Tweet
Re: Cable splicing
Here's some opinions/comments, for what it's worth:
--I use one of those Craftsman plastic mallets, with a red side and a yellow side, instead of the rawhide mallet, to hammer down the splice. Start with the red end and finish with the harder yellow end.
--When measuring the cable length, after the first end is spliced, for the second end, I mark the desired cable length with a Sharpie, then make another mark 6" short of the first. Then, when the cable end is fixed in the splicing clamp I can measure from the second mark to the inside of the thimble with a 6" steel rule and get a more precise measurement of the proper length.
--They must not have had good cable cutters available when this method was published, no need for the torch, chisel etc.
--There are different ways to do the taper tucks 4 and 5. I don't do half then half, in a 19 strand cable I remove 6 of 19 strands for tuck 4 and 6 of 13 for tuck 5, roughly dividing it in thirds. Otherwise the strands for tuck 5 seem awful small. More often than that I use the taper method found in textbooks from the Stinson School of Aeronautics: tuck 4 is a full tuck, done just like tucks 2 and 3, then 3 alternating strands are cut, and for tuck 5 the remaining three are tucked over one and under two.
Spanish Bucker Jungmanns didn't use any taper, just six tucks, then all strands cut off.
--I don't hammer the splice after each tuck, it seems to work just as well to hammer the whole thing after it's done, but that may depend on splicing technique. On the last two tucks, don't cut off the free strands before hammering, I leave about an inch sticking out until everything's hammered down, then cut them flush with diagonal cutters. If you cut flush and then hammer down the splice the strands might suck back in and undo themselves. Hammer, then cut flush, them maybe hammer a little more to smooth out the cut ends.
--You used to be able to get waxed linen cord from Aircraft Spruce, but I don't think they have it anymore. I guess I'll figure out where to get more when I run out. Modern dacron cord would probably work OK. I buy a spray can of Minwax polyurethane varnish and spray two coats on the finished splice. Incidentally, American and British aircraft used linen cord to wrap the splices- German, French, and Spanish splices are wrapped with brass or copper wire.
--If you're doing a Piper pre-war product, the correct splice is a Roebling Roll Splice (the standard AN five-tuck splice is a box splice). In the AN splice illustrated, in the first tuck, steps 6 and 7 are roll tucks instead of box tucks, you can see the difference. In a Roebling Roll Splice the first tuck is exactly the same as the first tuck of an AN box splice. After that each strand is tucked like steps 6 and 7 of the first box splice, instead of over one and under one it's around one and out the same opening where the strand started. Piper used a six tuck roll splice, three full tucks, then two adjacent strands cut, the remaining four roll tucked, then two more adjacent strands cut, then the last two strands roll tucked. Piper used cord wrapping, which was color coded, painted instead of varnished or shellacked: red for rudder cables, yellow for elevator, blue for ailerons, and black for the parking brake cable on a J-4. If you're really a stickler for authenticity Piper started wrapping the cord from the thimble end, wrapping over a free end which trailed out past the taper of the tuck, and finished with five half hitches at the end of the splice taper.
Anyway, some splicing tidbits, everybody who tries it will develope some of their own techniques to accomplish the same things....
Also, an interesting web site, with cable splicing (without a clamp) included: http://thevintageaviator.co.nz/reference/cable-splicing
-
Here's some opinions/comments, for what it's worth:
--I use one of those Craftsman plastic mallets, with a red side and a yellow side, instead of the rawhide mallet, to hammer down the splice. Start with the red end and finish with the harder yellow end.
--When measuring the cable length, after the first end is spliced, for the second end, I mark the desired cable length with a Sharpie, then make another mark 6" short of the first. Then, when the cable end is fixed in the splicing clamp I can measure from the second mark to the inside of the thimble with a 6" steel rule and get a more precise measurement of the proper length.
--They must not have had good cable cutters available when this method was published, no need for the torch, chisel etc.
--There are different ways to do the taper tucks 4 and 5. I don't do half then half, in a 19 strand cable I remove 6 of 19 strands for tuck 4 and 6 of 13 for tuck 5, roughly dividing it in thirds. Otherwise the strands for tuck 5 seem awful small. More often than that I use the taper method found in textbooks from the Stinson School of Aeronautics: tuck 4 is a full tuck, done just like tucks 2 and 3, then 3 alternating strands are cut, and for tuck 5 the remaining three are tucked over one and under two.
Spanish Bucker Jungmanns didn't use any taper, just six tucks, then all strands cut off.
--I don't hammer the splice after each tuck, it seems to work just as well to hammer the whole thing after it's done, but that may depend on splicing technique. On the last two tucks, don't cut off the free strands before hammering, I leave about an inch sticking out until everything's hammered down, then cut them flush with diagonal cutters. If you cut flush and then hammer down the splice the strands might suck back in and undo themselves. Hammer, then cut flush, them maybe hammer a little more to smooth out the cut ends.
--You used to be able to get waxed linen cord from Aircraft Spruce, but I don't think they have it anymore. I guess I'll figure out where to get more when I run out. Modern dacron cord would probably work OK. I buy a spray can of Minwax polyurethane varnish and spray two coats on the finished splice. Incidentally, American and British aircraft used linen cord to wrap the splices- German, French, and Spanish splices are wrapped with brass or copper wire.
--If you're doing a Piper pre-war product, the correct splice is a Roebling Roll Splice (the standard AN five-tuck splice is a box splice). In the AN splice illustrated, in the first tuck, steps 6 and 7 are roll tucks instead of box tucks, you can see the difference. In a Roebling Roll Splice the first tuck is exactly the same as the first tuck of an AN box splice. After that each strand is tucked like steps 6 and 7 of the first box splice, instead of over one and under one it's around one and out the same opening where the strand started. Piper used a six tuck roll splice, three full tucks, then two adjacent strands cut, the remaining four roll tucked, then two more adjacent strands cut, then the last two strands roll tucked. Piper used cord wrapping, which was color coded, painted instead of varnished or shellacked: red for rudder cables, yellow for elevator, blue for ailerons, and black for the parking brake cable on a J-4. If you're really a stickler for authenticity Piper started wrapping the cord from the thimble end, wrapping over a free end which trailed out past the taper of the tuck, and finished with five half hitches at the end of the splice taper.
Anyway, some splicing tidbits, everybody who tries it will develope some of their own techniques to accomplish the same things....
Also, an interesting web site, with cable splicing (without a clamp) included: http://thevintageaviator.co.nz/reference/cable-splicing
-
Comment