Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

Return to Tube DIY Asylum

Message Sort: Post Order or Asylum Reverse Threaded

Shaft Extensions / Panel Bearings

63.246.183.22
Posted on July 10, 2017 at 19:23:55
Triode_Kingdom
Audiophile

Posts: 10042
Location: Central Texas
Joined: September 24, 2006
 My upcoming preamp project will need a long shaft extension from the rear-mounted selector switch. From past experience, I know that 1/4" panel bearings often don't hold the shaft in position very well. They tend to create more side play than when a switch or pot is mounted directly to the panel, and sometimes they even rattle if the knob is "flicked" with a finger. I'm wondering if anyone has found an alternative to these bushings, maybe something made from hard-wearing plastic or other material? I have the machinery to DIY a solution, but I'd rather spend my time doing circuit design or wiring.







 

Hide full thread outline!
    ...
RE: Shaft Extensions / Panel Bearings, posted on July 10, 2017 at 20:41:33
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 Perhaps an additional support at approx. the mid-point of the long shaft, in addition to the panel bearing will solve the problem. Check this at McMaster-Carr out. I'm thinking that part # 5912K1 will do nicely. Aluminum standoffs can be used to get the pillow block's location just right.


Eli D.

 

RE: Shaft Extensions / Panel Bearings, posted on July 10, 2017 at 23:45:31
Triode_Kingdom
Audiophile

Posts: 10042
Location: Central Texas
Joined: September 24, 2006
 Thanks for the suggestion, but I don't see how that could be relied on to reduce end play at the front panel. A live bearing doesn't necessarily improve the fit between the shaft and hole, and any free play at the pillow block would be angularly magnified several inches away at the front panel. Do you know of a particular bearing/bushing intended for panel mounting that might exhibit a tighter fit than the usual offerings?


 

RE: Shaft Extensions / Panel Bearings, posted on July 11, 2017 at 03:12:14
Uncle Mike
 I'm not quite clear on what your are trying to accomplish. A support for a switch with a long shaft or an arrangement to extend a shaft through the panel. In the latter case they are common in electrical switchgear and the coupling should provide enough play that your concern should not be a concern. I'm off on a road trip so I don't have the time to search. If you could elaborate further I'll check in periodically. Or it might spark Eli's or someone else's imagination. I did find the link below.

 

RE: Shaft Extensions / Panel Bearings, posted on July 11, 2017 at 07:34:31
BillWojo
Audiophile

Posts: 186
Location: NJ
Joined: July 7, 2017
 First make sure your not using a 6mm shaft 0.240" in a 0.250 bearing mount. If that looks good maybe use some high viscosity grease or silicone damping fluid on the shaft.

BillWojo

 

RE: Shaft Extensions / Panel Bearings, posted on July 11, 2017 at 07:38:06
Triode_Kingdom
Audiophile

Posts: 10042
Location: Central Texas
Joined: September 24, 2006
 Keystone in the US also manufactures parts like that. The fit between shaft and hole is somewhat variable, and it often gives the knob a clunky feel that I dislike. I suppose there are a couple reasons this doesn't happen directly at the shaft of a switch or pot. For one thing, the manufacturer has control over the dimensions of both the shaft and hole, so tolerances can be tighter. Also, the parts are usually designed to be greased, which cushions the effect.

When I assembled the front panels for my SETs a few years ago, I bushed the holes for push switches with press-fit Delrin inserts. That worked really well, but it requires additional time that I was hoping to avoid in this case. Maybe there's no choice. I could use a 3/8" panel bearing and bush it down to 1/4", or maybe turn down the 1/4" shaft where it passes through the standard panel bearing and add an internal plastic sleeve. Like I say, was just hoping I could buy my way out of doing this. :)


 

RE: Shaft Extensions / Panel Bearings, posted on July 11, 2017 at 08:59:22
6bq5
Audiophile

Posts: 4385
Location: SF Bay
Joined: August 16, 2001
 The original RM-5 from Music Reference used bearings as you mentioned in the OP and onece we solved certain issues -below - they worked quite well-
the only issue we had was galling then the bearing and shaft were the same material-
The comment above regarding sizing is appropriate and will - if addressed properly - make a difference in the Knob feel-

Delrin or PTFE (Teflon(r)) make excellent bearings but can be a challenge to machine correctly-
Happy Listening

 

RE: Shaft Extensions / Panel Bearings, posted on July 11, 2017 at 10:37:03
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 McMaster-Carr part # 4575N33 is a 2 bolt, flange mounted, double shielded, ball bearing. Mount that item on the inside of the front panel.


Eli D.

 

RE: Shaft Extensions / Panel Bearings, posted on July 11, 2017 at 13:18:44
Triode_Kingdom
Audiophile

Posts: 10042
Location: Central Texas
Joined: September 24, 2006
 That looks interesting, I hadn't thought about using a press-fit bearing. That would definitely hold the shaft in place. I wish the specs listed end play, but it's probably pretty good on a greased and sealed bearing. I'll order one of those as soon as I make up a larger order (shipping cost and all that). Thanks!


 

RE: Shaft Extensions / Panel Bearings, posted on July 11, 2017 at 16:14:08
amnesiac
Audiophile

Posts: 717
Joined: August 21, 2002
 while roller-bearing might be nice considering mechanical feedback and such you might find a simple phosphor-bronze bush with a oring groove might be the best solution. A bronze shaft with grove in it might be simpler still and the heavier the moving mass I suspect the better it will feel. Do a small cnc run and ebay the other half.

 

carve one out of PEEK, posted on July 11, 2017 at 18:05:10
PakProtector
Audiophile

Posts: 12363
Joined: May 14, 2002
 it is a lot tougher than Delrin. It threads well too. I use it for firing valves in 3650 psi air rifles...:)
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

RE: carve one out of PEEK, posted on July 11, 2017 at 18:35:43
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 PEEK is tough stuff. The flange mount for the ball bearing I mentioned is made of PEEK.


Eli D.

 

Switchcraft 1/4" jacks, posted on July 12, 2017 at 05:37:46
Alpha Al
Industry Professional

Posts: 2958
Location: N. Carolina
Joined: February 16, 2004
Contributor
  Since: December 3, 2015
 Remove the tip contact, and these make excellent shaft bushings.

I have used #11 jacks for this, and also the nylon version (#111N?).

 

Page processed in 0.036 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]