[Lmecano]

Hello everyone,

I'm quite lost with my HTD-3m pulley. The torque is transmitted throughout a stop screw.
The pulley are in aluminium, probably not 7022 grade...

Every time, after using it few minute, the screw become loose.

I tried :
- Screw + nut
- Screw + liquid thread blocker (mild one, not the hard one)
- Screw + nut + liquid thread blocker
- 2x stop screws at 90° with the full options above


Every time, the screw is living its best life and do not stay tight.
The issue is that it's used to control the 3x axis of a milling machine, so backlash because of the pulley is not appreciated


Does anyone have an idea or faced the same issue ?


Thank you o/

[awerby]

Is the set screw pushing on a keyway, or a flat on the shaft? Or is it trying to hold onto the round part of your shaft? If it's the latter, that's not going to work - it will gall the shaft and become impossible to remove. Better get it off of there before that happens. If your set screw is bearing on a key or flat, is fully engaged in its threaded hole and still won't hold with thread locker, your pulley is defective and needs replacement.

[metalmayhem]

I've had problems with chinese pullies like that . they were sloppy on the threads so I tapped them and added bigger set screws

[peteeng]

Hi Mecano - Use loctite on the shaft to pulley surface. Peter

[Lmecano]

Hello everyone, thanks for your reply

The set screw is in front a flat surface/keyway.

At the end, I have bought M4 helicoil and used them inside the existing thread.
So far, so good ! The material was probably too soft.

CNC working, let the chips begin

[joeavaerage]

Hi,
not necessarily convenient, but a key and key way are the gold standard. I can and do cut key ways , and on occasion splines on my machine.

The spline pictured was cut with a 1.5mm X 8D endmill. The tool path required some patience and practice. I restricted the spline depth to 10mm, so
not a huge amount of engagement, but none-the-less it works and has done for some time. It is the coupling to the spline input shaft of my trunnion table
gear reducer.

As a matter of scale, the outer diameter is 30mm, and the minor inner diameter is 22mm and 18 splines.

Certainly saved having to pay someone to make it for me.

Craig