MAKING A REPLACEMENT COMBINATION LEVER FOR THE K4 1361 PT 3

[Trainman4602]

I have finished the new combination lever. I used the Caswell Ind plating system to plate the rod with electroless nickel.

Here is the video.

https://www.youtube.com/watch?v=ndkYHEI ... e=youtu.be

[ccvstmr]

Dave,
I found your recent video submissions interesting. Thank you. Not sure these should have been titled Combo Lever...but instead, how to plate parts.

You made an interesting comment in Part 1 that got my attention. You start with a piece of metal bar stock and a design, and cut away everything that doesn't look like the part you want...in this case, a combination lever. You started by drilling critical hole locations. For those of us that aren't trained as machinists, tool & die makers, pattern-makers, etc...knowing how or where to start can be the biggest challenge. I've heard that cutting metal chips is the easiest part of the work we do...but knowing where to start and how to hold the item is the key. In particular, when starting with a raw casting. Whether type of tutorial provides ideas for future "how to" videos is your call. But I can say this is an area that sometimes stumbles me...in addition to knowing what kinds of machining tolerances are acceptable...when and where (which parts).

btw...you made a comment during the plating process intro video about the type of water suggested. There are various types of water...but they are not the same. Tap water, while filtered and treated may contain impurities that would affect the plating process. I'm not sure how much different RO (reverse osmosis) or distilled water is, but in the distillation process, all impurities should be left behind and provide only clean, condensed water free from salts, metals, or other impurities that could adversely affect a "good" plating job.

Going back to your combo lever repair...I want to ask, how do you compensate for the additional plating material in the critical holes you drilled at the start of the combination lever fabrication? The holes would be slightly smaller after you pulled the part(s) from the plating bath. ...or do you go back and ream those a 2nd time? Just curious. Carl B.

[Trainman4602]

Hi Carl
I didn’t worry about the small amount of plating that was deposited in the holes. BTW electroless plating will plate in holes as opposed to electro plating that will not do that.

I made the pins to fit the holes. When first built the hole were reamed to .169. Over the years they elongated to .175. I happened to have a number reamer set so I reamed them to .177 #16 . I made new pins and bushings to match.

I plan on doing video on how to set up castings for machining. This will be on the construction, instruction of the 0-4-0 but the methods can be used on any locomotive.

[Harold_V]

You started by drilling critical hole locations.

That can be risky, especially when a large amount of material is removed from the part, in particular when the metal removal is not uniform about the centerline of the material. The risk is movement of the part, causing the hole to lose proper orientation ( it may lean when it must be at a right angle). Make sure that if you choose this route, the part will still be functional if you experience such movement.

Drilling (and tapping) holes is typically the last operation when parts are machined, for that reason.

Harold

[Trainman4602]

I use hot rolled for this part everything stayed in place with no distortion.

[Harold_V]

I use hot rolled for this part everything stayed in place with no distortion.

Good choice, Dave, much wiser than choosing cold rolled material, which has a higher level of stress.

Harold

[10 Wheeler Rob]

Dave, is there any post plating heat treat done? Some materials have issues with hydrogen embrittelment from plating processes. I am not sure if this process can cause it it or not.

[Trainman4602]

Hi Rob

I am not sure on that. The rod that broke was in service for ten years.

[Harold_V]

Dave, is there any post plating heat treat done? Some materials have issues with hydrogen embrittelment from plating processes. I am not sure if this process can cause it it or not.

Iron alloys subjected to chemical action (like plating) are subject to hydrogen embrittlement, which lowers ductility and can lead to failure. If there's the least doubt about the piece in question being affected, a bake @ 375°F or slightly higher, for several hours, would eliminate any hydrogen that has been absorbed.

Harold