So tried the needle retainer last night...did not go very smooth
I worry a bit about PLA printed parts flying around at high RPM so I tried printing it in Nylon first. Plus Nylon is less dense than PLA so should be lighter. That did not go so great:
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Taulman 910 warps less than most nylons...but can still warp. I added fresh gluestick to my glass and tried again - the one in the background came out pretty good...but I couldn't get a needle through it. I wound up drilling out the hole a bit to clean it up and it seemed good.
Except my bearing wouldn't fit...was a little too snug. So...ok...let's just try it in PLA and if I like it I'll deal with Nylon later.
I wound up using a small brass sleeve as a spacer along with the cut down washer I used before to keep the brass spacer from wearing against the flywheel:
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This seemed to work fairly well...except it does put the needle out further than my old setup which I'm not huge on:
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I don't think that slight bend in the needle is a huge deal...but still not super happy about it.
Anyway swapped flywheels since the old one's threads were shot. I only used 3 screws to hold the old flywheel...and I'm only using 2 on the new one because the 3rd is going to be a bit tricky to remove due to the damage on the flywheel from my failed bearing almost a year ago:
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But I did get it on...and fired it up. First cut didn't look so great. Much more ragged than what I usually get. When I installed the needle I noticed that it did have a little bit of play up and down in the retainer. I wonder if I'm using a thinner needle (0.62mm) than mobeast? Except I had tried slightly thicker needle first and it didn't fit at all....
Anyway, started cutting and the cuts just didn't look as clean as I was used to. Not terrible but not like I have come to expect from my needle cutter. But I let it go...until about halfway through the sheet I I noticed it was suddenly dragging between cuts....uh...oh. It was also sounding worse and worse so I canceled the cut and took a look at what was going on:
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Well, that's not good.
The needle was pulling through the retainer! Needle was still cool, as was the guide and the bearing. But the motor itself was hotter than I expected. I'm really not sure how this could even have happened since there shouldn't be any real stress on the needle in that direction.
One thing that came to mind was that some of my raw needle stock was a little sticky (overspray from the spray glue I use to hold some materials down on when cutting them.) but I had cleaned it off with acetone first and oiled my oiler so the needle felt smooth and seemed to run with no real drag.
I'll try it again...maybe give the nylon retainer another try. And I'll probably sand the spacer down a bit more so the needle has a straighter shot. But so far my experience with the needle retainer hasn't been spectacular