How exactly do you copy keys?

[tomasfuk]

Being disgusted by inaccurate keys copying in standard locksmith workshops and copy centers, I decided to do it myself.
I don't know how exact keys are required by other manufacturers, but (ASSA Abloy) FAB requirement is ± 30 µm (both cut position and depth). But usual inaccuracy is 100 µm in depth, longitudinally even worse.
Recently I acquired an older key duplicator in a perfect condition:

and installed a longitudinal measurement of the tracer position:

what enabled me to adjust the tracer position with accuracy within < ± 10 µm.
Now I am able to copy keys in tolerance of ± 15 µm if I work carefully, not in a hurry.
I am able to code new keys too, but the inaccuracy of my templates must be added - thus let's say ± 30 µm in total. The depth can be within ± 15 µm if I cut in two steps, with a measurement in between.
And what about you, folks?

[jeffmoss26]

I have a Cole 3K duplicator that I purchased used for $40 from a hardware store that closed a few years ago. Needed a new belt and the wheel sharpened, so another $30 or so and it works fairly well for my needs.

[kwoswalt99-]

I bought an old Curtis 2h from a guy online, through the mail, really cheaply. I keep it under my bed for now, until I get the cutter sharpened. It runs nicely, but I don't think it would cut within microns.

[cledry]

[tomasfuk]

As nobody answered my question (how exactly do you copy keys?), I suppose nobody knows it

[cledry]

Stick the key in the left side, stick a blank in the right side and cut the key. What more do you want? It isn't complicated. As for adjusting the key machine that is also so simple you do not even need any measuring devices beyond a couple of blanks and a cylinder with original keys that is of a tight tolerance. If you can get 3 generations of a BEST key for example you won't have to worry about most other keys.

The machines I pictured are all used daily to cut many hundreds of keys a day. 1 job yesterday required 280 keys alone. Earlier in the week we cut over 1400 keys in one day using two of our Bravo machines.

What exactly are you asking?

[tomasfuk]

Stick the key in the left side, stick a blank in the right side and cut the key. What more do you want? It isn't complicated. As for adjusting the key machine that is also so simple you do not even need any measuring devices beyond a couple of blanks and a cylinder with original keys that is of a tight tolerance...1400 keys in one day using two of our Bravo machines.

What exactly are you asking?

This is almost the same story which I have heard from my nearest locksmith, when I complained of their keys, far out of tolerance, made for our master keyed system. Some of the keys were cut even 0.15 mm deeper and the locks did not work smoothly then.

If you don't use any measuring devices and calibrate your machine only using pre-cut templates and eyes, you cannot get under 100 µm tolerance. With very precise templates and 20 µm shims you may get even under 50 µm.

Thus, what I am asking is, what the accuracy of the keys made by you is? Do you know that?

[globallockytoo]

Most cutting wheels are not perfectly round, so when adjusting the depth, simply put two identical key blanks in the respective vices. the cutter should just barely touch to object blank and you can tell so, when it misses a little on every revolution. It may not be the ultimate in accuracy but it works well for most duplications.

[tomasfuk]

... simply put two identical key blanks in the respective vices. the cutter should just barely touch to object blank and you can tell so, when it misses a little on every revolution. It may not be the ultimate in accuracy but it works well for most duplications.

I don't know with which tolerances produce the blanks other manufacturers, but I know how is it at FAB. Height ± 100 µm.

For a quick verification I just measured 3 FAB brass blanks (from the same package). Results: Blank #1 8.50-8.54 mm, #2 8.48-8.50 mm, #3 8.52-8.56 mm. Thus, taking randomly any 2 of them and executing such calibration means inaccuracy of up to ± 80 µm plus inaccuracy of the method ("when it misses a little on every revolution") let's say 20 µm, i.e., ± 100 µm in total.

