SEB AR250 front rest...SORTED.

[Grey Kiwi]

My AR250 front rest has performed well...but the last couple of weeks the joystick has felt quite free and loose to operate.
Then I noticed that the front bearing (green arrow in photo) of the joystick shaft was sticking out of the main body by about 2mm.
So I whipped the bag holder, etc off and could look down inside the body...and saw the other bearing in the main plate (that the bag holder mounts to) was also sitting forward by about 2mm.
Both joystick bearings had come loose from their housings.
So...slightly loosened the locking grub screws that hold the bearings and pushed the joystick shaft back inwards (no force...it just seated back in easily), and then tightened both the grub screws (quite firm...but not gorilla strength).
Everything seems to work fine again, and that loose feeling has gone.
But...if I twist the handle I see that the front bearing (green arrow in photo) turns with the shaft...so it obviously grips on to that. Of course the actual outer race of that bearing doesn't move as it's now locked in again.
The inside bearing that you see when looking in from the joystick handle view (red arrow in photo) is seated home and the grub screw tight...but when I rotate the handle its shaft turns loosely inside that bearing inner race. The bearing does not turn with the shaft.
I'm guessing that is a slightly loose fit to allow for the apparent lengthening/shortening of the shaft position as you traverse up/down or left/right and the shaft needs to slide slightly in/out.
Any AR250 owners can confirm if their inside bearing race is a firm fit to the shaft or is theirs like mine?
I've already flicked an email to Chris, but I know he views here too...so hoping he might chime in as well.
Thanks.

 

[ChrisLionel]

Hi Kelvin, I am going to post this reply I sent you through email.

Sorry for this issue you are having. Was there an impact towards the center shaft? It's quite abnormal that both bearings got loose from their housing. But it is fixable.

To fix this you should follow these steps:

1. Remove the top plate

2. Loosen the set screw on the body which is pressing against the front ball bearing (closes towards target paper) and pull out the center shaft from the body.

3. Take out the sliding blocks out of the body

4. Push in the ball bearing that's sticking out back in until it is flush against the back (do not scratch the backside of the horizontal sliding block as it will cause roughness when moving the joystick)

5. Rotate the set screw clockwise until it's just touching the ball bearing, then rotate it by only about 10-15 degree of rotation so it locks the ball bearing in place, then insert the center shaft to the ball bearing to check if the ball bearing can still move without much interference, there shouldn't be too much resistance otherwise it will cause your joystick action to be stiff. Adjust tension of the set screw if needed.

6. Take out the center shaft and reinstall the sliding blocks back into the body.

7. Reinsert the center shaft from the front into the body and sliding blocks.

8. Tighten the set screw on the body pressing against the front bearing, you should adjust the tension of this set screw while the joystick is installed to adjust the stiffness of the movement to your liking. (Don't set the set screw too loose as you still need rotational resistance to stop the joystick from rotating while you try to move it).

9. Reinstall the top plate

** Make sure that through out this entire process the inner chamber of the body and the sliding blocks are free from debris like sand and rocks as those could cause scratches inside the joystick movement and hence roughness when moving the joystick.

Please let me know if the problem still persists. If the rest is still not functioning well you can send the rest to my service agent in Australia to get it fixed. I'll give you his details should you need it

Best regards,
Chris

 

[Grey Kiwi]

Many thanks Chris.
All done...I took a few photos along the way and have popped up a thread on RFC about stripping/cleaning the AR250 rest.
Mine is absolutely working fine now. Lovely and smooth again. Seems the main problem was that both bearing locking screws had worked loose.
So I thought I'd share the photos and your guidance over on RFC. I could repeat it all here of course, but depends if anyone here wants it too.
https://www.rimfirecentral.com/thre...embly.1329286/?post_id=13747466#post-13747466