Rebuilding an old lock

[DianneB]

(I know the forum header says no automotive discussions but I don't see another place for this post and it more about a conventional cylinder lock, so I hope it is okay here.)

I am restoring an old motorcycle (1967 Honda Dream) and some previous owner had gutted the cylinder (rather than take it to a locksmith to get a new key made) for the main ignition switch and all of the original internal pins and springs are gone. These switches are EXTREMELY rare and fetch insane prices when they do come available so there is considerable incentive to rebuild this lock. The ignition switch is also keyed-alike with the steering lock and I have a key that fits the steering lock so I should have what I need to get this lock functional again.

The pin holes measure 0.100" diameter and the top holes are blind and 0.200" deep so I will need hollow top pins to contain the springs. There are only 3 pins in this lock but security is not an issue due to the age of the machine (and not many people carry around 48 year old motorcycle keys!) so I really only need to create one pin. Unfortunately I can not find lock parts specifically for Honda and the best local locksmith says they can't help me so this is going to be a one-off DIY project.

I am thinking that I can buy K&S brass tube in 2mm size (0.0787") diameter for upper pins, silver solder on a solid end, and slip a suitable size spring in the tube to form the top pin.

For the bottom pin I can use 2mm solid brass rod and mark/cut the lengths by placing the key in the cylinder and marking the length at the surface of the cylinder.

I am not a locksmith, just a mechanically inclined amateur machinist, so I hope I am on the right path here!

Thoughts? Suggestions? Advice?

[MacGyver101]

Sounds like you're on the right path there.

As an alternate suggestion for your top pins, it might be easier to make more of a "piston"-shaped driver: you could use the same rod that you're considering for your bottom pins.

Leave yourself a small bottom section that has the same diameter as your bottom pins, and then turn the rod to a thinner diameter to make an upper section that will fit inside the spring (rather than around it). (i.e., if you cross-sectioned it, it would look like an upside-down letter "T", with the spring wrapped around the thin portion.) It'll give you equally-good stability for the driver (the pin won't be able to flip over and bind in some weird position), and it'll still give support to the spring.

You could likely just make the pins by chucking some of your brass rod into a drill, and sanding it down like it's on a lathe.

Just a thought?

[DianneB]

Thanks for the suggestion! It was much easier to make a T-shaped top pin.

I found that 12 Ga. copper wire was the perfect size for pins (0.122 in a 0.125 hole) so with the help of a pin vise, the drill press, files, and a modeller's saw, I made a set of pins and they worked! Unfortunately I didn't consider the fact that the key can be removed in two positions and I hadn't plugged the second hole so when the key turned past the open hole, the cylinder pin dropped part way in - OOPS! - and I had a time getting the lock apart again! Unfortunately I only had one spring of a suitable size and it got buggered getting the lock apart after "the incident" so I need to find a source of tiny springs before I try again.

[MacGyver101]

Sounds like you're well on your way! Excellent! You may want to round the bottom of your bottom pin (the portion that contacts the key), just to help reduce wear... but that looks really good.

A local locksmith should be able to get you replacement springs for next to no cost... otherwise, you can probably get a replacement rim cylinder from your local hardware store for $5 and strip it down for five new springs.

[Raymond]

Look at any business that fixes flat tires. The throw-away valve stems contain a stainless spring that should work well for you. If you have to shorten one put the cut end up into the blind hole.
Use your drill and a file to round the points of your bottom pins where they contact the key. Just barely take the sharp corner off the other end so it wont catch when turning.
So far - good work.

[billdeserthills]

You can find a very good spring inside any Bic lighter, or any disposable lighter for that, it will be under the flint
Just remove the stainless steel cap & the sparkwheel, It may be a bit too strong for your purpose. If you like, you
can pm me your mailing address and I'll mail some small parts & springs for your worthy project

[cledry]

Surprised your locksmith couldn't help you. I have numerous pin kits that with a little work would work for your lock. National cabinet pins are .101" diameter, there are many shops that will have pin kits for older cars as well that might work for you. The t-pins could be made from current Schlage F-line pins.

[dll932]

Thanks for the suggestion! It was much easier to make a T-shaped top pin.

I found that 12 Ga. copper wire was the perfect size for pins (0.122 in a 0.125 hole) so with the help of a pin vise, the drill press, files, and a modeller's saw, I made a set of pins and they worked! Unfortunately I didn't consider the fact that the key can be removed in two positions and I hadn't plugged the second hole so when the key turned past the open hole, the cylinder pin dropped part way in - OOPS! - and I had a time getting the lock apart again! Unfortunately I only had one spring of a suitable size and it got buggered getting the lock apart after "the incident" so I need to find a source of tiny springs before I try again.

I think copper would be too soft for pins and would wear quickly. Just my 2c.

[DianneB]

I had given up on fixing the 'combination switch' lock on my 1967 Honda Dream motorcycle and was using it as a simple (non-locking) switch until someone gave me another switch earlier in the winter. Unfortunately the switch I was given was a U.S. model that has 5 positions whereas the Canadian switch has 6 positions. Both switches allow the key to be removed in either of 2 positions but not the rest.

While scratching my head over how to wire the 5-position switch, it occurred to me that the U.S. switch would have the same pins and springs as the Canadian switch used to have and it should be possible to put the U.S. pins and springs in the Canadian switch body IF I were brave enough to risk it! So I took the American lock apart.



Since there are 6 upper springs and pins (3-pin lock with key removable in 2 positions) I was going to need something to hold each of these in place as I inserted the rest and to hold them compressed while I slipped the cylinder in. I rolled up a tube from some thin brass sheet and had a go at it.



After an hour's work (and a fair does of frustration!) I had it all together AND IT WORKS! The bike will now have the proper combination switch.

Thanks everybody for your suggestions and support!

[femurat]

It's nice to hear this story ended well. Thanks for the follow up.

Cheers

[GWiens2001]

Glad you had the courage and and skill to give a shot. Nice work!

Gordon