I took 3 identical steel blanks from KABA GEGE (from the same package) too. Results: Blank #1 8.74-8.87 mm, #2 8.73-8.84 mm, #3 8.76-8.85 mm. Thus, taking randomly any 2 of them and executing such calibration means inaccuracy of up to ± 140 µm plus inaccuracy of the method ("when it misses a little on every revolution") let's say 20 µm, i.e., ± 160 µm in total.

No wonder that after such calibration the factory key works perfectly, a copy of it works mostly, and copy of a copy works only under wiggling with the key.

[cledry]

30 years of doing this day in and day out tells me that 3 generations is perfectly fine on a tight tolerance lock. I have never seen the need to be more accurate than this but often we can go a few more generations. I cut a key, if the customer brings it back I check it with a dial caliper. If it is within specs I will look for marks on the key (impressioning marks), if I see none I will assume that the key is low and adjust .003" up. 9 times out of 10 this fixes the issue.

Garbage in = garbage out.

Good code key or good original and bad duplicates almost never happens using the machines we have.

[tomasfuk]

... I will look for marks on the key (impressioning marks), if I see none I will assume that the key is low and adjust .003" up. 9 times out of 10 this fixes the issue....

No surprise - my experience is that 90% of key copies are low.
Just for illustration - the machine I have purchased from inheritance was calibrated so, that the distance between the keys was by 0.4 mm shorter than the distance between the tracer and the cutter. Thus, even if the copy was too low, it worked if pushed into the plug up to the stopper.

[cledry]

The tolerance of most locks is at least .003" plus or minus. Most keys that don't work in my experience are because they are copies of copies. The spacing can be adjusted with two blanks , no need for a dial indicator. Now are you going to tell me the dial indicator is also more accurate? OK then what about lateral bearings and bearing run out? Just because the shoulder stop is adjusted correctly doesn't mean the relationship of the copy dog to the cutter is also 100%.

Not only do I have 30 years experience cutting keys and masterkeying locks, I also have calibrated many machines for satisfied customers. All with the same goal of 3 generations with no noticeable issues. I also am trained as a machinist so I understand tolerances. In theory 100% accuracy is the most desirable. In reality you work within tolerances.

If you are getting 90% bad keys cut by local locksmiths perhaps you can start a business adjusting their machines. Sounds like where you live they could use some help.

[tomasfuk]

... Now are you going to tell me the dial indicator is also more accurate? OK then what about lateral bearings and bearing run out? Just because the shoulder stop is adjusted correctly doesn't mean the relationship of the copy dog to the cutter is also 100% ...

My dial indicator enabled me to measure it. The lateral allowance of the cutter bearings is 30 µm relaxed and 70 µm under a really strong axial push and wiggling.

If you are getting 90% bad keys cut by local locksmiths perhaps you can start a business adjusting their machines. Sounds like where you live they could use some help.

I am afraid there is no real demand for such service here. As one guy told me in our local lockpickers forum, it's a business. The cylinders are worn out sooner, the manufacturers sell more cylinders, the locksmiths install more locks and make more key copies, everybody is happy.

To be honest, recently I found one reliable locksmith shop which makes good copies, within 30 µm tolerance in depth. Tested them after few months, with the same result. But it's not a rule in my town, it's an exception. When I made a compliment to them, the boss told me that they regularly adjust their machines.
As they like my dog too, I would visit them more often if it were easier to find a place for car parking near

[cledry]

Did you ask that locksmith that cuts the accurate keys and adjusts his machines regularly exactly how he adjusts his machines? Seems to me he might be able to answer your question.

[tomasfuk]

Did you ask that locksmith that cuts the accurate keys and adjusts his machines regularly exactly how he adjusts his machines? Seems to me he might be able to answer your question.

Maybe sometimes I will ask him such questions. As he uses digitally controlled (CNC) machines, I can imagine that such adjustments consist of cleaning, lubrication, sharpness checking, allowances tightening and some self-calibration procedures running.

My intention when I was opening this discussion thread was to know how much different the locksmiths' aproach to the accuracy in other countries is. Thank you for your replies - it seems you hold it under control and in reasonable limits. I wished if I have had more feedback from the others ...