How to cut fiber optic cable?

[Rich Mullikin]

Re: How to cut fiber optic cable?

Thad,

It seems like you have had a lot of opinions on repairing fiber optics. I too had a problem with the fiber cable leading to my left front turn signal on my '69. My cable was broken and the end was shreaded so it needed to be cut and I had to splice a new piece to complete the run to the turn signal. I also was missing the rubber connector that attaches the cable to the nipple on the side of the turn signal housing.

I guess I wasn't bright enough to know that the cable could not be repaired so I purchased one of those repair kits that you will find in most of the Corvette catalogues. I needed the repair kit primarily for the additional length of cabling to complete the splice. I cut the old frayed cable with Craftmans Handi-Cut cutters and they made a pretty clean cut on the fiber (by the way these cutters work great on heater and vacuum hoses also). My next concern was how to attach the cable to the turn signal housing without the original connector. I was talking to a friend of mine (who also posts on this board as well) and he asked me if I thought one of the rubber vacuum caps (bullet shaped) would work. I thought it would be worth a try so he went into his tool box and pulled out a number of different color and size caps. The one that looked about right happened to be black but was a little long. He gave that to me and I brought it home to see if it would work. I had to trim about 3/8 of an inch off the end and it fit right over the nipple on the housing. It looks almost identical to the original connector. I took an awl and punched a hole in the closed end so that the cable would pass through it. It slipped right over the nipple perfectly.

Now I was down to figuring out exactly how to splice the two cable ends. Another friend in the communications business gave me a piece of wet sand paper to polish the ends of the cable. This stuff was really fine grit. When you pass your hand across it the paper feels smooth. I wet the paper and rubbed both ends and I am sure that this probably helped but to be honest these 51 year old eyes had a very difficult time seeing whether this made a difference. I was now ready to butt splice the two cables but I was just not comfortable with using shrink tubing and then taping over top of the repair (which is what the repair kit tells you to do). Since this was going to be a butt splice I had a difficult time convincing myself that over time the shrink tubing and tape would maintain the integrity of the original repair. So, another friend who works at a machine shop took a small piece of the fiber cable with him to work and made me a small round (tube shaped) aluminum ferrule about an inch and a half long. He drilled a hole through the entire length of the ferrule so that the cable would just barely fit through it. I then took the new piece of cable that was now attached to the turn signal and inserted it into one end of the ferrule. I took the other end that I had repaired and slid it into the other end of the ferrule. I then wrapped some tape around the ferrule so that I could test the light passage to the console. It worked pretty well. I then went back to the aluminum ferrule and just barely crimped each end so that I had a snug fit and the cable could not pull out of it. Be careful crimping this cable, you just want to put pressure on the insulation and not damage the fiber. Then I wrapped the entire repair with electrical tape and the repair is not noticeable to the naked "judges" eye. After owning this car for 11 years all of the optics work on the console.

This may sound like a lot of work but it really wasn't that bad. Plus it was a lot cheaper than a new wiring harness. Good luck with yours!

Rich

[Rich Mullikin]

Re: How to cut fiber optic cable?

Thad,

It seems like you have had a lot of opinions on repairing fiber optics. I too had a problem with the fiber cable leading to my left front turn signal on my '69. My cable was broken and the end was shreaded so it needed to be cut and I had to splice a new piece to complete the run to the turn signal. I also was missing the rubber connector that attaches the cable to the nipple on the side of the turn signal housing.

I guess I wasn't bright enough to know that the cable could not be repaired so I purchased one of those repair kits that you will find in most of the Corvette catalogues. I needed the repair kit primarily for the additional length of cabling to complete the splice. I cut the old frayed cable with Craftmans Handi-Cut cutters and they made a pretty clean cut on the fiber (by the way these cutters work great on heater and vacuum hoses also). My next concern was how to attach the cable to the turn signal housing without the original connector. I was talking to a friend of mine (who also posts on this board as well) and he asked me if I thought one of the rubber vacuum caps (bullet shaped) would work. I thought it would be worth a try so he went into his tool box and pulled out a number of different color and size caps. The one that looked about right happened to be black but was a little long. He gave that to me and I brought it home to see if it would work. I had to trim about 3/8 of an inch off the end and it fit right over the nipple on the housing. It looks almost identical to the original connector. I took an awl and punched a hole in the closed end so that the cable would pass through it. It slipped right over the nipple perfectly.

