Ebit pick up for LL SW's

[wazzou]

Hope this helps

Jim
(Attachment Link)
(Attachment Link)

With the knowledge that I don’t have mine open in front of me...
I assume there are 4 of these needed per loco?  2 mirrored to this?
It’s bent down at the right, correct?  Does that contact the wheel tread?
What is the purpose of the rectangular cutout?

[peteski]

Aren't those the same as what MT gives you with their couplers?

Jim states he used 00-90 screws.  So yes, those are the same as MTL screws.  But MTL screws are steel, not brass.  Looks liek Jim used flathead screws for clearance. Maybe fillister head where he filed down the head flat. 

00-90 screws with multiple head types and length are widely available hobby item.   Hobbits, Micro Fasteners, KS Metals, and even Walthers carries those.  Make sure to buy ones that are not too long.

[Ed Kapuscinski]

Jim states he used 00-90 screws.  So yes, those are the same as MTL screws.  But MTL screws are steel, not brass.  Looks liek Jim used flathead screws for clearance. Maybe fillister head where he filed down the head flat. 

00-90 screws with multiple head types and length are widely available hobby item.   Hobbits, Micro Fasteners, KS Metals, and even Walthers carries those.  Make sure to buy ones that are not too long.

Hence the reason I asked for the specifics of the one he had success with.

[mmagliaro]

I would never use brass for this.  Use phosphor bronze.  Brass isn't springy, will not maintain pressure, and will oxidize.
You can get ready-cut strips of phosphor bronze from Eilleen's Emporium:

https://eileensemporium.com/index.php?option=com_hikashop&ctrl=category&task=listing&cid=1100&name=phosphor-bronze-flat-strip&Itemid=189

You can also find it on eBay.

[diezmon]

The reason Ebit's version had an offset tab contacting the chassis was to have a notch in the center which follows the notch in the walkway.  I don't have the loco handy, so I'm not sure what that  notch is for (probably for a tab which holds the shell and walkway together).
 
Your version covers that notch.  Not sure how that will work out.  Also, the motor is in the center of the chassis. Will the tab make a good contact with the metal chassis in that area?

I really like Jim's self-contained solution. While it is more work to install, I like the fact that the shell is free of any pickup parts which can get mashed when the shell is removed and installed.

It worked out fine. I was just showing an earlier version.  As I said, i'm going to try the template.

[Jim Starbuck]

With the knowledge that I don’t have mine open in front of me...
I assume there are 4 of these needed per loco?  2 mirrored to this?
It’s bent down at the right, correct?  Does that contact the wheel tread?
What is the purpose of the rectangular cutout?

A few more details:
The screws are indeed leftovers from MT 905 Z couplers with no modification.
As for the tab, that’s just how it comes off the sill. The long part of the tab at the left in the photo contacts the tab on the truck exactly the way it does when connected under the sill as stock.
The rectangular cutout is where the plastic tab on the sill protrudes and gets melted over securing (kinda) the brass pickup strip onto the plastic sill. It could actually be snipped off flush with the right side of the vertical tab as it serves no purpose.

[nsbob]

     Do most N scale locomotive manufacturers use brass or phosphor bronze for their contact strips for electrical pickup?  They look like they are brass to me, but I'm not sure.  It would be helpful if someone could use a caliper to measure the thickness of the contact strips from an appropriate Kato or Atlas (or both) diesel locomotive and post that information here.  I would do it but I don't own a caliper.  I do realize that the length and width of the strip may have an impact on the its flexibility.

[Ed Kapuscinski]

A few more details:
The screws are indeed leftovers from MT 905 Z couplers with no modification.
As for the tab, that’s just how it comes off the sill. The long part of the tab at the left in the photo contacts the tab on the truck exactly the way it does when connected under the sill as stock.
The rectangular cutout is where the plastic tab I on the sill protrudes and gets melted over securing (kinda) the brass pickup strip onto the plastic sill. It could actually be snipped off flush with the right side of the vertical tab as it serves no purpose.

You are my

[wazzou]

A few more details:
The screws are indeed leftovers from MT 905 Z couplers with no modification.
As for the tab, that’s just how it comes off the sill. The long part of the tab at the left in the photo contacts the tab on the truck exactly the way it does when connected under the sill as stock.
The rectangular cutout is where the plastic tab I on the sill protrudes and gets melted over securing (kinda) the brass pickup strip onto the plastic sill. It could actually be snipped off flush with the right side of the vertical tab as it serves no purpose.

