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Saturday, May 27, 2017

Now available: 3D printed Scale-Craft truck bolsters

If you have worked with any Scale-Craft trucks you know that a percentage of the Bakelite bolsters have shrunk and warped. In this condition, they are not usable, the trucks won’t roll. I have at this point a lot of these, saved in a box in hope that someday I could use the pins in new bolsters. My experiments were not real fruitful. 

But now, thanks to Jeffs OO (Jeff Barker) on Shapeways, we now have excellent new bolsters to use to replace the bad ones. They are listed here, I used the version “3D printed in Black Strong & Flexible: Black nylon plastic with a matte finish and slight grainy feel.” They come affordably priced in groups of 16.

The first photo gives an overview of the product. As always, click on the photo for a better view. In the middle is a fresh and unused S-C bolster in shiny Bakelite, unusable actually as there is no practical way to put pins in it (maybe S-C pushed them in place with heat?). The other bolsters seen are all the new 3D printed ones, which have the slightly rough finish. They are black and don’t require painting, but the inside material is still white, so the cuts at the sprue locations will be visible (but not very).

Building them up is simple. After cutting them off the sprues the first step is to drill out the holes. The pin holes you need to drill out with a number 50 drill (keeping a #51 drill handy too, you need it to touch up the axle holes in the sideframes). Next you need pins. Depending on the old bolster these will be easy or not so easy to harvest, but all you have to do really is use pliers and break them out of the Bakelite, which if you are lucky (see UPDATE) will eventually shatter and crumble. I did this over a small bowl to catch the parts and waste. Eye protection being a good idea, too.

This second photo gives a little more detail. The bolster as produced matches the S-C bolsters in size exactly. However, in a lot of situations a bolster that is a little longer is handy. As a result, most of these that I have built up I have put a small washer on with the pin to extend the width of the bolster. It is actually a washer that S-C provided in their kits, I have quite a few around. Thin plastic stock would work as well.

The pin itself you press into place with large pliers. Try not to put them on too far! They are really hard to pull out, but clearly are not going anywhere. Placed correctly the sideframes will be held in place very squarely.

I have been able to build a number of trucks up fairly quickly. These bolsters will really solve some problems. One type of truck in particular, S-C 4-wheel passenger trucks, they need very long and very square bolsters to roll well, and these will certainly help these cars out. They will help out any S-C truck! I am very pleased with every truck I have rebuilt so far.

You could use screws to make the pins too, but really, I think recycling the vintage pins is the way to go.

One other thing worth noting, in a lot of situations with non-S-C cars you need to use a screw bigger than fits in the hole in a S-C bolster. Back in the day people drilled them out, but I hate to try to modify them at this point (for fear of breakage), so this was a big issue. With these new bolsters, drilling the screw hole bigger is not a problem at all, you can use a very large screw if needed and even countersink the head. The material itself drills very easily and is strong.

In short, this product is great and was hugely needed. Trucks rebuilt with these bolsters should roll well for years and years; I plan to buy quite a few more, as I have plenty of all the other parts needed for trucks.

UPDATE: A couple quick items. First, with S-C 6 wheel passenger trucks you don't normally need the spacers I add to most freight trucks. It is worth checking your sideframes to see what you need in relation to the wheels you are using (they vary by production runs) and how deep the holes are for the axles.

The bigger update is about harvesting the needed pins from old bolsters. At first it went pretty fast, as for some bolsters the Bakelite will shatter easily. After the easy ones were done it got ... harder. Basically, the Bakelite is not all the same after all the years (perhaps produced in different batches), and many bolsters when you get to it won't break at all! I have to put them in a bench vise and crush from a couple angles, and then use pliers as the Bakelite has a tar-like quality (if that makes sense). It is no deal breaker as now I am well into my second dozen 3D bolsters, but it is a little more work to get the pins.

Oh, and I did figure out a way to use that new, vintage bolster (seen in the first photo), the "small pin" type of pin seen on some trucks has a pattern than is favorable to pushing on to these Bakelite bolsters. I have five of those and they will be going on trucks soon.

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