Now I was down to figuring out exactly how to splice the two cable ends. Another friend in the communications business gave me a piece of wet sand paper to polish the ends of the cable. This stuff was really fine grit. When you pass your hand across it the paper feels smooth. I wet the paper and rubbed both ends and I am sure that this probably helped but to be honest these 51 year old eyes had a very difficult time seeing whether this made a difference. I was now ready to butt splice the two cables but I was just not comfortable with using shrink tubing and then taping over top of the repair (which is what the repair kit tells you to do). Since this was going to be a butt splice I had a difficult time convincing myself that over time the shrink tubing and tape would maintain the integrity of the original repair. So, another friend who works at a machine shop took a small piece of the fiber cable with him to work and made me a small round (tube shaped) aluminum ferrule about an inch and a half long. He drilled a hole through the entire length of the ferrule so that the cable would just barely fit through it. I then took the new piece of cable that was now attached to the turn signal and inserted it into one end of the ferrule. I took the other end that I had repaired and slid it into the other end of the ferrule. I then wrapped some tape around the ferrule so that I could test the light passage to the console. It worked pretty well. I then went back to the aluminum ferrule and just barely crimped each end so that I had a snug fit and the cable could not pull out of it. Be careful crimping this cable, you just want to put pressure on the insulation and not damage the fiber. Then I wrapped the entire repair with electrical tape and the repair is not noticeable to the naked "judges" eye. After owning this car for 11 years all of the optics work on the console.

This may sound like a lot of work but it really wasn't that bad. Plus it was a lot cheaper than a new wiring harness. Good luck with yours!

Rich

[Tony H.]

Re: How to cut fiber optic cable?

Rich,

Thanks for sharing your success on fiber optics repair with us. Sounds like that would make a great Restorer article. It would be great with some pictures.

Tony

[Tony H.]

Re: How to cut fiber optic cable?

Rich,

Thanks for sharing your success on fiber optics repair with us. Sounds like that would make a great Restorer article. It would be great with some pictures.

Tony

[Jack H.]

Re: How to cut fiber optic cable?

Hah, to the naysayers! See, it can be done, mon....

[Jack H.]

Re: How to cut fiber optic cable?

Hah, to the naysayers! See, it can be done, mon....

[George Daina]

Yo, Mr. Humphrey, think ya blew one.......

this time. Have to disagree with ya on this one. The key to the fiber optics repair is the aluminum ferrule. Rich stated the ferrule was made for him by a machinist friend. Now, how many Joes out in the real world have an in with a machine shop? Now you might say I'll pay for the machine shop to make me a ferrule, after all, it can't take that much time to make it, can it? The machine shop owner, in kind will reply, "How deep are your pockets, Bud? You see, it isn't worth our time or effort for a one shot deal. We take jobs that have long runs, and then to take a man off the line and shut his machine down for a couple of hours while he plays around and makes one ferrule, naw, just not worth it."

Jack, been there, done that and was shown the door. I stand by my premise that the average restorer won't have any luck repairing the fiber optics cable.

Hey Rich, ya wanna get rich?

[George Daina]

Yo, Mr. Humphrey, think ya blew one.......

this time. Have to disagree with ya on this one. The key to the fiber optics repair is the aluminum ferrule. Rich stated the ferrule was made for him by a machinist friend. Now, how many Joes out in the real world have an in with a machine shop? Now you might say I'll pay for the machine shop to make me a ferrule, after all, it can't take that much time to make it, can it? The machine shop owner, in kind will reply, "How deep are your pockets, Bud? You see, it isn't worth our time or effort for a one shot deal. We take jobs that have long runs, and then to take a man off the line and shut his machine down for a couple of hours while he plays around and makes one ferrule, naw, just not worth it."

Jack, been there, done that and was shown the door. I stand by my premise that the average restorer won't have any luck repairing the fiber optics cable.

Hey Rich, ya wanna get rich?

[Jack H.]

Re: Yo, Mr. Humphrey, think ya blew one.......

This post responded to TWO anomalies that I mentioned in prior posts:

(1) Can pick-up end of fiber be repaired? (2) Is light pipe continuity intact?

The original/original post dealt with #1 saying all attempts resulted in NO light at the output. I later mentioned verifying #2 because, despite a 'sloppy' pickup end trim, you'd get SOME illumination at the output IF #2 wasn't an issue.

As far as end ferrule goes, I've seen folks carefully un-crimp the originals (takes patience), slide off, strip appropriate insulation, and re-mount/crimp the original ferrule to regain proper pickup length and get 'fresh' ends to work with. This post confirms one guy was able to freshen up his pickup end....

This post goes further to say he found internal continuity breach in the light pipe (my issue #2). Further he WAS able to repair using a splice method. Yep, he went to a local machinest who volunteered to cut a ferrule to be use IN-LINE at his splice....

As far as claiming this is uneconomic or out of reach of the ordinary restorer, I disagree. I saw one repair done locally that worked 'reasonably' (some transconductance loss across the pipe) that was done with 'spit & bailing wire' technology.

Use of mirror finish wrap around point of splice helps to couple and boost transmission of 'scattering' that's inevitable in the splice of stranded fiber (a 'killer' to high performance frequency division multiplexed opto systems). The quick & dirty repair I refer to was done this way:

(1) Insulation was stipped at break in pipe. (2) Ends were trimmed without 'sawing' then lightly polished. (3) Ends of both insulation sides were swabbed with epoxy as

well as exposed fiber strands UP TO their ends. (4) Metal foil tape was cut and wrapped around the 'splice'

to give some internal reflection. (5) Splice was left in clamp to let epoxy harden. (6) After epoxy hardened, already installed heat shrink tubing

was slid over metal foil and heated. (7) Harness with repaired light pipe was re-wrapped.

