DiY Pin Tumbler Lock

[JK_the_CJer]

Overzealous Intro

Ah I can hear the haters and the naysayers alike already: "It can't be done", "You'll die!", "Who cares?", they say. Well friends, I have taken the first steps down the road to enlightenment. I am building...a fully functional 5 pin tumbler cylinder...from scratch. Tis true, I'm armed with little more than Dremel (or generic equivalent), but now is not the time for hestitation but Action! I will be happy to answer any questioning regarding my ghetto-as-heck fabrication methods. My hope is that this will inspire others to go above and beyond this poor excuse of an implementation. Now go forward bravely my friends as we advance the art of fiddling with locks.

Design

A basic pin tumbler lock is not very complicated from an engineer/jerry-riggers perspective. We'll obviously need some sort of hollow tube for the shell (stationary part), a block of some material or some smaller tubes to comprise the bible, and a plug. The plug is the main obstacle; more specifically the keyway. How can we hope to replicate those wonderful and complex cuts and wards without resorting to some nasty machining/trickery. The answer for now is: we don't. This may seem like a cop-out and honestly it is. However, I feel for now the best way to go is a straight and wardless keyway. "But, but what will stop the pins from falling JK!?". I'm glad you asked; all we have to do make a very straight cut down the length of the plug (solid 1/2 rod) that protrudes halfway through the diameter. Then when we drill our pin holes, only drill until they meet this cut. As long as the cut is narrower than the pins, they will stay put (like a ward in other keyways).

Cutting the Keyway

Unless you have the steadiest hands on the planet (with this group you just might), cutting the slot for the keyway freehand is going to be impossible at best. What we need is some sort of jig. While looking around Ace Hardware for ideas for said jig I spotted this beauty: Dremel Plunge Router Attachment (about $30). It basically turns your Dremel into a router and a drill press. It's not quite that easy though; after all these are round tubes/rods of metal not flat pieces of wood. But with a little fiddling you can figure out a decent way to cut a straight line. I chose to use aluminum for the plug because i already had some of it in 1/2". Here was the result:

http://img511.imageshack.us/my.php?image=diykeywayqy5.jpg

Tip: It's much easier to set up a rig for this cut if you have c-clamps instead of one pair of locking vice-grips. Also dont cut the plug to length until you have made the keyway cut completely.

Cutting the Shell

While I was in Ace, I started looking around for a tube with inside diameter of 1/2". I stumpled upon a piece of brass (sweet) that i believe is called a coupler. It's basically a copper tube with a pretty good wall thickness but both end have large threads on the outside. A Dremel with a cut-off wheel slices right though these things. Just chop off the threads and you have the beginnings of a shell:

http://img456.imageshack.us/my.php?image=diyshellxr1.jpg

Drilling the Pin Holes

This is by far the most time-consuming process. I tried several different things here, but one thing is certain: you must have some sort of drill press. That nifty little Dremel attachment did the trick just fine. What I did was first drill the shell, Then place the plug inside and poke a sharpie marker through the shell's hole to mark the plug. Then drill the plug's pin hole. There is no clear answer for when to stop drilling that I can tell. Just go slowly and test fit a pin often. Make sure your bit is the correct size (mine was 7/64"). Also be sure that you are in fact as close to 180 degrees from the keyway slot as possible. I got halfway through drilling hole 5 in the plug before by bit went dull (dont buy el-cheapo Walmart bits):

http://img524.imageshack.us/my.php?image=diyalmost5id0.jpg

More to come...

So far the lock can be picked with 4-pins (even without a bible). Once completely I'll cut a key out of something like a hacksaw blade. The next steps for me are finishing that last hole, adding a bible, plug face, and perhaps a plug retention thingie. Any and all ideas, comments, criticisms, insults, and praise are welcome.

[UWSDWF]

old news i saw thoes pictures hours ago

nice

[JackNco]

old news i saw thoes pictures hours ago

nice

we all did, but thats one heck of an effort. good on you, keep us posted how the "bible" goes

[raimundo]

much easier to hand make would be a lever lock, mostly plates riveted or screwed together, start with the key and build to fit it. Locksmiths in Japan were doing this as recently as the early 1970's they worked on site and built to fit the job.

