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Couplers
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Todd Fisher
Does anyone happen to have any extra long shank lower shelf, double shelf or type Fs they could spare??
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Kevin Packard
I'm in the same boat. I have tons of standard E's, but am in desperate need of long shanks. Unfortunately I think we're out of luck.
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Todd Fisher
Yes unfortunately I think you're right, haven't heard anything from Frank and so far nobody has tried to make operational versions. Only dummies.
On Sun, Jan 5, 2020, 6:59 PM Kevin Packard <kevinpackard@...> wrote: I'm in the same boat. I have tons of standard E's, but am in desperate need of long shanks. Unfortunately I think we're out of luck.
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I'm curious what it would take to diecast the long shank E couplers instead of investment cast them?
-- Ryan Harris Fort Worth, Texas
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Tim L
A steel tool at about $20,000 worth (and that's probably a low end figure).
Of course if Frank had his tool made to take inserts then it would cost less as one would only have to tool a long shank insert instead of a whole tool; and then ask Frank to use his tool with your insert. On 06/01/2020 18:29, Ryan Harris wrote: I'm curious what it would take to diecast the long shank E couplers instead of investment cast them?As to no one has done any working ones yet, well, one simply doesn't just jump straight into investment casting, even Frank took years to get into investment casting of couplers and I'll bet a lot of experimentation was done before we ever saw the first investment cast coupler. Still, it should only take some research, I imagine that there would be many companies in the US that could print and cast the couplers. I'd start sniffing around companies that do rapid prototyping, and places that do jewellery or ornamental casting. The cost could be quite a bit higher than what Frank charged though. - Tim
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Kevin Packard
I may have a temporary solution. I successfully converted Sergent's long shank 3D file (ETop100P_DLP_40x30) into something that can be 3D printed. Using Fusion 360 I stitched together all the individual pieces to make the whole model one solid piece. I ran a test print (Elegoo Mars SLA printer) in three different orientations and it looks like they all worked. Every detail is captured crisply and nearly perfect. I'm going to final cure them today and assemble a couple with metal knuckles and lowers, then see how they work.
I realize they are plastic and will not have the strength or longevity that metal will have. But they may work as a stop-gap. I may have also found the solution to the metal problem as well. They make 3D printing resins for casting as well. You print the part in this resin, cast it like you would for wax, then burn out the resin. It's made so that it burns out cleanly and doesn't leave any ash or film leftover. Then all you need to do is pour the metal and break it out of the cast after it cools. Lots of work, yes, but this might be the only way to get the couplers we need in metal. -Kevin
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Kevin Packard
I put together a couple couplers this morning and have tested them out. They do work, though they are not nearly as smooth operating as all metal. The resin tends to hold the ball, as well as the knuckle. It takes more force to open the knuckle, and to close it. It's far easier to couple to a car with all metal couplers because that one will have a knuckle that opens and closes easily.
I did have to widen the ball space a bit, as well as the coupler box pin hole. Besides that there were no fit issues. Here's one of the frets after printing:  One of the couplers removed from the supports and cleaned up  Assembled with ball, metal knuckle, and metal lower shelf   Installed on a Walther's 50' boxcar  Coupled to a standard E  Coupled to a long shank lower shelf E  I'll keep testing. Time will tell how it does in the long run. There are other resins I might want to try. The have "engineering" resins that are tough and designed to be used for moving parts. We'll see. -Kevin
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Mark Lewis
Very nice, Kevin. Mark Lewis
On Mon, Jan 6, 2020 at 2:01 PM Kevin Packard <kevinpackard@...> wrote: I put together a couple couplers this morning and have tested them out. They do work, though they are not nearly as smooth operating as all metal. The resin tends to hold the ball, as well as the knuckle. It takes more force to open the knuckle, and to close it. It's far easier to couple to a car with all metal couplers because that one will have a knuckle that opens and closes easily.
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Bill Keene
Kevin,
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Lookin’ Good! Also, looking forward to the results of the longer term testing. I am also assuming that this long shank could be assembled with the standard Type E coupler knuckle. The shelf couplers are far into the future if my modeling period. Cheers, Bill Keene Irvine, CA
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Kevin Packard
Bill - yes, the shank portion of the coupler is the same for either version. Just choose which lower you want to put on there.....lower shelf, or normal. Both of those parts are still made by Sergent I believe.
-Kevin
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This looks very promising. Thanks for moving forward with this.
