# Roller bearing trucks



## Burl (Jan 2, 2008)

In another thread, I had some trucks 3d printed in nylon. They needed a few tweaks, and at the time, I thought I could offer them for sale through Shapeways. Unfortunately, Shapeways has continued to jack up their prices to where I wasn't happy with what I was getting. So I decided to go a different route.

I had some side frames printed in high-res acrylic, with the intent of making a rubber mold & casting resin copies. The brown set in the photo is the master. I also felt I could get better detail in the bearing caps this way too.










The bolsters will still be printed in nylon, as these are too complex to cast. The outter (visible) springs will also be 3d printed in nylon. My experimentation taught me that nylon springs just aren't strong enough, but they are scale diameter. I played around with using wire springs behind them and found a combination that should give me truly working sprung trucks.










At this point, I want to copy-cast the side frame three more times so I can make a mold that will give me one set of trucks in one pour of resin.


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## Scott (Jan 29, 2008)

Awesome work mate. Would love to see the finished result.


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## Burl (Jan 2, 2008)

Here's an almost-ready-for-paint shot. I haven't put the springs in yet either.

What I have learned so far: 

1) drilling out the resin bearing caps is too tricky. I think I will have them printed in acrylic and save myself the headache.

2) Cost: even with me casting the side frames, there's still $80 worth of parts in one set of trucks. $42 of that is wheels & bearings. I'm questioning whether there would be any interest in making this a for-sale item or not.


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## Scott (Jan 29, 2008)

Mate, being in the same boat as you I fully understand and appreciate your quandary. Even if you sell to a small niche market - a lot of people will support you and look for your work. 

Not only designing journals / axle sets but also scale wheels no-one else has on offer. (sigh)

People like us are the next generation of influence within the industry. While some of the manufacturers may not be beating down the door and offer us jobs and cash. Its what we do that inspires others plus gives us the drive to continue to raise the bar.


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## David Leech (Dec 9, 2008)

Burl,
I assume that these are 1/29 scale, are they?
Also, by 'one set of trucks', are you talking two trucks?
Regards,
David Leech, Delta, Canada


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## Burl (Jan 2, 2008)

David: yes, they are 1:29, and I meant a pair.


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## Burl (Jan 2, 2008)

I really wanted to wait till the light was better outside, but its been cloudy for 3 or 4 days & I'm going stir crazy. These were shot inside. I will try to get some better photos next week.


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## Greg Elmassian (Jan 3, 2008)

You can photoshop to bring out the detail... I did that and they look nice.

What is the bearing for the axles? It appears that it is the large end caps for the axles, which I don't think will work.

Greg


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## Paul Burch (Jan 2, 2008)

Burl,
The Aristo rollerbearing trucks with metal wheels have been averaging about $45.00 a pair on Ebay if that is any help to you. As of late they seem to be listed less and less.


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## Burl (Jan 2, 2008)

Greg: I'm not sure what you're asking? The bearing is a flanged 1/8" x 5/16" ball bearing.


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## bnsfconductor (Jan 3, 2008)

The openness of the springs really seals the deal for me. That looks like a real truck, but I think I need to Bad Order it because the brakeshoe looks like it has too much travel..  BTW that's a compliment! When you do an Initial Terminal Test, you have to measure the brake piston travel, and ensure that there is 'sufficient' brake shoe.
Are the wheels semi-scale wheels? The flange doesn't look chunky and thick like normal.


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## Burl (Jan 2, 2008)

Here's a shot of the inside of the side frame:


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## Burl (Jan 2, 2008)

I was a little generous on the brake shoe placement because I didn't know how much space I needed to allow for the truck flexing. 

The wheels are from Gary Raymond. I don't recall him referring to them as semi-scale. The model number is A 33 BL (33" in 1:29).


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## Greg Elmassian (Jan 3, 2008)

Thanks Burl! I shoulda known it would be top quality, as well as great looking.

Greg


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## bnsfconductor (Jan 3, 2008)

Burl said:


> I was a little generous on the brake shoe placement because I didn't know how much space I needed to allow for the truck flexing.
> 
> The wheels are from Gary Raymond. I don't recall him referring to them as semi-scale. The model number is A 33 BL (33" in 1:29).


Looks a lot better than commercial models....