[JK_the_CJer]

UPDATE:

Screw Up

Well I decided to go with individual tubes for the bible design. I cut them, bored out the holes in shell, and silver soldered them in. I used the same vice grips that had been holding the cylinder during drilling, cutting, etc.. What I didn't count on was: very hot brass deforms much easier then cool brass. After I soldered the tubes in place, I was feeling pretty good about it. Then I tried to slide the plug in to test. It stopped about a quarter of the way in...hard. The shell had been deformed by the combination of intense heat and pressure from vice grips that were holding it.

Repairable?

I tried everything I could think of: squeezing it, hammering a rod through it, grinding it. In the process I removed the tubes for better workability. In the end nothing worked. I still have a fully functional (although quirky) plug, but no shell for it. I may just try to make the shell again, but I doubt it will line up very well. I think it'll be worth it to just start again and utilize the experience gained from this attempt. I'll update when I start DiY Pin Tumbler v.2.

Summary

Be careful when applying any pressure to hot metal.

[Shrub]

Just so that you know, a fully clocked up milling machine still can not produce a series of holes that are 100% perfectly inline so useing a dremel in any part of making a lock is not advised and any drill press used must be clocked to the best you can and everything bolted and clamped down but again the only way to make a half decent attempt would be to use a milling machine and do it all at one setting from one block then split the parts after,

[JK_the_CJer]

Shrub: That all goes without saying

However just so you know; before I added the tubes, I was using rubber bands to act as springs and a bible. The lock was quite functional this way. Not using precision tools simply makes the tolerances really loose and thus easy to pick. In all honesty, picking this lock didn't feel very different from picking a Kwikset cylinder. On my next attempt I will try to make everything tighter by clamping and using my drill press/router attachment more to my advantage though. I think the quality/workability I saw in the outcome of this attempt makes trying again with a Dremel very much worth it.

Now maybe you can help me with something; you seem pretty knowledgable on this sort of thing. I'd like to drill through the shell + plug at the same time as you suggested. However, as you can imagine, the plug would be able to spin inside the shell during drilling and produce sloppy results. Do you know of a good way to lock the shell and plug together temporarily?

[mercurial]

Really interesting project you are working on!
I look forward to seeing version two!

First, let me qualify my advice, by saying that I do not have anywhere near the metalworking experience of many on this site, an I have done no milling/machining etc - so my advice below is just a product of me thinking about this, rather than actual experience doing it.

My idea to facilitate accurate drilling of the plug and shell, by drilling them together is as follows :

- Cut the length of the plug and shell with an extra couple centimetres length.

- Now, clamp/hold them together as best you can, and drill a hole right through them about a centimetre from each end.

Now, I assume you would be able to use these holes to secure the plug and shell together - maybe by using screws or even wire twists through these holes at each end?

Whilst these holes will not be accurately drilled, they should allow you to find a simple means of securely fastening the two pieces together, allowing you to drill the pinholes themselves more accurately.

Afterwards, you just have to cut both the ends off the plug and shell, removing the unwanted hole at each end that was used to brace them together.

Hope that might prove to be of some use, and I look forward to seeing your progress!

...Mark

[jgencinc]

I was going to suggest the same thing, but with a few differences. Use a rolled pin. They seem to hold a little tighter than just a screw. After everything was drilled, cut off the extra part of the shell leaving the plug long and using the rolled pin to keep the plug from falling out. Sort of as the retaining clip.

I think if you attached the bible to the shell, then used the pin to hold the plug, you could put the bible in a vise to hold it as you drilled straight through everything at once.

You might also try putting some shims around the plug to keep it level while drilling. The metal strips from the little white theft deterrent tags are great.

I also have no to little experience with metal work, so what I suggest may not be the best idea.

Good luck.

[Shrub]

Theres so many ways,

You could follow the above or in the way your doiung things i would think about cutting the plug and facing it up to the right size, make the lock basically and drill the holes last,

When drilling the holes i would put some soft wood on either end that coveres the plug face and lock face, i would then simply clamp across the ends so the clamps feet are on either bit of wood, tighten this up and the small pressure you should be useing to drill the holes will not move it,

Remember to get the best accurate holes in your situation you would need to centre drill the hole, drill it out in varying drill sizes until youve worked up to the finished hole size,

Unless you get some serious accuracy in on the job your alway going to make a very pickable lock, if your intention is merely to make a lock then forget what im saying as its wrong i assume you want to make a hard to pick lock but i admit i cant remember what you put in your original post and perhaps should go and read it

You may be better simply marking it all out as best you can and then go from there instead of relying on how true your slides or vices (or whatever your useing) are,