Something you should know (bump-keys)

[Shrub]

I'd walk a mile outta my way to use the metric system.

I liked that one

Devildog,
I was in the same boat as you but ive recentally cut off the shoulder all together, put the key in the lock and pull it slightly back to take out any backlash it may have (it sould still be seated correctally) then cover the bow with hot glue from a glue gun, when its nearly set pull the key out and then after a few secs of blowing on it put it back in until cold,

This will leave you with a key that now has a shoulder in the normal place but made out of glue, there is enough spring in the glue to allow for bumping, ive only got the process to work after ive started doing this to the bump keys i make, its thanks in part to the tool video and to NKT also, zeke has also helped a lot on the making of the keys to begin with, thanks guys

[Shrub]

DD,

Sorry i as mistaken, ive been playing a bit more and re read what i was told elsewhere,

cut your bump key as normally suggested, too much of the shoulder or the tip will mess it up, run you file accross the tip once or twice and take off the 1-2mm from the shoulder, put the key in the lock and pull it back to take any back lash out if any, you should have the gap at th shoulder visible,
With your hot glue then go around the shoulder and 1/3rd of the way up the bow, when setting pull the key out and run it under a trickle of cold water building up to a normal running cold tap,

When back in the lock it will have no gap due to the glue but you should be able to push it in under a bit of pressure until it hits the shoulder of the original blank,

Then squarely hit the bow of the key dead centre and when you hit it dont instantly remove the hitting stick, let the energy follow through, if you are holding the lock in you hand make sore you arent moving away from the stick just as you hit it,

With your index finger and thumb hold the key in such a way that at the same time as you hit it you can lightly rotate the key in either direction after each unsucessful hit rotate the key back again, a couple of hits and the lock should pop, if not remove the key and check for any excessive brass marks on the cuts, if you are useing a machne to cut them give it a quick rub with emry paper as the little steps a cutter can leave doesnt help,

Ive not practiced in a door yet but i guess you hold the key more or less the same but obviously from the front,

Watch the bump vid and you can see how Barry holds euros and flicks the key each time, when i was trying with a constant pressure it never worked, takes a little practice but you will get there.

[Crazyman67]

Hello....i have a KW1 bump key that i cannot get to work....i think i may have ground too much off of the shoulder or tip. Does anyone have the link to zeke's guide to bumping...i tried searching, but could not find it.

[raimundo]

many bump keys do not have the shoulder cut back, you just pull the key back one pin and strike it. Volkov probably has not explored the various materials for making a hammer, its amazing how much the right hammer makes a difference.
If you are cutting the bump keys on a machine, even if you are copying from a depth key, you can just pull the key you are copying back in the cutters jaw by the width of one or two matchbook covers and copy it straight ahead. no need then to cut back the shoulder, the cuts are offset on the copy.

[keysman]

I have found the most important factor is timing.. if your timing is off , it doesn’t really matter if your shoulder is cut correctly , the tip is filed a small bit , or the room temperature is correct .

When the pins are struck by the slopes of the key they “bounce” away from the slope. They then hit the top pins .and in que ball fashion, the bottom pins “dead stop” while the top pins continue to travel away from the bottom pins, creating a ‘space”. It is at this time the turning force needs to be applied.

Yes this all happens in a fraction of a second, one of the engineers here can probably give a better explanation and exact amount of time that the “gap” exists.

I have the best results with liberal doses of (the evil ) WD-40 or similar lubricant and a wooden hammer handle . I have found a turning tool is required if you don’t like sore fingers, I use a 1/8 in rod about 3 in long ( I don’t know what it was in a previous life)

Your mileage may vary.

[p1ckf1sh]

Yes this all happens in a fraction of a second, one of the engineers here can probably give a better explanation and exact amount of time that the “gap” exists.

Good explanation. While I am no engineer, I think it is not possible to give an estimate as to how long the time window for successful turning is. There are too many factors, force of bump, strength of springs, etc. Also, one thing that affects the bumping process is the bitting itself. If there are lots of high/lows bumping will be harder. A lock with an even bitting, like 2-4-3-4-2 will be easy. Also, a "deep bitting" (i.e. long pins) will make things easier, because the shearline is closer. But then there is the risk of accidentally pushing a bottom pin over the shearline...

[JackNco]

hey all been a while since i was on here

ive made 6 bump keys so far and got 5 working using a padlock as a hammer... so kinda crude

i place my thumb lightly against the key and move it side to side rather than put presure on it... and its more in the swing than how har u hit the key. try and get as much of a swing in the wrist, about a 90° swing ad pull back slightly as u do. i get them open in about 5/6 hits max.

btw i walked in a locky up the rd from me and explaine what i wanted and why i wanted it, he promptly cut the key and had a chat about picking with me. a few days later i went in with some stronger keys ide had cut from the master in the market (HD KEYS with thicker shoulders, like the bump kys u buy in the uk r make from) and handed it to him at wich point he game me his mobile number n told me 2 call him direct for any other bump keys i wanted making, so if anyone in the UK is after one cutting let me know.