Microtrains Coupler Question - body mounting

[mike_lawyer]

Hi guys -

I am working on body mounting some couplers on Kato Mikado tenders for two PRR L-1 conversions.  Two questions:

1.  I have a set of pre-assembled MT 1015s.  However, those couplers seem to set up too high for the Mikado tender.  Any recommendations on an MT coupler with a lower setup to use?

2.  When using this set of MT 1015s, I ran into a problem.  Once installed using the supplied screw, the coupler would no longer self-center.  If I remove the screw and take the coupler off, they then self-center again.  Any idea why an MT coupler would no longer self-center after being installed with the stock screw?  That's the first time that has ever happened to me.

[EL3632]

1. Not sure if this is what you are looking for, but Micro Trains sells a conversion kit for the Kato Mikado, number 2002. It should be available from most online retailers. This includes a coupler that fits in the existing tender truck, though you may not want that. If that is the case, look for an "underslung" coupler, like the 2004-1, which has the top of the knuckle closer to the height of the plastic that makes up the centering mechanism (can't think of a better way to phrase that).
2. I think your screw is in too tight, try loosening it half a turn and see what happens.

[wazzou]

2.  When using this set of MT 1015s, I ran into a problem.  Once installed using the supplied screw, the coupler would no longer self-center.  If I remove the screw and take the coupler off, they then self-center again.  Any idea why an MT coupler would no longer self-center after being installed with the stock screw?  That's the first time that has ever happened to me.

The only time I've run into that is due to the screw being fastened too tightly.

[bbussey]

Agreed.  Just loosen the screw until the coupler pivots freely.

[randgust]

wait...what?

Are you saying the coupler is too high on the tender sill or too low?  If it is too low, the underslung coupler is the solution.   If it is too high, look for some of the shims that come as standard equipment in a 1015/1016 package.   Goo will hold them on until you can get the screw in.   If it's as much as .020 off, a styrene scrap of anything from .020 to .o40  with a 1/16 hole in it (.0625) or better proper .045 clearance hole for the screw will bring it down.

I'd be at least a little suspect of the contact strips in the tender set too stiff jacking the tender up, too.   My L1 had the cast metal tender body, that wasn't going to happen, but newer ones are lightweight resin.

[mike_lawyer]

The coupler is too high on the tender.  Good idea with regard to a shim.

With regard to the coupler not recentering, if I loosen it, the coupler will be too loose on the tender.  It's really strange, I never had that happen before.

[drgw0579]

>With regard to the coupler not recentering, if I loosen it, the coupler will be too loose on the tender.  It's really strange, I never had that happen before.

I occasionally have this problem. It's basically because we're trying to use the same screw to mount the coupler and keep it aligned.   N scale couplers don't have a cast pin to engage into the mounting surface.
  Wish they had that, but then you'd have to drill a second hole.   Unfortunately, the center area of the coupler is sometimes weak, and tightening it enough to prevent the coupler from turning also depresses it enough to bind the moving parts of the coupler.

I put a very very small amount of glue on the surface where the coupler is to prevent it from turning.  Don't put too much or it will seep into the coupler, preventing it from working!  For me, I use canopy glue, but CA would work.

Bill Kepner

[jdcolombo]

The problem you are having with the screw is that the surfaces of the coupler box and tender floor are too slippery.  As a result, in order to keep the coupler box from moving, the screw has to be too tight and is compressing the coupler box, which keeps the coupler from re-centering.

Here's what I would do.  First, try roughing up both the top of the coupler box and the mounting area on the tender floor with some 80 or 100-grit sandpaper.  Delrin is slippery; make it less so.  Far less so.  Be agressive about this.

If that doesn't work, then put a TINY drop of thick CA cement on the rear 1/32" (or so) of the coupler box, and screw it down.  You're going to have to work fast to get the coupler centered since the CA will set up in seconds after the two surfaces come in contact.  If this worries you, you can try a tiny drop of rubber cement, which will give you more time to get the coupler straight.  The key here is TINY DROP - you don't want any of the cement to foul the coupler insides.  Use a toothpick.  But don't resort to this until you've tried technique #1.

I've found that when I have this problem, technique #1 (roughing up the surfaces) works about 60% of the time.  But the other 40% of the time I have to use some cement.

If you need to use a shim, which it sounds like you do, cut a rectangular piece of styrene (usually, .020 thickness will do the job), and cement it using liquid plastic cement to the tender floor (I'm assuming the tender floor is plastic; if it is metal or delrin, use CA and be sure to rough up the surfaces before gluing).  Then be sure to rough up the shim before trying to mount the coupler.

John C.

[mike_lawyer]

Bill and John, those are excellent points about the problem of trying to keep the coupler aligned and mounting it.  I am going to try the "rough up the surface" technique and will report back.

[nkalanaga]

If there's room, you can also make the shim a bit wider, and glue a plastic strip on either side of the box to keep it from moving.  Styrene cement won't stick to MT's plastic, so even if a little gets on the box, it won't gum anything up.