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## David Leech (Dec 9, 2008)

Assuming that the bearings are fixed in the side frames, and that the axle is a good tight fit in those bearings, does it still allow the trucks to 'flex'?
I have thought about using bearings, but I always wonder if it makes things too rigid.
Regards,
David Leech, Delta, Canada


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## Burl (Jan 2, 2008)

David: I tried 3mm ID bearings first, thinking they'd fit the axle tightly. Some did & some were too tight. The axles are 3mm, but I guess I was asking too much of the tolerances. So instead of a tight fit, I went up to 1/8" ID - which is about 0.007" larger than the axle diameter. That let them roll free while flexed, plus 1/8" x 5/16" is a more common size for bearings, so they are cheaper.

I guess Aristo did the same thing, since theirs seem to have a little play in them too.


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## SD90WLMT (Feb 16, 2010)

Aah, but judging by all the brass bushings I have been playing with on Heavy Weight cars...they made a rather large gap between the axle diameter and the busing diameter...somewhere around 0.035" larger in diameter...

Rather loose to me...I have given serious thoughts on having replacement bushings made with a bit less tolerance slop...

I have seen axle "vibrating" from this looseness....just being hand pushed on track ..I tell ya..I did not figure it out guickly either....

The bushings seem to be a match to those in the roller bearing trucks on hoppers n box cars also!

Dirk


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## Burl (Jan 2, 2008)

The sun popped out today just long enough to get some good close-up photos:




























And the "builder's photos":


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## ewarhol (Mar 3, 2014)

Very Nice. I'm in need of changing some arch bar style trucks for roller bearing, when can we expect these?


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## Burl (Jan 2, 2008)

Gary is currently out of the wheels I need for these, but says they are next up in production. I'm waiting on him to get back to me.


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## CliffyJ (Apr 29, 2009)

Beautiful work, Burl, as always!


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## Burl (Jan 2, 2008)

Today I tried dying some bolsters I had printed. I figured it was worth a try, since Shapeways charges a dollar a part to dye them for you. For my first attempt, I used two ounces of brown Rit dye, and one ounce of black Rit dye. In retrospect, I probably should have left the black out all together. If you think your eye are playing tricks with you, they are not. They came out.... dark blue!


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## CliffyJ (Apr 29, 2009)

Great idea Burl. As always, great design and execution. And I'm sure you'll get the colors right, one way or the other.

I've lately learned the hard way not to get the colored stuff from SW. I'd thought they used colored nylon powder, but like you say, it's just a post-processed dye application. The problem for me was that with the extra handling steps, small pieces kept getting lost. (Now I see why you sprue your pieces together which, after the per-part price hikes, I now do as well).

Further, they have to batch them with like-colored parts, which adds time to accumulate to make it worth it on their end. It took about 6 weeks to get all the black parts for my flanger! But they made good, with a deep discount. So I can't complain really.

Still, now I'll just be using just white, and spraying. Well, maybe dying, if you come up with better results. Thanks very much for posting. I'll be interested in which dye (yours or theirs) holds up better.

Cliff


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## Burl (Jan 2, 2008)

Another advantage to attaching all your parts together is that they'll all be printed with the same orientation. I didn't do that with my bolsters, but it doesn't bother me because its not such a stand-out part. I did have some side frames come back one time with very visible scan lines on one, and not on the other. After that, I decided to have one printed in acrylic and use it as a master.

I'm OK with the blue. I'm just trying to save myself some time because these will get spray painted brown, and anything other than white is preferable.


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## CliffyJ (Apr 29, 2009)

Yep, I've seen that phenomenon quite a bit. Had 108 seats printed for a theater model. Half were smooth and half were textured, like wood grain. Haven't tried acrylic, interesting...

So you cast those bolsters? In one piece? Using, what, a glove mold approach?


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## Burl (Jan 2, 2008)

No, I cast the side frames. Bolsters are still printed in nylon. Sorry, didn't mean to be confusing.


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## CliffyJ (Apr 29, 2009)

OK, I get it now, thanks Burl.


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## xtcbct (Jul 15, 2008)

Wow, these look great, are these going to be available pre-assembled? Wheels and all? You've got a product here, I think the demand is there in the G Scale community!


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## Burl (Jan 2, 2008)

Yes, they will be pre-assembled, for a couple reasons. I think I can wind my own springs out of music wire, which (surprisingly) saves quite a bit of money. Also, the springs are tricky to install if you have never done it before. If I lose one, no big deal. If you lose one, then its a hassle. 

I had considered offering them as a kit, which would be immediately cheaper for the customer, but then you're buying your own wheels, bearings & springs. 

Unfortunately, I'm hung up waiting on wheels right now...


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## rntfrmme (May 23, 2013)

Great work with lots of detail. Good luck


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