Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on October 07, 2021, 06:53:20 am

Title: Star washers for pots.
Post by: joesatch on October 07, 2021, 06:53:20 am
For the purposes of grounding what washers are to be used on the pots?

This.
(https://www.stewmac.com/globalassets/product-images/m003000/m003500/m003503-lock-washer/4389-4-3000.jpg)

Or This.
(https://m.media-amazon.com/images/I/61x8caiYGML._AC_SL1000_.jpg)
Title: Re: Star washers for pots.
Post by: sluckey on October 07, 2021, 07:01:21 am
For the purposes of grounding what washers are to be used on the pots?
I just use whatever was supplied with the pot. And I don't rely on pot bodies for any circuit grounds. There's no need to ground the pots. Heck, you could mount the pots on a fiberglass board and they will perform just fine.
Title: Re: Star washers for pots.
Post by: EL34 on October 07, 2021, 07:32:49 am
These work fine for keep jacks, pots and switches from rotating
They are located here

https://hoffmanamps.com/MyStore/catalog/MiscHardware.htm (https://hoffmanamps.com/MyStore/catalog/MiscHardware.htm)
Title: Re: Star washers for pots.
Post by: joesatch on October 07, 2021, 08:41:06 am
These work fine for keep jacks, pots and switches from rotating
They are located here

https://hoffmanamps.com/MyStore/catalog/MiscHardware.htm (https://hoffmanamps.com/MyStore/catalog/MiscHardware.htm)

Are those aluminum or steel?  I think i need steel.
Title: Re: Star washers for pots.
Post by: EL34 on October 07, 2021, 08:43:55 am
They are steel
You could crush an aluminum washer easily and that would not work to lock down a part
Title: Re: Star washers for pots.
Post by: acheld on October 07, 2021, 09:49:27 am
You are showing two types of star washers -- internal and external.  There are other types as well.

The external type does not work with typical pot installations.   The external serrations must be crushed between the part (or a washer) and the chassis.  Normally this can not occur in the amps we build because the pots are mounted offset away from the chassis with an internal lock nut on the stem.

That's not to say that you couldn't use them in some situations . . .

https://www.mcmaster.com/standard-washers/lock-washers/
https://www.boltdepot.com/Washers.aspx?nv=l

are good starting place to look at some of these.  There are many others. 
Title: Re: Star washers for pots.
Post by: EL34 on October 07, 2021, 09:53:03 am
The star washers go on the inside of the chassis
The trim washer and nut go on the outside of the chassis
Title: Re: Star washers for pots.
Post by: acheld on October 07, 2021, 10:06:24 am
Doug, so you do use the external tooth lock washers?

From inside to out, this is how I mount pots:

pot with threaded stem
lock nut -- this is probably better thought of as an adjustment nut for the stem height
lock washer
chassis
flat washer
nut

The external serrations won't get crushed in this scenario.   

LOL, I thought everyone mounter their pots the same way.    :w2:  I guess not!  :icon_biggrin:
Title: Re: Star washers for pots.
Post by: joesatch on October 07, 2021, 10:10:06 am
thanks folks i am now more confused than ever. Mounting star washer on outside of chassis?  Internal vs external washers?  huh?
Title: Re: Star washers for pots.
Post by: EL34 on October 07, 2021, 10:15:14 am
thanks folks i am now more confused than ever. Mounting star washer on outside of chassis?  Internal vs external washers?  huh?

There is no confusion
The washers are used to lock things down so they can't be rotated
Why would you put an ugly star washer on the outside of the chassis?





Title: Re: Star washers for pots.
Post by: labb on October 07, 2021, 10:59:44 am
I normally use Alpha pots and they all have an anti rotational pen. Requires a 1/8 hole.
Title: Re: Star washers for pots.
Post by: EL34 on October 07, 2021, 11:16:44 am
Another point about using the star washers is that the teeth are going to bite into the surface
You would not want to be doing that to a faceplate



Title: Re: Star washers for pots.
Post by: sluckey on October 07, 2021, 11:17:38 am
He's not trying to keep them from rotating...

For the purposes of grounding what washers are to be used on the pots?
Title: Re: Star washers for pots.
Post by: EL34 on October 07, 2021, 11:20:26 am
He's not trying to keep them from rotating...

For the purposes of grounding what washers are to be used on the pots?


Yes, I know
They are used to lock parts in place as I stated in reply #2
Title: Re: Star washers for pots.
Post by: PRR on October 07, 2021, 08:31:09 pm
Make everybody happy:
Title: Re: Star washers for pots.
Post by: Willabe on October 07, 2021, 10:19:56 pm
Make everybody happy:

Yes!     :laugh: