1970 Cadillac door key

[Scot Minesinger]

The duplication of the square key that works ignition and door seems to be fine on ignition, but not door.  These are cheap home improvement store duplications, should I go to a quality locksmith and have blank duplicated or is there something I'm missing?  I have the original that operates the door, but that is it.  Like to have a few more.

[Eric DeVirgilis CLC# 8621]

I'd say odds are better going with a specialist. If you have a working original, this should not be a problem for a competent locksmith.

[Jeff Rosansky CLC #28373]

Mite be worth pulling the lock and having a key made. After a while these keys get worn down and you could end up spending $$ on an incorrect blank. The nubs on mine are not as pronounced as they one were after 47 years...... the key I mean

Jeff

[bcroe]

The duplication of the square key that works ignition and door seems to be fine on ignition, but not door.  These are cheap home improvement store duplications, should I go to a quality locksmith and have blank duplicated or is there something I'm missing?  I have the original that operates the door, but that is it.  Like to have a few more. 

If you look closely, the key has 6 lengths along the active end, which
are ground or cut to fixed standard heights.  Originally there were 4
heights, later they went to 5.  If you carefully compare the original
key that works to the copy that doesn't, you will see they aren't cut
identically.  Probably a micrometer will show how much error on
height there is.  If its cut high, just a bit of filing might solve the
problem.  Too low, start over.  I cut my own with a cheap machine
and measure with a dedicated key mike.  There is also a "punch"
style that will just cut notches to the number you set. 

Don't trust the store.  Bruce Roe

[Scot Minesinger]

Bruce,

Thanks, and two things:

1.  It kills me that I have to invest in the right machines and tools to perform routine jobs on cars just to have it done right, such as and especially tire mount and balance, ac charge, oil changes, and now add keys to the list.

2.  You have all your classic GM cars keyed the same, do you have to change the ignition and door locks or can you modify them to work with your key?

[bcroe]

Bruce,  Thanks, and two things:

1.  It kills me that I have to invest in the right machines and tools to perform routine jobs on cars just to have it done right, such as and especially tire mount and balance, ac charge, oil changes, and now add keys to the list.

Yea, story of my life.  Fortunately I took a basic mail-order locksmith
course in 1969, and picked up the basic knowledge & tools. 

2. You have all your classic GM cars keyed the same, do you have to change the ignition and door locks or can you modify them to work with your key? 

I don't know if they are classics, but all 5 are keyed the same.  They cover
77 to 81, all with column ign locks.  You may note a letter on each key,
like A to E relating to the groove pattern.  If locks have the same letter,
they can be re tumblered to be the same; otherwise the key won't go in. 
This is not rocket science. 

I use 2 lock sets; 5 ign locks of the same code, and 10 door + 5 trunk
locks of a same code.  I did have a little trouble getting the standard into
my 77 column, had to tap a retainer or something.  Pretty much all trunk
locks are the same.  I see 2 variations in door locks; one sticks out a bit
farther internally than the other.  I have gotten away with using the wrong
length at least once.  I think there was a lighted ring on the Eldo which I
threw away; maybe it could have been retained. 

Initially I just had a part time locksmith make up enough locks for the
cars, maybe 3 at the time.  Easy to check operation on the table, then
install them in each car.  I never did anything with the glove box, which
I never locked.  When I got another car, I just swapped 4 locks with the
outgoing car; sometimes I made or had made another set.  I got mixed
results with locksmiths, some were just wrong (I fixed). 

Once the ign locks (with multiple drivers) became so worn, I just made
new ones to a new code.  This for nearly 35 years.  I was thinking of
putting a GM lock on my tractor.  My house locks are all the same house
standard, maybe 10 before I sold the other house.  Bruce Roe