The Home Machinist!

Looks like this is about the best it's going to get fitting the bearings I want to use.
Will laser cut from 3/8" plate, maybe step up to 1/2" for HD versions.
Glenn, your messages must be full, my reply to yours is just sitting in my outbox.

RK,

This forum software is a bit odd. Outgoing Messages will stay in your outbox until the recipient logs in next. Then they are downloaded to the recepient. They don’t go out automatically, but they do go out, assuming the forum member continues to log in.

Gpb

Ryan,

Found a few pics of Bettendorf freight trucks on line. Also, roamed around a bit in my photo archive and found a couple of photos of my existing Ottaway trucks. They are very basic, crudely constructed actually, but they work. Also, just to round out the options, I found a couple of prototype truck photos I gathered over the years.

So here’s a range of option for the side frames.

First up, Mike Hawkins, at C&H Railroad, is making and selling replacement Ottaway frames (12” ga). Not sure of price, but will ask him when he calls this week. Appears he is using the same 4 bolt bearings you are thinking about. Here is a link to his side frames. Nearly identical concept to your CAD drawing, near as I can tell.

https://www.google.com/search?q=ottaway ... Oq0mwBRjrM:


Next up, a link to some Tom Bee Trucks in 7.5” gauge. tom Bee has a very good reputation in the hobby. They work very well- long service life, low maintenance, high quality.

For 12” gauge, as an option for your design, one could weld short lengths of round stock horizontally to the ends of the frames, then bore out to accept axle bearings and races. This is basically how the Ottaway trucks are constructed. Except the bearing cap appears to be a casting, welded to the outside of the side frame.
The link below has a nice video showing how Tom Bee’s trucks are designed and assembled.

http://www.islandpondrailroad.com/tombe ... t_spec.htm

Next up, prototype Bettendorf freight car side frames. Note the thickness of the frame between the bearing assembly and the bolster cut out - might be worth adding a little meat in this area in your CAD drawing.
1907 Great Northern Pullman trucks- pedestal style, still in service on the Napa Valley Wine Train
Finally, cheesy original Ottaway flame cut side frames, mounted on my tender. Un-sprung. They do work...surprisingly.
And, another Ottaway tender. Better end view. I’ll need to look at my trucks more closely, tomorrow. They appear to be rigid construction, with the bolster welded to the side frames. There must be a lot of play in the bearing caps to stay on the track.

Glenn Brooks wrote:RK,

This forum software is a bit odd. Outgoing Messages will stay in your outbox until the recipient logs in next. Then they are downloaded to the recepient. They don’t go out automatically, but they do go out, assuming the forum member continues to log in.

Gpb

That's not how it works. A PM remains in one's Outbox until it is OPENED by the recipient, at which time it then appears in the Sent box. The recipient may log in numerous times between the time it is sent and not cause it to move to the Sent box. By having it function this way, the sender knows that it has been received and (hopefully) read.

H

Thanks for the pictures Glenn.
I think I will add some meat to the top of the arch's like you recommended, maybe use 1/4 of an elipse to get the right shape, and call it good. I did find some self aligning bearings in a stamped 2 bolt sheet metal housing that I could recess into the truck side and cover with a bearing box, but I'm not really impressed with them as they were far less load capable and twice the cost.
I'm set on bearings because as small as our wheels are in this hobby, the axle RPM at 8mph is about the same speed as a car going 40-45 mph.
There are many laser cutting places around anymore, I don't doubt the C&H guy can offer a competitive price on his side frames, but it's the additional shipping that is going to hurt. Also, because I have access to CAD, it lowers the price greatly because the processor can simply import my drawings and go. In the past when we didn't have CAD, the laser cutter had to draw my sketch into CAD and send it back to me to approve @ $40/hr.

Ryan

Here’s a couple photos of my drop flat car trucks. Looks like the bearings are a pretty big at 2 inches width and they work pretty well on the frame. So maybe your adjustable bearings will be just fine. Not look disproportional.

Also measured width of frames on the ottaway trucks at 3/8” and they also work very well at that width.

Glenn

I'd say we are all good then:) Those are basically the same thing I'm using, I'd bet that those are self-aligning, but have permanently set in rust so they probably won't move much anymore.
I added some meat to the top of the arches and sent the drawing file off for pricing, we'll see what they come back as.
What kind of flange width you got there Glenn?
IBLS specs for 15" gage have a max of .350", with a .515" gap between the rail and the check rails, which I am using for my 12" gage as none are given. Figure a little extra flange can't hurt as long as my radius aren't too tight and I space the check rails properly.

Something I may look into...a ways down the road, is having some caps CNC lathed that will fit over the end of the axles and collar on the flanged bearings, simulating an "updated" roller style bearing cap. This could be well greased and would keep the rust at bay.

If they are in a housing like that, then they are typically self-aligning bearings. Only a few types have straight bores and are retained with snap rings.
For those who may not know, the bearing has a spherical OD, and the same OD is machined into the iron housing. FYI, they are not intended to move like that on a regular basis, and may be very stiff, especially when new. They are made this way so that any mis-alignment between the shaft and the mounting surface, when they are installed, will not result in any broken parts or excessive loads and wear on the bearings themselves.

If you get some bearings and they feel too stiff to flex in the housing like you want them to, then you can run the bearings out, and take a thousandth or two out of the bearing seating surface in the housing with a flap-wheel. Be sure to put the bearings back in the same way or your grease hole (in the bearing OD) will not align with the grease groove in the housing.

You're right, some of them are pretty stiff. I don't think it's an issue on the locomotive as it will have a constant weight, but I may loosen up the bores in the riding car and the bulkhead flat cars so they track better when empty.

Here is the revised drawing with more meat around the top, I also increased the radius's at the triangular openings.

I think this is the pattern I want to go with. I added some meat to the top, increased the fillets, and angled the ends.