bump keys - cut to code

[Mutzy]

Question about bump keys; at my work, we have an instacode code cutting machine. Which makes cutting bump keys a heckuva lot easier to do. The Question is, would it work any better to align the key so that the cuts are further down the key? So that when the key goes in, it catches all the pins, but it can still be pushed in a bit more (the pins run up the ramps a bit. This is instead of filing the shoulder(s) back. Of course, the amount of play would be the deciding factor, so maybe cutting a few? Small/medium/maximum play keys?

Would this be more effective in bumping?
I found this---> *pdf file* that talks about bump keys an excellent source of info.

thoughts?

[Chucklz]

It is definately better to move the key slightly. Experiment a bit. I would suggest you try to make a 5 pin bump key have the same peak on the tip as the other peaks. I have such a bump key, and it works very well for 5 and 6 pin locks.

[maxxed]

I would suggest that you have a lockcore out of a cylinder pinned to the deepest cuts for that type of lock, cut a key slightly deeper and then adjust spacing until you notice the pins move but make sure the pinns do not go above the shear line.

[Mutzy]

thanks guys - will experiment when i go back to work. would i be right to assume that moving the key a large amount would be good for small pins, and bad for large pins? Do you have more than one bump key for a certain profile?

[zeke79]

Yes, that is the best way I have found to cut my bump keys. It prevents having to file the shoulder away by hand and allows consistent bumpkeys to be made. Great question!

[maxxed]

I have found that bump keys cut using a radius cut to be more effective, maybe it's just me. The best I can suggest is experiment with all the variations you can come up with and see what works best for you.

[vector40]

What a great idea. Amazed I haven't seen this yet.

[Raccoon]

I'm communicating with someone who is cutting me various styles of bumpkeys. This thread covered everything we're trying; out from the shoulder (1/2 mm as is OFFICIALLY suggested, 1/2 pin-spacing, 1/4 pin-spacing), and trying different type cuts.

The bitings I think would be most promising are 90 degree cuts (45 degree slopes) cut at 1 pin depth below the lowest pins for that lock. So, 777 for a Kwikset and 10,10,10 for most decent locks. Then take a gauge or caliper and find where the slope reaches the lowest pin depth (eg, 666 or 999) and file the peaks of the key flat. You can also use a machine to cut the peaks to 666 or 999. This will prevent the pins from being forced above the shear line.

Alternatly, if you know exactly how deep the key needs to be inserted before the slope brings the pins above 666 or 999, you can cut back the shoulder or cut ahead the key that far. (Though, I think filing down the peaks would be simpler and foolproof)

[Mutzy]

why would you need to file the peaks down? Do they (pointed peaks) make the pins shoot up too far?

[maxxed]

The bitings I think would be most promising are 90 degree cuts (45 degree slopes) cut at 1 pin depth below the lowest pins for that lock. So, 777 for a Kwikset and 10,10,10 for most decent locks. Then take a gauge or caliper and find where the slope reaches the lowest pin depth (eg, 666 or 999) and file the peaks of the key flat. You can also use a machine to cut the peaks to 666 or 999. This will prevent the pins from being forced above the shear line.

Alternatly, if you know exactly how deep the key needs to be inserted before the slope brings the pins above 666 or 999, you can cut back the shoulder or cut ahead the key that far. (Though, I think filing down the peaks would be simpler and foolproof)

Cutting keys to a 10,,10,10 and then cutting down the peaks to a 9 on a schlage will leave .015 on the key. This would not be effective.
I have 3 code machines and 5 different cutters, the bump keys cut with the radius cutters ( I have 2 different profiles ) worked better than any of the angle profiles.
The best results, on Schlage, came from a key cut .030 below a 9 cut and the spacing adjusted so that the pins moved .015 - .020.

[Mutzy]

I found cutting a C4 key (australian standard keyway) to the maximum 10 cut, and pulled the key out about 1.5mm it works quite well.

New question: What do you use to cushion the impact of the shoulder hitting the plug. I now have a few cylinders with dented plug faces...

[maxxed]

I have been experimenting with cutting down the head of the key and useing a 1/2" brass rod notched to accept the modified key. The rod will spead the impact over a larger surface area.

[Raccoon]

I have been experimenting with cutting down the head of the key and useing a 1/2" brass rod notched to accept the modified key. The rod will spead the impact over a larger surface area.

I can't seem to picture what you're describing. Are you using the rod as a tensioner? How does a rod spread impact?

[skold]

I found cutting a C4 key (australian standard keyway) to the maximum 10 cut, and pulled the key out about 1.5mm it works quite well.

New question: What do you use to cushion the impact of the shoulder hitting the plug. I now have a few cylinders with dented plug faces...

Got Zip Tie?

I am to assume by 10 you mean 9. You should also do some C4R's and LW5 and its reverse also.

[Mutzy]

no, the C4 key (key car no# 405) has the normal cuts of 0 - 9. An even deeper cut is the 10 cut, (which is rarely used, the only time i've seen it is on an extensive master key system.) but for programming sake is referred to also as an 'A' cut.
I have found that going a whole cut deeper, and creating a larger shoulder gap (1.5-2mm) works.

I tried a zip tie, but it squishes too easily, so i had to either replace them regularly, or look to something else. I'm thinking a rubber washer of some sort. Any other ideas people