Failed to impression: DOM RN euro-profile

[mapafe]

It looks like You could just measure how much further till the torpedo pin is in the right position & when it stops marking, just cut another 20 to 25 thousands & leave that pin alone, after that until all the other pins are done marking

You would still have to find out which pin stack contains the torpedo-pin. The torpedo-pin is not necessarily the last pin giving marks; as you can see in my animation, pin 4 (torpedo pin) gives its last mark at frame 19, while pin 2 and 5 (regular pins) give their last marks at frame 20.

Your comment does lead to an interesting thought; is it possible to distinguish which pin is the torpedo-pin during impressioning, just by its behaviour? I think it might be possible, but I'd have to investigate on a few locks with different combinations of pins. My guess:

When the lock goes into a "false-set" state during impressioning (say 5-10 degrees of rotation on the core), in the following steps, mostly the torpedo-pin will be binding and making marks. Only just before you hit the "catching" action of the torpedo-pin, it might allow a few other pins to mark, those are not torpedo-pins.



For example (see animation):

Step 1-12: normal impressioning, alternating marks on all pins..
Step 13: lock core goes into a "false-set"
Step 14: mark on 4
Step 15: mark on 4
Step 16: marks on 3 and 4
Step 17: mark on 4
Step 18: mark on 4
Step 19: marks on 2 and 4
Step 20: marks on 2 and 5
Step 21: no more marks

In steps 14-20 (after the "false-set") the majority of marks are from pin 4, so that would be the torpedo-pin.

Time for experimentation, we're getting somewhere!

[GWiens2001]

There can be more than one torpedo pin, too. If you file a cut down and it starts marking AND it stops marking again, then stop filing that pin stack, make note of it, and move on to another pin stack.

If you file and it starts marking, but never stops marking until you hit the bottom depth of the key pins at rest, then that bitting was already at the proper height. When you start another blank, just leave that cut where it was.

Gordon

[mapafe]

There can be more than one torpedo pin, too. If you file a cut down and it starts marking AND it stops marking again, then stop filing that pin stack, make note of it, and move on to another pin stack.

If you file and it starts marking, but never stops marking until you hit the bottom depth of the key pins at rest, then that bitting was already at the proper height. When you start another blank, just leave that cut where it was.

Gordon

Excellent addition!
Strangely enough one of the first tests I did was with a stripped lock, containing only two stacks with different lengths of torpedo-pins, and it impressioned all the way without problems, always giving good marks! This might have been a lucky shot, related to the specific difference in pin length (perhaps countering the anti-impressioning effect of each single pin).

[JamesOzment1]

I noticed on spools sometimes they don't leave distinct marks,however they do usually leave a blunted "polished" very faint dimple. are you using magnification great enough to see if there is a spot on stack 4 of the blank that is slightly smoother than normal impressioning?

[mapafe]

I noticed on spools sometimes they don't leave distinct marks,however they do usually leave a blunted "polished" very faint dimple. are you using magnification great enough to see if there is a spot on stack 4 of the blank that is slightly smoother than normal impressioning?

This probably isn't the case in the DOM RN locks I've tested so far: the torpedo-pin gives very clear marks all the way until the point where it catches and is "lifted" from the blank (no longer touching). I think my lighting and magnification are sufficient (10x impressioning magnifier).

[mapafe]

For a test of the new procedure, I replaced the large torpedo-pin (left) with the smaller one (right) in the same practice lock.

torpedo-pins.jpg

This is the impressioning procedure:

dom-rn-impressioning-smaller-torpedo-pin.gif

1: Blank key
2: Remove nickel
3: Remove nickel
4: Marks on 1 2 5
5: Marks on 2 5
6: Marks on 2 3 5
7: Mark on 5
8: Mark on 5
9: Mark on 5
10: Mark on 3
11: Mark on 3
12: Mark on 3
13: Mark on 3, tiny false set
14: Marks on 3 4 5
15: Marks on 4 5
16: Mark on 4 (crater mark)
17: Mark on 4 (crater mark)
18: Mark on 4 (rotation gives click as torpedo tail catches)
19: Marks on 3 5 (click as before)
20: No marks, but filed pin 4 from 6.91
21: Open! (plus mark on 4)

The smaller torpedo-pin in position 4 exhibits the same behavior as the larger one; it's tail catches fully at step 20, lifting the torpedo-pin out of the core. The torpedo-pin is still binding and blocking further rotation, but no longer in contact with the blank key, thus no longer giving any marks. The last few marks (step 19) are given by other pins. Some methods to determine at which position the torpedo-pin is, using the notes:

* Which pin gave the longest sequence of marks just before all pins cease to mark? Pin 4
* Which pin gives the most marks after the lock goes into false set? Pin 4 (5 times)

I will try to acquire more DOM RN locks to test this impressioning procedure.