Now, epoxy, razor blade, foil tape and heat shrink ARE readily available to ANYONE without tooling/setup. But, a bright metallic cylinder ('ferrule') to replace the foil tape/epoxy probably isn't that hard to home brew either....

Point is/was, is it POSSIBLE to repair? I said YES, but you have to have patience AND be willing to accept some transconductance loss. And, here's one NDB poster who said he's been there, done that, got the T-shirt. I DO agree with you, if you want the very best results possible, fork over the $$$ and replace the fiber wiring harness' affected....

[Jack H.]

Re: Yo, Mr. Humphrey, think ya blew one.......

This post responded to TWO anomalies that I mentioned in prior posts:

(1) Can pick-up end of fiber be repaired? (2) Is light pipe continuity intact?

The original/original post dealt with #1 saying all attempts resulted in NO light at the output. I later mentioned verifying #2 because, despite a 'sloppy' pickup end trim, you'd get SOME illumination at the output IF #2 wasn't an issue.

As far as end ferrule goes, I've seen folks carefully un-crimp the originals (takes patience), slide off, strip appropriate insulation, and re-mount/crimp the original ferrule to regain proper pickup length and get 'fresh' ends to work with. This post confirms one guy was able to freshen up his pickup end....

This post goes further to say he found internal continuity breach in the light pipe (my issue #2). Further he WAS able to repair using a splice method. Yep, he went to a local machinest who volunteered to cut a ferrule to be use IN-LINE at his splice....

As far as claiming this is uneconomic or out of reach of the ordinary restorer, I disagree. I saw one repair done locally that worked 'reasonably' (some transconductance loss across the pipe) that was done with 'spit & bailing wire' technology.

Use of mirror finish wrap around point of splice helps to couple and boost transmission of 'scattering' that's inevitable in the splice of stranded fiber (a 'killer' to high performance frequency division multiplexed opto systems). The quick & dirty repair I refer to was done this way:

(1) Insulation was stipped at break in pipe. (2) Ends were trimmed without 'sawing' then lightly polished. (3) Ends of both insulation sides were swabbed with epoxy as

well as exposed fiber strands UP TO their ends. (4) Metal foil tape was cut and wrapped around the 'splice'

to give some internal reflection. (5) Splice was left in clamp to let epoxy harden. (6) After epoxy hardened, already installed heat shrink tubing

was slid over metal foil and heated. (7) Harness with repaired light pipe was re-wrapped.

Now, epoxy, razor blade, foil tape and heat shrink ARE readily available to ANYONE without tooling/setup. But, a bright metallic cylinder ('ferrule') to replace the foil tape/epoxy probably isn't that hard to home brew either....

Point is/was, is it POSSIBLE to repair? I said YES, but you have to have patience AND be willing to accept some transconductance loss. And, here's one NDB poster who said he's been there, done that, got the T-shirt. I DO agree with you, if you want the very best results possible, fork over the $$$ and replace the fiber wiring harness' affected....

[Chuck G.]

Re: Yo, Mr. Humphrey, think ya blew one.......

Hi George. I "patched up" one of my fiberoptic cables by simply using an electrical "butt splice" connector. I don't remember what gauge. I removed the plastic insulation, leaving me with the tubular metal center. Put each end of the fiberoptic cable in the butt connector and gently "crunched" them, just enough to hold them together. Had placed heat shrink tubing on prior to this....shrunk the tubing....it works fine. It seems just as bright as the others....they are all rather dull anyway on a sunny day. I really didn't think that this was a tough repair. Maybe ignorance was bliss. Hope this helps. Chuck

[Chuck G.]

Re: Yo, Mr. Humphrey, think ya blew one.......

Hi George. I "patched up" one of my fiberoptic cables by simply using an electrical "butt splice" connector. I don't remember what gauge. I removed the plastic insulation, leaving me with the tubular metal center. Put each end of the fiberoptic cable in the butt connector and gently "crunched" them, just enough to hold them together. Had placed heat shrink tubing on prior to this....shrunk the tubing....it works fine. It seems just as bright as the others....they are all rather dull anyway on a sunny day. I really didn't think that this was a tough repair. Maybe ignorance was bliss. Hope this helps. Chuck

[George Daina]

Yeow....got beat up on this one....

Gentlemen, I stand to be corrected. Think this may be a good subject for the paper.

[George Daina]

Yeow....got beat up on this one....

Gentlemen, I stand to be corrected. Think this may be a good subject for the paper.

[Jack H.]

Friends?

Tain't out to beat ya up. Trying to cover my backside! Friends?