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Todd Fisher
Kevin do please let us know how this goes. If you could do this for double shelf and type Fs as well that'd be awesome.
On Mon, Jan 6, 2020, 3:42 PM George <gsebastiancoleman@...> wrote:
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Keith Getter
Very nice Kevin!!
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Very interested to see how this works out as I also missed the boat on them when Sergent was producing them! Thank you, Keith
On Jan 6, 2020, at 14:01, Kevin Packard <kevinpackard@...> wrote:
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Hi Kevin,
Try lubricating the plastic with graphite and see if the knuckle moves more easily. (Just shade it with a pencil if you don’t have powdered graphite.) Cheers, Jeff.
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Kevin That’s pretty Amazing. Rob B
On Jan 6, 2020, at 11:01 AM, Kevin Packard <kevinpackard@...> wrote:
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Sounds great, Kevin. These couplers look fantastic!
-- Ryan Harris Fort Worth, Texas
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Kevin Packard
Jeff - I did use dry graphite when I put the ball in, and it helped. The knuckle could certainly use some of it. I'll give that a shot on the next set I assemble.
-Kevin
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Tom Colasurdo
Kevin: Very nice work !!! Thank you for sharing your experiments / results ... really look forward to hearing results from operating. I'm guessing these are HO scale couplers? What size ball was installed in the coupler? Frank Sergent mentioned to me in one of his e-mails that he utilizes a 2 mm ball in the S scale couplers ... as I've been playing with Frank's 3-D files for the S scale couplers I came to the same conclusion that the cup holding the ball needed to be sized a little larger (believe the dimension in the model was 1.6 mm) ... how much did you enlarge the dimension on your experimental coupler? I also experienced sluggish knuckle operation on first printed samples ... I'm changing the cylinder dimension that holds the knuckle ... if that doesn't work, I may change the cylinder to a cone shape. Since I had AutoDesk Inventor available to me, I'm currently assembling the modified parts in one file so I can add constraints ... I'm hoping this feature will let me animate and check for operational interference before I have the parts printed again. These couplers are too good to give up on and revert to more readily available couplers ... staying the course, and your progress provides encouragement and optimism. Thanks again ... have a great night. V/r, Tom C.
On Monday, January 6, 2020, 02:02:21 PM EST, Kevin Packard <kevinpackard@...> wrote:
I put together a couple couplers this morning and have tested them out. They do work, though they are not nearly as smooth operating as all metal. The resin tends to hold the ball, as well as the knuckle. It takes more force to open the knuckle, and to close it. It's far easier to couple to a car with all metal couplers because that one will have a knuckle that opens and closes easily. I did have to widen the ball space a bit, as well as the coupler box pin hole. Besides that there were no fit issues. Here's one of the frets after printing:  One of the couplers removed from the supports and cleaned up  Assembled with ball, metal knuckle, and metal lower shelf   Installed on a Walther's 50' boxcar  Coupled to a standard E  Coupled to a long shank lower shelf E  I'll keep testing. Time will tell how it does in the long run. There are other resins I might want to try. The have "engineering" resins that are tough and designed to be used for moving parts. We'll see. -Kevin
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Frank Sergent
Hey Kevin, looks like you are getting very close. Go look at the pictures
in the sergent engineering groupsio page “Treeing 3D prints”. Look at the
IMG_1095.jpg picture. All the 3D models are designed so they can be 3D printed
with no support structure. I’m convinced that you don’t have to go to investment
cast metal with the resins that are available today. You may have to modify the
coupler designs slightly to beef up the cross section of the shanks where the
hole that receives the “rivet” from the bottom part fits. Also, all my 3D model
files have pre-distorted knuckle hinge pins that allowed the final product to
come out correctly on my printer. You’ll have to modify the design in that area
to give predictable geometry from your printer. Also, a good UV curing process
is very important to get usable parts whether you are investment casting or not.
Congratulations!
Frank
From: Kevin Packard
Sent: Monday, January 06, 2020 5:31 PM
Subject: Re: [Sergent Engineering] Couplers Jeff
- I did use dry graphite when I put the ball in, and it helped. The
knuckle could certainly use some of it. I'll give that a shot on the next
set I assemble. -Kevin
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Mike Conder
Frank, are those couplers shown 3D printed in wax for lost wax casting? And Kevin, great work, did you do that on a resin printer? If so, which resin did you use? Mike Conder
On Mon, Jan 6, 2020 at 8:56 PM Frank Sergent <fsergent@...> wrote:
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