Oh... OK, I see now.  So you do do this at all 4 corners then using the original tabs.
Thanks.

[peteski]

I would never use brass for this.  Use phosphor bronze.  Brass isn't springy, will not maintain pressure, and will oxidize.
You can get ready-cut strips of phosphor bronze from Eilleen's Emporium:

https://eileensemporium.com/index.php?option=com_hikashop&ctrl=category&task=listing&cid=1100&name=phosphor-bronze-flat-strip&Itemid=189

You can also find it on eBay.

Ok, I took some measurements.
The original strips installed in these models is only 0.08mm or 0.003" thick!  Probably because these are very short, so they have to be really flexible.
Next are the long strips used in Kato diesels.  These are 0.13mm or 0.005" thick.
I suspect that 0.010" would be too stiff.

I believe that these strips are phosphor-bronze, but I also have phosphor-bronze material which has much more "coppery" (pinkish) color.  I suspect there are multiple types of phosphor-bronze alloys.
And I also know that  brass also comes in soft or hard alloys, so it can be springy enough to make decent pickup strips (of course phosphor-bronze would be better).

As for as oxidation goes, BP and brass will oxidize.  Brass seems to oxidize quicker, but I do have some PB that has signs of oxidation.

And I would leave that tab which keeps the walkway attached to the shell alone.  But I guess I just like to have the option to separate it if needed.  I also like Jim's solution of screwing existing strips to the chassis the best.

Jim, I forgot that the MTL Z scale couplers include short flat-head brass 00-90 screws.  The N scale couplers have been including steel 00-90 fillister-head screws for some years now. Before that they were including crappy and soft molded white-metal 00-90 screws for many years. If the N scale couplers included brass screws, it is before my time.

[wazzou]

And I also know that bras also comes in soft or hard alloys...

Hmmm, that helps explain the tenderness I’ve been told about over the years.   

[peteski]

Hmmm, that helps explain the tenderness I’ve been told about over the years.   

ROTFL - thanks for that badly needed chuckle - in the midst of the pandemic!
You know, it is all about those underwires.  The soft-cup ones have none.   Cross your heart! Front-closure are the most convenient. The ones with 4 clasps in the back are major PITA! 

[Jim Starbuck]

Oh... OK, I see now.  So you do do this at all 4 corners then using the original tabs.
Thanks.

Correct.
There are two left and two right contact tabs/ strips. Same location, orientation and operation as stock just fastened to the chassis via screws instead of a melted blob holding them to the sill.
When you put the sill/ shell back on the bottom of the sill goes down to the top surface of the tab. Same location as it was in the stock position.
The tapped hole location is important that it’s not too high thus keeping the shell from nesting down properly or too low that the brass tab becomes visible under the sill. The shell is still located and held to the chassis by the bumps on the chassis and dimples inside the shell.
I didn’t measure anything just eyeballed it. I held the tab with flat needle nose plies on the long side and gently drilled the holes in the vertical tabs. It only takes a slight touch for the bit to go through without catching and wadding up the tab. The same condition as drilling a twist bit through any thin material.
All the tabs got drilled in slightly different locations that’s why I held them up to the chassis to mark the tapped hole location.
I disassembled the chassis and drilled the frame halves laying flat on a wood block on my small drill press. Slow and gentle are the words of the day because the backside of the hole location isn’t flat and the drill will walk off to one side easily if not done carefully. I remember being able to crowd the tab to one side of the frame slot or the other to minimize this.
This will make much more sense as you look at a bare frame half.

Jim

Oh, and the reason I used the brass MT screws is because I had them laying on my bench and the only small tap I own is a 00-90.
Those little MT screws are my modeling equivalent to Frank’s Red Hot Sauce...I use that sh** on everything.

[nsbob]

Peteski:
     Thanks for providing the measurements of the contact tabs/strips.  Like I said, I don't have a caliper and your information is very helpful.

[Chris333]

Here is my dirty pic of them. Yes there is a small notch (not seen) for the body clip. This is so easy to do, no tape measures were used. Just bend "something" 90 degrees and make sure it reaches out to the truck tabs.