SP NG Diesel #1 (GE 50T) - Triennial or Bust

[senorgilamonster]

Today I did some cleanup on one of the sideframes and 2 of the equalizer bars. Not finished, but definitely better looking. With that done, I was able to cut and test the base plate for the springs. It is longer than the width of 3 springs (I only plan on 2, but gives me the ability to add another if I need to) + a little extra on each end. It is also longer than the slot that goes through the equalizer bar, so it acts as a spacer to prevent the bars from squeezing together on the springs.

It passes through the bars with a little to spare as well. The plan is to put a groove in the base for the bar to rest in thus keeping the assembly secured under the pressure of the springs. I have outlined the spring base in yellow: Sideframe not in place for visibility

I will bore a shallow hole in the base plate for each spring to set into...alternatively I could put a short nylon shaft to keep the spring from shifting. In any event, the spring bottoms simply cannot fall out due to the dimensions of the openings once the sideframe is in place...but I've seem too many missing springs in my short time in the hobby, not to put some sort of mechanism in place.

As far as the axles...I decided that the axles aren't too long - my tool is too short. I am going to get a replacement bed for the lathe thus making a 16" and add a steady rest...that should solve that problem.

[rkcarguy]

I would put a piece of paper as a "shim" in there between the bearing blocks and the bushing, then fill that bushing/side plate hollow with PC7.
Most important, I notice your bushing notch is not centered. When you epoxy these to the side plates, you'll need to shim the side plate on a flat table, or use something so your bushings are in the same plane, if that makes sense, or your aluminum bearing blocks will not be aligned to each other.

[senorgilamonster]

Thanks for the input.

Today I drilled out the rest of the pillow blocks. Then I decided to test the planned width between the truck's sideframes to see if I messed up my calculations. I cut a few scraps of wood to hold the sideframes in place. Everything measured out correctly - AND there is sufficient room for me to mount a motor on each axle, fit them inside of all of the frame pieces, and still get them in underneath the floor of the deck/floor of the locomotive.

This test also allowed me to discover that my spring floor plate design had a bug in it. That is why the plate is not in place in the test pics below. I'll have to give some though on how to fix it.

BTW - how do you all recommend opening out the holes in the pillow blocks for the bearings? Bearing OD is 1.36".

[rkcarguy]

That's great everything fits, it looks good coming together.
So are you going to be splitting or clamping the bearings in any way, or just press fit into the blocks?
Either way, it needs to be fairly accurate and I'm not sure what you've got for equipment aside from your lathe. I'd probably toss a big drill in the mill and then finish bore the blocks to size.

[senorgilamonster]

I was thinking of pressing ball bearings into the blocks. I like the surface mount pillow blocks a lot, but don't have the clearance unless I spread the sideframes out a lot.

I am upgrading the lathe...sold my mini mill because I could never get the work secured enough to get decent results. I've seen a post doing it on the lathe with a 4 jaw chuck and then boring. I don't have a 4 jaw, and have never bored anything (other than people I talk to). I could possibly access a mill, but the skill problem still remains.

see May 22nd post here: https://www.largescalecentral.com/forum ... wer?page=2

[rkcarguy]

Boring is pretty easy, and on a mill you could set up a stop on a vice and drill/bore one block after another. I'd prefer that over spending a bunch of time dialing in each block on a 4-jaw chuck.
I'd say 1-1/4" bit, then bore to your 1.36", or whatever you need for a couple thousandths press fit.
What's the dimensions on your blocks?

[Pontiacguy1]

Don't press your bearings into the journal box. Press them on the axle, or loctite them, and then allow the OD of the bearings to float some inside of your journal box. Don't allow the axle to float through or run loose in the bearing inner ring. That should be fixed to the revolving member, in this case your axle.

[rkcarguy]

I'm wondering, could he use some large O-rings on the outside of the bearings, and split/clamp the blocks so they grab them? It would still allow movement plus the "squish" of the o-ring wouldn't require such tight tolerances on the bores.

[Pontiacguy1]

Seems to me like that would make it even more complicated than it needs to be. Single row radial ball bearings have some amount of radial play in them, and will be able to take some amount of misalignment on their own. Make the bore of your axle box a little bit larger than the OD of the bearing, say 0.020" or 0.030", and you will have more than enough to be able to take up any misalignment that you would encounter. The bearings can also slide sideways some in your axle boxes for things like going through switches and such. You'll want the axle boxes to be able to shift sideways about 1/16" or so, to help with going through switches, diamonds, etc...

