Kato Mikado driver diameters and cutting TT grooves

[Rasputen]

I tried cutting a groove in the standard Kato driver using my Sherline, in the same way I cut the Life-Like drivers, but it came apart before I could get enough depth.  I took another driver apart without cutting it and I discovered the reason - there is a step in the standard driver tire ID that prevents you from cutting a .040 inch wide groove to the proper depth:



As you can see, there is only .040 inch total width there that you can cut into.  This means that you might
be able to cut a .025 inch wide groove, and either make the Kato traction tires narrower, or use Plasti-Dip as
suggested.  These were from the first run, so I don't think they are any different in this regard.

Those eBay ones must have been sitting around somewhere because the latest ones came in plastic bags.

[SkipGear]

I tried cutting a groove in the standard Kato driver using my Sherline, in the same way I cut the Life-Like drivers, but it came apart before I could get enough depth.  I took another driver apart without cutting it and I discovered the reason - there is a step in the standard driver tire ID that prevents you from cutting a .040 inch wide groove to the proper depth:



As you can see, there is only .040 inch total width there that you can cut into.  This means that you might
be able to cut a .025 inch wide groove, and either make the Kato traction tires narrower, or use Plasti-Dip as
suggested.  These were from the first run, so I don't think they are any different in this regard.

Those eBay ones must have been sitting around somewhere because the latest ones came in plastic bags.

There may be a difference in the revised drivers. They have the hub molded into the rim instead of a seprate part. That step probably can't be there as it would be an undercut in the casting or a real pain to turn on a lathe in mass production.

[Big4Man]

Toney, FWIW As mentioned earlier, I have a stash of these and not currently in the market. However, If I were and were following this thread, I would seriously consider the BFS before spending that kind of $$. But that's just me. Some others may consider their time more valuable and opt to pay more for a discontinued item. That's fine with me too.
My original comment was perhaps a little too sharp edged for some here. 
As I have no problem with someone tinkering around trying to create a better solution to a problem. I honestly did not realize these were worth their weight in gold. I also hated to see someone going to all this trouble if I have a spare set laying around.

Lets see spot price on gold ~$1,600/oz. Does anyone have the weight of these drivers?   

[Lemosteam]

Think it was meant to be a tounge in cheek answer and not a viable solution Pete! 

Jon

It was, but to be perfectly honest I've never seen a Connie driver!  I took no offense whatsoever!

[robert3985]

I tried cutting a groove in the standard Kato driver using my Sherline, in the same way I cut the Life-Like drivers, but it came apart before I could get enough depth.  I took another driver apart without cutting it and I discovered the reason - there is a step in the standard driver tire ID that prevents you from cutting a .040 inch wide groove to the proper depth

Arghh...!! That is what I was afraid might be the case.  A key-slot cut into the tire ID to retain the tire on the driver center!

Looks like the only way to do this is to cut the tire off (which destroys it) after getting it as concentric as possible in the holding tool, and at the same time, turn the driver center down so the raised key disappears.  Then turn a new tire with the correctly proportioned TT slot in it (of course, no key-slot on the ID of the tire) and possibly one or two very small, shallow slots turned on the ID of the tire (to give the epoxy something to grip on to), then press the tire onto the hub with a very small amount of epoxy or slow-setting JB-Weld swiped onto the inner surface of the tire.  A pure press fit would be better...especially on the electrical pick-up side.

Actually not a very difficult machining procedure, but make sure the driver hub is as concentric with the axle hole as possible, measuring and zeroing the run-out of the tire before cutting it off, which with an independent 4-jaw chuck should not be difficult at all. The new tire could be machined from "white brass", nickel silver or stainless stock...or even aluminum, but that would be my very last choice.

Any way ya look at it, you need a lathe to do this. 

I'll state the obvious and say that it would be a lot cheaper just to buy the Kato TT replacement drivers when you see 'em offered...even at $12 shipping...if you don't own a lathe, tooling and have sufficient experience as to machining set-ups and procedures.

But, it's good to know that if the TT drivers cease to remain available, and you know a model railroader with a lathe and some experience under his/her belt, I am sure that some kind of deal could be struck (money, trade, beer) to do the above procedure.

Cheers!
Bob Gilmore

[peteski]

Bob, for all the fancy (yet simple) precision machining operations (especially the last one where you would create entire new metal tire) woudl cost you (in time spent doing it) more than the cost of a TT driver in eBay. Not to mention that you would need hundreds (um, thousands) of dollars worth of equipment. Unless you are saying all of this with your tongue in your cheek, I think this is a perfect example of over-thinking the problem. 

Other comments:
I think that leaving 0.006" (if you are perfectly precise) thickness under the groove is cutting it too close (pun intended).  I think that in this situation even small blow to the outside of the driver (like having the loco hit the table from a height of several inches - which can happen) would probably damage that driver.

Also the old and new drivers have totally different construction. In the new drivers the entire wheel back, center hub  and the tire/flange is a single piece of metal.