1/14 CAT 390D LME

[Jw.]

Hi Guys, I have recently Started building an all aluminum 1/14 scale 390D LME. Progress will be slow as I am making everything on a manual mill and lathe and this will be the first time I have ever used a mill or lathe. -Jeff




Prototype for the track pads. Still needs some work.



Drive line parts so far.

Roller cut from 7/8 rod. Still need to cut 17 more.


Was going to make the drive hub 1 piece but I could not find anyway to turn a 3inch dia. rod with my micro lathe. Seems all the chucks only hold 2.4 inchs or so. Anyway I will be makeing it out of three pieces.

[Jw.]

Undercarriage so far.

[dabears]

Wow looks like a great start so far! You'll be a master at the mill and lathe by the time your done with with build. Keep up the great work

[Hemi1966]

Nice to see someone building 390. When I started building CAT 374 my other choice was 390, but It's so big in 1:14 scale that I end up doing slightly smaller 374.

[Madda]

I started designing 390 just few weeks ago. It will be interesting to see what you come up to and also get some ideas from you. Are you using any CAD system for help? What mill/lathe do you have?

Post some pics of machining next time too!

Good luck!

[rc_farmer]

Another nice bucket build to follow, keep up the good work!

[Jw.]

Thanks guys.

Originally Posted by Hemi1966

Nice to see someone building 390. When I started building CAT 374 my other choice was 390, but It's so big in 1:14 scale that I end up doing slightly smaller 374.

My first choice was going to be the 374 but just before I was going to start my plans CCM just released their 1/50 390D LME model so I went with that instead.

Originally Posted by Madda

I started designing 390 just few weeks ago. It will be interesting to see what you come up to and also get some ideas from you. Are you using any CAD system for help? What mill/lathe do you have?

Post some pics of machining next time too!

Good luck!

No cad just good old handwritten blueprints and all the dimensions I am taking from the CCM 390D LME. Which not everything is perfectly scale on the model. For example the bottom roller I machined already. Turns out is not wide enough for the tracks on the model. I'm using a Taig mill and a micromark micro lathe 6X10. I'll be sure to post some machining pics later. I plan on making everything myself as much as I can. Hydraulics and all.

Originally Posted by rc_farmer

Another nice bucket build to follow, keep up the good work!

Indeed I hope to make myself a nice ME bucket like Ari's 374D. Can't promise it will be as nice as his though.

[Jw.]

Start of the bolt pattern. First time using a rotary table. Didn't know till half way through I was .010 off center. Its barely noticeable. I'm not liking this latest version of photobucket at all.

[Jw.]

Second bolt pattern. Now this one I was dead on for sure this time and it came out perfect.



44 holes drilled and tapped. Plus 24 teeth cut. I will eventually switch the screws over to hex head but for now cheap socket head screws will do.

[Jw.]

First attempt at making a 2 piece mold for the track pad and link bolted together out of a plaster cast. Since I don't have a cnc machine.

I was not sure if it was going to work and it didn't. It failed and cracked. The plaster it still slightly pliable after it sets(30 minutes or so) so I thought I might be able to slide it out ok. Even if I had added more water to soften it even more. The undercut on the track pad still would have deformed the mold. It was just a test anyway to see how the whole process goes.

The search is on for other methods. I'm considering lost wax, lost foam, or prototype metal mold casting. I will find a way to get this done. 102 track pads to go.






On the left side mold. On the bottom of the track pad is where the undercut is. That's where it cracked on me. Also I forgot to make a sprue or vent holes.

[Dieselholic]

Wow that final looks great! Can't wait to see the rest of it

[Madda]

Dude, you used mill for the first time and made that nice sprocket? You are a serious talent!

From where do you get your tips on how to mill?


Keep it up, seems very promising

[kerst]

Great project! It is going to be really interesting, especially the casting part.

Kerst

[grumpygrady]

i have a few links about making sand molds to do what you need ,let me know if you want them ,
but the best way is doing lost wax and using a wax tree and casting thirty or more at one time in a investment mold ,
and by the way plaster of paris will cause a exploration of hot metal because you can't bake all of the water out of it .

[Jw.]

Originally Posted by Madda

Dude, you used mill for the first time and made that nice sprocket? You are a serious talent!

From where do you get your tips on how to mill?


Keep it up, seems very promising

Thanks Madda. It took me forever trying to get that thing done. Lots of head scratching and late nights watching you tube on machining. There's machining videos on there for everything it seems. That and trial and error got me through. I'll probably cast it like my tracks to make a second piece.

Originally Posted by kerst

Great project! It is going to be really interesting, especially the casting part.

Kerst

Thanks Kerst. Casting has been quite difficult but I think I might have figured it out.

[Jw.]

Originally Posted by grumpygrady

i have a few links about making sand molds to do what you need ,let me know if you want them ,
but the best way is doing lost wax and using a wax tree and casting thirty or more at one time in a investment mold ,
and by the way plaster of paris will cause a exploration of hot metal because you can't bake all of the water out of it .

I would appreciate those links very much I sorta skipped over sand molds because I thought the undercut on the track pad would be impossible to mold. I've looked into the lost wax and everyone says its an expensive process with all the equipment needed. I only thought about taking that route as a last resort if all other methods failed. We'll see if it ends up that way. As far as plaster of paris, I didn't know about the water issue. Is there any way around it? I was going to fire it in my kiln to dry it. I would think 1832 degrees Fahrenheit would be enough to dry it completely. I haven't found a lot of info on casting metal into ceramics and what Ive found. The info on the slurry mixture they used for plaster is always different or not very in depth.

[Jw.]

My first negative silicone mold attempt that I'll use to make a positive silicone. Them I'll use it to make my negative plaster mold. In the final third picture, the mold came out quite well except for a few bubbles around the bolts. This was a result from most likely not vacuum degassing the silicone before I poured. I would have except I have yet to make a vacuum chamber and get myself a pump. Those are on the list next.

[Jw.]

Second attempt was a failure again but I'm getting closer. Air bubbles all over and it cracked.



Third plaster mold attempt. Once again there were a few tiny bubbles in the silicone that can be seen as imperfections on the edge of the track pad.



Third time worked. Almost. Although it did not crack on me I still have a few air bubbles. Again I'm sure I can easily take care of those once I get my vacuum chamber built.

[Lil Giants]

So the plaster castings might be good for how many liquid metal pours? And what type of metal will you be using?

[Jw.]

Originally Posted by Lil Giants

So the plaster castings might be good for how many liquid metal pours? And what type of metal will you be using?

10 to 15 pours per mold I am guessing. I was going to use aluminum A356 but I'm concerned about durability so I will be using Zinc Alloy 27. It is stronger and has a tensile strength of cast iron.