We used to make a bearing that was pressed into a rubber outer ring. This was used on fan shafts and stuff like that, and was only used for damping purposes, to keep vibration of the unit down.

[senorgilamonster]

Dimension of the blocks is 2" x 2" x 1.5". The largest, reasonably priced drill bit I have seen is 1". I agree 1 1/4" would means less work.

I'll press onto the axle, but I am curious as to why it makes a difference. I've seen recommendations for both ways online and I am one of those guys who likes to understand the reasons behind things. - you answered the question of how much wider to bore the hole, so thanks.

First, I discovered a way to make the pillow blocks with only a drill press. I would consider this a contingency at this point, but if I had discovered it at the beginning, I might have gone this route: Drill the correct diameter hole in 1/4" aluminum bar stock. Cut 2 of those for a 1/2" thick bearing. Just make the remaining layers blank and cut to size. Add layers to the desired thickness. On the layers where you need slots milled on the edges, just make that layer narrower. Align all of the layers and drill. Assemble with nuts and bolts or bolts and threaded plate(s). clean up the edges, etc.

Having said that, I will be using the lathe. I worked on a scrap piece to make sure that I had figured out a way that I could bore the blocks. I used a hole saw with a 2" ID to cut a 1/4" slot in the outer face of the block (I want to finish this side with a dome cover anyway). I cut back the remnants of the corners. This left me with a round surface that I could get into my 3 jaw chuck. Then I ran the pilot hole followed by a 1/2" drill. Then used a carbide boring tool to widen the hole out to .6. I did not bother to face the block since it was a test on scrap anyway. The scrap block had a wider "shaft" on that end, so I did go ahead and turned it a bit. The result was a nicely bored hole with a concentric outer dia too. I was rather pleased with myself.

The only thing is that the bored hole seems to have a slight bevel to it internally.

In the end, I have decided to go ahead and buy a 4" 4 jaw chuck. Centering in the 4 jaw will take way less time than I spent doing it the way that I did, and the cost of (probably) multiple hole saws is lost, so why not put that money against the chuck. (worst case scenario could be $100 in throw away tooling vs a $150 chuck.

Since I realized that I was going to disassemble my lathe next week (for the longer bed), I went ahead and ordered a 2 axis DRO kit for it as well. That means (not counting the chuck) that I am adding $350 in upgrades to my Harbor Freight lathe. In the end that probably means that I could/should have bought a better lathe to start with. I just thought that I should acknowledge that before it gets pointed out multiple times.

Finally,the reward if you have made it this far: MORON ALERT - Back on page 7 I groused about how long it took me to get an axle trued up in the lathe and how much difficulty that I had facing it. I had the wrong set of jaws on the chuck! I was trying to hold the outside with the inside jaws. Jeez. I am almost too embarrassed to admit it publicly.

[rkcarguy]

I have a couple tricks up my sleeve for large holes in aluminum, just for future reference. Grizzly tools offers these:

http://www.grizzly.com/products/Forstne ... CaEALw_wcB

I used lots of lubricant and a slow RPM along with heavy "feed" pressure and was able to make several large holes in aluminum plate. A caveat is you need some HP to turn one of these in aluminum, I had to be careful not to stall out my 1HP drill press when I stepped up to a 1-7/8" bit.

As for the tapered hole, maybe the cross slide is moving when you are boring, or the boring bar is deflecting?
I looked at and moved the carriage and cross slide on a display model harbor freight lathe, and after running all the lathes I've experienced in my machinist days I just couldn't pay money for one of those things.

[Harold_V]

The only thing is that the bored hole seems to have a slight bevel to it internally.

That's not all that uncommon. Two things to address.
First one---make sure the bar is NOT touching the bore anywhere but the tip. In small diameter holes, it's not uncommon for the bar to make contact behind the tip, so it floats on the bore created. By examining the bar after taking a cut, you should be able to see signs of contact, as there's usually traces of aluminum that has galled on the bar.

Make sure the tool is quite sharp. If you are using a carbide boring bar that has not been further sharpened, pretty good chance it's not sharp enough, or it may even have a damaged tip. A diamond wheel provides the best possible fix, although you may achieve success by hand honing with a diamond hone. Pay particular attention to the amount of relief, as small bores demand a huge amount of relief.

Assuming a sharp bar, it may be necessary to rotate the bar slightly, to achieve the needed relief. There's no reason for a bar to bore a tapered hole unless it's dragging. Movement of the part (a slide moving) won't cause taper. It will cause a mislocated bore, however, and you'd see evidence of that when the bar was retracted.

H