Spinner lesson

Two-year-old FLGPBK01 resin on a Form 1+ The bearing holes seem to shrink hours after printing. I got impatient with sanding, and applied a hammer. Don’t! (laughing)

I use Tough for my fidget spinner needs. You want a little more “give” than the GP resins have for the press fit. I bet Durable would work well too, but I haven’t tried it for this.

That’s a nice looking spinner, it’d look really good in blue!

I’m not laughing…I understand.

One hint though, the proper file (for whatever the task) beats sandpaper for most applications. Granted, there are literally scads to choose from and knowing what shape and cut one needs is an art in itself and a good one “ain’t cheap”. But…usually no better tool for the job.

If I were to suggest two files for most prints about your size they would be a 6", smooth cut crossing file (not cheap) [this is for inside holes and curved outer surfaces) and a 4" or 6" smooth cut mill file (very reasonably priced) [this is for flat surfaces but can also be used on flat or curved outer surfaces]. Buy good brand name files or you will have wasted whatever you spent.


I’ve also used an adjustable reamer on the GP resins. That’ll keep your hole nice and round. I haven’t tried a reamer on Tough. I think it’d work once the part was cured well.

And hand files are so much easier…as a jewelry artist, I don’t use needle files except on rare occasions. A #2 half-round hand file is a great addition, but about $30 for a good one.

Yes, I got my “file experience” from 5+ years as a self-(un)employed gunsmith and that experience carried over as I have done jewelry making, silversmithing and pewtersmithing for many years and taught the same.

I did find though that proper filing technique was one of the more difficult skills for my metalsmithing students to become proficient at. Not exactly sure why that is but I have a theory or two…but I won’t bore you with them.

I found that many metalsmiths who work on the jewelry scale tend to reach for a needle file when a larger file would get the job done quicker and also with a higher degree of precision.

One of my students said to me once “you love tools”. I guess she was right !

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That’s an interesting tradeoff: A file would be quicker, but I doubt my ability to make a good cylinder. Thank you for the suggestion!

Oh yes…don’t get me started on my love of Fretz hammers. Momma doesn’t buy fancy shoes anymore. Not when there are Fretz hammers and Formlabs resin to be had!

And @Paul_Hollingshead, the reamer sounds like a better solution, although I haven’t used one. Although most reamers are conical, and might not give you a good even hole. I would probably use a slotted mandrel and medium grit sandpaper. These come in 1/4", 3/8", and 1/2" for about $10. The only disadvantage would be the sandpaper becoming clogged.

I purchased some other small drum sanders, but they are expensive and you have to buy a whole package of one grit for about $17. The coarsest grit is 240.

Here’s one more…as @TJFejka mentioned, a file is probably best. I like these Kate Wolf cylinder burs from Rio Grande. They are designed for hard wax so they are a finer cut, and I’ve used them successfully on Formlabs resin. They are smoother than many of the cylinder burs I’ve found online. She also has a cool wax trimmer that fits on a Foredom (or other) flex shaft that keeps the bur perfectly vertical.