Custom chassis fabrication?

[mike_lawyer]

I plan on redesigning the Kato frame to make it thinner to fit a Bachmann shell and coreless motor. I plan on first recreating the frames in CAD, then start to make changes to a duplicate file. 3D print in plastic to see if everything goes together and when good, get it 3D printed in metal. Take it slow and have some good calipers, if you can get the base frame made, you can start to modify it. To modify the x-8-x frame to a x-10-x frame, I'd personally design the first axle slot, and then use a linear repeat function to duplicate the number of axles that I want, that way it's faster, more accurate, and easier to change/fix.

Sounds like you are on the same path as I am!  I have two main goals - 1) to make a 5th driver slot, and 2) make the motor cavity wider to accommodate 10mm coreless motors or other 10 mm width motors.  I am also thinking it might be neat to have the option to have the 5th driver gear powered by another idler gear.  That way, you could choose to either have the 5th driver gear-powered, or powered by the siderods.

PM me if you would like to collaborate on this project.  I have a bunch of Mikado frames in my parts box for reference. 

[chessie system fan]

Along similar lines, I've thought about turning a Bachmann 2-8-0 into a 2-10-0 or 2-8-2.  I've gotten this far with the design.



I'd try reproducing my spare Kato 2-8-2 mechanism too but I'm not skilled enough with steam to be confident I could put it back together again.   

[peteski]

Along similar lines, I've thought about turning a Bachmann 2-8-0 into a 2-10-0 or 2-8-2.  I've gotten this far with the design.

I'd try reproducing my spare Kato 2-8-2 mechanism too but I'm not skilled enough with steam to be confident I could put it back together again.   

You haven't picked up those skills from your father?     Joking of course.
But on a serious note, if you don't live too far from Ron, I suspect he could assist you in the reassembly (or reassemble the loco himself).

Actually IMO, this is one of the easiest locos to reassemble as no fussing with siderods is required.  All you have to worry about is that the gear driven wheelsets have their counterweights lined up.

[chessie system fan]

As a preteen ~20 years ago the only diesel that gave me trouble was a first run Kato F3 truck with those funky pickups.  I think that was the first and last time I've ever needed to ask for help. 

A Kato mike might be the one loco he's never disassembled? 

My main worry is damaging the siderod linkage in the process.  Since I haven't needed to disassemble mine yet I haven't risked it.  I'm sure I'll get around to it one day.

[pjm20]

Along similar lines, I've thought about turning a Bachmann 2-8-0 into a 2-10-0 or 2-8-2.  I've gotten this far with the design.

Looking good, I had the 2-8-0 chassis in mind as well to modify, and it looks like you have a great start! It will be a great way to get lower drivered 2-8-2s and 2-10-0s.

[Lemosteam]

Speaking as someone who has tried metal printing, tolerances and size requirements are too large to handle the needs that a chassis would require (right @peteski ?)

I have multiple iterations of the Kato Mike chassis for 5 and 6 axle configuration nearly complete already using the original Kato motor, but they could easily be revised to a different one.

Also to consider is chassis balance, extending one end or the other could unsettle the Mike balance.

I think @draskouasshat has already tried this with a brass caster without success.

[mike_lawyer]

Speaking as someone who has tried metal printing, tolerances and size requirements are too large to handle the needs that a chassis would require (right @peteski ?)

I have multiple iterations of the Kato Mike chassis for 5 and 6 axle configuration nearly complete already using the original Kato motor, but they could easily be revised to a different one.

Also to consider is chassis balance, extending one end or the other could unsettle the Mike balance.

I think @draskouasshat has already tried this with a brass caster without success.

Do you mean that you have CAD drawings of a Kato Mikado with 5 and 6 axles, or that you have modified an existing Mikado chassis for those additional drivers?  The extra driver slot is the most important thing for me, I can always use a Dremel to ream out the motor cavity to make it larger.

I have tried using styrene blocks to make a 5th driver slot on an existing chassis, and it is extremely difficult to get everything working properly such that there is smooth rotation of the drivers at slow spend, and lack of bobbing up and down with the 5th driver.

[Lemosteam]

Do you mean that you have CAD drawings of a Kato Mikado with 5 and 6 axles, or that you have modified an existing Mikado chassis for those additional drivers?  The extra driver slot is the most important thing for me, I can always use a Dremel to ream out the motor cavity to make it larger.

I have tried using styrene blocks to make a 5th driver slot on an existing chassis, and it is extremely difficult to get everything working properly such that there is smooth rotation of the drivers at slow spend, and lack of bobbing up and down with the 5th driver.

CAD, but it is nowhere near complete.  Its not just the driver slots. the pins inside that the idlers rotate on must be accurately sized AND positioned relative to the driver slots, to ensure proper gear mesh.

If you are referring to grafting a printed piece onto the end of a cutoff chassis, then that MIGHT work

[draskouasshat]

Mike, you're going to have to keep practicing building better mechanisms until someone comes out with a proper one with 63" drivers. The shrinkage rate of brass made it a not worthwhile venture.
You can great on a cast resin portion of a copied Mikado frame. That does work fairly well so you can stretch forward.

Drasko

[tehachapifan]

I fussed with a 3D software program once for hours on end. Only managed to draw a cylinder. Most un-intuitive program I ever saw!

[mike_lawyer]

Mike, you're going to have to keep practicing building better mechanisms until someone comes out with a proper one with 63" drivers. The shrinkage rate of brass made it a not worthwhile venture.
You can great on a cast resin portion of a copied Mikado frame. That does work fairly well so you can stretch forward.

Drasko

Do mean kind of like splicing two Mikado frames together to add a 5th driver?  I have thought about trying that out, but haven't worked up the courage to try it. 

Mike

[draskouasshat]

Do mean kind of like splicing two Mikado frames together to add a 5th driver?  I have thought about trying that out, but haven't worked up the courage to try it. 

Mike

Yup. That's the way i do it anymore. It's easier for boiler fitment.

[mike_lawyer]

Yup. That's the way i do it anymore. It's easier for boiler fitment.

I have a bunch of spare frames around that I could use.  Do you have a template you use to cut the frames for splicing?  That would be really helpful.  I have looked at the Mikado frame a bunch of times, but I haven't figured out a good cut guide.  Any help there would be appreciated.

Mike

[peteski]

Speaking as someone who has tried metal printing, tolerances and size requirements are too large to handle the needs that a chassis would require (right @peteski ?)

You are not lying.

[narrowminded]

I have a bunch of spare frames around that I could use.  Do you have a template you use to cut the frames for splicing?  That would be really helpful.  I have looked at the Mikado frame a bunch of times, but I haven't figured out a good cut guide.  Any help there would be appreciated.

Mike

In a mill it could probably be cut and then each end faced and pinned to set the axle centerlines perfectly.  Maybe even be done by machining to insert an axle set in one of the center positions if there was a benefit to maintaining the chassis end features.  But what about the rest of the components?  Drive rods, valve linkage, etc.