Depth cut accuracy.

[Mini]

Hello,
I am trying to file keys by hand and was going to use a digital calipers to measure my cuts and compare them to the depth charts I have. I was looking at two different calipers with accuracy .001" and .0005" and was wondering how accurate I must be in order to make the pins meet the shear line.

Thank you.

[Mini]

Also I think your search function is defunct.

[zeke79]

Depending on what lock brand you are working with you can be a couple to a few thousandths too shallow or around .005" too deep and still operate pretty well. You may be a bit "clicky" when you turn the key at .005" too deep but the key will still function pretty well.

[Eyes_Only]

If in doubt, file less. If you need to take off more, file less. You can always go back and file more to correct the cuts but if you file too much off then you're screwed.

[maintenanceguy]

I've seen key specs written +- (plus or minus) .002"

In almost every situation, accuracy to the thousandths is good enough. It's very, very rare to need accuracy to the ten thousandths.

Even machinest's rarely have to be that precise and most couldn't if they wanted to.

[raimundo]

but boss, this is the third time I cut it and its still too short.

[WOT]

Schlage's tolerance is 1/1000" on spacing +1/500" , -0" on depth.

This is pretty hard to achieve without using a punch.

[Eyes_Only]

Unless you have great attention for detail and have nothing but time on your hands.

[zeke79]

Schlage does fine being cut a few thousandths too deep but if you start to get a thousandth or so too shallow and you will start to see tight turning keys.

[WOT]

Schlage does fine being cut a few thousandths too deep but if you start to get a thousandth or so too shallow and you will start to see tight turning keys.

This is a big deal for institutions. Poorly cut keys that are hard to turn will accelerate wear on locks around the institution.

[zeke79]

I agree but look at it like this. Every manufacturer of blanks is a bit different. A US Locks blank will cut to a different root depth than say a Jet blank will.

Do you recalibrate every time you switch brands of blanks? I try to stick with the same brand but at times it can be out of stock in which I have to settle for something else. I always try to come in no more than .001" deep and allow no cuts to be shallow. In a perfect world we could guarantee not to be more than .0005" off but even with the same brand of blanks you get boxes that cut different and you can put the keys out there a couple thousandths off and not even realize it unless you mic each key. It's not your machine, it's not you, it's the blank that caused the difference.

Basically if I cut the key and it operates the lock smoothly without being tight or clicky my job is done.