Laser cut car keys - experiences - cost ?

jpaul · 18 Nov 2017 at 11:37

On an older E46, so no contactless start, the master key has become worn, so is sometimes sticky in the ignition.

I was considering purchasing a blank from ebay (£2, shops do not seem to hold e46), and having it cut in a shop, from the reserve key, and then transferring the transponder myself.

Has anyone done similar, any recommendations in the Cambridge area ?

The guy on the market suggested 'only' £7 to cut it, but I am perhaps sceptical that a high end machine is needed to duplicate/cut it.

(tip : Unfortuantely only came late in life to the joys of lock lubrication - Kasp graphite powder )

adam cool dude · 18 Nov 2017 at 13:53

Ask that dude from gone in 60 seconds. He knows where to get them.

jpaul · 18 Nov 2017 at 19:59

bit more research - on ebay

BMW 3 Series Diamond Remote Key Case With Blade Cut to your locks!!

Get a new key blade cut from a photo of your old key!
We cut to precise tolerances - our keys are guaranteed to fit your locks, or your money back!
Want to go ahead? Its easy:
1. Click 'Buy it now!'
2. Send us an ebay message with a clear photo of one side of your original key blade (you can leave it in the fob too )
3. Your new blade will arrive in the post, cut, ready to fit perfectly into your original key fob.
Easy as that - and whats more, there's no risk for you!
Total guarantee - Total peace of mind!

Express Auto Keys
Kent
BR6 6BG

£17, seem to have good feedback.

Not sure what the insurance company would think, but even visiting a regular key-cutter, if they want to see proven ownership they could keep a copy and visit your home later.
(they would not have the transponder so immobiliser would still be effective)

...but surprising you can make a key accurate enough from a photo.

mrk · 18 Nov 2017 at 20:23

Any key cutting place will be able to cut an accurate key no problem. Then you just swap around the internals.

Your only problem will be that BMW keys charge the battery from the ignition during driving. Obviously this is something you will lose by getting a non OEM key cut.

Also the internal PCB may not fit in aftermarket blank key cases because there's more sticking out on the OEM PCB (the transponder/charge coil, for example).

Here's one of those aftermarket ones: https://www.ebay.co.uk/itm/New-Fits...782387?hash=item2eff10bbf3:g:5wwAAOSw4CFYwsI7

The solution for you will be in three stages.

1: Buy a blank key and get a local key place to cut the key, or buy a blank key from eBay where they cut your key based on a high res photo.
2: Buy just the remote fob PCB on eBay for a BMW diamond key (more on this later)
3: De-solder the transponder from the original PCB, this will still work because it works via induction. You can then glue it to the front inside of the new key.

This way, your original transponder is still being used, so the car starts, the key has been cut so the barrel turns, and the last bit is to initialise your new fob so central locking works.

1: Site inside the car, lock all the doors with the button on the centre console
2: Put the key into the ignition, turn it once then take the key out and hold it up to the roof of the car near the rear view mirror
3: Hold the unlock button and press the lock button 3 times. The doors will unlock then lock to signal success

You will also need your original master key when doing the above, because initialising the central locking erases any previously initialised key, so you will need to just raise the old key to the roof and do step 3 with that as well. You'll now have two fobs that lock and unlock your car.

I've now had 2 aftermarket PCBs after the first one died 2 years in. The 2nd one's lock button broke apart a year in as well. I don't think they are reliable due to poor quality micro switches really, hence just caved and ended up getting a new OEM master key instead and keeping the old master as a spare.

If your insurance has key cover, you may be able to claim on that for a new genuine key if your key itself is damaged.

jpaul · 18 Nov 2017 at 21:04

Thanks, I have not take the key apart yet, but from bimmerforums had though the transponder was below component

I thought it was an unpowered, self contained, component like an rfid, and that 10 in total were created at car birth, with 3 delievered in the original keys

I do soldering, but would be a bit concerned about unsoldering a chip, when it played such an important (immobilizer) role, but, it is probably resilient to esd, and only 8 legs.

(Having one key for the central locking and another key that fitted the lock barrel, and started the car, would be ok too)

mrk · 18 Nov 2017 at 21:39

Ah that is the quartz clock crystal according to everything I've seen online, here's a diagram showing what each bit is:

Also going by that, it seems I was mistaken about losing battery charging by swapping the internals into a new key housing. The battery is charged via inductive current from the ignition, the same way the transponder is powered. So as long as you don't damage the coil, it's all good.

With that in mind, I'd just get a blank key and swap the whole PCB into the new key and have the key cut. If it all fits and buttons press as normal, then you're sorted.

jpaul · 19 Nov 2017 at 13:21

Thanks, I will do as you suggest.

I am still a bit surprised by ability to cut from a photo, there must be more margin & fewer pins, than I thought

jpaul · 21 Nov 2017 at 09:33

Interesting - may get a more accurate key cut from a service where you send a picture to an online service.

- at least for bm keys, apparently 6 pins with 4 possible depths on either side of blade - if you send a picture they determine what original profile of key was, and cut that;
but if you go in a shop and they use old one as a pattern for new one it could be less accurate.