I am planning to rebuild my KW transformer. I have the service manual info which is very helpful. Looking at the docs not sure if the Control arms just lift off or some other magic must be done to get the case off. Don't want to break anything. I am looking to replace the carbon rollers, the screw terminals, the cord, and getting it back to top condition. Any hints or advice from others that have done this before would be greatly appriciated.
Thanks...Dean
Generally, just pull straight up on the top arm; sometimes (depending on this and that) you'll need to pry (carefully) with a screwdriver, or two of them. There's an aluminum spacer between the handles. The lower handle should just slip off, but may require some encouragement. The whistle handle just slips off. With the four screws out, the case should slide off, though it may tend to stick to the terminal plate panel at the bottom on the back. Be sure to keep track of how it all comes apart, so you can remember what goes where when you put it back together. Watch out for the direction pushbuttons which sit loosely on top of "spikes" with springs under them -- just be ready to keep track of them if they "get loose" or fly around.
To get at the rollers, you have to remove the top plate. This means unsoldering a couple of wires; then straighten the tabs of the coil brackets which protrude through the top plate. These are in danger of breaking after several unbendings and rebendings, so work gently and bend them as little as possible to get the top plate off, and at the end, to re-secure it.
To replace the rollers, crush them with pliers, and then cut the rivet with side-cutting pliers. (See the ZW Model "R" section of the service manual -- page 597 in my Greenburg version. It warns NOT to try to bend the tabs holding the roller bracket.) I didn't have any trouble peening the new rivets to hold them in place, even working on the kitchen table. Be sure the rollers rotate freely before you seal the whole thing back up. (Comment based on sad first-hand experience.)
-- Martin
lioneroar88...thank you, that worked, I got the control handles off
Martin ... appriciate the info, I have the cover off of the kw and getting ready to dive in, thanks again for sharing your knowledge and I will follow your advice.
God bless TCA 05-58541 Benefactor Member of the NRA, Member of the American Legion, Retired Boss Hog of Roseyville , KC&D Qualified
ChiefEagles...Your card stock idea sounds like a very good idea. I will give it a try. Thanks. I guess to "Ping" the end you just position the roller rivet flat on a table and use a punch, nail, etc., of the proper diameter to flare out the end of the roller rivet. Oh yeah, I have enjoyed reading all the good banter over on your coffee pot forum and the photos of your layout. Thanks for sharing.
Dean (watinva),
There is really some excellent advice above, especially the part about using the cardstock to keep the bracket from closing down and pinching the roller. Whereas the wiper arms themselves are quite springy, the clips at the very end that hold the axle-and-roller are as brittle as all get out -- at least in my experience. Once you get the old rollers crushed, cut the axle with a small diagonal pliers being extremely careful not to let the bracket expand. If it does, you will have to squeeze the sides back parallel and this could very well be the last straw.
I have considered a different approach to avoid "peening over" or expanding the axle to hold it in place. It causes much less stress on the bracket to attach it with a dab of solder. However, the axles that I got from my parts dealer didn't want to "take solder," although the tabs will. Also, the axles were annoyingly short, leaving little to work with. In the end, I cleaned everything up as well as possible, and put a blob of solder over the head end (the already mushroomed one) thus mechanically entrapping it* and preventing it from backing out. (There is very little force tending to cause it to back out anyway.) A friend suggested that a drop of expoxy could accomplish the same thing, also with no stress, no strain. Has anyone tried either of these methods?
While you are in side, take an eraser and clean the carbon from the path on the coil where the rollers run. I suggest moving the eraser back and forth along the length of the wires rather than across them, so as not to put any force that would tend to separate them, especially at the edges of the coil. No need to overdo this.
You might also use a big rubber-band or the like to hold the assembly together while the top plate is off. While I was "in there" I replaced the old copper-oxide rectifier with a modern, high current (40 amp) silicon diode) and cleaned the whistle-switch contacts.
Certainly replace the power cord, and don't forget to tie the strain-relief knot in it at the appropriate place. Use the old one as a template, if it was original.
During re-assemby I put a little Teflon power (graphite might have been better) between the throttle handles, the base, and the aluminum separator plate to try to keep the motion of one throttle handle from affecting the other. (Under no circumstances use oil or grease for this.)
Just a few thoughts; no guarantees! Good luck!
* The solder doesn't have to adhere to the head of the axle for this to work. It just has to adhere to the bracket (which it will) and totally bury the axle-head so it can't back out. The "hold" is thus simply a mechanical bridge and not a solder-bond to the axle itself. There is plenty of room for a substantial blob of solder. Hope this is clear.
