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Lock cylinder question

Posted: Sun Feb 07, 2016 4:58 pm
by Aki Ruohonen
I started work on the door locks (for square door handles) which has been disassembled in my shelf for ages. I started to put them together and noticed the difference between the two. What is going on here and from which model is the smaller diameter key barrel from?

Re: Lock cylinder question

Posted: Mon Feb 08, 2016 10:59 am
by James Davies
Interesting Aki. Is the key barrel smaller on one or is the button internal diameter larger one one? The key barrel off my '53 looks more like the one on the right, with the circular groove very close to the edge.

Both of those look very original though. Hmm.

Maybe Rick Albro or Ned Gorski have some insight. They've looked at lots of these.

Re: Lock cylinder question

Posted: Mon Feb 08, 2016 6:25 pm
by Aki Ruohonen
The internal diameter of the cylinder holding the lock piece is the same and it looks that these parts are identical. Both have the screw retaining the lock piece in place. The outer diameter of the lock piece on the left side item is 15.3mm while in the one in right 14mm.

James Davies wrote:Interesting Aki. Is the key barrel smaller on one or is the button internal diameter larger one one? The key barrel off my '53 looks more like the one on the right, with the circular groove very close to the edge.

Both of those look very original though. Hmm.

Maybe Rick Albro or Ned Gorski have some insight. They've looked at lots of these.

Re: Lock cylinder question

Posted: Thu Feb 11, 2016 9:55 am
by Rick Albro
Aki, the cylinder on the right is simply worn out, that does not mean that it cannot be saved. The lock cylinder are actually made of a relatively soft material compared to the handle which is Zamak, a zinc aluminum alloy. If the plating is worn through then the softer metal erodes away or possibly this cylinder has been previously over polished. You should have about 0.005-0.010" clearance on these although some have more than 0.050"! I would guess that you have 0.100-0.150" gap here. When you cast a metal there are bulk properties and surface properties... the surface tends to have some oxygen diffusion and often forms a harder skin or surface. Once you have eroded through this harder surface the part tends to continue to degrade. If you try to build this all up with plating the plating may not adhere well as plating that is that thick on pot metal sometimes has to large of a difference in material properties. You may not be able to make the right cylinder look right be functional and be durable all at the same time. Given that choice I would give highest priority to durable then make it look as good as possible and be functional... or find a new cylinder that is in better shape.... or you can cast a new one... What is the gap between the outer diameter of the cylinder where the gates are versus the inner diameter of the button. This gap will determine the functionality more than the the gap that you show for the exterior "shoulder".

Re: Lock cylinder question

Posted: Sun Feb 14, 2016 3:07 pm
by Aki Ruohonen
Thanks for the help Rick and James. I took it apart again today and it seems that the outer lip has been machined/ground down for unknown reason. The inner part in standard measurements. So I need to track down a another one.

Re: Lock cylinder question

Posted: Sun Feb 14, 2016 4:26 pm
by Martin Benade
If only the outer lip is machined down possibly a brass ring could be pressed on and everything re-chromed. It depends on whether you can find a better one, and how perfect you need it to be.

Re: Lock cylinder question

Posted: Sat Mar 26, 2016 12:19 pm
by Aki Ruohonen
Just wanted to update this as came across with another cylinder from my stash of parts to which the lock part fitted perfectly. The id of that is smaller while the other measuments match the big id versions. It seems there have been different version, perhaps different suppliers?

Br,
Aki

Re: Lock cylinder question

Posted: Wed Apr 06, 2016 1:28 am
by Rick Albro
Aki,
There are several different series of lock cylinders used throughout the range of pre A's. All series of lock cylinders take the same key blanks and have the same internal "interstitial" space for the key to fit into. These handles were not meant to be taken apart and as such many of the surviving handles and related parts have been restored many times and over the years there has also been extensive creative fixes and attempts to reproduce these handles and parts. There is some variation in original parts and when added with restoration attempts and other "fixes" the variations become more pronounced. With parts like these, I would use caution in claiming multiple suppliers and versions of the part. When the pre A cars were being made the Schumann agreement pretty much dictated that there would not be competition or multiple suppliers especially for parts made with critical resources. Given the scarcity of original parts even when new the likely scenario probably involves some form of restoration attempt or reproduction attempts after the cars and its handles were ready for its first major door handle maintenance. The code book for the keys indicates these cylinders were used on several other cars of the same time period but even so the handles were different just the cylinders were common. The pre A lock cylinders and buttons are really quite challenging to make and to keep good tolerances. The newest of these handles would be 60 years old by now and most likely have been replated at least once. If they haven't been replated, then then have likely given in to excessive oxidation leaving the dimension and tolerances questionable at best. There is a reason why these are hard to find in good condition and why the are expensive when you do find them. I would consider yourself fortunate to have found all the parts to restore. I would also offer my encouragement to keep looking for all the small parts that you will need along the way to completing your cars. Small victories can keep a project alive. Best of luck to you and your project!

if you read the post viewtopic.php?f=1&t=36688&start=15 there is a more extensive list of key codes. .... there are 625 possible combination of keys in pre A lock cylinders! Not all of these are used. Many combinations are duplicated and some keys with different codes have the same cut. The cuts and codes are more about next nearest neighbors and not about permutations.

Re: Lock cylinder question

Posted: Sat Sep 23, 2017 8:19 pm
by Rick Albro
Perhaps AKI is right that there are two different sizes of outer diameter lock cylinders. I have two original cylinders and their corresponding buttons which they both fit in very well with little gap. One of the cylinders is 0.050" smaller in diameter than the other. All other dimensions appear to be the same. The thickness of the outer "ring" is the tell tale sign of the small versus large cylinders. The thickness of the button corresponds to either the large or small diameter of the cylinder. The small cylinder is known to have come from a 54 and the larger came from a 56. I have worked on cylinders from a 53 which are known to be original and had the larger diameter. Most of the cylinders that I have seen are the larger diameter cylinders. If you are piecing together a set from lose pieces this could be a problem... large cylinders can be turned down but small cylinders need corresponding large walled buttons. Kudos to Aki for noticing this difference! I will post a few more images to show these differences.

The thickness of the button is all in the ID where the cylinders fits. The outside dimensions of the buttons are the same. The only difference is in the diameter of the cylinder shoulder. Aki's lower image above shows one large and one small cylinder, I would guess these came from different cars. A very subtle difference but one that can be notice when not paying attention to the correct assembly.

I don't think there were different suppliers. I think, after having cast a few of these from raw materials, that each button and cylinder pair are mated and that the smaller diameter cylinder represent the largest acceptable variation. Working with unmatched cylinders and buttons has always required greater care to get the clearances right. Aki gives 15.3 and 14 mm as the diameters that the cylinder fit into and I measure 13.7 and 15mm as the diameters of the cylinders... that is a .3 mm or about 0.010" gap which is what it should be.

If you have a pre A with known original door handles I would be interested in weather you have large diameter or small diameter cylinder locks.