Self centering, best solution yet


George Hofmann
 

On this forum I have proposed several solutions for self centering but I am always striving to improve. I admire the Kadee "whisker coupler" technique and wondered if it could be adapted. I grabbed my last #158, took a pair of pliers and yanked out the whiskers. They are crimped to the shank (more on that later). I glued the whiskers onto a Sergent narrow shank using CA in the same orientation as on the Kadees. I installed the result into an Accumate box and ... Viola! It works! Perfect repeatable centering, unrestricted lateral movement and importantly, very little force required to move the shank from side to side. The freedom of movement is important because that can sometimes be the difference between a successful coupling or not. If there is slight misalignment such that an open knuckle touches a closed knuckle the two couplers can sometimes slide apart to allow the join rather than pushing the open knuckle closed. This is more likely to occur if there is little resistance to sideways motion.

But that was my last #158. What to use for more whisker material? I got suggestions from another forum that the material was either carbon fiber or stainless steel and that it was .004" diameter. I searched fruitlessly for those materials. But the other day when rooting through my stash of railroad things I ran across a long tube that contained a (nearly) invisible strand of something. The label said "superelastic Nitinol .008". A lightbulb appeared above my head. This Nitinol wire is straight, stays straight, is super springy and is almost indestructable. 

I took out the (nearly) invisible wire and cut two pieces from it each 8mm long. I glued them on like the whiskers before, Tried it again in a box and... Huzzah! It works! These whiskers are a little stiffer than the Kadee ones because these are twice the diameter. They work but I'm going to acquire some .004 or .005 going forward. I saw a price of $8 for a 36" piece. You can get about 30 cars out of such a length. The technique works equally well using a standard shank in a wide box. The whiskers should be a little longer for the standard shank.

There is a short learning curve involved. I apply medium Starbond CA using a toothpick to the vise held coupler. Then using a fine tweezers I lay the wire in place with one end flush with the end of the shank. I carefully center and align it on the shank. Then I hold it down with a knife blade while detaching the tweezers. It could be squirted with accelerant at that point. Or just withdraw the blade and leave it alone for a while. The wire needs to be in solid contact with the shank for the entire contact length to assure that the angle of the wire is correct i.e. so that it matches the shank angle exactly. It can be pushed down with the knife blade without disturbing the positioning. This technique is non-destructive and reversible. See the pictures below.

I'm thinking that it might be advisable to bias the shanks slightly off center in the direction of the knuckle. It seems logical that this might decrease the chances of fouling the knuckle but further testing is required. If the conclusion is correct it should be possible to adjust the neutral position using a styrene shim between one whisker and the box wall.

Not that it matters but I'm pretty sure that Kadee is using this material. It looks like it and acts like it. Further the Kadee whiskers are crimped in place. That would be consistent with this conclusion since you would not want to apply heat to Nitinol in the manufacturing process.

Have fun. Otherwise there's no point in any of this.

George
Edgewood, WA





Leni Bogat
 

Genius!!!


Edward Sutorik
 

IF you have a mill, you could build a fixture that could hold and position a coupler body on its side so that:

you could cut a groove down the side that would hold the wire.  It would both provide easy alignment and also give  more surface area for the glue bond.

I'm looking at a catalog that is showing engraving cutters with a tip radius.  A 90 degree cutter can have a tip radius of .0025, which would be good for .005 wire and smaller.  Same for a 60 degree.


Of course, a manufacturer could include such a groove from the beginning.


Ed

Edward Sutorik


Leni Bogat
 

If I may may modify an adage to suit  the purpose, a manufacturer could also include the whiskers from the beginning. And, on behalf of those with eyes as old as mine, a fully assembled option for ready to install couplers. I would gladly pay a bit more not to require a microscope in order to assemble them myself. After seeing how they look on a few cars, I want them for my entire fleet, but I can’t count on having enough years left to accomplish the task.

Leni 

On Dec 13, 2021, at 3:02 PM, Edward Sutorik via groups.io <Edwardsutorik@...> wrote:

IF you have a mill, you could build a fixture that could hold and position a coupler body on its side so that:

you could cut a groove down the side that would hold the wire.  It would both provide easy alignment and also give  more surface area for the glue bond.

I'm looking at a catalog that is showing engraving cutters with a tip radius.  A 90 degree cutter can have a tip radius of .0025, which would be good for .005 wire and smaller.  Same for a 60 degree.


Of course, a manufacturer could include such a groove from the beginning.


Ed

Edward Sutorik


Peter York <peterdyork@...>
 

Or better still, a manufacturer could provide them with the wires attached. I can dream, can’t I?

On Dec 13, 2021, at 3:02 PM, Edward Sutorik via groups.io <Edwardsutorik@...> wrote:

IF you have a mill, you could build a fixture that could hold and position a coupler body on its side so that:

you could cut a groove down the side that would hold the wire.  It would both provide easy alignment and also give  more surface area for the glue bond.

I'm looking at a catalog that is showing engraving cutters with a tip radius.  A 90 degree cutter can have a tip radius of .0025, which would be good for .005 wire and smaller.  Same for a 60 degree.


Of course, a manufacturer could include such a groove from the beginning.