Dean -- If you want to peen the rivet (rather than using the solder technique), as you suggested, flatten (or flare) the end of the rivet with a centerpunch or something. You can use the side of an ordinary carpenter's hammer (claw hammer) as the "anvil." It doesn't take much flattening of the rivet to hold it secure. And I wish I had heard of (or thought of) the cardstock idea when I did it (the first time).
On the solder technique -- sounds good to me -- I may try it. But I certainly wouldn't use epoxy -- It seems to me that there's too much chance of problems getting it loose the next time. Maybe some other type of glue would work, though.
Martinden and Dean,
Whether one uses the "solder-lump" method, or the "epoxy-lump" method, he can figure on having to grind it off next time. I found I had to do some grinding with my Dremel tool to get the original ones out, as the peening (squeezing, more likely) had "upset" the axle-holes and they were very much out of round.
I replaced the rollers on two ZW's and a KW -- for a total of 10 rollers -- all in the same day, all successfully. What ever you do, make sure the rollers roll smoothly and DO NOT DRAG. If one drags, you'll be back inside the beast in short order. If they roll, they will last quite a while. My method pays homage to the notion of first doing the patient no harm. Your mileage may vary.
Wolverine -- Can't you just melt the solder and (at the same time) pull/push the rivet out with pliers? And if that doesn't work, I'd try de-soldering wick (or a desoldering gizmo).
On peening: As I remember, once the rivets were cut (with the sidecutters), the pieces just slipped out. I worked on my KW twelve or thirteen years ago, so it's not all real fresh in my mind, but I think if I had had any trouble getting the old ones out (including the one I put in and had then to remove shortly because the roller wouldn't turn), I'd remember it. Possibly people who had put yours in (repairmen) were just over-enthusiastic with their hammers? Also, if they were factory-original, since these transformers were made over quite a few years, it seems possible that different techniques (and perhaps different equipment) was used during the production span; that could account for variations even in the original ones.
I'd just observe again that not much flattening or flaring is necessary to secure them, and that, as I remember, pretty gentle tapping is all that's necessary.
Martinden,
Whatever works.
I got some of my ideas from a "Backshop" video by Jim Barrett of the other forum. As I recall, Jim noted that most of us don't have exactly the same tools that the factory uses, and substituted a soldering method. However, my replacement axle seemed shorter than his,* and was made of some material (aluminum, maybe) that solder would not readily adhere to. Therefore I was at a disadvantage on both counts, but managed to find a way with what I had, by "mechanically" stopping the axle from backing out. My guess is that the factory uses some kind of special rivet-pliers, and never pounds or taps anything, no matter how gently.
* I've had this problem a lot....
These "techniques" all make me smile since I saw the light: the easiest and best way to secure the pins is with a pair of pliers! Squish the hollow part of the rivet 90 degrees to the axis of the pin; what you are left with is a flat, fan shaped retainer.
No stress on the arm, no spacing cards needed, no hard to reach soldering or messy epoxy, perfect!
Just wanted to say "Thanks" to everyone for all the good ideas. Got the carbon rollers and new cord installed and the KW looks and works like new. It is ready for another 50 years.
Dean
Sorry to bring back an old thread, but I am about to attempt to replace the rollers on a ZW. Like many others, I do not own special rivet tools.
Watinva, what method did you use on the KW, and did it hold up well?
Sulafool, did you simply squeeze the end of the rivet, or did you also bend it a bit?
Does anyone else have advice?
Thanks.
jjm,
Use bent nose pliers to smash the hollow end of the rivet shut. Get the pliers as close to the bottom of the contact arm as you can, this will ensure that the rivet will hold everything tightly.
jjm
I choose the "peening" method where you peen the rivet by flattening (or flareing) the end of the rivet with a centerpunch or something. You can use the side of an ordinary carpenter's hammer (claw hammer) as the "anvil." It doesn't take much flattening of the rivet to hold it secure. This worked well for me. The rivets I had seemed a little long and I had to watch out so they did not touch when the 2 rollers pass by each other. It was a little trickey getting the roller, arm, and rivet assembly on its side laying flat on the head of the hammer so I could tap on the rivet with the centerpunch/hammer, but it can be done. Looking at my zw it looks like the roller mechanism is a little different than the kw so the other recommended methods of solder or benting the rivet head might save you from having to disassemble the zw to get the arm/roller/rivet in a position where you can peen the rivet with the hammer. Others who have done this with the zw would know better than I. I think Olsens toy trains has a document from the lionel service manual on how to change the rollers on a zw. Here is the link to the zw info at Olsens http://pictures.olsenstoy.com/searchcd31.htm?itm=671 If you need more info then just start a topic on this and I am sure those in the know will help. Hope this helps.
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