Bamboo, the Camphor Laurel that's already in place and some thin aircraft ply possibly.

There's a thread on the subject here: What Oz timbers are similar to Hickory? - Woodwork Forums

Thanks, Hermit. Very interesting build. I suppose the keyhole cover might have been useful to keep dirt and such out of the mechanism. Maybe indoors, it wouldn't have mattered.
Also I see how you can swap out the spring for experimenting with various woods. Those will be interesting experiments.
Do you suppose you can stiffen the spring my keeping the middle thicker and tapering/thinning the ends to fit? At the same time, I can now imagine how the strength of the key material has to work against the spring.

Originally Posted by Robson Valley

Thanks, Hermit. Very interesting build. I suppose the keyhole cover might have been useful to keep dirt and such out of the mechanism. Maybe indoors, it wouldn't have mattered.
Also I see how you can swap out the spring for experimenting with various woods. Those will be interesting experiments.
Do you suppose you can stiffen the spring my keeping the middle thicker and tapering/thinning the ends to fit? At the same time, I can now imagine how the strength of the key material has to work against the spring.

So I'm not the only one still awake. (Just realised, Robson, you're not in Oz. It's daytime where you are.)

You're right about the cover for dirt and stuff, but as you also say, indoors it doesn't matter. (I like the shape of a keyhole.)

The spring could work well if tapered toward the tip, (making it progressive), but not at the end that's anchored, or it might break at the point where it's attached to the main body.

It's a matter of getting just the right amount of spring tension, by carefully choosing timber type and thickness, to keep wear/stress to a minimum while making sure the lock still works well. (Having said that, it's surprising how good it feels already, with the Camphor Laurel for a spring.)

Edit: The other desired property of the spring is a good shape memory, for lack of a better term, so that it continues to fully return the latch bolt to the locked position over time.

Looking good so far I have seen wooden locks before but not seen one being built. As for the spring as long as the spring is left in the locked position then it should alway return there(hope that made sense)

Originally Posted by Diggerdelaney

As for the spring as long as the spring is left in the locked position then it should alway return there(hope that made sense)

That's reassuring.
I would have thought that because the spring is being flexed regularly in only one direction, it might acquire a bow over time.

Wow Steve,

That didn't take long. I guess the book was inspiring to you. Looking forward to how this comes out.

Bret

Hi Steve
I have built about 30-35 locks ,some from the book and some of my own design,as no doubt you will also.I mainly used old hammer handles for the spring.
I had one test lock that screwed together(not glued) I used this for test purposes.
A few things bust the spring.
1.very fast key turning,kids seem to turn it very fast.The spring may snap like a carrot.
2 Don't glue the spring in the bottom and round the slot it fits in on the edges.It reduces a bad stress point on the spring.
3.Thickness is critical and no flaws in the cutting,sand smooth as you can.spring rate alters dramatically with just a few rubsof sandpaper.
Round the lond sides over so it does'nt start to bind on the case after awhile
You dont need preload on thespring to hold the tongue in place.

Ah yes, Hermit, we are so out of synch = days, seasons, even the sun in your northern sky, south for me. I have an ICOM world clock here, N polar projection, where I see Sydney time at the moment is near noon (8P here).
I find it hard to imagine a blacksmith bashing these locks out of red+ hot iron.

Originally Posted by Robson Valley

Ah yes, Hermit, we are so out of synch = days, seasons, even the sun in your northern sky, south for me. I have an ICOM world clock here, N polar projection, where I see Sydney time at the moment is near noon (8P here).
I find it hard to imagine a blacksmith bashing these locks out of red+ hot iron.

you posted this at 1.06pm our time.Hope that helps

I just completed a long-winded post with replies to everyone, then got a message that my PM Inbox was overflowing, clicked on it and it replaced the page with all of my work.

I'll try again later when I have more time.

My pieces of Ash and Yew arrived this morning, for the spring testing. Thanks, Woodwould for that.

Also, the Hickory and Tallowood pieces arrived today from Wizened of Oz, so it's all systems go. Thank you Brian.

Edit: Today's progress is following, 2 posts down.

Originally Posted by Hermit

I just completed a long-winded post with replies to everyone, then got a message that my PM Inbox was overflowing, clicked on it and it replaced the page with all of my work.

I'll try again later when I have more time.

Sucks when automated messages screw up typing, no really way to auto save on the net.

I am watching with interest as I would like to make one out of plexy glass so my Nephews can see inside the locks and how they work

Kat.