Hex bolt shaft option

[doudar]

Mostly for @eMadman and not tested outside of cad yet (I'm sure he will soon though), files have been included for a metal shaft using a 1.5" 5/16" bolt in place of the printed shaft we've been using. If it all fits and works, this should be a much more robust solution as well as preventing any knob cup wobble from bent shafts in the past.

Files are Hex 40T Gear and Hex Knob Cup

[eMadman]

looks good! I'll have to make a trip out to home depot for the bolts. Everything I've got is metric and maxes out at M5. Likely would be stronger than the plastic itself. Looks like a captive nut on the inside of the cup might not be a bad idea. Might save having to deal with a socket wrench there. Embarrassed as I am to admit it, I'm a hobbyist maker without a useful socket set. Ha!

[doudar]

Grab an M8 while you’re at it. It should work as well. I think they’re interchangeable except for the threads. Just don’t go longer than 1.5” or your knob insert won’t fit.

[eMadman]

Grainger seems to have the parts and I happen to need more machine scres. I'll toss these into my order.

For the IC4 mod, I'm trying to combine the cup and insert. I think I see a happy path to do that with this design and have a captive jam nut with embedded in it. This will certainly end up being the strongest part in the enclosure.

[eMadman]

Making some changes to the CAD - the 5/16"x1.5" nuts and bolts I have from grainger have bigger heads than in the model. I think I have the changes to where I like it... I'll need to go back into the cup file and provide an updated one. I ended up going to town and merging this with the IC4 insert to make for faster printing. I should have one printed in the next day or two

[eMadman]

bolt and nut are both 12.5mm across the flats. I have 5mm deep for the bolt head, 6.75mm deep for the nut.

In the cad, it's 12.1mm across the flats. I also neglected to get jam nuts so I added space for a standard nut on the knob cup

Tolerances were a bit too exact. My printer can usually do down to 0.2mm with no issues, closer than that, there's a chance it'll be too tight.

Going to print it now... should be ~2-2.5 hours

[eMadman]

Initial results: wasted a lot of time using my 0.6mm nozzle. Couldn't get a good mesh on the gears. I'm well tuned for larger objects on 0.6mm, but the gears gave me issues.

Attempt 2 with 0.4mm nozzle: I love the heft of it and it's rock solid. I'm using blue loctite to prevent accidental loosening.

[doudar]

I'm currently doing my first print on the hex shaft. It should be done in the next hour.

Interesting you are having issues with the gear mesh with the .6 nozzle. I don't seem to have any issues with it. What's your layer height and which slicer are you using?

[eMadman]

0.4mm layers (also tried 0.3mm) and Superslicer (latest version). I think the bigger issue is the blobs/zits/stringing I'm getting between the teeth. I tried using a hobby knife to clean it up, but it still found reason to skip often.

I started using the big nozzle in the last few months so I know there's a lot more tuning I can do

[doudar]

I’m doing .3mm @ 70mm/s @ 250c for petg with the .6mm nozzle. I’d like to go to .4mm height but I run into volumetric issues- the E3D heat block can’t keep up.