Sunday 10 April 2011

The Danlock (model B)

Update 2019 - Dan Feldman has retired from producing puzzles now but his son, Boaz Feldman, has taken on the mantel and now producing his own extremely wonderful designs as well as making new copies of the Danlock. You can now easily buy from his Etsy store.

The Danlock arrived a few days ago from Israel. I bought it direct from Dan Feldman himself - he is very obliging (even kept one for me until the end of the month so I would have the cash to pay him!!!). He accepts PayPal payments - it is $100 including P&P.

The puzzle arrives in the original Nabob padlock box. Inside is the lock with a whole key attached to the haft and a broken one attached also via a thin keyring (it can be easily removed). There is a nice cloth bag labeled with "Danlock" for transporting it and a sealed envelope containing the solution.

This is a pretty solid bit of kit - weighing in at 10¾oz/300g and appears to be made of solid brass. It is not a particularly pretty puzzle - obviously it was a normal working padlock before Dan got at it! There are a few marks on it that may be from lock manufacture or, more likely, from being held in a vice whilst Dan worked his magic. I don't think that this detracts from it in any way. Other than this, there is no sign at all that Dan has interfered with the lock at all.

The keys are real padlock keys. The instructions state that the lock is to be opened first and then returned to the condition it began in. They say that you do NOT need any tools other than what is provided to you - you do not even need to use the fine keyring which is used to hold the pieces of the broken key.

Opening the padlock is pretty easy - after general poking, prodding and tugging at things followed by a few moments thought, you bite the bullet and do the obvious, if somewhat frightening manoeuvre and stuff the key shard into the lock and push it further in with the other end. So within a few minutes, bang the lock is open!
So you think: "Is it that it? Is it all going to be that easy?"
Let me assure you that NO it is not that easy!

Putting it back together is actually the main challenge and it is a pretty tough one - it is split into 2 separate tasks.

The first task - removing the key shard. It is easy to establish what is required but finding the method to do it took me about ½ hour. The most important thing for this part of the quest is to look at everything you have and think laterally.

Danlock fully open (shard retrieved)

The second task - after the first task you are left with all the pieces separated but no obvious way to return it to the starting positions. You can open and close the locking mechanism using the whole key but in the open position the key cannot be removed to put it back on the haft. In the locked position you cannot put the damn thing back together!!!
After an hour I broke for a bite to eat and then to watch some TV with my wife (I do need to do something non-puzzle related with her occasionally!!!). During the next hour or 2 I kept thinking about it and picking it up and fiddling without success.

After a rest I went back to it. I reiterate - look at everything. It took another hour before it hit me with a bang what was needed. Only it wouldn't work! Why not?? I was sure I had it right but no! Definitely not working!! So back to the drawing board - careful examination revealed why it wouldn't work and what to do about it. I retried my initial theory with a special modification and it worked!
This particular trick is what marks a Danlock B as different from model A. I don't think it adds much but the extra twist is a bonus.

Overall the mechanism is absolutely marvellous - it is a pleasure to do this puzzle again and again and again!

I have given this to a few friends and they have all managed to open it (although the special model B "issue" has delayed a few). So far not a single person has managed to work out step 2. This is very gratifying for me - I consider myself still to be a moderately poor amateur at mechanical puzzles and having opened the Danlock and done the 1st part of the reassembly in about 20-30 minutes, watching people's failure (and no-one even got close to solving the second stage) I feel that maybe I am progressing in this "profession"!!!

I am delighted to own this puzzle and have had to promise a colleague to bring it in for him every week until he gets it! It has given me a thirst for more good puzzle locks. When I showed "she who must be obeyed" the Popplocks she walked away shaking her head making noises about getting a lawyer and getting "everything"!

Maybe I should wait a while - she still doesn't know about the Maze burr!!!

Update 2019 repeated - Dan Feldman has retired from producing puzzles now but his son, Boaz Feldman, has taken on the mantel and now producing his own extremely wonderful designs as well as making new copies of the Danlock. You can now easily buy from his Etsy store.


  1. Everyone raves about this puzzle lock, so I borrowed one and tried it out (it was a model B). While I was able to solve it entirely back to the starting position after a week or so, I didn't really like it that much. I suppose this means I am not a puzzle lock kind of guy. I like pure geometrical challenges, rather than something that exploits differences from your expectations based on experience with real locks.

  2. Each to their own! It may not have been your "thing" but it kept you puzzling for a week which is a good thing. If you like geometric puzzles then consider the puzzles by Vinco or some burr puzzles. The revomaze would also be a really good challenge for you.

  3. I've got probably at least 10 VinCo puzzles. I have solved the blue RevoMaze but the green one hasn't caught my fancy. I've got almost every Hanayama made ...

  4. Wow George! That is quite a collection! I agree that the green isn't the best revomaze. I would suggest that you get the bronze - it is superb! There are many hours of puzzling and being a dynamic maze there is a lot of learning to do. It took me probably 40 plus hours! I wouldn't jump straight to silver as it is a real b'stard and much too big a jump from blue.

  5. Revomaze is certainly my top choice for puzzles. if you can do blue and you are a decent puzzler, i'd skip green. bronze is my favorite. silver presented a good challenge, but it was gruelling at times. hoping gold is better, but bronze is certainly worth the coin.

  6. DanLock B is now available for sale. Please contact for further details.

  7. I can’t seem to be able to get one of these locks tried the email address but nothing