adapter for the lathe gear, other lathe with gear bore 20 mm

[bestbean]

Fitting lathe gear is avaiable.
There is a stl-file for a gear-to-stepper-adapter. But i have different lathe, gear bore is 20 mm, with groove 5 mm large and groove depth of 2,5 mm.
It's quite common for 9x20 lathes.
May i ask for a stl?

[kachurovskiy]

Hi, sure, can you please point to the exact STL file you want modified? Thank you.

[bestbean]

Thank you, these are basic things i forgot about.

1. 8 mm
2. 10 mm
3. 20 mm
   From datasheet for stepper 23HE45-4204S:
   

[kachurovskiy]

Thank you, please find the STL file here: stepper-to-gear-adapter-20mm-10mm.zip

[bestbean]

Ligthning fast, thank you!
I don't understand how to fix gear on the adapter.

[kachurovskiy]

It's intended to be a friction fit. Forces on those gears are pretty small so that might be enough. If not, please post a picture of the whole thing assembled and we'll figure something out.

[bestbean]

So that might be enough also for my lathe.
Thank you a lot, you made my day!

[bestbean]

After heavy use, 2 of this 3D-printed adapters knackered.
It holds a 71 tooth modul 1 steel gear, maybe this has to to long leverage.
Before mounting T5 gears and tooth belt, i would like to try a adapter made of steel.
Ideas?

[kachurovskiy]

Hi @bestbean, good to hear from you again. Assuming you printed with 100% infill last time, if not - then that would go a long way making your part stronger.

Can you please post the photo of the mechanical failure for better understanding?

Some options:

• Print another copy with 100% infill from PETG
• Optionally, clean the gear thoroughly from grease and glue the new adapter in with cyanoacrylate (you can remove it later by heating to the temperature of boiling water if needed)
• Model and print the entire gear instead of just the adapter. Then the weak point would be the shaft-to-gear flat (unless if already is)
• For any of the above options, order a print on JLCPCB from a potentially stronger material
• And of course you already mentioned switching to the belt instead

Good luck!

[bestbean]

Wow, that was fast! Pretty good suggestions.
Yes, Stepper shaft-to-adapter flat is the weak point. It is no more flat.
I've already glued the adapter to the NEMA23 axle, i let it dry until tomorrow.
I don't think it will last long.

[kachurovskiy]

Cool! If you get a chance, please do share the picture of the failure for our education :) Thanks!

[kachurovskiy]

Or you can have it printed from stainless steel for 7 euro :)

[bestbean]

shipping to germany, custom fees and tax plus 42.- ...

[kachurovskiy]

Try picking Global Standard Direct Line? I also got an address in Germany.

[bestbean]

Ok, thanks!

[bestbean]

Ordered. 16,13.- all incl.

[bestbean]

Meanwhile, the adapter is here now.
I had to file it down, the bore was intended for plastic.
Material is stainless steel A4.
Should last for long time.

[kachurovskiy]

Woah, looks awesome. How accurate are the dimensions?

[bestbean]

I destroyed the stepper by pushing the adapter to hard on the spindle.
Replacement stepper already here.

[kachurovskiy]

Sorry to hear that 😔 Did you hammer it on or use the woodworking clamp?

[bestbean]

A woodworking clamp or similar would work on a stepper with dual end, what i not have.
So i heated the gear with mounted adapter and forced it onto the spindle.
Stepper now makes funny noises and moves erratically back and forward in low speed.

[bestbean]

For mounting the adapter to the new steppers spindle, i think about positioning the stepper in perpendicular position so, that i can hold the axle with a grip plier, supported by vise. So, eventually applied stronger force can't hurt the stepper, i hope.

[bestbean]

I didn't measure the dimensions. It was not much.
The *.stl was dimensioned for plastic, i presume.
The ABS-adapter from same *.stl was a perfect fit.

[bestbean]

Works finally..
I glued the the adapter with loctite 638 (esigned for the bonding of cylindrical fitting parts, particularly with narrow bond gaps approaching 0.25 mm).

The 2 steel gears are not particulary noisy, even at higher speeds. Molybdenum grease helps, as on many parts of a lathe..