Ed

Edward Sutorik


John Degnan <scaler164@...>
 


Good idea... but I'd like to throw out a simpler idea I had about 7 years ago for auto-centering my "S" scale Sergent couplers... an idea that doesn't require any form of gluing.  Check out the photos and video on the "PROTOTYPE  PHOTOS  AND  VIDEO" table near the bottom of the following page.

http://www.trainweb.org/seaboard/SScaleGearBox.htm

I used a draft gear box from Kadee a 802 or 808 coupler for this prototype-test build, and as the video shows, it worked flawlessly.


John Degnan
Scaler164@... 


George Hofmann
 

John:
I had mentioned in previous postings that others had already come up with similar ideas. I believe that your concept was one that I was referring to. But I think your method will not work in the narrow Accumate boxes. This whisker technique works in any box.
Thanks for exposing your technique again. The more choices the better. We need to remove all excuses for not using these little marvels.
G


Dale Buxton <dbtuathaddana@...>
 

Thanks George, 
Way to go Sir! Great out of the box thinking. I agree that this probably is the best solution for centering these.

Dale Buxton

On Mon, Dec 13, 2021 at 09:54 George Hofmann <george.hofmann@...> wrote:
On this forum I have proposed several solutions for self centering but I am always striving to improve. I admire the Kadee "whisker coupler" technique and wondered if it could be adapted. I grabbed my last #158, took a pair of pliers and yanked out the whiskers. They are crimped to the shank (more on that later). I glued the whiskers onto a Sergent narrow shank using CA in the same orientation as on the Kadees. I installed the result into an Accumate box and ... Viola! It works! Perfect repeatable centering, unrestricted lateral movement and importantly, very little force required to move the shank from side to side. The freedom of movement is important because that can sometimes be the difference between a successful coupling or not. If there is slight misalignment such that an open knuckle touches a closed knuckle the two couplers can sometimes slide apart to allow the join rather than pushing the open knuckle closed. This is more likely to occur if there is little resistance to sideways motion.

But that was my last #158. What to use for more whisker material? I got suggestions from another forum that the material was either carbon fiber or stainless steel and that it was .004" diameter. I searched fruitlessly for those materials. But the other day when rooting through my stash of railroad things I ran across a long tube that contained a (nearly) invisible strand of something. The label said "superelastic Nitinol .008". A lightbulb appeared above my head. This Nitinol wire is straight, stays straight, is super springy and is almost indestructable. 

I took out the (nearly) invisible wire and cut two pieces from it each 8mm long. I glued them on like the whiskers before, Tried it again in a box and... Huzzah! It works! These whiskers are a little stiffer than the Kadee ones because these are twice the diameter. They work but I'm going to acquire some .004 or .005 going forward. I saw a price of $8 for a 36" piece. You can get about 30 cars out of such a length. The technique works equally well using a standard shank in a wide box. The whiskers should be a little longer for the standard shank.

There is a short learning curve involved. I apply medium Starbond CA using a toothpick to the vise held coupler. Then using a fine tweezers I lay the wire in place with one end flush with the end of the shank. I carefully center and align it on the shank. Then I hold it down with a knife blade while detaching the tweezers. It could be squirted with accelerant at that point. Or just withdraw the blade and leave it alone for a while. The wire needs to be in solid contact with the shank for the entire contact length to assure that the angle of the wire is correct i.e. so that it matches the shank angle exactly. It can be pushed down with the knife blade without disturbing the positioning. This technique is non-destructive and reversible. See the pictures below.

I'm thinking that it might be advisable to bias the shanks slightly off center in the direction of the knuckle. It seems logical that this might decrease the chances of fouling the knuckle but further testing is required. If the conclusion is correct it should be possible to adjust the neutral position using a styrene shim between one whisker and the box wall.

Not that it matters but I'm pretty sure that Kadee is using this material. It looks like it and acts like it. Further the Kadee whiskers are crimped in place. That would be consistent with this conclusion since you would not want to apply heat to Nitinol in the manufacturing process.

Have fun. Otherwise there's no point in any of this.

George
Edgewood, WA





Andy Reichert
 

I'm sorry about failing eyesight. I'm getting up there myself, so I do understand. But speaking as someone who still manufactures as my retirement hobby,  I can assure you, offering a ready assembled option for tiny inexpensive items is the easiest way to waste a ton of time earning 50 cents an hour that I know.

"A bit more" economically is actually several times the cost of the unassembled item.

Andy

On 12/13/2021 1:14 PM, Leni Bogat wrote:
If I may may modify an adage to suit  the purpose, a manufacturer could also include the whiskers from the beginning. And, on behalf of those with eyes as old as mine, a fully assembled option for ready to install couplers. I would gladly pay a bit more not to require a microscope in order to assemble them myself. After seeing how they look on a few cars, I want them for my entire fleet, but I can’t count on having enough years left to accomplish the task.

Leni

On Dec 13, 2021, at 3:02 PM, Edward Sutorik via groups.io <Edwardsutorik@...> wrote:

IF you have a mill, you could build a fixture that could hold and position a coupler body on its side so that:

you could cut a groove down the side that would hold the wire.  It would both provide easy alignment and also give  more surface area for the glue bond.

I'm looking at a catalog that is showing engraving cutters with a tip radius.  A 90 degree cutter can have a tip radius of .0025, which would be good for .005 wire and smaller.  Same for a 60 degree.


Of course, a manufacturer could include such a groove from the beginning.


Ed

Edward Sutorik
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George Hofmann
 

Well you know, Mr. Lei (UP4096 in this group) who has taken up the manufacturing of Sergent design couplers in China might be able to pull it off. I hope he views this thread.
On the other hand Kadee might have a patent on this technique.
G